STOCK: ,

6 /

Classification and 

Distribution of the 

Recent Hemicytheridae I 

and Trachyleberididae 

(Ostracoda) Off Northeastern 

North America

GEOLOGICAL SURVEY PROFESSIONAL PAPER 564

/-, ^ : * - - - j
&

Classification and 

Distribution of the 

Recent Hemicytheridae 

and Trachyleberididae 

(Ostracoda) Off Northeastern 

North America

By JOSEPH E. HAZEL

/; 

v, , I

X GEOLOGICAL SURVEY PROFESSIONAL PAPER 564

Descriptions of two families of 

Recent marine ostracodes from off 

northeastern North America

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1967
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEW ART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

Library of Congress catalog-card No. GS 67-150

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 65 cents (paper cover)
CONTENTS

Abstract._____________________________

Introduction. _________________________

Acknowledgments.--- _ _-___---_____-___

Previous studies-__---_-_-_-_-_________

Classification. _ ________________________

Morphologic features used in delimitation. 

Frontal muscle scars._ _____________

Adductor muscle scars____________

Soft parts_____---_-_-----___---___

Muscle scars in relation to phylogeny_ 

Systematic paleontology._______________

Family Hemicytheridae-____________

Subfamily Hemicytherinae. _____

Genus Hemicythere^ ________

Elofsonella- _________

Baffinicythere- _______

Nereina. ____________

Patagonacythere _ _____

Muellerina_ _________

Aurila. ----_____-___

Nor manicy there. _____

1

1

2

2

5

6

7

8

8

9

13

13

14

14

15

16

18

19

20

23

23

Systematic paleontology Continued

Family Hemicytheridae Continued

Subfamily .Thaerocytherinae_ _ _.

Genus Thaerocythere- -__-__

Subfamily Campylocytherinae__

Genus Bensonocythere----- _

Family Trachyleberididae _______

Subfamily Trachyleberidinae___ 

Genus A ctinocythereis _ _ _ _ _.

Acanthocythereis ~ _ _ _ 

Robertsonites _______

Carinocythereis _.___. 

Subfamily Echinocythereidinae_.

Genus Echinocythereis ______

Rabilimis- _ _________

Subfamily Pterygocythereidinae_

Genus PterygocythereisSubfamily Cytherettinae. _______

Genus Cytheretta, __________

Subfamily indeterminate. _______

Genus indeterminate _______

References. 

Index.

Page

24

25

26

27

29

30

31

34

35

35

36

36

38

38

39

40

40

42

42

42

47

ILLUSTRATIONS

[Plates follow index]

PLATE 1. Nereina, Aurila, and Normanicythere.

2. Baffinicythere and Hemicythere.

3. Muellerina.

4. Patagonacythere, Thaerocythere, Elofsonella, and Pterygocythereis.

5. Bensonocythere and Actinocythereis.

6. Robertsonites and Echinocythereis.

7. Muellerina.

8. Baffinicythere.

9. Baffinicythere, Thaerocythere, and Patagonacythere.

10. Bensonocythere.

11. Bensonocythere, Actinocythereis, and Nereina. 

FIGURE 1. Map showing location of samples--___-_---__-_-------------

2. Phylomorphogenic trends in muscle-scar development_________

3

12

TABLE

TABLE 1. Distribution of species of the Hemicytheridae and Trachyleberididae off 

northeastern North America.____________________-__---------_--

Page

III

CLASSIFICATION AND DISTRIBUTION OF THE RECENT HEMICYTHERIDAE AND 

TRACHYLEBERIDIDAE (OSTRACODA) OFF NORTHEASTERN NORTH AMERICA

By JOSEPH E. HAZEL

ABSTRACT

Eighteen species of hemicytherids representing 10 genera and 

3 subfamilies and 13 species of trachyleberidids representing 9 

genera and 5 subfamilies have been described or are herein described as occurring off northeastern North America or the west 

coast of Greenland from about lat. 40° N. to nearly 80° N. Two 

subfamilies are described as new; these are the Thaerocytherinae of the Hemicytheridae and the Echinocythereidinae of the 

Trachyleberididae. The Campylocytherinae are shown to have 

hemicytherid anatomy, and are lowered from family rank and 

considered a subfamily of the Hemicytheridae.

The family Hemicytheridae is considered to be composed of 

three subfamilies the Hemicytherinae, Campylocytherinae, and 

Thaerocytherinae n. subfamily. The latter taxon comprises the 

genera Thaerocythere n. genus, Jugosocythereis, Hermanites, 

Quadracythere, Bradleya, Aquitaniella, Verrucocythereis, and 

Puriana. The previously described genera of this group have 

most often been classed in the Trachyleberidinae; however, 

Thaerocythere, Jugosocythereis, and Puriana have hemicytherid 

anatomies and this is suspected for the other genera. The 

genera of the Thaerocytherinae usually have four adduetor muscle scars and two frontal scars. The family Trachyleberididae 

is considered to be composed of seven subfamilies: the Trachyleberidiinae, Echinocythereidinae, Brachycytherinae, Pterygocythereidinae, Gytherettinae, Buntoniinae, and Mauritsininae. 

The new subfamily Echinocythereidinae is proposed for the 

genera Echinocythereis, Raibilimis n. gen., and questionably 

Bosquetina.

The complex muscle-scar pattern found in most Neogene and 

Quaternary genera of the Hemicytherinae is shown to have developed from the Trachyleberidinae in a series of steps that pass 

through the Thaerocytherinae and the Hemicytherinae.

Four genera are new: Bafflnicythere (type species Cythere 

costata Brady, 1866) of the Hemicytherinae, Bensonocy there 

(type species Legummocythereis whitei Swain, 1951) of the 

Campylocytherinae, Thaerocythere (type species Cythereis crenulati Sars, 1865) of the Thaerocytherinae, and RaUlimis (type 

species Cy there miraUlis Brady, 1868) of the Echinocythereidinae. One species, Bensonocy there americana, is new.

INTRODUCTION

The U.S. Geological Survey and the Woods Hole 

Oceanographic Institution are engaged in a joint geological investigation of the Continental Shelf and slope 

of the Atlantic coast of the United States (Emery and 

Schlee, 1963). As a part of this program, I have under 

study the ostracodes from several hundred bottom-surface samples taken on the Atlantic Continental Shelf 

and slope from Florida to Nova Scotia. To facilitate 

the physical and biological studies, at least for the purposes of publication of results, the shelf-slope area was 

divided into three parts. Initial effort in most of the 

disciplines was placed on the northern area from about 

the latitude of Asbury Park, N.J., to Nova Scotia 

About 400 samples have been processed from this area. 

Ostracodes were found in approximately 200 of these, 

and about 70 species have been identified.

Many of the more commonly occurring species in this 

northern area are in need of taxonomic revision. 

Therefore, it was decided to study the Hemicytheridae 

and Trachyleberididae because, in terms of numbers of 

individuals they, particularly the hemicytherids, dominate the fauna. This will make the lists to be published in later biogeographic studies more meaningful 

and useful.

The fauna of the area contains many arctic elements, 

a fact already noted by Cushman (1906) and Blake 

(1929, 1933). Therefore, for comparative purposes, 

several samples from the Davis Strait, Ungava Bay, 

Foxe Basin, Baffin Bay, and Kane Basin were studied 

and are included in this taxonomic study.

Considered here are 13 species of trachyleberidids arranged in 9 genera and 5 subfamilies, and 18 species of 

hemicytherids arranged in 10 genera and 3 subfamilies. 

One trachyleberidid subfamily and one hemicytherid 

subfamily are new. Three hemicytherid genera and one 

trachyleberidid genus are new. One hemicytherid species is new. The new taxa are Echinocythereidinae 

(Trachyleberididae), Thaerocytherinae (Hemicytheridae), Thaerocythere (Thaerocytherinae), Ba-ffvnicythere (Hemicytherinae), Bensonocy there (Campylocytherinae), RaJbilimis (Echinocythereidinae), and 

Bensonocy there americcma n. sp.

New and previously described species which have not 

been recently revised are described. Genera for which 

there is additional information are diagnosed and discussed. Carapaces or valves are illustrated for nearly 

all species found. Dissections of living specimens were
RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

made where possible and the soft parts are illustrated 

for those species not covered by Cushman (1906), Sars 

(1925),or Elofson (1938,1941).

All the samples used and the exact number of specimens of each species found in each sample are listed in 

table 1. Also included in table 1 are all the localities 

off northeastern North America at which trachyleberidids or hemicytherids were found by previous workers, 

and the species identified at each locality.

The samples (locations on fig. 1) are arranged in 

order of decreasing latitude. Because latitude and 

longitude data were not given for most of the samples 

other than those being used in the joint project of the 

U.S. Geological Survey and Woods Hole Oceanographic Institution, approximate coordinates were 

based on geographic data provided by the authors with 

the help of information obtained from the Board on 

Geographic Names and from gazetteers.

The samples shown on table 1 were selected for this 

study from a much larger number of samples which are 

being used in a regional biogeographic analysis. These 

particular samples were selected because they (1) contain a large and (or) diversified faunule, (2) give latitudinal coverage of the study area, or (3) contain rare 

elements of the total hemicytherid-trachyleberidid 

fauna.

The illustrated specimens have been deposited in the 

collections of the U.S. National Museum.

The type materials of Cushman (1906) and Blake 

(1929, 1933) are lost (Puri, 1958a; Neale, 1959). 

Cushman's and Blake's papers were neontologic treatments, and illustrations of the valves and carapaces are 

minimal. However, collections from the vicinity of 

these authors' localities have allowed confident identifications of most of their species. The types or specimens of Brady (1868 a, b, 1870a), Brady and Crosskey 

(1871), Brady and Norman (1889), and Norman (1877) 

have not been examined. However, the illustrations in 

those papers which contained illustrations are, in general, fair to good, and identifications were not difficult. 

Swain's (1963) types and the types of most of the 

species described from the Atlantic coast Miocene are 

in the U.S. National Museum and have been examined.

ACKNOWLEDGMENTS

I am indebted to E. H. Benson and L. S. Kornicker 

of the U.S. National Museum who have provided comparative materials and publications for my use. Dr. 

Benson also constructively criticized parts of this manuscript. Work on some of the genera of this paper and 

preliminary studies of some samples were begun in 1963- 

64 while I was a National Science Foundation postdoctoral fellow (NSF Fellowship 43092) at the Museum of

Comparative Zoology of Harvard University. I am 

grateful to Ernst Mayr, Director of the Museum, and 

to his staff, in particular H. B. Whittington, for the 

courtesies extended me during my stay at that 

institution.

Geological Survey colleagues who deserve special 

thanks for their advice during preparation of this manuscript are J. T. Dutro and I. G. Sohn; thanks are also 

due A. E. Palmer for critically reading the manuscript. 

The photographs of the ostracodes were taken by 

 E. H. McKinney and retouched by Elinor Stromberg;

PREVIOUS STUDIES

The first hemicytherids or trachyleberidids listed or 

described from the Atlantic off northeastern North 

America appear to be Oythere septentrionalis Brady, 

Cythere costata Brady, and Oy'there clathrata (Eeuss) 

of Brady (1866). The species C. clathrata of Brady includes both Oythereis tuberculata Sars, 1865, and Oythereis angidata Sars, 1865. These taxa were described 

by G. S. Brady in 1866 from a sample near the Hunde 

Islands off the southwestern coast of Greenland at approximately 68°52' N., 53°07/ W.

Brady (1868b) published another list for the Hunde 

Islands locality, adding more species, and described or 

listed species from Cumberland Inlet (66° 10' N., 67° 15' 

W.) and the Davis Strait (67°l7' N., 62°21' W.). One 

trachyleberidid was found at the Cumberland Inlet 

locality and eight trachyleberidids and hemicytherids 

at the Davis Strait locality.

Brady (1870a) followed with a report on the Eecent 

ostracodes from the Gulf of St. Lawrence in which he 

identified 29 species. Eleven of these would now be 

considered hemicytherids or trachyleberidids. Brady 

and Crosskey (1871) studied the marine Pleistocene 

ostracodes from the samples taken at Portland, Saco, 

and Lewiston, Maine, and Montreal, Canada. Thirtythree species were identified; seven of these are either 

trachyleberidids or hemicytherids, and six of these have 

been identified from Recent localities.

Norman (1877), reporting on dredgings taken by 

H.M.S. Valorous expedition to the Davis Strait in 1875, 

listed hemicytherid or trachyleberidid species from Holsteinsborg Harbor, Greenland, approximately 66° 55' N., 

53° 35' W.; Godhavn Harbor, Greenland, approximately 

69°15/ N., 53°33' W.; and in Davis Strait at 66°59' N., 

55°21' W., 64°05/ N., 56°47' W., and 67°50' N., 55°27' 

W.

Brady (1878a) published lists which contained hemicytherids and trachyleberidids from localities in the 

Kane Basin area off Ellesmere Island. These localities 

were: Franklin Pierce Bay, approximately 79°25' N., 

75°00' W.; off Victoria Head, Bache Island, approx-
PREVIOUS STUDIES

_ , _^_-

"S*L ^SJ in r^-A" ~/ "oarfrne : .rN '; n~ S 

. r,.. .^r - - ^V>W- \V- f ^ninsuia^^l/N^^^t 

S} <AXEL HRiBERG/L- M ? ^2Js??^vr* '

V V^JSLAND ^ \^| f . y3r3*«^>^V V 

^^.EHeiRiagnes^^fe:^ , \\ H/^^'/t //S / 

ifJano -^^ - -

Xi « S \ i \

X .c f \ ' V*x 1 , v r <M->

i ,,^ " i "" ^v-i-K

lOy^X'

FIGURE 1. Map showing location of samples used by previous authors and in the present study. The sample numbers 

are those used in table 1. Dashed line is 200-meter depth contour.
TABLE 1. Distribution of species of the Hemicytheridae and Trachyleberididae off northeastern North America

[Sample sources are as follows: Gos, BCF, and P, current studies by the U.S. Geol. Survey and the Woods Hole Oceanographic Institution; A-l, W. H. Adey, U.S. Natl. Mus.; codes for published localities (followed by year of publication) are B, Brady; B-N, Brady and Norman; Bl, Blake; C, Cushman; N, Norman; Ne, Neale; L-T, Loeblich and Tappan (number is their sample number). X indicates species reported in literature; numbers indicate number of specimens found per sample in this study (carapaces were counted as one specimen)]

Sample

No. (locality on fig. 1)

1 

2 

3

4 5 67

8 

9 

10

11 12 13 14 

1516 17 

18 

19 20 

21 22 23 24 25 26 

27 

28 

29 

30 31 32 33 34 35 36 37 38 39 

40 41 

42 

43 44 

45 46 47 48

Source

B 1878.. .B 1878 B-N 1889 

B 1878 

B 1878 . 

B 1878 

L-T 23.... .L-T 27 - B-N 1889 

N 1877, B-N 

1889. 

B 1866, 1868- . N1877... 

B 1868 

N1877.-- 

N 1877, B-N 

1889. 

B-N 1889 

L-T 34 .

B 1868.. .N 1877--- ,-

L-T42 - - L-T 21.... ....

L-T 22. ...

L-T 30 ..

L-T 29 

A-l....... ... .

B 1870 -

Nel961-. .

B 11929, 1933.. 

Gos 1043---.-Gos 1021----..

BCFS96 

Gos 1147... ...

BCFS108 

Gosl046-..._

BCF S83. ....

C 1906 C1906.... .... .

Gos 1054..... .

BCF W81_ 

Gos 1287-... ..

BCFW34. 

BCFN52A... BCFN56A-.P5. ......

P8.. ...-

Gos 1072......

Location

Geographic

Cape Frazer.... . _ ... Hayes Point... __ .-. Dobbs (?Dobbin) Bay. Franklin Pierce Bay.. Bache Peninsula.

North Wolstenholme 

Island. 

Vaigat Strait. ........ Davis Strait... _ -....

Godhavn Harbor.

H unde Islands. ... _ .

..do.....- ----- .do ...... . 

Holsteinsborg Harbor. 

Davis Strait..... ......

Foxe Basin .. ...

Cumberland Inlet __ Davis Strait - Frobisher Bay... ..... .do. 

Kneeland Bay.. ......

.---.do __ -.- _ ..

White Bear Arm. ...

Gulf of St. Lawrence.. 

Cabot Strait. . ... . 

Mount Desert Island-- 

Gulf of Maine. _ _ .

. do 

Browns Bank ____ . ..do... 

Stout Swell--.--..---.

Northeast Channel _ .

Vineyard Sound ___ Martha's Vineyard ....

Atlantic Shelf... ......

Atlantic Shelf - . do ......

 do 

.do ... ..... 

..... do. .-- .. .

Latitude 

north

79°44' 79°42' 79°35'

79°25' 7915' 78°37' 76°27'

70°00' 

69°31' 6915'

68°52' 67°50' 6717' 66°59' 

66°55'

66°55' 66°43' 

6610' 64°05'6310' 62°59' 61°30' 60°08' 60°00' 52°47' 

48°00' 47°30' 44°20' 44°08' 4319' 42°53' 

42°50' 42°41' 42°20' 

4211' 41°30/'4117' 40°48' 40°20' 4015' 

40°07' 

40°07' 40°06' 

40°02' 39°54'

Longitude 

west

71°36' 73°00'

75°00' 

74°30' 

74W 70°00'

52°30' 56°01' 

53°33'

53°07' 

55°27' 

62°21' 55°21' 

53°35'55°30' 

80°07' 

6715' 56°47' 

67°50' 

67°45' 67°28' 

69°00' 

67°47' 68°00' 56°07' 62°00' 60°00' 6815' 6813' 

70°27' 

66°25' 

64°00' 

67°22' 6815' 

65°30' 

70°45' 

70°45' 

70°43' 

6716' 67°23' 7315' 

68W

69°05' 

69°24' 71°44'

Depth (meters)

199-130 

70 91

26-30 

69 

69 124-46

198 110-iO

1120-140 

40 

1 

110 i 14-70

113

31 

810 

146 

55 

31 

UOO-290 

73 66 3-9 

120-500

13-24 

57 37 

147 

116 203 

208 

122 

14 26 

23 

57 

82 

36 

111 165 

133 138 

92 

139

Hemicytheridae

e

aj1 

.1

X

X

i

X 

1

3e

1

1

tq

1

X

X

X

1

98

j

X

e

1 

1

3

X

1

2

7

28 

4

X

25 

12

X

e

1

e

i

2

1

X

X

5

1029 

2 

2 

X

36 30

1

i 

t8 

1nq

6

3 

X

XX

X

10

13 

3

30 

X

9 

118

1

X

8

eS

I

XX 

X

X

2

3 

1

20

Nertina angulata

1210

X

XX X

X

4 

3

4

16 

1

96

1

 S

11

18

1

11 

3

- s 

s

1

89 

18

3

34

2 

65 

3 

4

2 

125

Muetterina canadtnsis

X

X

X

300 

95 

15

230 

101 

3

7

X

21 1

30 

19:

3

25 

80

Muetterina abyssicola

X

X

115

1

Aurila sp.

X

9

Normanicythere leioderma

7

1

V?

74

Thaerocythere crtnulata

X

7

19Q

1 

1i

?i

136

Bensonocythere americana

8

10

71

| 

1

so

X

X

3

5

Trachleberididae

Actinocythereis dawsoni

X

9 

4

1

X

29

§ 

1.i.3

i

-T

X

9,

3

is

1 1

1

i

X

X

X

Robertsonites tuberculata

X

11

5

XXX

X

1013

3

XX

X

Carinocythereis whiteii

X

g ;* «

1

'1 

&i

1

1

9,

1

1

7

Echinocythereis planisbalis

7

| 

.s

9,

Rabilimis septentrionalis &

1

1 

§>

8

5

12

Cytheretta edwardsi

X

\9,

|

X

" Cythereis" phalaropi

X

Composites of two or more samples.
CLASSIFICATION

imately 79° 15' N., 75°27' W.; off Hayes Point, approximately 79°42' N., 71 °36' W.; Smith Sound, approximately 78°37' N., 74°00' W.; and off Cape Frazer, 

approximately 79 °44' N., 71° 15' W.

In 1889, Brady and Norman published the podocopid 

part of their monograph of the ostracodes of the North 

Atlantic. This important paper relisted most of the 

localities given above; and the following localities, at 

which hemicytherids or trachyleberidids are known to 

occur, were added by Brady and Norman: Dobbs Bay 

(? = Dobbin Bay), approximately 79°35/ N., 73°00/ 

W.; in the Davis Strait at 69°31' N., 56°01' W., and 

66°55' N., 55°30/ W.; and "off Bache Island, about lat. 

78° N."

Cushman (1906) described the marine ostracodes of 

Vineyard Sound. Localities in Vineyard Sound (approx. 41°21' N., 70°45' W.) and adjacent Buzzards Bay 

(41°30/ N., 70°45' W.) yielded five species of trachyleberidids and six hemicytherids. Blake (1929, 1933) 

listed or described three hemicytherids and four trachyleberidids from the Mount Desert Island area, 

Maine, approximately 44°20' N., 68°15/ W.

Neale (1959) studied Normanicythere leioderma. 

(Norman, 1869) and showed its known distribution. 

No new locality information was given for northeastern 

North America. Neale (1961) added localities for N. 

leioderma in the Cabot Strait (47°30' N., 60°00' W.) 

and possibly in Hudson Strait (61°30' N., 69°00' W.). 

A locality on the raised beaches of Lake Champlain, 

N.Y., was also given.

Interest in the marine ostracode fauna of the eastern 

coasts of Canada and the United States has not been 

great, Indeed, if it were not for G. S. Brady and his 

coauthors, the only comprehensive works we would have 

to refer to would be those of Cushman (1906) and Blake 

(1929, 1933). The Atlantic coast south of Cape Cod 

likewise has received scant attention with only papers 

by Sharpe (1908), Tressler (1940), and Tressler and 

Smith (1948) having been published.

Other works which did not deal directly or in part 

with the eastern North American fauna but were used 

extensively in this work include Sars (1925, pt. 11, 12, 

p. 177-208), Brady (1868a), and Elofson (1938, 1941, 

1943). In his study of the Pleistocene Gubik Formation ostracodes from the Alaskan Coastal Plain, Swain 

(1963) dealt with several of the species that I or my 

predecessors have identified from the eastern coast of 

North America.

CLASSIFICATION

The family Trachyleberididae and subfamily Trachyleberidinae were described by Sylvester-Bradley 

(1948) for Oythereis and related genera which had been

placed in the Cytheridae Baird, 1850. In the family, 

Sylvester-Bradley includes genera which we now consider hemicytherids and trachyleberidids. He does not 

give a list of genera for the subfamily but includes 

Cythereis, Oligocythereis, and Trachyleberis in the systematics section of the paper.

Puri (1953c) describes the Hemicytherinae as a subfamily of Cytheridae, stating that Hemicythere and 

Trachyleberis are not closely related and both cannot 

be included in the Trachyleberididae.

Treatises by the following authors deal, at least in 

part, with post-Paleozoic ostracodes: Pokorny (1958), 

Chernysheva (1960), Moore (1961), and van Morkhoven (1962, 1963).

Pokorny (1958) does not recognize either SylvesterBradley's Trachyleberididae or Puri's Hemicytherinae 

and places the genera that have been referred to these 

taxa in the subfamily Cytherinae Baird. He states 

(1958, p. 256) that "a paleontologically differentiated 

diagnosis [of the Cytherinae] is, at this time, hardly 

possible." He considers the Hemicytherinae and Trachyleberididae as unnatural (nonphylogenetic) units.

In the treatise edited by Chernysheva (1960), the subfamily Trachyleberidinae is placed in the Cytheridae 

and divided into the tribes Hemicytherides, Trachyleberidides, Pterygocythereidides, and Schizocytherides.

In the treatise edited by Moore (1961), the families 

Hemicytheridae and Trachyleberididae are placed in 

the superf amily Cytheracea.

Van Morkhoven (1962, 1963) considers the Hemicytheridae and Trachyleberididae as subfamilies of the 

Cytheridae.

The diagnoses of the family group taxa considered 

in both the Eussian (Chernysheva, 1960) and the American treatise (Moore, 1961) are based on the carapace 

morphology. The classification of the family group 

taxa presented by van Morkhoven (1962,1963) is based 

primarily on soft parts. Van Morkhoven (1962, p. 98) 

summarizes his position on the classification: "The 

framework of this classification is formed by the welldefined taxonomic units of the biologist based of soft 

parts. As nearly as possible, the fossil groups have 

been fitted into this framework, according to those 

characters of the valves which at the present moment 

are considered the most reliable for this purpose."

Van Morkhoven (1962, p. 96-98) discusses the state 

of the ant and goals of ostracode taxonomy, and laments 

the fact that the paleontologists have split the family 

Cytheridae (Cytheracea of Moore, 1961) into many 

families and subfamilies solely on the basis of carapace 

morphology. This, he believes, may lead to the establishment of polyphyletic taxa and to increasing discordancy between the classifications of the zoologist and
6 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

the paleontologist. Van Morkhoven recommends cooperation between the two disciplines in order to construct a classification that will be useful to both.

As van Morkhoven points out, the paleontologists 

have split the Cytheridae into many families, subfamilies, and genera. However, the Cytheridae (= Cytheracea of Moore, 1961) are the most abundant and diverse 

group of marine ostracodes found as fossils from the 

Upper Cretaceous to the Kecent, and paleontologists 

have worked extensively with this fcaxon in recent years, 

whereas zoologists, in general, have not. Paleontologists have been less active with, for example, the 

Cyprididae ( = Cypridacea of Moore, 1961), which are 

not particularly abundant or diverse as fossils, whereas 

the zoologists have been very active with this group 

and have split it into many subfamilies, tribes, and 

genera. The zoologists have split those groups upon 

which they have concentrated much in the same manner 

and to the same degree that paleontologists have divided 

the Cytheridae. The zoologists have, of course, emphasized the soft parts, often ignoring the carapace.

I agree with van Morkhoven that the classification of 

Kecent and extinct related forms should be set up in 

conjunction with the zoologist. However, the zoologists 

who have concentrated, at least in part, on marine 

podocopid ostracodes since the death of G. O. Sars in 

1927 can almost be counted on one hand, and the resulting literature is sparse. In contrast, the number of 

paleontologists who have worked on Cenozoic (including Kecent) podocopids is very large, and the literature 

is voluminous. It is true that, in the description of 

families, subfamilies, and genera and in the contribution 

of classification schemes, paleontologists generally have 

not paid proper attention to the anatomy of living 

forms. However, I believe paleontologists have recognized the importance of soft-part morphology more 

than the zoologists have recognized the importance of 

carapace morphology. Because of the limited number 

of zoologists working with marine podocopids, it may 

be some time before a satisfactory classification can be 

set up in conjunction with the zoologists.

A recent publication by one of the foremost zoologists 

working with cytheracean ostracodes illustrates the differences in philosophy and rate of introduction of new 

taxa by the two disciplines. Hartmann (1964) presents 

a classification of the late Tertiary and Quaternary 

genera of Trachyleberidinae and Hemicytherinae (considered subfamilies of the Cytheridae) and gives, for 

the extant genera, lists of living species. Hartmann 

recognizes 21 genera in the Trachyleberidinae; only 3 of 

these were described by zoologists. Of the 21,1 would 

consider 1 genus invalid (Archicythereis} and 17 actually assignable to the Trachyleberididae; the other 

3 I would place in the Hemicytheridae.

Hartmann places 16 genera in the Hemicytherinae; 

12 of these were described by paleontologists. I would 

consider three of these to be trachyleberidids. Hartmann places 18 species in the genus Hemicythere Sars. 

Two of these are questionably placed there, and one is 

footnoted and explained to belong to the newly described genus Palaciosa. This leaves 15 Recent species 

in Hemicythere. Of Hartmann's 15 species, I recognize 

only 3 as belonging to Hemicythere and distribute the 

rest among at least 6 genera. This illustrates the more 

conservative classification constructed by the zoologist 

using, primarily, the appendages alone.

The classification of the Trachyleberididae and Hemicytheridae presented here is based on a combination of 

what I consider the more important hard- and softpart features. I contend that the structure of the appendages, particularly the antennules (five or six joints) 

and mandibles (simple or complex branchial plate), is 

the most important criterion for delineation of the 

Hemicytheridae-Trachyleberididae group at the family 

level. Muscle scars and shape are most important at 

the subfamily level. Hingement, type of duplicature, 

details of shape and muscle scars, and primary ornamentation are most important at the generic level. 

Secondary ornamentation and details of all the above 

are species criteria.

MORPHOLOGIC FEATURES USED IN DELIMITATION

On the problem of distinguishing Hemicytheridae 

from Trachyleberididae, Pokorny (1964a, p. 282) concludes that the subfamily Hemicytherinae (Hemicytheridae of Moore, 1961) is a group of horizontal 

classification that is, not natural or phylogenetic. 

This is not precisely true. There is general agreement 

among paleontologists that the Hemicytheridae arose 

from the Trachyleberididae. This is the derivation of 

one taxon from another of equivalent or lower categorical rank and is, by almost anyone's definition, a case 

of monophyly or natural derivation. In fact, it is the 

family Trachyleberididae that is more unnatural but 

not necessarily nonphylogenetic. Some genera are included (Moore, 1961) which are now known to be 

anatomically hemicytherids; I feel that others will 

prove to be hemicytherids when dissections are made.

Pokorny (1964a) reviews the different diagnostic 

features used for the delimitation of the Hemicytheridae 

and Trachyleberididae (frontal muscle scars, adductor 

muscle scars, hinge, normal pore canals, sculpture, and 

soft parts) and concludes that these characters have 

developed along parallel lines and "that none of them
MORPHOLOGIC FEATURES USED IN DELIMITATION

is reliable when taken isolated [and] at the present state 

of knowledge even their combination cannot lead to a 

satisfactory result because of a considerable lack of information about their phylogeny." Pokorny is correct 

in that some of the individual characters are not reliable 

for separating the Hemicytheridae from the Trachyleberididae, although there are just as many levels of 

reliability as there are characters.

Pokorny's (1964a) comments on the unreliability of 

the hinge and gross (primary) sculpture for use at the 

family level are valid. However, in my opinion, he 

unjustly minimizes the value of frontal and adductor 

muscle scars and soft-part anatomy. The examples 

cited by Pokorny do not warrant his conclusions. Because these are the very criteria I have leaned heavily 

upon for construction of a classification, Pokorny's paper deserves further detailed comment.

FRONTAL MUSCLE SCABS

Van Morkhoven (1962, p. 48) points out that it is 

not known if the so-called antennal muscle scars are 

really attachment areas for muscles running to the 

antennae or to some other part of the body. Dissections have not been made which show such a connection. 

He recommends use of "frontal scars" for the muscle 

scars in front of the adductor row and above the mandibular scars. This terminology is followed herein. 

Frontal scar is synonymous with antennal scar as used 

by most authors.

Pokorny (1964a) uses the Jurassic genus Pneumatocythere Bate as an argument against the use of 

frontal scars for delineation of the HemicytheridaeTrachyleberididae group. Bate (1963) described either 

a single scar or multiple frontal scars in the same species 

of Pneumatocythere. However, the Jurassic genus is 

a member of the distantly related Progonocytheridae. 

Frontal muscle scars may be a poor taxonomic criterion 

in the Progonocytheridae, or at least in Pneumatocythere, but this seems to have little bearing on the Hemicytheridae-Trachyleberididae problem. As Simpson 

(1961, p. 145) has summarized this problem, "Identical 

characters may in one group characterize a species or 

even be a mere variation in a species * * *, in another a 

genus, and in another a family."

Clearly, if Pokorny had known of an example in the 

Trachyleberididae or Hemicytheridae, he would have 

chosen it. Such an example does exist. Some Cretaceous species of the campylocytherine genus Antieythereis are known to have a single J-shaped frontal 

scar. Most related Cenozoic genera are known to have 

two or three frontal scars, and Paleocene and Eocene 

species of Anticythereis have two frontal scars. The 

new genus Bensonocythere* described herein, is obviously a campylocytherine by its morphological characteristics regardless of the type of frontal scars ( it has 

two). This genus has living representatives, and dissections show that it is a hemicytherid.

Thus, at least in the Campylocytherinae, there is a 

phylomorphogenic trend toward division of the frontal 

scars; this parallels the overall development of the divided frontal scars of the Hemicytheridae from the 

single scar typical of the Trachyleberididae. This is 

an exception to the general observation that the Trachyleberididae have single frontal scars and the Hemicytheridae possess divided frontal scars. This does not 

seriously handicap an otherwise usable classification; 

there are exceptions to any rules we might construct. 

The great majority of hemicytherid genera have two 

or more frontal scars, whereas most of the Trachyleberididae have a single frontal scar.

Mauritsina Deroo and Kikliocythere Plowe and 

Laurencich, two genera described as having multiple 

frontal scars, were used by Pokorny to show that families unrelated to the Hemicytheridae may possess multiple frontal scars. The muscle scars, adductor as well 

as frontal, for these genera are very peculiar; indeed, 

Deroo (1962) felt it necessary to erect a subfamily for 

them. The muscle scars of Mauritsina and Kikliocythere are probably in need of further study; however, 

the two genera also have other distinctive characteristics 

which easily separate them from the Hemicytheridae. 

The pecularities of these two Cretaceous genera do not 

bear directly on the Trachyleberididae-Hemicytheridae 

problem.

Pokorny (1964a, p. 277) points out that, although 

the type species of Bradley a Hornibrook and some other 

species also placed in that genus by Hornibrook (1952) 

possess frontal scars much like Hemicythere, Bradleya 

lactea pakaurangia Hornibrook, 1952, has a V-shaped 

frontal scar with a second oval scar above it; and Bradleya semivera Hornibrook, 1952, has only a V-shaped 

scar. Bradleya lactea pakaurangia has a rather different shape from most of the other Bradleya described 

by Hornibrook, and I do not consider it congeneric with 

the type species. It would seem more closely related to 

Jugosocythereis. Bradleya semivera also differs from 

other Bradleya species described by Hornibrook (1952) 

and probably is a trachyleberidid. Hornibrook (1952, 

p. 43) had his doubts about the Bradleya placement of 

B. semivera, for he writes: "this species is classed tentatively as Bradleya."

Pokorny (1964a, p. 277) states that "Patagonacythere Hartmann, 1962, a hemicytherine genus according to the soft parts and the three antennal muscle scars, 

has a carapace like Costa Neviani, 1928, a trachyleberine 

genus." Patagonacythere in fact does not closely re-
RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

semble Costa, but bears a strong resemblance to Ambotitracon Hazel, 1962, a hemicytherine genus with three 

frontal scars; this is discussed by Benson (1964, p. 27).

Pokorny (1964a, p. 277) is disturbed by the fact that 

Echinocythereis has a double frontal scar but is obviously a trachyleberidid by the morphology of the antennules and mandibles. The six-jointed antennules and 

complex exopodites (branchial plates) of the mandibles 

do make E chinocythereis a trachyleberidid. Therefore, 

the development of the double frontal scar must parallel 

the development of this feature in the hemicytherids. 

Indeed, and this seems to be Pokorny's principal objection to the use of frontal scars, multiple frontal scars 

have developed from the trachyleberidines at least in 

the Thaerocythermae, Campylocytherinae and Echinocythereidinae, and possibly in the Mauritsininae. The 

Hemicytherinae very probably developed from the 

Thaerocytherinae and not directly from the Irachyleberidids. To try to classify these four subfamilies into 

families on the basis of only the presence or absence 

of multiple frontal scars would certainly produce a 

horizontal classification.

I agree with Pokorny that subdivision of the Trachyleberididae-Hemicytheridae group into phyletically 

significant groups on the basis of gross frontal scar pattern alone would be difficult. However, it is very doubtful if the Mauritsininae type of multiple frontal scars 

could be confused with those of the Hemicytheridae. 

In addition, the genera of the Mauritsininae are otherwise morphologically distinct.

The double frontal scar of the Echinocythereidinae 

parallels the development of this feature in the Hemicytheridae. However, there should be little difficulty 

in separating this subfamily from the hemicytherid 

subfamilies on other characters such as shape. In addition, we know that living Echinocytherinae possess 

the appendages of the Trachyleberididae.

Rather than "the taxonomic importance of the divided frontal muscle scar [being] generally 

small * * *" (Pokorny, 1964a, p. 278), I interpret it as 

of great importance. The Mauritsininae are made up 

of only two genera and the Echinocythereidinae contain only three. Therefore, more than 35 of the Trachyleberididae genera have only the single U-shaped 

frontal scar; and all the genera of the three subfamilies 

of the Hemicytheridae, except Anticythereis which apparently has one or two frontal scars, possess double or 

triple frontal scars. Certainly this makes the divided 

frontal muscle scar of generally great taxonomic importance.

ADDUCTOK MUSCLE SCABS

Pokorny (1964a, p. 278) states that "as an iteratively 

realized character the subdivision of the adductor

muscle scars cannot be taken as a reliable criterion for 

the natural delimitation of the Trachyleberidinae and 

the Hemicytherinae."

The only subfamily of the Hemicytheridae having 

consistently split adductor scars is the Hemicytherinae. 

The Thaerocytherinae and Campylocytherinae, which 

appear to have arisen from the Trachyleberidinae in the 

Paleocene and Senonian, respectively, generally possess 

a trachyleberidid type of adductor scar pattern. The 

Hemicytherinae were, in my opinion, derived from the 

Thaerocytherinae in the Paleocene and, therefore, are 

not directly derived from the Trachyleberididae.

The subfamily Brachycytherinae, which is here tentatively included in the Trachyleberididae, has split adductor scars and a J-shaped frontal scar. The taxon 

may or may not have evolved from the Trachyleberidinae. Even if it is included in the Trachyleberididae 

its genera are morphologically far removed from the 

Hemicytheridae and no confusion should exist in distinguishing brachycytherines from hemicytherines. 

Therefore, the divided adductor scars of the hemicytherinae are a useful criterion for distinguishing the 

Hemicytherinae from the other subfamilies of the Hemicytheridae and from the Trachyleberididae.

SOFT PAKTS

Pokorny's statement (1964a, p. 281) that five-jointed 

antennules are more phylogenetically advanced than the 

six-jointed type is correct. He also indicates that fivejointed antennules developed polyphyletically. Apparently this would minimize the use of antennules in 

separating the Trachyleberididae from the Hemicytheridae. This is an unnecessarily strict view of polyphyly. In the first place, the term polyphyletic means 

very little unless one qualifies it with the level or levels 

in the hierarchic system to which he is applying the 

term. Second, we are concerned with the question of development of one taxon from another and are interested 

in a particular character's development, polyphyletic or 

otherwise, only because of this question. Several families of ostracodes, for example the Cytherideidae and 

Limnocytheridae, possess five-jointed antennules. Obviously, neither of these taxa has developed from the 

Trachyleberididae; there are too many other differences 

regardless of the type of antennules. But most everyone agrees that the Hemicytheridae did develop from 

the Trachyleberididae. In this context, the derivation 

of the five-jointed antennules of one taxon from the sixjointed antennules of another taxon of the same rank is 

certainly a monophyletic one. Within the Trachyleberididae-Hemicytheridae group the type of antennules 

can be used with complete reliability to separate the two 

families.
MUSCLE SCARS IN RELATION TO PHYLOGENY 9

Pokorny (1964a, p. 281) quotes the statement by Reyment (1960, p. 121) that Trachyleberis has antennae 

with six joints as well as six-jointed antennules and 

that this is very different from the four-jointed (protopod plus endopod) antennae of Buntonia, which also 

is a trachyleberidid. This erroneous statement cannot 

possibly cast doubt on the validity of the use of the antennules or antennae. In fact, Trachyleberis has fourjointed antennae (Harding and Sylvester-Bradley, 

1953); no podocopid has six-jointed antennae.

MUSCLE SCARS IN RELATION TO PHYLOGENY

Within the Trachyleberididae-Hemicytheridae group 

the antennules, whether five or six jointed, and the mandibular exopodites (branchial plates), whether complex 

with five setae or simple with one or two, are the most 

valuable criteria for placing a genus in one family 

or the other. If the genus is extinct, or information on 

the soft parts is not available, the carapace shape and 

muscle scars particularly are most useful.

The oldest of the nine trachyleberidid or hemicytherid subfamilies is the Trachyleberidinae which has a 

stratigraphic range of Jurassic to Recent. The genera 

of this subfamily possess four adductor muscle scars 

which are arranged in a near-vertical row. There is 

one J-, U-, or heart-shaped frontal scar. Because this 

type of muscle-scar pattern was in existence long before 

any other type in the Hemicytheridae-Trachyleberididae group appeared, we can refer to both the J-shaped 

frontal and four discrete adductor scars as primitive; 

most genera of the Trachyleberididae possess this 

pattern.

Workers have known for some time that the musclescar pattern is a useful criterion for distinguishing 

Hemicytheridae from Trachyleberididae in the absence 

of information on the structure of the appendages. As 

denned by Howe (in Moore, 1961 p. Q300), the Hemicytheridae have one or two of the four adductor scars 

divided and also have two or three frontal scars. All 

genera which have this muscle-scar pattern are hemicytherids, but not all hemicytherids have this pattern.

Several genera have a carapace morphology somewhat 

intermediate between morphologies normally considered 

typical hemicytherid and typical trachyleberidid. 

Such genera as Hermanites, Jugosocythereis, Bradley a* 

Aquitaniella, Quadracy there, Verrucocythereis, and 

Puriana fall in this class. Depending on the author, 

some of these have been placed first in one and then in 

the other family. To further complicate matters, 

whereas these genera have a vertical row of four almost 

always undivided adductor scars, they have two frontal 

scars. Most authors have considered all these genera as 

trachyleberidids. A notable exception is van Mork231-538 O 67 2

hoven (1963) who considers the two frontal scars a 

hemicytherid characteristic and places Quadracythere 

and Bradleya in the Hemicytheridae. The Cretaceous 

species assigned to Bradleya, at least the ones described 

or discussed by Hazel and Paulson (1964), have trachyleberidid frontal scars and are probably true trachyleberidids referable or, at least closely related, to the 

recently described genus OertUella-.

I have recently had the opportunity to study the soft 

parts of Jugosocythereis aff. J. deltoides (Brady, 1890) 

and Puriana fissispinata Benson and Coleman, 1963. 

These two species have the five-jointed antennules and 

simple mandibular branchial plates typical of the Hemicytheridae. These genera, plus Quadracythere, Bradleya, Hermanites, Verrococythereis, Aquitaniella, and 

the new genus Thaerocythere, which are intermediate in 

their carapace morphology, including the muscle scars, 

are placed in the Thaerocytherinae new subfamily. 

The range of the subfamily is Paleocene to Recent.

A second group of genera which nearly always have 

divided frontal scars but undivided adductor scars have 

been placed in the subfamily Campylocytherinae Puri, 

1960. Living genera of the Campylocytherinae also 

possess a hemicytherid anatomy.

Both these hemicytherid subfamilies seem to be a 

cladogenic development from the Trachyleberidinae, the 

Campylocytherinae appearing first in the Santonian 

and the Thaerocytherinae in the Paleocene.' Thus, the 

most primitive muscle-scar pattern in the Hemicytheridae has adductor scars like the Trachyleberidinae, but 

the primitive frontal scar of this subfamily has given 

way to two discrete scars in most species; however, some 

Cretaceous and Paleogene species of Campylocytherinae 

maintain the single J-shaped frontal scar. The 

campylocytherines continue on to the Recent but have 

never been abundant and apparently were not progenitors of another major group. The Thaerocytherinae, 

though not comprised of many genera, are an important 

phylogenetic link between one of the more diverse and 

abundant ostracode families of Cretaceous and Paleogene seas and one of the more diverse and abundant 

groups of Neogene and Quaternary seas, the 

Hemicytherinae.

Within the Hemicytheridae, muscle scars and shape 

delineate the subfamilies. The muscle scars for most 

genera of the Campylocytherinae are like those for the 

genera of the Thaerocytherinae. The distinctive ovate 

shape (widest posterior to middle) in dorsal view of the 

campylocytherine genera, however, makes separation 

easy.

The Hemicytherinae can be divided into two groups 

on the basis of the frontal muscle scars. Four hemicytherine genera are known to have only two frontal
10 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

scars Pokornyella, Nephokirkos, Absonocytheropteron, and Hemicy'there. The muscle scars of UrocytJiere 

have not been described, but as van Morkhoven (1963) 

avers, the genus is very closely related to Pokornyella. 

It seems likely that Urocythere possesses only two 

frontal scars. The rest of the hemicytherine genera 

seem to possess three frontal muscle scars. Muellerina 

and Pokornyella are the oldest known genera of the 

Hemicytherinae, occurring in rocks as old as Paleocene.

Keij's (1957) illustration of the type species of 

Pokornyella, P. limbata (Bosquet, 1852), seems to show 

three frontal scars, but in the text he states that the 

genus has only two frontal scars. Oertli (1956) 

describes two frontal scars for P. limbata. Van Morkhoven (1963, p. 152) states that one or more adductor 

scars on Pokornyella may be divided. Keij's (1957) 

illustration of the type species shows four undivided 

adductor scars. Ho we and Keyment (in Moore 1961, 

p. Q306) give four adductor scars for the genus. Oertli 

(1956, p. 98) states that the adductor scars agree with 

those of Heterocythereis, Aurila, and Hemicytheria 

that is, with a split dorsomedian scar. S6nmez-G6kc.en 

(1964) states that Pokornyella limbata has four 

adductor scars and two frontal scars.

Van Morkhoven (1963, p. 153) places the early and 

middle Eocene Gythere ventricosa Bosquet, 1852, in 

Pokornyella. Keij (1957) describes and illustrates this 

species as having four undivided adductor scars and 

three frontal scars. I am inclined to think that the 

lower scar, which is set further away from the second 

scar than the second is from the first, is a mandibular 

scar and not a true frontal scar.

I would place in Pokornyella five of the six late 

middle Eocene species described as Hemicythere by 

Howe (1951); these are Hemicythere phrygionia, H. 

lienosa, H. cribraria, H. ~bellula, and H. mota. I have 

observed the adductor muscle scars of H. lienosa, and 

there seem to be four undivided scars. The frontal and 

adductor scars were observed on specimens of H. mota, 

and there are two frontal scars and four adductor scars. 

Brachycythere ogboni Reyment, 1963, described from 

the Paleocene of Nigeria, appears to be a Pokornyella. 

Keyment (1963, p. 116) states that the species has two 

frontal scars and a vertical row of four adductor scars.

My interpretation of the muscle scars for Pokornyella 

is that there are only two frontal scars and four or 

sometimes five (dorsomedian scar split according to 

Oertli, 1956, and van Morkhoven, 1963) adductor scars.

It is significant that Pokornyella usually has four undivided adductor scars and two frontal scars, for this 

is the muscle-scar pattern usually found in the 

Thaerocytherinae. However, the carapace shape both 

in lateral and dorsal 'view clearly ally Pokornyella to

the Hemicytherinae. Pokornyella is considered to be 

the most primitive known member of the Hemicytherinae.

Except for Hemicythere, all the genera of the Hemicytherinae which have only two frontal scars first appear in the Paleogene. Pokornyella has a known range 

from Paleocene to Oligocene. Urocythere, Nephokirkos, and Absonocytheropteron have been found only 

in the Eocene. Of the hemicytherine genera with three 

frontal scars, only Muellerina is known from the lower 

Paleogene. Of the remaining 17 hemicytherine genera 

with three frontal scars, 1 appears in the Oligocene, 5 

appear first in the Miocene, 3 appear in the Pliocene, 5 

in the Pleistocene, and 3 genera are known as yet only 

from the Recent.

The subfamily Thaerocytherinae is composed almost 

entirely of individuals and species which usually have 

four discrete adductor muscle scars in an oblique or 

vertical row. The dorsomedian scar is usually elongated but rarely divided. Pokornyella is known to 

possess either a discrete or divided dorsomedian adductor scar. Nephokirkos has two frontal scars and a 

divided dorsomedian adductor scar (Howe, in Moore, 

1961, p. Q305). Absonocytheropteron also possesses 

two adductor scars (Krutak, 1961), however, on the two 

known species the dorsomedian scar is undivided. 

Nephokirkos and Absonocytheropteron are here considered to be more closely related to Pokornyella and 

Urocythere than to other hemicytherines.

In general, the species of other genera in the Hemicytherinae have the dorsomedian adductor scar divided. 

The genera in which this scar is variously divided or 

undivided are all Paleogene. Except for Muellerina 

and Aurila, all the genera which have the dorsomedian 

scar rather consistently divided are Neogene or Quaternary. These genera can be divided into two groups; 

those genera which contain species which also have ventromedian adductor scar divided but which also have 

species with this scar discrete, and those genera in which 

the ventromedian scar is generally consistently divided. 

Those genera which apparently have the ventromedian 

scar consistently divided do not appear until the Miocene. Two first appear at this level (Orionina, Caudites), one in the Pliocene (Ambostracon) , three in the 

Pleistocene (Normanicythere. Nereina, and Elofsonella) , and three in the Recent (Patagonacythere, Palaciosa, and Australicythere.) Genera which have either 

the ventromedian scar discrete or divided first appear 

in the Paleocene (Muellerina) , one genus appears in the 

Oligocene (Aurila), two genera appear in the Miocene 

(Mutttus and Hemicytheria) , three in the Pliocene 

(Urocythereis, Hemicythere, and Heterocythereis) , one
MUSCLE SCARS IN RELATION TO PHYLOGENY 11

in the Pleistocene (Baffinicy there], and one in the Recent (Tyrrhenocy there].

In the hemicytherines related to Pokornyella (the 

Aurila and Pokornyella groups in text fig. 2), there is, 

therefore, a trend toward division oj one of the two 

frontal scars possessed by the Paleogene representatives 

to form the three scars found in most Neogene and 

Quaternary members of the lineage.

The oldest hemicytherine with three frontal muscle 

scars seems to be Muellerina parallelokladia (Munsey, 

1953) from the middle Paleocene of Alabama. This 

species extends the range of the genus back from the 

Oligocene. No Eocene species have yet been found. 

The Muellerina lineage (text fig. 2) probably evolved 

from the Thaerocytherinae independently, and the splitting of the frontal scars went on at a more rapid rate 

than in the Pokornyella lineage.

What anatomical change is concomitant with this 

scar division is as yet problematical; however, Neale 

(1959) suggests that development of the multiple frontal scars is connected "with the great development of 

the exopodite of the second antenna and its associated 

antennal gland * * *." Whatever its causation, the 

development of two scars from one of the Trachyleberidinae and the time successive development of three 

scars from two in the Hemicytherinae must be considered a phylomorphogenic trend.

There is, therefore, a trend through time in the Hemicytherinae toward division of the median adductor muscle scars. The oldest members of the subfamily have 

either the dorsomedian scar divided or discrete and the 

ventromedian scar discrete (Paleocene to Oligocene). 

Species which the the ventromedian scar sometimes divided do not appear until the Oligocene, and genera in 

which the ventromedian is consistently divided do not 

appear until the Miocene. The splitting of the median 

adductor scars, first the dorsomedian and the ventromedian, is considered a phylomorphogenic trend.

Because in the Hemicytheridae the oldest subfamily 

which could have given rise to the Hemicytherinae, the 

Thaerocytherinae possesses, with rare exceptions, four 

undivided adductor scars and two frontal scars, these 

two characters can be considered primitive for the 

Hemicytheridae; and the divided adductor scars found 

in the Hemicytherinae, as well as the three frontal scars 

of most of the genera, can be considered advanced. In 

the Pokornyella lineage the genera with only two frontal scars and discrete ventromedian and variously discrete or divided dorsomedian adductor scars appear before those genera with three frontal scars, divided dorsomedian adductor scars, and variously divided ventromedian adductor scars. In the Muellerina lineage all 

the genera have three frontal scars and divided dorsomedian adductor scars, but forms with discrete ventromedian adductor scars appear in time before those with 

divided ventromedian scars. The more advanced scar 

patterns are derivable through stages from the pattern 

first displayed by the Thaerocytherinae and ultimately 

by the Trachyleberidinae. This muscle-scar sequence 

is considered a phylomorplhogenic trend that reflects the 

phylogenetic development of the Hemicytherinae from 

the Trachyleberidinae through the Thaerocytherinae.

Text figure 2 gives a tentative phylogenetic scheme 

for the Trachyleberididae and Hemicytheridae. The 

muscle-scar types known in each taxon are also shown in 

the figure. The number of described genera is also 

given.

The fact that some muscle-scar types are found only 

in particular taxa is evidence of the taxonomic importance of muscle scars. Only one type of scar is found 

in some subfamilies for example, Cytherettinae, Trachyleberidinae, and Echinocythereidinae. This is also 

generally true for the Pterygocythereidinae and Buntoniinae; however, the dorsal adductor scar seems to 

divide on some Pterygocythereidinae (Hazel and Paulson, 1964), and some Buntoniinae have been described 

with divided frontal scars (Reyment, 1960; Apostolescu, 1961). These are rare, however, and for this 

reason are not shown on the diagram.

Two very similar patterns are known in the Mauritsininae; those found in Mauritsina and its possible descendent Kikliocy there. Two patterns are also known 

in the Brachycytherinae; those found in Brachycythere 

and its descendent Digmocythere. In each of the 

above, the range of a particular scar pattern is the 

same as that of a particular taxon.

In the Campylocytherinae, three basic scar patterns 

are found. In this subfamily the ranges of scar patterns are not entirely coincident with ranges of taxa. 

Single and double frontal scars have been described for 

Anticythereis, and double and triple antennal scars have 

been described for Leguminocythereis. A phylomorphogenic trend is present, however, because the single 

frontal scar gives rise to the double frontal scar which 

gives rise to three scars.

In the Hemicytherinae, heterogenous groups are represented by some scar types. For example, the musclescar types found in the Muellerina, Orionina, and Aurila informal taxonomic groups are very similar; however, these groups of genera represent two principal 

lineages within the subfamily. Here again there can 

be seen phylomorprogenic trends towards division of 

the frontal scar and, first, the dorsomedian adductor 

and, then, the ventromedian adductor scars. The more 

primitive muscle-scar type is found in the Pokornyella 

group. This includes Pokornyella and Urocythere,
12 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

FIGUBE 2. Tentative phylogenetic scheme for the major formal and informal taxonomic groups of the Trachyleberididae 

and Hemicytheridae, also showing the general type of muscle-scar pattern found in each major grouping.

which surely are closely related, and NephoJcirkos, and 

Absonocytheropteron, whose relationship to each other 

and the other two genera is not at all clear. In this 

group there are only two frontal scars, and the dorsomedian adductor scar is sometimes not divided.

Such genera as Aurila, Mutilus, Heterocythereis, 

Hemicytheria, and Tyrrhenocy there are very probably 

descended ultimately from Pokomyella and (or) Urocythere. They possess a muscle-scar pattern with three 

frontal scars and have the ventromedian adductor sometimes divided.

Hemicythere may be the only Neogene and Quaternary hemicytherine genus retaining only two frontal 

scars, a possible exception being Neogene and Quaternary species that have been referred to Procythereis. 

The ancestry of Hemicy there is not clear. Even though 

it is the nominal genus of the family, it appears to be 

unique.

The Neogene and Quaternary genera here placed in 

the Orionina group apparently have the ventromedian

adductor scar consistently divided; included are Orionina^ Ambostracon, Nereina, Patagonacy there, Australicythere, Elofsonella, and Palaciosa. Baffinicythere, in which the ventromedian scar is not divided, is 

also included. These genera are probably descended 

from ostracodes of the Muellerina group, which includes Muellerina, Urocythereis, and N ormanicythere. 

Ambostracon is similar to Caudites and Orionina, which 

are no doubt closely related ostracodes (van den Bold, 

1963a). Benson (1964) considers Australicythere. Patag onacy there, and Anibostracon to be related. Nereina 

and Elofsonella are also probably related to these genera. In addition to other similar features, Orionina 

and Caudites possess the peculiar pillar structure proximal to the fused zone of the calcified inner lamella. 

This is also present (van den Bold, 1963a) in the genus 

Palacwsa,. Baffinicy there is included in this group, 

though in some ways it is not a typical representative. 

It has an undivided ventromedian scar, and the females 

are rather auriform in lateral outline; this outline is
SYSTEMATIC PALEONTOLOGY 13

reminiscent of genera of the Aurila group. However, 

the males are totally unlike anything in the Aurila 

group, being very elongated. The primary ornamentation of the genus is more similar to that found in genera 

included in the Oriordna group. Even though the 

genus is known only from Quaternary deposits, it has 

several primitive characters.

The muscle scars are as yet not known for the genus 

Procythereis Skogsberg. Puri (1953c) places Hemicythere calhounensis Smith in Procythereis. I have 

not been able to determine what the muscle scars of 

this species are. Hemicythere calhounensis, although 

probably not a PoJeomyella, bears a close resemblance 

to species of that genus and could be one of the "transitional" Miocene forms referred to by van Morkhoven 

(1963, p. 152). If this is true, then the muscle scars 

may prove to be like those of Pokornyella and extend 

the range of the Pokornyella type of muscle scar into 

the Miocene. It remains to be proven that Hemicythere 

calhounensis, a tropical Miocene species, is congeneric 

with the Eecent Antarctic species Skogsberg (1928) 

placed in his genus Procythereis.

When the data on muscle-scar patterns are combined 

with data on other morphologic features, it appears that 

the Hemicytherinae are divisible into several tribes. 

At present there is not, to my satisfaction, enough 

morphologic and distributional information available 

on some genera to formally propose such a division. 

Tentatively, however, this important subfamily seems 

to be composed of five major groupings which are here 

treated as informal taxonomic groups. The Orionina 

and Aurila groups, mentioned above, probably represent two valid taxa. Pokornyella, Urocythere, and 

probably Nephokirkos and Absonocytheropteron may 

represent a third taxon. The genus Hemicythere, even 

though it is the nominal genus of the family, appears 

to be unique and may represent a monotypic tribe. 

Another taxon may be represented by Muellerina, Urocythereis, and Normanicythere.

Muscle scars are, of course, subject to variation just 

as other features of the carapace, and their study must 

be attacked from within the framework of population 

systematics. Whereas the pattern within a species is 

very consistent, variants are not uncommon; and it is 

risky to judge the pattern for a species from that seen 

on an individual. The pattern of a genus cannot generally be considered known if only the scars of a single 

species have been delineated, unless, of course, the genus 

is monotypic.

Muscle scars are generally not easily seen, and it is 

discouraging to examine numerous specimens without 

being able to resolve the pattern of a single one. Excellent preservation does not always help, and often

slightly abraded specimens show patterns the best. 

Muscle scars aid but are not a panacea for delineating 

genera or species. Many of the genera in the Hemicytheridae were described without the knowledge of the 

muscle-scar patterns of the type or other species. However, muscle scars are extremely useful criteria for 

placing genera within subfamilies and relating subfamilies within families; for this reason the type of 

muscle-scar pattern displayed by the species of proposed 

genera should be searched for assiduously.

SYSTEMATIC PALEONTOLOGY

All types and illustrated specimens are deposited in 

collections of the U.S. National Museum.

Measurements of specimens are indicated by the notations L and H for length and height. The number of 

specimens measured is noted by N and is followed by 

the mean (M] , standard deviation (Sd) , observed range 

(OR], and coefficient of variation (F).

The descriptive terminology used is principally that 

of Moore (1961) and van Morkhoven (1962, 1963). 

One new term is proposed. The so-called antislip tooth 

that is prominent in some genera of the Campylocytherinae and other subfamilies actually has nothing to do 

with the hingement. Most recent authors have recognized this and indicated such by carrying antislip tooth 

in quotes. Dissections of two species of Bensonocy there 

show that the "antislip tooth" is a site for the attachment of dorsal body muscles. It is therefore homologus 

with the large dorsal muscle scar or scars found in many 

genera. The term "dorsal muscle platform" is proposed 

for this feature.

Subclass OSTRACODA Latreille, 1802

Order PODOCOPIDA Sars, 1865

Suborder PODOCOPINA Sars, 1865

Super-family CY!PHERACEA Baird, 1850

Family HEMICYTHERIDAE Puri, 1953

Diagnosis. Carapace auriform, subquadrate, subrectangular, oblong, or subtrapezoidal in lateral view, 

often produced posteroventrally; elliptic or ovate in 

dorsal view; surface ornamentation variable; few marginal denticles; hinge amphidont or modified amphidont; marginal areas wide; anterior and posterior vestibules usually present; radial canals generally many; 

eye tubercle absent or moderately developed; adductor 

muscle scars a near-vertical row of four scars, one or 

both of the middle scars, and sometimes the dorsal scar, 

may be divided; two or three frontal scars; antennules 

with five podomeres; endopodite of antennae with three 

podomeres, exopodite well developed; exopodite of mandible (branchial plate) reduced to one or two setae; 

chitinous supports in knees of thoracic legs.
14 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Discussion. As considered here, this family comprises the following three subfamilies:

Campylocytherinae Puri, 1960, Santonian to Recent 

Hemicytherinae Puri, 1953, Paleocene to Recent 

Thaerocytherinae Hazel, new subfamily, Paleocene to 

Recent

Subfamily HEMICYTHERINAE Puri, 1953

Diagnosis. Auriform to subquadrate or subrectangular in lateral view; generally elliptic in dorsal view, 

widest at or in front of middle; adductor muscle scars 

usually with single upper and lower scars and two pairs 

of divided scars or one pair and one single scar between; 

two or three frontal scars.

Discussion. This subfamily can be distinguished 

from the Campylocytherinae by its more elliptic shape 

in dorsal view and the presence of divided adductor 

muscle scars. The divided adductor muscle scars also 

separate the Hemicytherinae from the Thaerocytherinae. The following genera are considered as members 

of the Hemicytherinae:

Pokornyella group

PoJcornyella Oertli, 1956, Paleocene to Oligocene 

Urocythere Howe, 1951, Eocene 

Nephokirkos Howe, 1951, Eocene 

Absonooytheropteron Puri, 1957, Eocene 

VProcythereis Skogsberg, 1928, Miocene(?), Recent

Orionina group

Australicythere Benson, 1964, Recent 

Palaciosa Hartmann, 1959, Miocene to Recent 

Patagonaoythere Hartmann, 1962, Recent 

Caudites Coryell and Fields, 1937, Miocene to Recent 

Elofsonella Pokorny, 1955, Pleistocene to Recent 

Ambostracon Hazel, 1962, Pliocene to Recent 

Nereina Mandelstam, 1957, Pleistocene to Recent 

Orionina Puri, 1954, Miocene to Recent

Aurila group

Mutilus Neviani, 1928, Miocene to Recent 

Aurila Pokorn}/, 1955, Oligocene to Recent 

Heterocythereis Elofson, 1941, Pliocene to Recent 

Hemicytlieria Pokorny, 1955, Miocene to Pliocene 

Tyrrhenocythere Ruggieri, 1955, Recent 

Baffinicythere Hazel, n. gen., Pleistocene to Recent

Hemicythere group

Hemioythere Sars, 1925, Pliocene to Recent 

Muellerina group

UrooytJiereis Ruggieri, 1950, Pliocene to Recent 

Muellerina Bassiouni, 1965, Paleocene to Recent 

Normamioythere Neale, 1959, Pleistocene to Recent

Genus HEMICYTHERE Sars, 1865

Type species, Gythereis villosa Sars, 1865.

Diagnosis. Subreniform; surface variously pitted; 

duplicature moderately broad; radial canals many; narrow vestibules present; hinge amphidont with smooth 

anterior tooth in right valve, postjacent socket, crenulate bar, multilobate elongated posterior tooth; two 

frontal muscle scars and five or six adductor scars.

Discussion. Van Morkhoven (1963, p. 136) states 

that the generic diagnosis of Hemicy'there "would seem 

to fit no other published species than the type." An 

opposite view is taken by Hartmann (1964, p. 107) who 

places at least 17 species in the genus.

The subreniform shape, distinctive hingement, and 

muscle scars are important features that characterize 

the type species. Gythere lorealis Brady, 1868, has the 

same shape as the type species, and Brady (1868b, p. 31) 

describes the hinge as "a crenulated median bar, with a 

moderately strong anterior tooth-like process [in the 

left valve]; in the right valve * * * a small anterior 

tooth and a slightly crenulated posterior projection." 

This is close to the described hinge of the type species. 

Gythere pulcJiella Brady, 1868, has the subreniform 

shape, but the hingement is incompletely known. 

Brady (1868b) states that Gythere rubida Brady, 1866, 

is closely related to C. pulchella and also compares it to 

Gythereis villosa. Therefore, it may also be a Hemicythere. There appear to be at least two, and possibly 

three, other arctic or boreal species in addition to the 

type species of Hemicythere. Van Morkhoven (1963, p. 

136) also mentions an undescribed species from New 

Zealand.

Stratigraphic range. Pliocene to Eecent.

Hemicythere cf. H. villosa (Sars, 1865) 

Plate 2, figure 4

1865. Cythereis villosa Sars, Vidensk, Selsk. Christiania, Forh.,

p. 42. 

1941. Cythereis (Eucythereis) villosa Sars. Elofson, Zool.

Bidrag fran Uppsala, v. 19, p. 287 (gives full synonymy

from 1865-1941). 

1943. Cythereis (Eucythereis) villosa Sars. Elofson, Archiv

Zoologi., v. 35A, no. 2, p. 9.

1952. Hemicythere villosa (Sars). Pokorny, Ustfedniho Ustavu 

Geol. Sbornik [Czechoslovakia], v. 19, p. 156.

1953. Hemicythere villosa (Sars). Puri, Washington Acad. Sci. 

Jour., v. 43, no. 6, p. 174, pi. 1, figs. 11,12.

1957. Hemicythere villosa (Sars). Wagner, * * * ostracodes 

du Quaternaire Recent des Pays-Bas * * *, p. 56, pi. 23.

1963. Not Hemicythere villosa (Sars). Swain, Jour. Paleontology, v. 37, no. 4, p. 828, pi. 99, figs. 4, 6; text fig. 

lOc (= Hemicythere borealis and Elofsonella concinna).

Measurements. One adult female measures 0.64 mm 

long and 0.37 mm high.

Discussion. Brady (1868b) reported this species 

from the Da vis Strait and later (1870a) listed it as 

occurring in the Gulf of St. Lawrence. Cushman 

(1906) reported it from Vineyard Sound. Only one 

adult specimen, a left valve which may be conspecific
SYSTEMATIC PALEONTOLOGY 15

with Hemicythere villosa, was found in the present 

study (sample 31). The specimen compares favorably 

with specimens of H. villosa from the North Sea area in 

shape and internal features, but the ornamentation is 

reduced to shallow pits, contrasting with the more 

coarsely pitted or reticulated North Sea specimens. 

More material will need to be examined to evaluate the 

taxonomic importance, if any, of this difference.

/Specimens found. Two, one adult female and one 

juvenile.

Occurrence. Various localities near the British Isles, 

North Sea, Norwegian Sea, English Channel, Bay of 

Biscay, Greenland Sea, Baltic Sea, Davis Strait, Gulf 

of St. Lawrence, and Vineyard Sound. Pleistocene of 

England, Scotland, Ireland, Norway, and Canada. In 

the present study, two specimens which may represent 

this species were found; one from the Gulf of Maine 

(sample 31) and the other near Martha's Vineyard 

(sample 39).

Repository. USNM 112728.

Hemicythere borealis (Brady, 1868) 

Plate 2, figures 3, 5, 6,10,11

1868. Cythere borealis Brady, Annals and Mag. Nat. History

4th ser., v. 2, p. 31, pi. 4, figs. 1-4, 6, 7. 

1889. Cythere borealis Brady. Brady and Norman, Royal

Dublin Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 147, figs.

18, 19. 

1963. Hemicythere villosa (Sars). Swain (partim), Jour.

Paleontology v. 37, no. 4, p. 828, pi. 99, fig. 4; not pi. 99,

fig. 6 or text fig. lOc (=Elofsonella concinna).

Diagnosis. Large; irregularly and coarsely pitted; 

characteristic depression in posteroventral area of 

valves; males relatively more elongate, but actually 

smaller than females.

Measurements in mm. 

Female: 

L.. .................

H. ..................

Male: 

L... ................

H. ..................

N

10

10

7

7

M

0.861

.501

.809

.452

Sd

0.018

.011

.021

.015

OR

0.838-0.900

. 488- . 525

. 775- . 833

.425- .462

V

2.1

2.2

2.6

3.3

Discussion. The carapace and soft parts of this 

species are well described by Brady (1868b) and Brady 

and Norman (1889). The latter authors point out the 

close relationship with the type species of Hemicythere. 

It is much larger than H. villosa and is.also distinguished by a depression in the posteroventral area of the 

valves. The species is undoubtedly a true Hemicythere.

Specimens found. 100.

Occurrence. Dobbin Bay, Davis Strait, Godhavn 

Harbor, and Holsteinsborg Harbor. Pleistocene of 

Alaska. In the present study the species was found to 

be abundant in White Bear Arm, Labrador, and rare 

in Kneeland Bay and Vaigat Strait.

Repository. USNM 112723-112727.

Hemicythere? pulchella (Brady, 1868)

1868. Cythere pulchella Brady, Linnean Soc. London Trans., 

v. 26, p. 404.

1868. Cythere pulchella Brady. Brady, Annals and Mag. Nat. 

History, 4th ser., v. 2, p. 32, pi. 5, figs. 18-20.

1869. Cythere pulchella Brady. Brady and Robertson, idem., 

v. 3, p. 369, pi. 20, figs. 1-3.

1874. Cythere pulchella Brady. Brady, Crosskey, and Robertson, A monograph of the Post-Tertiary Entomostraca 

* * *, p. 157, pi. 3, figs. 29-37.

1889. Cythere pulchella Brady. Brady and Norman, Royal 

Dublin Soc. Sci. Trans., 2d, ser., v. 4, no. 2, p. 34, pi. 

15, figs. 7, 8.

Discussion. This species was reported from the 

Davis Strait by Brady (1868b). I have not identified 

it in my material.

Occurrence. Various localities in the British Isles, 

Scheldt Eiver in the Netherlands, and Davis Strait. 

Pleistocene of Scotland and Ireland.

Genus EIOFSONELIA Pokorny, 1955 

(=Paracythereis Elofson, 1941)

Type species, Cythere concinna Jones, 1857.

Diagnosis. Subtrapezoidal in lateral view; strong 

anteroventral rim, low but distinct muscle swelling; 

surface pitted or reticulate; hinge strong holamphidont; 

three frontal muscle scars; median two adductor muscle scars divided.

Stratigraphic range. Pleistocene to Eecent.

Elofsonella concinna (Jones, 1857) 

Plate 4, figures 10, 11, 13

1857. Cythere concinna Jones, A monograph of the Tertiary

Entomostraca * * *, p. 29, pi. 4, figs. 7a-f. 

1941. Cythereis (Paracythereis) concinna (Jones). Elofson,

Zool. Bidrag fran Uppsala, v. 19, p. 289 (gives full

synonymy from 1857-1941). 

1943. Cythereis (Paracythereis) concinna (Jones). Elofson,

Archiv Zoologi, v. 35A, no. 2, p. 9. 

1955. Elofsonella concinna (Jones). Pokorny, Carolinae Univ.

Acta Geologica, v. 3, p. 10, figs. 3-7. 

1963. Elofsonella concinna (Jones). Swain, Jour. Paleontology.

v. 37, no. 4, p. 829, pi. 98, figs, la, b; pi. 99, figs, lla-c,

text fig. 12c. 

1963. Hemicythere villosa (Sars). Swain (partim), Jour.

Paleontology, v. 37, no. 4, p. 828, pi. 99, fig. 6; text fig.

lOc; not pi. 99, fig. 4 (=Hemicythere borealis). 

1965. Elofsonella concinna concinna (Jones). Bassiouni,

Dansk Geol. Foren., Medd., v. 15, no. 4, p. 511, pi. 2,

figs. 1, 2.
16 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

1965. Elofsonella concinna neoconcinna Bassiouni, idem., pi. 2, 

fig. 3a-c.

Diagnosis. Subtrapezoidal in lateral view: strong 

anterior rim; surface with ridges and pits which may 

be strongly or weakly developed.

Measurement in mm. 

Female: 

L.. .................

H_- ...........

Male: 

L.. .................

H.. .................

N

19

19

6

6

M

0.998

.576

1 029

.552

Sd

0.091

053

.062

.035

OR

0. 900-1. 215

Q7K_ 1 lot

efVY- 58S

V

9 1

9.2

6.0

6.3

Discussion. Jones (1857) described Oythere concinna from Pleistocene deposits of Yorkshire, England. 

The species has been subsequently reported many times 

from the Pleistocene and Recent. Bassiouni (1965) 

gives an incomplete synonymy for the species, but apparently restricts Elofsonella concinna sensu stricto to 

the Pleistocene and names E. concinna neoconcinna for 

the Recent forms, at least those of Elofson (1941) and 

Pokorny (1955). The two subspecies are distinguished 

by differences in surface ornamentation. Elofsonella 

concinna neoconcinna is said to possess a reticular ornamentation with the reticules divided by fine branches, 

whereas E. concinna concinna is ornamented with fine 

pits and has an indication of a reticular sculpture developing on the lower half of the valves.

Both the pitted ^and reticulate forms are living off 

northeastern North America and, further, can be found 

in the same samples. Therefore, Elofsonella concinna 

concinna and E. concinna neoconcinna are not chronologic subspecies as implied by Bassiouni. Both types 

were found in samples from Ungava and Frobisher 

Bay (60° to 63° N.). Only the reticulate form was 

found farther north; however, only three specimens in 

all were found north of 63° N. Only the pitted form 

was found in two samples from the Gulf of Maine. 

This would seem to indicate a variation with latitude; 

however, all the specimens illustrated from the Pleistocene of Alaska (70° N.) by Swain (1963) seem to be 

the pitted form. In a sample in which both forms occur 

in some abundance (sample 24), a gradational series 

from one form to the other occurs. Therefore, it is not 

likely that the two forms represent closely related morphologically similar species. I am inclined to consider 

this pitted-to-reticulate variation infrasubspecific in 

nature, and at least until more knowledge on the geographic distributions of the morphotypes is known, 

synonymize Bassiouni's two subspecies.

The specimens found in the Gulf of Maine are nearly 

15 percent smaller than those found in the colder waters

to the north. Thus, the species shows considerable variation in size as well as ornamentation.

Specimens found. 82.

Occurrence. Baltic Sea, North Sea, Norwegian Sea, 

Barents Sea, near Iceland, near Spitzbergen, various 

localities in the British Isles, Kane Basin, Gulf of 

Maine, Gulf of St. Lawrence, and Vineyard Sound. 

Pleistocene of Alaska, Maine, England, Scotland, Ireland, Denmark, and Norway. In the present study the 

species was found in samples from near North Wolstenholme Island, the Foxe Basin, Frobisher Bay, Kneeland 

Bay, Ungava Bay, and the Gulf of Maine.

Repository. USNM 112764-112766.

Genus BAFFINICYTHERE n. gen.

Type species, Gythere costata Brady, 1866.

Etymology. Baffin, from Baffin Bay, plus the genus 

Gythere.

Diagnosis. Elongate subrectangular (males) to subtrapezoidal or auriform (females); ridges form a triangle in posteroventral area of the lateral surface; small 

vestibules at anterior and posterior; radial canals many, 

swollen at midlength; hinge holamphidont, posterior 

tooth of right valve reniform; ocular sinus conspicuous; 

normal pore canals scattered, sieve type; muscle scars 

consist of three unsplit adductor scars, one (dorsomedian) split adductor, and three rounded frontal scars 

with the median scar forward; nodes between central 

muscle field and mandibular scars and between central 

muscle field and dorsal scars.

Discussion. I interpret this genus as being related to 

such genera as Ambostracon, Orionma, Elofsonella, 

Caudites, Nereina, and Patagonacythere, though perhaps less closely related to any of these than they are to 

each other. The two species here placed in Baffinicythere have muscle-scar patterns similar to the above 

genera but differ in having the ventromedian scar undivided. The females of Baffinicythere are somewhat 

auriform in lateral view, a characteristic of the Aurila 

group, but Baffinicy there differs from this group by 

being strongly sexually dimorphous, the males being in 

no way auriform but subrectangular. In this respect, 

and in some primary ornamental features present in 

both sexes, such as major ribs, the genus resembles 

genera of the Orionina group. Particularly diagnostic 

for Baffinicy there is the triangle formed by the intersection of ribs in the posteroventral area of the lateral 

surface.

The genus is proposed for the species Cythere costata 

Brady, 1866, and Gythereis emarginata Sars, 1865. 

Brady (1868a) first pointed out the close relationship 

between these two species. I have not seen the types of
SYSTEMATIC PALEONTOLOGY 17

Gythere costata. However, the type species has been 

well illustrated by Brady (1866), Brady, Crosskey. and 

Eobertson (1874), and Brady and Norman (1889). It 

is a distinct and easily recognized species.

Baffinicythere is known from about 80° N. to about 

59° N. in the eastern North Atlantic and from about 

80° N. to about 41° N. in the western North Atlantic.

Stratigraphic range. Pleistocene to Recent.

Baffinicythere costata (Brady, 1866) 

Plate 2, figures 7, 12-15; plate 8, figures 1-8

1866. Cythere costata Brady, Zool, Soc. London Trans., v. 5, p.

375, pi. 60, figs. 5a-f. 

1869. Cythere costata, Brady. Norman, Shetland final dredging

report, pt. 2, British Assoc. Adv. Sci., rept. 38th Mtg., p.

290. 

1874. Cythere costata. Brady, Crosskey, and Robertson, A

monograph of the Post-Tertiary Entomostraca * * *, p.

166, pi. 5, figs. 21-24. 

1878. Cythere costata. Brady, in Nares, Narrative of a trip to

the Polar Sea during 1875-6 * * *, v. 2, no. 7, p. 254. 

1889. Cythere costata. Brady and Norman, Royal Dublin Soc.

Sci. Trans., 2d ser., v. 4, p. 164, pi. 16, figs. 7, 8.

Diagnosis. Large; very strong sexual dimorphism, 

males much longer than females; posterior leg of bifurcated posteromedian ridge angles towards posteroventral area, anterior leg better developed than posterior leg; posteroventral area with several moderately 

strong denticles; eye tubercle present.

Measurements in mm. 

Female: 

L... ................

H........ ....... ....

Male: 

L.. .................

H.. .................

N

14

14

13

13

M

1.120

.646

1.166

.592

Sd

0.063

.033

.043

.029

OR

1. 038-1. 250

. 575- . 688

1. 088-1. 200

.550-. 638

V

5.6

5.1

3.7

4.9

Description. In lateral view, subrectangular (males) 

to subtrapezoidal or auriform (females); surface 

coarsely reticulate; prominent rib runs from eye tubercle around anterior rim, along anterior half of ventrolateral area then curves upward and bifurcates, one 

leg continuing parallel to ventral outline, the other 

curving upward towards posterodorsal area where it is 

joined by a less prominent ridge leading from posterior 

end of first leg; these ridges form a triangle in the 

posteroventral area; main ridge curves anteriorly to 

form short dorsolateral ridge in posterior half of valves; 

muscle swelling broad, indistinct, at conjunction of several reticulation riblets. Lanceolate in dorsal view, 

valves subequal, left valve slightly larger. Hinge 

holamphidont; posterior tooth large, reniform, smooth, 

connected to anterior deep socket behind a strong, stepped, smooth tooth by a smooth bar; left valve complimentary, posterior socket open to interior; marginal 

areas broad with anterior and posterior vestibules; 

radial canals many, swollen in middle; ocular sinus conspicuous; normal pore canals scattered, sieve type. 

Muscle scars a vertical row of scars, the dorsomedian 

scar distinctly divided; and three frontal scars, two large 

round scars in oblique row, with small third scar set 

below and behind second scar.

Antennules have five podomeres; tufts of very fine 

setae on anterior edge of second podomere; one seta at 

distal end of posterior edge of second podomere; one 

seta at distal end of anterior edge of third podomere; 

fourth podomere has three setae one thin, one medium, 

and one large at anterior midlength, one of which comes 

from side of podomere and three like sized setae at anterodistal end and one long thin seta at posterodistal 

end; fifth podomere has one large and at least two other 

smaller setae. Endopodite of antennae has three podomeres, exopodite poorly developed on males and not 

seen on females, three terminal claws; cutting edge of 

mandible has many well developed teeth; thoracic legs 

have chitinous supports in knees and strong terminal 

claws.

Discussion. Baffinicythere costata has the same 

basic pattern of ornamentation as does B. emarginata, 

but differs in detail (see diagnosis). Baffinicythere 

costata is larger and the males of this species are actually longer than the females; the opposite is true in B. 

emarginata. The lower frontal muscle scar of B. 

costata is small and easily overlooked.

Specimens found. 117.

Occurrence. Near the Hunde Islands, Holsteinsborg 

Harbor, near Franz Josef Land, Franklin Pierce Bay, 

and Smith Sound. Pleistocene of England and Scotland. In the present study the species was found in 

samples from near North Wolstenholme Island, the 

Vaigat Strait, the Foxe Basin, Frobisher Bay, Ungava 

Bay, White Bear Arm, and the Gulf of Maine.

Repository. USNM 112686-112688, 112729-112733.

Baffinicythere emarginata (Bars, 1865) 

Plate 2, figures 1, 2, 8, 9; plate 9, fig. 2

1865 Cythereis emarginata, Sars, Vidensk. Selsk. Ohristiania,

Forh., p. 38. 

1941 Cythereis (Eucythereis) emarginata Sars. Elofson, Zool.

Bidrag fran Uppsala, v. 19, p. 283 (gives full synonymy

from 1865-1941). 

1943 Cythereis (Eucythereis) emarginata Sars. Elofson,

Archiv Zoologi, v. 35A, no. 2, p. 8.

Diagnosis. Relatively small; males shorter than females; posterior leg of bifurcated posteromedian ridge 

vertical and more strongly developed than anterior leg; 

eye tubercle not well developed.
18 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Measurements in mm. 

Female: 

L.. ........ ... ....

H...................

Male: 

L.. .................

H.... ...............

N

20

20

16

16

M

0.816

4Q9

.766

.426

Sd

0.043

.030

.038

.020

OR

a

77E_A QAfl

. 450- . 562

. 725- . 850

Af\(\ AK.f\

V

5.3 A i

4.8

4.7

Discussion. The soft parts of this species were illustrated by Sars (1925) and Cushman (1906). Cushman 

shows the antennules to have six podomeres; however, 

this is undoubtedly a drawing or observational error.

Baffinicy there emarginata is smaller than B. costata 

and differs in details of ornamentation. The males of 

B. emarginata are smaller than the females; the opposite is true in B. costata.

Specimens found. 201.

Occurrence. North Sea, Norwegian Sea, near Spitsbergen, near Iceland, near Franz Josef Land, Greenland Sea, Barents Sea, Franklin Pierce Bay, Davis 

Strait, Godhavn Harbor, Holsteinsborg Harbor, near 

the Hunde Islands, Gulf of St. Lawrence, Vineyard 

Sound, and Buzzards Bay. Pleistocene of England, 

Scotland, Ireland, Norway, and Maine. In the present 

study the species was found in samples from near North 

Wolstenholme Island, the Vaigat Strait, Kneeland Bay, 

Ungava Bay, White Bear Arm, the Gulf of Maine, 

Browns Bank, and near Martha's Vineyard.

Repository. USNM 112691, 112719-112722.

Genus NEKEINA Mandelstam, 1957 

(=Finmarchinella Swain, 1963)

Type species, Nereina barenzovoensis Mandelstam, 

1957 (? = Gythereis angulata Sars, 1865).

Diagnosis. Subtrapezoidal to subrectangular in lateral view; venter flattened: elliptic in dorsal view; surface pitted, may be rugose; sexual dimorphism strong, 

males more elongate and much lower at posterior than 

females; hinge of right valve consists of very elongate 

multilobate anterior tooth connected to elongate multilobate posterior tooth by crenulate groove; left valve 

complementary; vestibules at anterior and posterior; 

many radial canals, swollen medially; selvage well developed; three frontal muscle scars; median two adductor muscle scars divided at sharp angle to valve 

length.

Discussion. The most distinctive character in Nereina is the unusual hingement. This type of hingement is not primitive, for its three-fold elements are not 

homologous with the three-fold merodont hinge. Pokorny (1964a, p. 280) states that"* * * Nereina would 

represent not the most primitive state of Hemicytherinae-hinge, but the final stage of a regressive evolution, 

comparable morphologically to some phenomena of 

f oetalisation, where larval morphology persists in adult 

forms."

Swain (1963, p. 813) proposed the genus Finmarchinella for the species Gythereis angulata Sars, 1865, and 

Gythereis flnmarchica Sars, 1865. The latter species 

was selected as the type. He describes the muscle soars 

for Finmarchinella presumably the scar pattern described is that of Gythereis angulata and not of O. finmarchica because G. finmarchica was not found by 

Swain, even though he selected it as the type species 

as consisting of "a row of three or four elongate spots 

on the posterior portion of median tubercle (a pit on 

internal surface) together with one or two spots on 

anterior slope of median node and an additional one 

or more spots anterior to median node." However, the 

muscle-scar patterns shown here on plate 11, figures 7 

and 8, for both species agree with the pattern described 

for the type species of Nereina by Ho we (in Moore, 

1961, p. Q305). Mandelstam (1957, p. 179) had already 

placed G. angulata in his Nereina. I consider G. angulata and G. -finmarchica to be congeneric; thus Finmarchinella is a subjective synonym of Nereina.

8tratigraphic range. Pleistocene to Recent.

Nereina finmarchica (Sars, 1865) 

Plate 1, figures 1-4, 6; plate 11, figure 7

1865. Cythereis finmarchicu Sars, Vidensk. Selsk. Christiania,

Forh., p. 41. 

1868. Cythere finmarcMca ( Sars). Brady, Linnean Soc. London

Trans., v. 26, p. 410, pi. 31, figs. 9-13. 

1874. CytJiere flnmarchica (Sars). Brady, Crosskey, and Rob-

'ertson, A monograph of the Post-Tertiary Bntomostraca * * *, p. 153, pi. 10, figs. 18-21. 

1889. Cythere flnmarchica (Sars). Brady and Norman, Royal

Dublin Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 163. 

1925. Hemicythere finmarchica ('Sars). Sars * * *, Crustacea of

Norway, v. 9, Ostracoda, p. 185, pi. 85, fig. 3.

Diagnosis. Small; coarsely, evenly reticulate; small 

dorsal muscle platform present.

Measurements in mm. 

Female: 

L. ..................

H.. ..............

Male: 

L.. .................

H...... .............

N

11

11

3

3

M

0.712

.391

Sd

0.019

.010

OR

0. 688-0. 750

.375- .415

. 675- . 700

. 325- . 350

V

2.7

2.6

Discussion. Nereina finmarchica is easily distinguished from N. angulata by its smaller size, more 

evenly ornamented surface, and by the presence of a 

dorsal muscle platform (the so-called antislip tooth of 

many authors).
SYSTEMATIC PALEONTOLOGY 19

Specimens found. 26.

Occurrence. Several localities off England, Scotland, and Ireland; Norwegian Sea, Barents Sea, Bay of 

Biscay, Davis Strait, Holsteinsborg Harbor, and near 

Cape Verde Islands. The species appears to be an 

arctic to cool-temperature form. The locality in the 

Cape Verde Islands (Brady and Norman, 1889) is inconsistent with its other occurrences and, tentatively, is 

considered to be based on a misidentification. Known 

also from the Pleistocene of Scotland and Norway. In 

the present study the species was found in Ungava Bay, 

the Gulf of Maine, and off Lower New York Bay.

Repository. USNM. 112701,112703-112707.

Nereina angulata (Sars, 1865) 

Plate 1, figures 7-11; plate 11, figs. 5, 8

1865. Cythereis angulata Sars, Vidensk. Selsk. Christiania,

Forh., p. 40. 

1941. Cythereis (Eucytherels) angulata Sars. Elofson, Zool.

Bidrag fran Uppsala, v. 19, p. 285 (gives full synonymy

from 1865-1941). 

1946. Hemicythere anyulata (Sars). Akatova, Dreifuyushchei

ekspeditsii glavsemorputi na ledokol'iiom parokode

"G. Sedov", 1937-1940 g.g., Trudy: v. 3, p. 227, text

figs. 5a, b. 

1951. Not Trachylelerisl cf. T.l angulata of Swain, U.S. Geol.

Survey Prof. Paper 234-A, p. 29, pi. 3, figs. 9-12. 

1957. "Hemicythermae" (Genre?) angulata ('Sars). Wagner,

* * * Ostracodes du Quaternaire Recent des PaysBas * * *, p. 61, pi. 38, figs. 1, 2. 

1957. [?] Nereina barensovoensis Mandelstam, Vsesoyuznogo

Paleont. Obshchestva, Ezhegodnik, v. 16, p. 180, pi. 3,

figs. 7, 8.

1963. Finmarchinella angulata (Sars). Swain, Jour. Paleontology, v. 37, no. 4, p. 813, pi. 97, fig. 22; pi. 99, fig. 9;

text fig. lie.

Diagnosis. Surface irregularly ornamented with 

reticulations and ribs; loop formed by one rib in area 

posterodorsal to muscle swelling.

Measurements in mm. 

Female: 

L.. ............... .

H. ...............

Male: 

L.. .................

H.... ...............

N

5

5

5

5

M

0.860

.480

.808

.423

Sd

0.010

.007

.046

.032

OR

0. 850-0. 875

. 475- . 488

. 750- . 875

. 375- . 462

V

1.2

1.5

5.7

7.5

Discussion. The poor illustrations of the type species 

of the genus, Nereina baremovoensis, preclude a close 

comparison of N. angulata with it. The photograph 

of a male of the type species by Ho we (in Moore, 1961, 

p. Q305, fig. 231, 3d) aids very little. The size, outline, and few morphologic features that can be distinguished from the available illustrations, as well as the 

rather inadequate description by Mandelstam (1957,

p. 180), are reminiscent of N. angulata. I suggest that 

future workers compare the two forms closely in order 

to contrast and define the differences between them.

Specimens found. 59.

Occurrence. Several localities off Ireland, Scotland, 

Northern England; North Sea, Laptev Sea, Norwegian 

Sea, Barents Sea, off Spitsbergen, off Iceland, Davis 

Strait, Hunde Islands, and Holsteinsborg Harbor. 

Pleistocene of England, Scotland, Ireland, Norway, and 

Alaska. In the present study the species was found in 

the Davis Strait, near North Wolstenholme Island, in 

Frobisher Bay, Kneeland Bay, Ungava Bay, White 

Bear Arm, the Gulf of Maine, and on Browns Bank.

Repository. USNM 112699,112709-112713.

Genus PATAGONACYTHERE Hartmann, 1962

Type species, PatagonacytJiere tricostata Hartmann, 

1962.

Discussion. Additional information about other 

species of Patagonacythere and a diagnosis of the genus 

in English can be found in Benson (1964). The diagnoses given by Hartmann (1962) and Benson (1964) 

are compatible except for the type of hingement.

Hartmann (1962, p. 251) describes the posterior tooth 

of the right valve in the type species as being crenate 

(gekerbt). Benson (1964) describes the hinge of PatagonacytJiere devevca (Mueller, 1908) and P. longiducta 

antarctica Benson, 1964, as holamphidont. Specimens 

of both P. devexa and P. longiducta antarctica, kindly 

provided by Dr. Benson, showed multilobate posterior 

teeth when stained with food dye. PatagonacytJiere 

dubia also has a multilobate posterior tooth in the right 

valve; thus it appears that the lobation of the posterior 

tooth is a taxonomic character of generic importance in 

PatagonacytJiere.

In addition to the species mentioned above, Benson 

(1964) also placed Cythere wyvilletJiompsoni Brady, 

1880, in the genus. PatagonacytJiere dubia is the first 

species recorded from the northern hemisphere.

StratigrapJiic range. Recent.

Patagonacythere dubia (Brady, 1868) 

Plate 4, figures 1, 6, 7, 9,12; plate 9, figures 1, 3, 5, 6

1868. Cythere dulia Brady, Linnean Soc., London Trans.,

v. 26, p. 409, pi. 32, figs. 75, 76. 

1877. Cythere dwlia Brady. Norman, Royal Soc. London Proc.,

v. 25, p. 209. 

1889. Cythere dulia Brady. Brady and Norman, Royal Dublin

Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 162.

Diagnosis. Narrow but prominent ridge runs from 

muscle swelling to anterior rim; posterodorsal loop 

poorly defined.
20 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Description. Carapace subquadrate to subrectangular; anterior broadly, slightly obliquely rounded; posterior produced below middle; anterior not denticulate; 

posterior has four or five prominent denticles; surface 

finely reticulate; sieve-type normal pore canals at end 

of short curved riblets which branch from main reticulation riblets; reticulate pattern radiates from moderate 

muscle swelling; anterior rim runs from eye tubercle 

around anterior and continues length of ventral surface; well-defined ventrolateral ridge; posterodorsal 

loop poorly defined; low, narrow but conspicuous 

ridge runs from muscle swelling to center of anterior 

rim. Carapace subelliptic in dorsal view, posterior 

compressed; left valve larger and overlaps right at 

cardinal angles. Hinge amphidont with large rounded, 

smooth anterior tooth having very prominent anterior 

step, moderately deep postjacent socket, sinuous and 

crenulate median groove, and multilobate elongate-reniform posterior tooth having about eight lobes; marginal 

areas wide having narrow anterior and wider posterior 

vestibule; about 40 radial canals around anterior and 

15 at posterior; canals tend to be swollen medially. 

Ocular sinus prominent. Two dorsomedian and two 

ventromedian adductor scars with single scars above 

and below these; upper adductor scar somewhat Lishaped, open towards anteroventer; three frontal scars, 

lower scar forward, middle scar most posterior; three 

raised (muscle attachment?) areas arranged in a triangle above muscle scars and still another above these.

Antennules have five podomeres; second podomere has 

one large seta at posterodistal end and very fine setae 

along anterior edge; third podomere has one large seta 

at anterodistal end; fourth podomere has three setae at 

nearly midlength, one large and one small on anterior 

edge and one coming from middle of podomere; third 

podomere has one large and one small seta in anterodistal half and one long but narrow seta in posterodistal 

half; fifth podomere has one large seta and two thinner 

but equally long setae at terminus. Endopodite of antennae has three podomeres; three strong terminal 

claws; exopodite well developed.

Measurements in mm. 

Female: 

L.. .................

H.. -. -

Male: 

L.. .................

H............. ......

N

10

10

1

1

M

0.995

.549

Sd

0.039

.025

OR

0. 938-1. 050

. 512- . 600

.925

.475

V

3.9

4.6

Discussion. Patagonacy there dubia is morphologically very close to P. longiducta (Skogsberg, 1928) 

but can be distinguished by the ridge in the anterocentral area and by its larger size. The posterior tooth of 

the right valve of P. dubia also has more lobations. I 

have observed an undescribed species of Patagonacythere in one sample from the Beaufort Sea off Point 

Barrow, Alaska, which is very closely related to P. 

dubia. This species, which could be only a subspecies 

of P. dubia^ differs principally by having two large 

nodes in the anterocentral area and no anterior rim.

Brady (1868a) described Cythere dubia from samples 

submitted to him by A. M. Norman. Brady's description fits my specimens, and the dorsal and lateral outlines are also a good fit for my specimens; however, the 

surface ornamentation is not shown by Brady's illustrations. The specimens I have referred to Brady's species 

were found in four samples; one from the Foxe Basin 

(67° N.), two from Ungava Bay (60° N.), and one 

from off southern Nova Scotia (43° N.). The fact that 

Norman (1877) reported Cy there dubia from a Davis 

Strait locality (67° N.) lends some confidence to the 

present identification. However, Brady and Norman 

(1889) do not mention the Davis Strait occurrence, but 

Mueller (1931) gives a Greenland occurrence of the 

species, presumably based on Norman's 1877 paper. I 

am fairly confident, but less than positive, of my 

identification.

Specimens found. 36.

Occurrence. Shetland Islands and Davis Strait. In 

the present study the species was found in the Foxe 

Basin, Ungava Bay, Frobisher Bay, and on Browns 

Bank.

Repository. USNM 112689, 112690, 112754-112758.

Genus MUELLERINA Bassiouni, 1965

Type species, Cythere latimarginata Speyer, 1863.

Diagnosis. Subrectangular in lateral view; posterior 

slightly produced below; surface coarsely pitted; pits 

may be arranged in longitudinal rows between low 

ridges; hinge modified amphidont, anterior and posterior multilobate teeth in right valve connected by narrow groove which opens anteriorly to receive small 

elongate tooth at end of median bar of left valve; two 

median adductor scars usually divided; three frontal 

scars; the lower two are very close together or fused; 

second podomere of endopodite of antennae very 

elongate.

Discussion. Species of Muellerina are generally 

smaller than those of Urocythereis Euggieri, and Muellerina is less produced posteroventrally. The surface 

pitting of Muellerina is generally not as coarse; and the 

pits tend to line up in rows, particularly in the area just 

above and behind the muscle swelling. The second 

podomere of the endopodite of the antennae is more 

elongate than in Urocythereis. Whereas,the frontal
SYSTEMATIC PALEONTOLOGY 21

muscle scars of Urocythereis consist of an oblique row of 

three scars, in Muellerina the lower scar is off line and 

very close or fused to the median scar. Bassiouni 

(1965) considers Muellerina to possess only two frontal 

scars. However, specimens of M. abyssicola, M. canadensis, M. parallelokladia, and M. lienenklausi that I 

have examined show either two discrete lower frontal 

scars or, commonly, a single dumbell-shaped scar. The 

two rounded ends of this scar are raised above the middle part, a fact indicating that the scar was formed 

mainly by two bundles of muscles rather than one. The 

lower frontal scar is often divided into two discrete 

scars in M. canadensis and M. lienenklausi. In M. abyssicola it is sometimes divided but most often is a dumbbell-shaped scar. According to Bassiouni (1965), the 

lower scar is not divided in the Oligocene M. latimarginata.

Muellerina has a carapace shape similar to that of 

Urocythereis, and the marginal areas and hingement are 

alike. The two genera seem very closely related, and 

Muellerina may be ancestral to Urocythereis.

Van Morkhoven (1963, p. 153) mentions the occurrence of Urocythereis on the east coast of North America, and Hazel (1965f) states that Urocythereis occurs 

off New England. The species that Hazel and, probably, van Morkhoven considered to be Urocythereis 

actually represent Muellerina.

Four species of Muellerina are known to occur in 

North America; these are M. lienenklausi (Ulrich and 

Bassler, 1904), M. canadensis (Brady, 1870), M. abyssicola (Sars, 1865), and M. parallelokladia (Munsey, 

1953). The last taxon is the oldest known species of 

the genus. It has been found in the Paleocene Porters 

Creek Formation of Alabama. Muellerina canadensis 

and M. abyssicola are known only from the Recent, but 

M. lienenklausi is also known from the Miocene of the 

Atlantic Coastal Plain and Florida.

Stratigraphic range. Paleocene to Recent.

Muellerina lienenklausi (Ulrich and Bassler, 1904) 

Plate 3, figures 3-6,11; plate 7, figures 1, 4, 5, 7

1904. Cythere lienenklausi Ulrich and Bassler, Maryland Geol.

Survey, Miocene [volume], p. 114, pi. 38, fig. 31. 

1904. Cythere micula Ulrich and Bassler, idem, p. 116, pi. 36,

figs. 18-20. 

1951. Trachyleberis ? martini ( Ulrich and Bassler). Swain, U.S.

Geol. Survey Prof. Paper 234-A, p. 29, pi. 3, figs. 8, 15. 

1951. Trachyleberist cf. T. micula (Ulrich and Bassler). Swain,

idem, p. 29, text fig. 31.

1953. Trachyleberis martini (Ulrich and Bassler). Malkin, 

Jour. Paleontology, v. 27, no. 6, 793, pi. 82, figs. 6-13.

1954. Murrayina martini (Ulrich and Bassler). Puri, Florida 

Geol. Survey Bull. 36 (1953d), p. 256, pi. 12, figs. 11-13, 

text figs. 8e, f.

231-538 O 67 3

Female: 

L.. .................

H...... .............

Male: 

L.. .................

H........ ...........

N

22

22

16

16

M

0.682

.377

.648

.330

Sd

0.028

.013

.018

.012

OR

0. 600-0. 725

.350- .400

.625- .675

.312-. 362

V

4.1

3.4

2.8

3.6

1954. Not Orionina lienenklausi (Ulrich and Bassler). Puri,

idem, p. 254, pi. 12, fig. 14; text fig. 8d. 

1957. Murrayina martini (Ulrich and Bassler). McLean, Bull.

Am. Paleontology, v. 38, no. 167, p. 86, pi. 11, figs, la-c,

2a,b, 3a-d. 

1965. Murrayina martini (Ulrich and Bassler). Pooser, Kansas

Univ. Paleont. Contr., Arthropoda, Art. 8, p. 60, pi. 21,

figs. 3, 5, 8.

Diagnosis. Small; quadrate; anterior broadly 

rounded; two ridges, formed as raised reticulation riblets, prominent, running slightly upwards and back 

from muscle swelling.

Measurements in mm. 

Discussion. This species has lately been carried in 

the genus Murrayina. When Puri (1953d) erected the 

genus Murrayina he included in it M. howei Puri, 1954, 

a new name for Cythere producta Ulrich and Bassler, 

1904, not Brady (1866), Oythereis gunteri Howe and 

Chambers, 1935, and Cythere martini Ulrich and Bassler, 1904, which Puri considered a senior synonym of 

Cythere micula Ulrich and Bassler, 1904. Murrayina 

howei was selected as the type species. Puri (1953d, 

p. 255) calls attention to a resemblance to Urocythereis 

and gives the muscle scar pattern as "consisting of 

posteriorly located two vertical rows of three scars, with 

two additional oblique rows of scars located anteriorly." 

It is very probable that the description of the muscle 

scars is based on what Puri called Murrayina martini, 

a hemicytherine with divided adductor and frontal 

muscle scars, because the type and other species placed 

in the genus by Puri possess the single U-shaped frontal 

scars and undivided adductor row of four scars of the 

Trachyleberidinae.

Ulrich and Bassler (1904) described Cythere martini, 

Cythere producta, Cythere micula, and Cythere lienenklausi. On the cotype slide of C. martini in the U.S. 

National Museum collections are six specimens, five females and one male. Three of the females (pi. 36, figs. 

11, 12, 15) and the male (fig. 13) were illustrated by 

Ulrich and Bassler. The carapace illustrated by their 

figure 14 is not present.

Cythere producta Ulrich and Bassler is represented 

by two right vales on one slide and a broken left valve 

(pi. 36, fig. 17) on a second slide. Sexual dimorphism 

is not mentioned by the authors but Maryland Miocene 

material has yielded many specimens of both males and 

females. The female of this species, in my opinion,
22 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

was described by Ho we and Chambers (in Howe and 

others, 1935, p. 21) as Cythereto gunteri. Therefore, 

Murrayina howei Puri and Gythere producta Ulrich 

and Bassler, not Brady (1866) should be synonymized 

under Murrayina gunteri, and this then becomes the 

valid binomen for the type species of Murrayina.

Ulrich and Bassler (1904) did not recognize the molting of ostracodes, and several of their species are based 

on juveniles. Oythere micula is represented by two left 

valves; both are molts (Ulrich and Bassler, 1904, pi. 36, 

figs. 18, 20). The right valve (fig. 19) is not present in 

the type material; and Puri (1953b, p. 750), in a critique of Swain's 1951 paper, incorrectly states that the 

original description of G. micula was based on molts of 

G. martini. It is true that these molts are conspecific 

with what Puri (1953d), Swain (1951), Malkin (1953), 

McLean (1957), and Pooser (1965) have called Gythere 

martini; but Gythere martini is quite a different thing, 

belonging in a different family. I have compared the 

molts of Gythere micula Ulrich and Bassler, which are 

penultimate or next to that, with molt sequences for 

Gythere martini, with molt sequences of what the above 

authors have called Gythere martini, and with molt 

sequences of specimens that I have identified as Gythere 

lieneriklausi Ulrich and Bassler. I conclude that 

Gythere micula, Gythere martini of most authors (but 

not Ulrich and Bassler, 1904, or Swain, 1948), and 

Gythere lieneriklausi are synonymous; the latter name 

has page priority over Gythere micula. The holotype 

of Gythere lieneriklausi is represented by an adult male 

left valve (Ulrich and Bassler, 1904, pi. 38, fig. 31) 

which is now unfortunately broken; however, the Eecent specimens are very similar to the Miocene holotype 

and they are included in Muellerina lieneriklausi, at 

least until more fossil material can be examined.

The appendages of Muellerina lieneriklausi are typically hemicytherid. The muscle scars consist of single 

upper and lower adductor scars with two divided adductor scars between. The frontal scars are three; the two 

lower scars very close together, sometimes fused.

Muellerina lieneriklausi is closely related to M. canadensis (Brady 1870), but can be distinguished from 

that species by its more quadrate shape, coarser ornamentation, smaller size, and more broadly rounded 

anterior.

Specimens found. 345.

Occurrence. Miocene of New Jersey, Maryland, 

North Carolina, and Florida. In the present study 

Muellerina lieneriklausi was found in samples from the 

Gulf of Maine, Browns Bank, Northeast Channel, 

Georges Bank, off Lower New York Bay, and several 

other localities on the Atlantic Shelf at about 40° N., 

70° W.

Female: 

L__ .................

H. . ...

Male: 

£.-. -,.

H. ........... ....

N

22

22

18

18

M

0.764

.394

.730

34Q

Sd

0.038

.021

.035

mo

OR

0. 712-0. 825

. 362- . 425

. 675- . 788

. 325- . 375

V

4.9

5.3

4.7

5.4

Repository. USNM 112740-112744, 112681, 112682.

Muellerina canadensis (Brady, 1870) 

Plate 3, figures 9, 12-15,17-20; plate 7, figures 2, 3, 6, 8

1870. Cythere canadensis Brady, Annals and Mag. Nat. History,

4th ser., v. 6, p. 452, pi. 19, figs. 4-6. 

1889. Cythere canadensis Brady. Brady and Norman, Royal

Dublin Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 166, pi.

15, figs. 14-15. 

1906. Cythereis canadensis (Brady). Cushman, Boston Soc.

Nat. History Proc., v. 32, no. 10, p. 377.

Diagnosis. Anterior obliquely rounded; posterior 

bluntly rounded, slightly produced below; surface ornamentation generally weakly developed.

Measurements in mm. 

Discussion. The surface ornamentation of this species is varied. On some specimens the pitting is greatly 

reduced and the surface appears almost smooth. 

Other specimens have rather coarse pits in the posterior 

half, but the pitting is reduced in the anterior half. 

Still other specimens are rather coarsely pitted over 

the entire surface. However, the pitting is generally 

not as coarse as that found on Muellerina lienenklausi.

Muellerina canadensis resembles M. dbyssicola (Sars, 

1865), but is easily distinguished from the latter by its 

less angular outline in dorsal view and more subdued 

marginal rim. Also see discussion under M lieneriklausi.

Specimens found. 896.

Occurrence. Gulf of St. Lawrence, Davis Strait, 

Godhavn Harbor, Holsteinsborg Harbor, and Vineyard 

Sound. In the present study the species was found in 

samples from the Gulf of Maine, Browns Bank, Northeast Channel, Georges Bank, Georges Basin, Stout 

Swell, off Lower New York Bay, and several localities 

on the Atlantic Shelf at about 40° N., 70° W.

Repository. USNM 112683-112685, 112745-112753.

Muellerina abyssicola (Sars, 1865) 

Plate 3, figures 1, 2, 7, 8,10,16

1865. Cythereis abyssicola Sars, Vidensk. Selsk. Christiania, 

Forh., p. 40.

1869. Cythere abyssicola (Sars). Norman, Shetland final dredging report, Pt. 2, British Assoc. Adv. Sci., rept. 38th 

Mtg., p. 290.
SYSTEMATIC PALEONTOLOGY 23

1874. Oythere latimarginata (Speyer). Brady, Crosskey and 

Robertson, Amonograph of post-Tertiary Entomostraca 

* * *, p. 163, pi. 16, fig. 6.

1878. Oythere latimarginata (Speyer). Brady, Zool. Soc. 

London Trans., v. 10, pt. 8, p. 389, pi. 64, figs. 8a-d.

1889. Oythere latimarginata (Speyer). Brady and Norman, 

Royal Dublin Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 156, 

pi. 15, figs. 16,17.

1925. Hemicythere latimarffinata (Speyer). Sars, * * * Crustacea of Norway, v. 9, p. 188, pi. 86, fig. 3.

1941. Oythereis (Paracythereis) latimarginata (Speyer). Elofson, Zool. Bidrag fran Uppsala, v. 19, p. 291.

1965. Muellerina abyssicola (Sars). Bassiouni, Dansk Geol. 

Foren. Medd., v. 15, pt. 4, p. 510, pi. 1, figs. 3-6.

Diagnosis. Strong anterior and posterior rims; 

valves inflated in area below and behind muscle 

swelling.

Measurements in mm. 

Female: 

L. ....... ...... .....

H.. .................

Male: 

L.. .................

H.. .................

' N

10

10

10

10

M

0.762

.428

.739

.381

Sd

0.008

.008

.017

.012

OR

0. 738-0. 800

. 415- . 438

. 712- . 762

. 362- . 400

V

2.4

1.9

2.3

3.1

Discussion. This species is easily distinguished from 

both Muellerina canadensis and M. lienenklausi by its 

stronger marginal rims. Muellerina abyssicola was 

described in 1865 by Sars from the Eecent; 2 years 

previous to this, Speyer (1863) had described Cythere 

latimarginata from the Oligocene of Germany. Except 

for Norman (1869) and Bassiouni (1965), all subsequent workers have placed Sars' species in synonymy 

with Speyer's. However, Bassiouni (1965) has shown 

that there are two species represented, and he reinstates 

Sars' name for the Quaternary forms referred to 

Oythere latimaryinata.

Specimens found. 116.

Occurrence. North Sea, Norwegian Sea, near Spitzbergen, near Iceland, Davis Strait, Gulf of St. 

Lawrence, Godhavn Harbor. Pliocene of Belgium, 

Pleistocene of Scotland and Denmark. In the present 

study the species was found in samples from the Georges 

Basin and Northeast Channel.

Repository USNM 112Y34-112Y39.

Genus AUBJLA Pokorny, 1955

(=Auris Neviani, 1928)

Type species, Cythere convexa Baird, 1850, (? = 

Gy there punctata Muenster, 1830).

Diagnosis. Auriform in lateral view; dorsal margin 

strongly convex; surface finely to coarsely pitted; 

posterior hinge tooth of right valve incised; three

frontal scars; dorsomedian adductor muscle scar 

divided, ventromedian scar may be divided. 

Stratigraphic range. Oligocene to Eecent.

Aurila sp. 

Plate 1, figure 5

1906. Oythereis albomaculata (Baird). Cushman, Boston Soc. 

Nat. History Proc., v. 32, no. 10, p. 378, pi. 35, fig. 83.

Measurements. One juvenile right valve is 0.550 mm 

long and 0.312 mm high.

Discussion. In sample 39 two juvenile valves of a 

species of Aurila have been found. This sample is from 

the same general area where Cushman (1906) found the 

specimens he, not without question, referred to Oythere 

albomaculata Baird, 1850, now the type species of 

Heterocythereis. No other species of Aurila have been 

found in this study, and it seems likely that my specimens and Cushman's are conspecific. The outline of the 

adult illustrated by Cushman is similar to that of 

females of A. laevicula (Edwards, 1944), but more 

specimens must be found before a comparison can be 

made.

Specimens found. Two juveniles.

Occurrence. In the present study the species was 

found in one sample off Martha's Vineyard. Specimens 

of a species which is probably conspecific were found by 

Cushman (1906) in Buzzards Bay.

Genus NORMANICYTHERE Neale, 1959

Type species, Oythere leioderma Norman, 1869.

Diagnosis. Elongate oblong in lateral view; carapace oblong in dorsal view; valves very inflated; surface 

generally smooth, but with pits sometimes forming at 

normal pore canal exists; strong holamphidont hingement; three frontal muscle scars; dorsal and two median 

adductor scars divided.

Stratigraphic range. Pleistocene to Eecent.

Normanicythere leioderma (Norman, 1869) 

Plate 1, figures 12-16

1869. Oythere leioderma Norman, Shetland final dredging report. 

Pt. 2, British Assoc. Adv. Sci., rept. 38th Mtg., p. 225, 

291.

1959. Normanicythere leioderma (Norman). Neale, Palaeontology, v. 2, pt. 1, p. 78, pi. 13, figs. 1, 2; pi. 14, figs. 1-8 ; 

text fig. 2, figs. 1-8; text fig. 3, figs. 1-6 (gives full 

synonymy 1869-1959).

1961. Normanicythere leioderma (Norman). Neale, Palaeontology, v. 4, pt. 3, p. 424.

1963. Normanicythere leioderma (Norman). Swain, Jour. 

Paleontology, v. 37, no. 4, p. 826, pi. 95, figs. 10, 17; text 

fig. lla.

1963. Normanicythere concinella Swain, idem, p. 827, pi. 95, 

figs. 18a-d; text fig. lib.
24 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Measurements inmm. 

Female: 

L.. .................

H.. .................

Male: 

L. ..................

H.... ...............

N

7

7

6

6

M

0.993

.550

1.017

.514

Sd

0.023

.010

.026

.021

OR

0. 962-1. 025

. 538- . 562

1. 000-1. 050

.488-. 550

V

2.3

1.8

2.6

4.1

Dismission. This species has been the subject of an 

excellent study by Neale (1959). The reader is referred to that paper for illustrations of both hard and 

soft parts.

The external exits of the normal pore canals do not 

form pits on most specimens of this species. However, 

on some, particularly males, pits are present, almost always in the posteroventral area of the lateral surface. 

Swain (1963) considers specimens of this type to represent a different species, Normanicy there concinella 

Swain; but the pitting may be in the nature of intraspecific variation.

Specimens found. 44.

Occurrence. Skagerrak, off southern Norway, off 

northwestern Scotland, near Iceland, near King Charles 

Land (=Wiches Land), Kane Basin, Cabot Strait, the 

Gulf of Maine, and possibly in Hudson Strait. Pleistocene of Yorkshire, England, New York, and Alaska. 

In the present study Normanicythere leiodemna was 

found in samples from Frobisher Bay, Kneeland Bay, 

Ungava Bay, and White Bear Arm.

Repository. USNM 112714-112718.

Subfamily THAEROCYTHERINAE Hazel, n. subfam.

Diagnosis. Subquadrate to subrectangular or subtriangular in lateral view; surface ornate; hinge strong 

amphidont; near-vertical row of four adductor muscle 

scars, dorsomedian and (or) ventromedian scars more 

elongate, dorsomedian scar sometimes divided; two 

frontal scars, the lower one sometimes U-shaped. Antennules have five podomeres; exopodites of antennae 

well developed.

Discussion. The genera of this subfamily can be distinguished from those of the Hemicytherinae by their 

generally more quadrate shape and by the four discrete 

adductor muscle scars possessed by most thaerocytherine 

genera. In most of the genera here placed in this subfamily, the dorsomedian adductor scar is not divided. 

Rarely, an individual will have this scar divided, but a 

greater number of specimens of a species and species of 

a genus will not. There is at least one important exception to this general rule.

In the Paleocene and Eocene, particularly in the Atlantic and Gulf Coastal Plains of the United States, are 

a number of related species which have been generally,

in recent years, carried in the genus Hermanites. Gythereis midwayenisis Alexander, 1934, is a typical example. These forms are probably referable to the 

genus Aquitaniella Deltel. One of the features which 

characterizes this group of species is a very well developed muscle node. In most Aquitaniella the dorsomedian scar is divided; thus, a divided dorsomedian 

adductor scar seems to be concomitant with a well-developed muscle node, at least in Aquitaniella.

The genera of the Thaerocytherinae tend to be more 

quadrate than those of the Trachyleberidinae and have 

two discrete frontal scars rather than one J- or Ushaped scar. The member genera of the Thaerocytherinae whose soft parts are known have the antennules 

with five joints and simple brachial plates on the mandibles as in the Hemicytheridae. The Echinocythereidinae have a muscle field like many of the Thaerocytherinae but are anatomically trachyleberidids and have 

a distinctive ovate shape.

Several Upper Cretaceous species bear a superficial 

resemblance to the Cenozoic genera Hermanites and 

Bradleya, such species, for example, as Cythereis verrwula Butler and Jones, 1957, and the Cretaceous 

species assigned to Bradleya by Hazel and Paulson 

(1964). On close examination, however, it can be shown 

that these species are probably referable to the recently 

described trachyleberidine genus Oertiella Pokorny, 

1964. OertlieUa may be an important link between the 

Thaerocytherinae and Trachyleberidinae.

Jugosocythereis has been little used since it was described. However, species of the genus are common in 

Eocene to Recent gulf coast and Caribbean faunas. 

The genus also occurs in the Pacific and Mediterranean.

The following genera are placed in the Thaerocytherinae :

Thaerocythere Hazel, n. gen., Miocene to Recent 

Jugosocythereis Puri, 1957, Eocene to Recent 

Hermanites Puri, 1955, Eocene to Recent 

Verrucocvthereis Euggieri, 1962, Miocene 

Quadracythere Hornibrook, 1952, Paleocene to Recent 

Bradleya Hornibrook, 1952, Eocene to Recent 

Puriana Coryell and Fields, 1953, Oligocene to Recent 

Aquitaniella Deltel, 1964, Paleocene to Recent

Though all the genera but one are still living, the soft 

parts are known only for Thaerocythere (Sars, 1925, 

and Elofson, 1938, for the type species), Jugosocythereis (original data), and Puriana (original data). 

I am fairly confident that when dissections are made of 

Hermanites, Quadracythere, Aquitaniella, and Bradleya they will show that these genera are anatomically 

hemicytherids. Van Morkhoven (1962, 1963) places 

Bradleya and Quadracythere in the Hemicytherinae. 

Van den Bold (1963b) places Quadracythere, Bradleya,
SYSTEMATIC PALEONTOLOGY 25

and Jugosocythereis in the Hemicytherinae. Mandelstam (in Chernysheva, 1960, p. 391) places Hermanites 

in the tribe Hemicytherides, and Hartmann (1964) 

places Hermanites in the subfamily Hemicytherinae. 

Puri (1953d) correctly placed Hermcmites in the Hemicytherinae at the time of original description. Most 

other authors have considered the genera here placed 

in the Thaerocytherinae as members of the Trachyleberididae.

Genus THAEROCYTHERE Hazel, n. gen.

Type species, Cythereis crenulata Sars, 1865.

Etymology. Thairos (Greek) meaning hinge plus 

the genus Cythere.

Diagnosis. Carapace generally subquadrate; thick 

shelled; surface has delicate to coarse reticular, sometimes rugose, pattern; anterior and posterior rimmed; 

very short dorsal rib in posterior half of valve curves 

downward at posterior ending in knob; ventral rib 

longer, more prominent; radial canals many, straight, 

ending in small marginal denticles; hinge very strong 

amphidont; large slightly reniform posterior tooth of 

right valve connected by deep slightly crenulate furrow 

to deep socket behind a large complex anterior element 

which consists of high rounded tooth with a raised 

elongate rounded platform anterior to the tooth; muscle scars a near-vertical row of four adductor scars, 

middle two elongate, and two rounded frontal scars in 

oblique row.

Discussion. This genus is placed in the Hemicytheridae on the basis of the five-jointed antennules 

coupled with the double frontal muscle scars. The row 

of four undivided adductor scars distinguishes Thaerocythere from most genera of the Hemicytherinae. 

Thaerocythere is not as lenticular in dorsal view, has a 

finer ornamentation, and possesses a different hinge than 

Quadracy there. Thaerocy there does not possess the 

characteristic two riblets on the muscle swelling of 

Jugosocythereis and has a different hinge; also, the 

lower frontal scar of Jugosocythereis tends to be 

U-shaped.

Thaerocy there is proposed for the following species: 

Cythereis crenulata Sars, 1865, Hemicythere schmidtae 

Malkin, 1953, Trachylelerisl cf. TA angulata (Sars) 

of Swain (1951, p. 29), and T. reesidei of Swain (1951). 

I have examined specimens of these species. A fourth 

species I have not seen specimens of, but which may 

belong to the genus, is Cythere oedichilus Brady, 1878. 

Thaerocythere schmidtae occurs in the upper Miocene 

(and perhaps Pliocene) Yorktown Formation of Virginia. Trachyleberisl cf. 71.? angulata of Swain was 

described from subsurface middle Miocene rocks of 

North Carolina. Trachyleberis reesidei of Swain

(1951) came from upper Miocene rocks, also from the 

subsurface of North Carolina. Thaerocythere^. oedichilus was described from the Pliocene Antwerp Crag 

of Belgium. Thaerocythere crenulata is known only 

from the Recent.

Thaerocythere crenulata (Sars, 1865) 

Plate 4, figures 2-5, 8; plate 9, figure 4

1865. Cythereis crenulata Sars, Vidensk. Selsk. Christiania,

Forh., p. 39. 

1941. Cythereis (Eucythereis) cretwlata Sars. Elofson, Zool.

Bidrag fran Uppsala, v. 19, p. 284 (gives full synonymy

1865-1941). 

1943. Cythereis (Eucythereis) crenulata Sars. Elofson, Arkiv.

Zoologi, v. 35A, no. 2, p. 9.

Diagnosis. Faintly, evenly, reticulate; anterior rim 

does not connect directly to eye tubercle in left valve.

Description. Thick shelled; subquadrate in lateral 

view; highest at anterior cardinal angle; anterior 

broadly, slightly obliquely rounded; posterior blunt, 

produced below; anterior has several very small denticles ; posterior has about 10 larger denticles at the posteroventral extension; surface faintly reticulate; individual reticules have many very small papillae; anterior 

rim not directly connected to eye tubercle in left valve; 

in right valve anterior rim bifurcates in anterodorsal 

area, one branch going to eye tubercle, the other around 

it; thick ventrolateral rib runs two-thirds length of 

valve; short dorsolateral rib in posterior half curves 

downward at posterior and ends in a knob; muscle 

swelling low and broad. Elliptic in dorsal view having 

compressed posterior; left valve larger, overlapping 

right at cardinal angles. Inner marginal areas moderately wide, crossed by simple straight radial canals; 

selvage moderately developed; hinge strong amphidont; 

posterior tooth of right valve very large, reinform, 

smooth, connected to deep anterior socket by a crenulate 

furrow; anterior tooth of right large, rounded and having very thick, prominent "step" anterior to tooth; left 

valve complementary; muscle scars a vertical row of 

four adductor scars, the middle scars elongate; two 

rounded frontal scars set obliquely in front; normal 

pore canals few, scattered, difficult to analyze because of 

thickness of valves, but at least some seem to be of sieve 

type. Males relatively more elongate than females, but 

actually shorter. Antennules have five podomeres; second podomere has hairs in proximal and distal areas of 

anterior edge and at mid-length on posterior edge, long 

seta at posterodistal end; third podomere has one medium-sized seta at anterodistal end; fourth podomere 

has two setae at mid-length, one on anterior edge, the 

other coming from side of podomere, and three distal 

setae, two at anterodistal and one at posterodistal end;
26 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

fifth, podomere has three distal setae. Endopodite of 

antennae has three podomeres, moderately developed 

exopodite, and three terminal claws. Data on soft parts 

fromSars (1925) andElofson (1938).

Measurements in mm. 

Female: 

L.. .................

H. ...............

Male: 

L...

H.... ...............

N

10

10

10

10

M

0.788

.476

.740

.427

Sd

0.016

.010

.015

.010

OR

0.762-0.812

. 462- . 488

. 725- . 762

. 415- . 438

V

2.0

2.1

2.0

2.3

Discussion. This species was described by Sars 

(1865) but first illustrated by Brady and Norman 

(1889). Sars (1925) and Elofson (1938) illustrate and 

describe the soft parts and carapace. The carapace illustrations of Sars and Elofson are adequate for shape 

analysis but do not show the ornamentation. The illustrations of Brady and Norman (1889) do show the surface features, and their identification of Sars species was 

accepted by Sars (1925) and Elofson (1938,1941) who 

treated the species taxonomically. The descriptions of 

the species by Sars (1865) (see Norman, 1869, for an 

English translation) and by Brady and Norman (1889) 

fit my specimens perfectly.

Thaerocythere crenulata is larger than T. schmidtae 

(Malkin, 1953). The individual reticules of T. 

crenulata are relatively and actually larger than those 

of T. schmidtae, but are relatively not as deep. The 

surface ornamentation of T. crenulata is uniform compared with the irregular ornamentation of pits, riblets, 

and nodes on Trachyle~beris ? cf. T. ? angulata of Swain 

(1951). The dorsal and ventral ribs of T. crenulata converge towards each other at their posterior ends at an 

angle smaller than that on T. schmidtae or Trachyleberisl cf. T. ? angulata of Swain (1951). Thaerocythere crenulata is reticulate, where as T. ? oedichilus is 

apparently more pitted. The dorsal rib of T. crenulata 

also does not extend into the anterior part of the carapace as it does in T. ? oedichilus.

Specimens found. 136.

Occurrence. Norwegian Sea, North Sea (Skagerrak), Baltic Sea, Shetland Islands, Godhavn Harbor, 

and Davis Strait. In the present study Thaerocythere 

crenulata was found on Browns Bank and in Georges 

Basin.

Repository. USNM 112692,112759-112763.

Subfamily CAMPYLOCYTHERINAE Furi, 1960

Diagnosis. Carapace quadrate to oblong in lateral 

view; ovate in dorsal view, widest behind middlp; surface smooth or reticulate; extremities smooth to moderately denticulate; eye tubercles absent to moderately 

developed; vestibules may be developed at anterior and 

posterior; hinge amphidont or modified amphidont; adductor muscle scars a near-vertical row of four; one, 

two, or sometimes three frontal scars; dorsal muscle 

platform may be present.

I would place the following genera in the Campylocyt herinae:

Campylocythere Edwards, 1944, Miocene to Recent 

Leffuminocythereis Howe and Law, 1936, Paleocene to

Miocene

Triginglymus Blake, 1950, Eocene

Bensonocythere n. gen., Oligocene( ?), Miocene to Recent 

Anticythereis van den Bold, 1946, Santonian to Eocene 

Chrysocythere Ruggieri, 1962, Maestrichtian to Miocene,

Recent (?)

Basslerites Howe, 1937, Eocene to Recent 

LeniocytJiere Howe, 1951, Eocene

Discussion In 1960 Puri erected the subfamily 

Campylocytherinae and placed in it C ampylocthere, 

Acuticythereis, Basslerites, Buntonia, and Thalmannia. 

Howe (in Moore, 1961, p. Q306), unaware of Puri's 

work, proposed the family Leguminocythereididae for 

Leguminocythereis, Triginglymus, Campylocythere, 

Acuticythereis, and Basslerites. Howe (1962) considers his taxon a synonym of Puri's. Benson and Coleman (1963), following Swain (1955) and Malkin 

(1953), synonymize Acutwythereis with Campylocythere; they otherwise accept Howe's diagnosis of the 

family level taxon, point out the priority of Campylocytherinae, and exclude Buntonia and Thalmannia. 

Apostolescu (1961) had already made Buntonia the 

nominal genus of a new and useful subfamily.

Van den Bold (1964) has restudied the type species of 

Anticythereis, Pseudocythereis reticulata Jennings, 

1936, Campanian to Maestrichtian, and states that the 

genus is allied to Velarocythere, a genus which he believes is transitional with Triginglymus. He believes 

that Anticythereis is an early form of Leguminocytherels and therefore belongs to the family Leguminocythereididae (^Campylocytherinae).

Van den Bold (1964) describes a Santonian species 

of Anticythereis and agrees with the placement by 

Apostolescu (1961) of several west African Eocene 

species in Anticythereis. Neither van den Bold nor 

Apostolescu describes the frontal muscle scars for any 

of these species. However, Keyment (1963) reports 

one of Apostolescu's species, A. bopaensis, from the 

Paleocene of Nigeria. He describes the frontal muscle 

scars of this species as "two muscle scars, which are at 

times coalesced."

Brown (1957) placed five species from the upper 

Campanian to Maestrichtion of North Carolina in his 

genus Velarocythere at the time of description. Hazel
SYSTEMATIC PALEONTOLOGY 27

and Paulson (1964) consider one of these, F. aracJioides 

(Berry, 1925), a trachyleberidid belonging to Veenia 

(Nigeria) Keyment (see also Keyment 1960, 1963). 

Van den Bold (1964) considers Velarocythere eikonata 

Brown, 1957, to be a junior synonym of the type species 

of Anticythereis; van den Bold also places Velarocythere cacumenata Brown, 1957, in Anticythereis. 

This leaves the types species Velarocythere scuffeltonensis Brown, 1957, and F. legrandi Brown, 1957. 

In my opinion these two species and Anticythereis 

reticulata (~V elarocy there eikonata] are congeneric. 

Thus Velarocythere becomes a subjective synonym of 

Anticythereis.

Brown (1957, p. 21) describes the muscle scars of 

'Velarocythere scuff eltonensis as a "subvertical row of 

three spots and a single anterior spot." Thus Anticythereis seems to have two antennal scars on some 

species (Tertiary) and a single scar on others 

(Cretaceous).

Howe and Laurencich (1958) place Cythereis 

saratogana Israelsky, 1929 (upper Campanian of 

Arkansas), in the genus Triginglymus. The illustrated specimen has more the shape of a male Anticythereis, and this species may be better placed in that 

genus.

Ohrysocythere Euggieri, 1962, has two frontal muscle 

scars and an outline in dorsal and lateral view that require its consideration as a member of the Campylocytherinae. Van den Bold (1964) places species in 

Ohrysocythere which have a stratigraphic distribution 

of Maestrichtion to Kecent.

The poorly known Eocene genus Leniocythere is related to Leguminocythereis (Howe, 1951) and is here 

included in the Campylocytherinae.

Butler (1963) has described a species of Leguminocythereis, L. crassus, with three frontal muscle scars. 

Howe (in Moore, 1961, p. Q306) and others have diagnosed the genus as having two frontal scars. Van 

Morkhoven (1963) diagnoses the genus with two or 

three frontal scars. Howe and Law (1936) describe 

three antennal scars for Leguminocythereis cookei 

Howe and Law, but van Morkhoven (1963, p. 176) 

would prefer to exclude this species from the genus. 

The muscle scars of the type species have not been 

described.

The soft parts are known with any completeness for 

only Bensonocythere and Basslerites. Swain (1955) 

describes the antennules and some other features for 

Gampylocythere concinnoidea Swain. The antennules 

of Basslerites, C ampylocy there, and B ensonocy there 

consist of five podomeres. The branchial plates of the 

mandibles of B ensonocy there consist of one plumose 

seta. It is on the basis of these two anatomical features,

coupled with the multiple frontal scars of most genera, 

that the Campylocytherinae are considered a subfamily 

of the Hemicytheridae.

Genus BENSONOCYTHERE n. gen.

Type species, Leguminocythereis whitei Swain, 1951.

Etymology. This genus is named in honor of K. H. 

Benson of the U.S. National Museum.

Diagnosis. Carapace quadrate to subrectangular or 

oblong in lateral view; no marginal denticles; posterior 

and anterior of nearly equal height; surface coarsely 

pitted; anterior rim has two paralleling ridges posterior 

to it; no eye tubercle; carapace ovate in dorsal view, 

widest in posterior half; anterior and posterior hinge 

teeth of right valve multilobate to nearly smooth; 

anterior tooth of left valve manifest as a strong swelling 

at anterior end of slightly crenulate bar; large dorsal 

muscle platform below hinge one-third from anterior 

end; vertical row of four adductor scars with dorsomedian scar most elongate; two frontal scars in 

oblique row, lower scar tending to be elongate.

Discussion. B ensonocy there is placed in the Hemicytheridae on the basis of its five-jointed antennules, 

vestigial exopodites of the mandibles, and double antennal muscle scars. It is placed in the subfamily 

Campylocytherinae on the basis of its muscle scars and 

ovate outline in dorsal view.

B ensonocy there differs from Leguminocythereis in 

shape, being relatively higher at the posterior, and the 

hinge of B ensonocy there is more weakly developed. 

The shape of B ensonocy there is nearly the same as that 

of Triginglymus, and Triginglymus also has the welldeveloped dorsal muscle platform; but B ensonocy there 

has no ocular sinus, as does Triginglymus, and the 

hingement is different, being more weakly developed. 

B ensonocy there can be distinguished from Campylocythere by its coarsely pitted surface; Campylocythere 

has a smooth to finely pitted surface.

The following species are referable to Bensonocythere: Leguminocythereis whitei Swain, 1951, Cythereis arenicola Cushman, 1906, Cythere calverti Ulrich 

and Bassler, 1904, and B ensonocy there ameriaana n. sp. 

Loxoconchal postdecliva Swain, 1948, probably represents still another species of the genus.

Stratigraphic range. Oligocene (?), Miocene to 

Kecent.

Bensonocythere whitei (Swain, 1951)

Plate 5, figures 2, 3, 8-10; plate 10, figures 1-8; Plate 11, 

figures 1, 2

1951. Leguminocythereis whitei Swain, U.S. Geol. Survey Prof. 

Paper 234-A, p. 43, pi. 3, figs. 14, 16-18; pi. 4, fig. 1.

1953. Leguminocythereis wJiitei Swain. Malkin, Jour. Paleontology, v. 27, p. 785, pi. 80, figs. 7-12.
28 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

1957. Leffuminocythereisl whitei Swain. McLean, Bulls. -Am. 

Paleontology, v. 38, no. 167, p. 80, pi. 9, figs. 4a-6.

1958. Leguminocythereis whitei Swain. Brown, North Carolina 

Div. Mineral Resources Bull. 72, p. 63, pi. 6, fig. 10.

1965. Triginglymus whitei (Swain). Pooser, Kansas Univ., 

Paleont. Contr. Arthropoda, art. 8, p. 36, pi. 15, figs. 2, 

5, 6, 8, 9.

Diagnosis. Coarsely pitted, the pits roughly arranged in vertical rows in dorsal half of valves with 

reticulation riblets forming sinuous vertical ridges; 

slight sulcus behind low muscle swelling.

Measurements in mm. 

Female: 

L. ..................

H

Male: 

L. ..................

H.. .................

N

11

11

12

12

M

0.793

.431

.743 o>Te

Sd

0.030

.020

(YIQ

.010

OR

0

7KArt QQQ

Ann, Afif)

7ftn_ 77^

QCO QQQ

V

3

0

4.6

2.6

2.7

The carapace morphology of Bensonocythere whitei 

has been described; however, the soft parts have not 

been. The following is a description of the appendages 

of the species.

Antennules have five podomeres; second podomere 

has one seta in anteroproximal area and one longer seta 

at posterodistal edge; third podomere has one thick 

seta at anterodistal edge; fourth podomere has one 

prominent seta and one or more longer but thinner setae 

at midlength on anterior edge and one prominent and 

one or more thinner setae at anterodistal edge; fifth 

podomere has one prominent seta and two lesser setae. 

Endopodite of antennae has three podomeres; three 

terminal claws; exopodite pronounced on both males 

and females. Mandibles have about 12 sharp teeth on 

cutting edge; branchial plate is one plumose seta. 

Thoracic legs have chitinous supports in knees.

Bensonocy there whitei is relatively less elongate, more 

coarsely pitted, and more bluntly rounded at the extremities than B. arenicola (Cushman, 1906). The pitting in B. whitei is more dense than that in B. calverti 

(Ulrich and Bassler, 1904), and the individual pits are 

larger; B. whitei is also more broadly rounded at the 

anterior than B. calverti. Bensonocy there whitei is 

very closely related to B. americana n. sp. but can be 

distinguished from that taxon by its larger pits and by 

being less angular ventrolaterally in the posterior half 

of the valves; it is also larger than B. americana.

Pooser (1965, p. 36) considers McLean's (1957) report of the species from the Yorktown Formation to be 

based on a misidentification. McLean (1957, p. 80) also 

had his doubts about placing his single specimen in 

Swain's (1951) species. However, the illustrations seem 

to be that of a typical male right valve of Bensonocythere whitei.

Specimens found. 137.

Occurrence. This species has not been previously reported from the Recent. Swain (1951) and Brown 

(1958) record its occurrence in the subsurface of North 

Carolina in deposits having a stratigraphic range of 

Oligocene (?), lower Miocene to Pleistocene. Pooser 

(1965) reports its occurrence in the upper Miocene of 

South Carolina, and Malkin (1953) and McLean (1957) 

report it from the Miocene of the Virginia-Maryland 

area. In the present study the species was found off 

Lower New York Bay and questionably near Martha's 

Vineyard.

Repository. USNM 112693,112694,112696, 112772- 

112775.

Bensonocythere americana Hazel, n. sp. 

Plate 5, figures 1,4, 5; plate 11, figure 3

Diagnosis. Small size; coarsely pitted; pits arranged at random.

Description. Carapace quadrate to subrectangular 

in lateral view; extremities obliquely rounded; subtriangular in end view; ovate in dorsal view; surface 

coarsely, randomly pitted; two ridges, interior one less 

well developed, parallel anterior rim; slight muscle 

swelling marked by small area with no pits; conspicuous 

elongate pit inside dorsal margin just anterior to middle; no eye tubercle; left valve larger, overlapping 

right strongly at cardinal angles; anterior marginal rim 

and outside ridge continue from anterior along venter. 

Internally, marginal areas wide; vestibules at posterior 

and anterior; about 20 straight radial canals around 

anterior, lesser number around posterior; hinge modified amphidont; terminal teeth of right valve multilobate; anterior tooth of left valve evident only as swollen 

end of median bar, right valve socket complimentary; 

posterior socket of left valve open to interior; muscle 

scars a vertical row of four adductor scars, the middle 

two more elongate; frontal scars not observed. Sexual 

dimorphism strong, females relatively more quadrate 

and wider. Specimens with workable soft parts were 

not found.

Measurements in mm. 

Female: 

L.. .................

H. .............. .

Male: 

L......... ..........

H. .- . 

N

3

3

2

M

0.679

.375

Sd

0.008

.013

OR

0.67&-0.688

. 362- . 388

. 712- . 762

.338- .388

V

1.2

3.5

Discussion. Bensonocythere americana is more 

closely related to B. whitei than to B. arenicola; it can
SYSTEMATIC PALEONTOLOGY 29

be distinguished from B. whitei by its smaller size and 

different surface ornamentation. Bensonocythere 

americana does not have the pits tending to be arranged 

in vertical rows in the dorsal half of the valves as does 

B. whitei. The males of B. whitei are smaller than the 

females, but those of B. americana are larger than the 

females. One valve of what may be another species of 

Bensonocy there very closely related to B. americana was 

found in sample 30 with specimens of B. americana. 

This female valve is much larger (0.88 mm) than, but 

is otherwise very similar to, female valves of B. americana. More material will have to be examined to determine if this is in fact another species or only an 

aberrant representative of B. americana.

Specimens found. 25.

Occurrence. This species has been found in samples 

from the Gulf of Maine, near Martha's Vineyard (all 

juveniles), and off lower New York Bay.

Repository. USNM 112697 (holotype), 112770, 

112771.

Bensonocythere arenicola (Cushman, 1906) 

Plate 5, figures 6, 7,11; plate 11, fig. 9

1906. Cythereis arenicola, Cushman, Boston Sac. Nat. History, 

Proc., v. 32, no. 10, p. 379, pi. 36, figs. 97-107.

1933. Cythereis (Hemioythere) arenicola (Cushman). Blake, 

Biol. Survey Mount Desert region, pt. 5, p. 239.

Diagnosis. Carapace elongate; subovate in end 

view; coarse pits randomly arranged over surface.

Description. Carapace elongate in lateral view; anterior and posterior of nearly equal height; extremities 

evenly rounded in left valves to obliquely rounded in 

right valves; surface ornamented with large randomly 

arranged pits, each with a sieve'type pore canal; no 

eye tubercle; two weakly defined ridges parallel anterior 

marginal rim; one very large elongate pit just anterior 

to middle and just inside dorsal margin; left valve 

larger, overlapping right strongly at cardinal angles; 

marginal rim and outer ridge continue from anterior 

along venter. Internally, marginal areas wide; vestibules at anterior and posterior; about 25 straight radial 

canals around anterior and about 15 around posterior; 

hinge modified amphidont, anterior tooth of left valve 

reduced to large swelling at end of smooth bar; terminal 

teeth of right valve multilobate; large dorsal muscle 

platform; no ocular sinus. Muscle scars a vertical row 

of four adductor scars, the dorsomedian one most elongate, and two oblique frontal scars, the lower scar forward and larger. Sexual dimorphism strong, males 

more elongate, narrower, and lower than females. For 

anatomy, see Cushman (1906).

Measurements m mm. 

Female: 

L

H- -,--- - 

Male: 

£-..._ - 

H. .- 

N

3 

3

3 

3

M

0.888 

.458

.858 

.388

Sd

0 

.007

.029 

.013

OR

0. 450-0. 462

.825- .875 

.375- .400

V

0 

1.5

3.4 

3.4

Discussion. Cushman's (1906) illustration of the 

carapace is not very informative; however, he describes 

the carapace morphology, and describes and fully illustrates the anatomy of the species. My dissected specimens agree with Cushman's illustrations and descriptions of the soft parts. In addition, the outline and 

carapace features described by Cushman fit the specimens I refer to his species.

Bensonocythere arenicola is distinguished from both 

B. whitei and B. americana by its more elongate shape 

in lateral view, more oval shape in end view, and by details of ornamentation.

Specimens found. Nine.

Occurrence. Gulf of Maine and Vineyard Sound. 

In the present study this species was found in samples 

from the Georges Bank, off Lower New York Bay. and 

on the Atlantic Shelf at 39°54' N., 7l°M' W.

Repository. USNM 112776-112778, 112702.

Family TKACHYLEBEKIDIDAE Sylvester-Bradley, 1948

Diagnosis. Carapace subtriangular to oblong in 

lateral view; may be alate; ornamentation varied; eye 

tubercles usually well developed; extremities denticulate; marginal areas narrow to wide; vestibules rare; 

radial canals few to moderately numerous, sometimes 

branched; hinge amphidont or modified amphidont; 

sexual dimorphism usually pronounced; valves of 

males may show asymmetry; adductor muscle scars 

usually four discrete scars, but may be complexly divided; frontal scar usually single J- or U-shaped, but 

may be divided; antennules with six podomeres; endopodite of antennae with three podomeres, exopodite 

usually weakly developed; branchial plates of the 

mandibles with five setae; thoracic legs of males may 

differ from females and males may show asymmetry 

of legs; legs usually without chitinous supports in knees.

Discussion. The Trachyleberididae as considered 

herein comprises the following subfamilies:

Trachyleberidinae Sylvester-Bradley, 1948, Jurassic to

Recent 

Echinocythereidinae new subfamily, Campanian( ?), Paleocene to Recent

Brachycytherinae Puri, 1954, Albian to Miocene 

Pterygocythereidinae Puri, 1957, Albian to Recent
30 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Mauritsininae Deroo, 1962, Turonian to Maestrichtian 

Cytherettinae Triebel, 1952, Campanian to Eecent 

Buntoniinae Apostolescu, 1961, Coniacian to Eecent

Anatomically, all the genera of the living subfamilies 

possess antennules with six podomeres and mandibular 

branchial plates with five setae. The Trachyleberidinae, Cytherettinae, and most Buntoniinae, possess almost the same type of central muscle field; that is, with 

a single J- or U-shaped frontal scar and four discrete 

adductor scars. The living cytherettines differ anatomically from most genera of the other two subfamilies by 

having the right first thoracic leg of the males characteristically modified. In addition, most of the species 

which have been referred to this subfamily have a very 

wide calcified inner lamella with the inner margin sinuous. The Cytherettinae and the Buntoniinae characteristically have a more subovate shape than the Trachyleberidinae. Some genera of the Buntoniinae may 

have a subtriangular shape (see Apostolescu, 1961).

Of the seven trachyleberidid subfamilies, the extinct 

Brachycytherinae is probably the least closely related 

to the nominal subfamily. Many recent American 

workers have considered Brachycythere as belonging to 

a taxon equivalent in rank to the Trachyleberididae, 

raising Puri's (1953d) subfamily to a family (Howe, in 

Moore, 1961, p. Q260; Hazel and Paulson, 1964; Benson 

and Tatro, 1964; Pooser, 1965). However, a number of 

taxa have been included in the Brachycytheridae which 

are seemingly not related to Brachycythere, making the 

family an unwieldy taxonomic unit. The Jurassic genera Amphicy there, Dictyocythere, and Macrodentina 

and the Jurassic to Lower Cretaceous Polydentina are 

included in the family by Moore (1961). Van Morkhoven (1963) includes the first three taxa in the Progonocytherinae; he does not treat Polydentina. The 

genera Alatacythere, Pterygocythere, and Pterygocythereis are also included in the Brachycytheridae in 

Moore (1961). These genera also are not closely related to Brachycythere, and should be referred to Puri's 

(1957a) Pterygocythereidinae. The distinctive adductor muscle scar pattern and very tumid carapace distinguish Brachy at/there and related genera from those 

of the Pterygocythereidinae. The Brachycytherinae 

are here tentatively considered to belong to the Trachyleberididae. However, further studies may prove 

that, if the subfamily is restricted to those forms with 

tumid carapaces and muscle scar patterns such as possessed by Brachycythere and Digmocythere, the taxon 

serves a useful purpose at the family level.

The Mauritsininae are accorded equal rank with the 

Trachyleberidinae (as a subfamily of Cytheridae) by 

Deroo (1962). He compares Mauritsina with Cythereis and the other genus of the subfamily, Kikliocythere, with Brachycythere. Howe and Laurencich 

(1958, p. 368) state that Kikliocythere probably should 

be assigned to the Brachycytherinae. Howe (in Moore, 

1961, p. Q260) assigns Kikliocythere to the Brachycythere. It may be that the subfamily may have arisen 

from the Brachycytherinae, but an origin directly from 

the stem group Trachyleberidinae is equally, if not more, 

possible. The subfamily Mauritsininae is distinguished 

from other trachyleberidids in that its genera possess 

very unusual multiple frontal and adductor muscle 

scars (Deroo, 1962).

The Pterygocythereidinae have muscle scars very similar to the Trachyleberidinae, Buntoniinae, and Cytherettinae, but are easily recognized by their very alate 

valves. The dorsal scar of the adductor row may be Cshaped or apparently sometimes divided (Hazel and 

Paulson, 1964).

The extinct Brachycytherinae have a frontal scar like 

the Trachyleberidinae but possess divided adductor 

scars (Hazel and Paulson, 1964). Genera of the subfamily also are recognized by their tumid carapaces and 

characteristic hingement.

The Cytherettinae were raised to family status by 

Howe (in Moore, 1961, p. Q268); however, the appendage morphology and muscle scars seem to me to call for 

a separation from the Trachyleberidinae by no more 

than subfamily rank. For the same reasons the Buntoniinae are included in the Trachyleberididae. The 

Cytherettinae and Buntoniinae appear to be very closely 

related.

The Echinocythereidinae possess two frontal muscle 

scars and four undivided adductor scars. In addition, 

the subovate shape and concentric surface ornamentation are distinctive.

Mandelstam (in Chernysheva, 1960, p. 398) proposed 

the subfamily Faluniinae for Falwiia Grekoff and 

Moyes, 1955, and three other genera which would seem 

not closely related to Fatunia. As Keij (1957) states, 

Falunia is probably a trachyleberidid. The genus is 

difficult to place in any of the existing subfamilies of 

the Trachyleberididae, and the Faluniinae may be valid. 

I have not had an opportunity to study the genus so the 

Faluniinae are not considered here.

Subfamily TRACHYLEBERIDINAE Sylvester-Bradley, 1948 

Diagnosis. Subtriangular, subquadrate, or subrectangular in lateral view; oblong in dorsal view, extremities may be compressed; extremities denticulate; four 

adductor muscle scars in near-vertical row; single J-, 

U-, or heart-shaped frontal scar.

Discussion. The genera of the Trachyleberidinae are 

more laterally compressed than those of the Echinocythereidinae or Mauritsininae. The latter two subfamilies possess different muscle-scar patterns, the
SYSTEMATIC PALEONTOLOGY 31

Echinocythereidinae having two frontal scars and the 

Mauritsininae possessing complexly divided adductor 

and frontal scars. The Buntoniinae and Cytherettinae 

have the same type of muscle-scar pattern but are 

shaped differently, both subfamilies being more subovate in lateral view and more elliptic in dorsal view. 

The Brachycytherinae are ventrally tumid and possess 

divided adductor muscle scars. The Pterygocythereidinae are alate ventrally.

The following is a list of Upper Cretaceous and 

Cenozoic genera usually considered to be referable to the 

Trachyleberidinae. The first 13 taxa seem to be typical 

for the subfamily. The remaining genera are either 

not known fully at present or do not closely resemble 

those genera generally considered to be typical of the 

subfamily. Further study of the taxon is certainly 

called for.

Trachyleberis Brady, 1898, Campanian(?) Paleocene to

Recent

Actinocythereis Puri, 1953, Eocene to Recent 

Acanthocythereis Howe, 1963, Campanian (?), Paleocene to

Recent

Cythereis Jones, 1849, Cretaceous 

Henryhowella Puri, 1957, Oligocene to Recent 

Murray met, Puri, 1954, Miocene to Pliocene (?) 

Occultocythereis Howe, 1951, Paleocene to Recent 

Costa Neviani, 1928, Miocene to Recent 

Oertliella Pokorny, 1964, Turonian to Maestrichtian 

Platycosta Holden, 1964, Campanian to Paleocene 

Idiocythere Triebel, 1958, Campanian to Eocene 

Neocaudites Puri, 1960, Miocene to Recent 

Trachyleberidea Bowen, 1953, Coniacian to Miocene 

Veenia (Veenia) Butler and Jones, 1957, Turonian to Maestrichtian

Veenia (Nigeria) Reyment, 1963, Campanian to Maestrichtian

Robertsonites Swain, 1963, Pleistocene to Recent 

Garinocythereis Ruggieri, 1956, Pliocene to Recent 

Cativella Coryell and Fields, 1937, Eocene to Recent 

Falunia Grekoff and Moyes, 1955, Miocene 

Hirsutocythere Howe, 1951, Eocene 

Platycythereis Triebel, 1940, Valanginian to Turonian 

Spongicythere Howe, 1951, Eocene 

Climacoidea Purl, 1956, Pleistocene 

Reticulocythereis Puri, 1960, Recent

Genus ACTINOCYTHEREIS Puri, 1953

Type species, Oythere exanthemata Ulrich and Bassler, 1904.

Diagnosis. Subrectangular to subquadrate in lateral 

view, anterior broadly, obliquely rounded, posterior 

bluntly rounded; extremities denticulate; surface 

spinose with spines usually alined in three rows; surface smooth between the spines, but riblets on some species form a pseudoreticular pattern; anterior rim broken 

into spines in ventral half; curved riblet runs from

prominent eye tubercle to spinose muscle swelling; 

characteristic three or four spines in front of and below 

muscle swelling, these sometimes connected by riblets 

forming a V or U open towards anterior; male carapaces show valve asymmetry with right valve indented 

in posteroventral area; marginal areas narrow to moderately wide, crossed by straight radial canals; hinge 

holamphidont; muscle scars a curved row of four adductor scars with a single J- or U-shaped scar in front.

Antennules with six podomeres, particularly strong 

setae at anterodistal edge of fourth and fifth podomeres; 

right legs of male differ from left legs, first thoracic 

right leg has only two podomeres and a claw.

Stratigraphic range. Eocene to Recent.

Discussion. Puri (1953a) distinguishes his genus 

Actinocythereis from Trachyleberis because Actinocythereis has the spines on the valve surface arranged in 

three distinct longitudinal rows. Van Morkhoven 

(1963) considers Actinocythereis as a subgenus of 

Trachyleberis differing only by having "the tubercles in 

the posterior half of the valves arranged in three more 

or less distinct longitudinal rows."

It is true that the type species of Trachyleberis, 

Cythere scabrocuneata Brady, 1880, shows very little 

linear arrangement of spines; but Trachyleberis lytteltonensis Harding and Sylvester-Bradley, 1953, T. 

thomsoni Hornibrook, 1952, and T. tridens Hornibrook, 

1952, are, in my opinion, closely related species and they 

all show some alinement of spines.

Puri (1953a) placed 8 species in his new genus Actinocythereis and 10 species in Trachyleberis. All 10 of the 

species placed in the latter genus show some alinement 

of the spines, as do, of course, those placed in Actinocythereis. There is a gradation in morphotypes in the 

North American and Caribbean species of the 

Trachyleberis-Actinocythereis group from those with 

very strong alinement of spines such as Cythere exanthemata to those such as Cythereis montgorneryensis 

Howe and Chambers, 1935, where the alinement is weak. 

The latter species along with similar taxa such as 

Trachyleberis citrusensis Puri, 1957, Cythereis quadrataspinata Howe and Law, 1936, Cythereis bermudezi 

van den Bold, 1946, Trachyleberis bollii van den Bold, 

1960, Actinocythereis allisoni Holden, 1964, and possibly 

Cythereis davidwhitei Stadnichenko, 1927, more closely 

resemble in shape and ornamentation the type species of 

Trachyleberis and possibly should be placed in that 

genus. Most of the remaining North American or Caribbean species assigned to Trachyleberis have a carapace 

shape and ornamentation like the type species of Actinocythereis and are better referred to that genus. Reticulate species often placed in Actinocythereis or Trachyle-
32 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

beris are better classified in the genus Acanthocythereis 

Howe, 1963.

In 1906 Cushman described some of the soft parts of a 

species he named Oythereis vineyardensis. I consider 

this species to be a typical member of the genus Actinocythereis. Cushman (1906) shows three setae on the 

fifth podomere of the antennules of A. vineyardensis. 

Harding and Sylvester-Bradley (1953) illustrate four 

setae for the fifth podomere of the antennules of both 

Trachyleberis lytteltonensis and T. scabrocuneata. 

Cushman (1906) describes the sixth podomere of Actinocythereis vineyardensis as having three setae. 

Harding and Sylvester-Bradley (1953) describe the 

sixth podomere of Trachyleberis lytteltonensis as having four setae. The sixth podomere of T. scabrocuneata 

is incompletely known.

Harding and Sylvester-Bradley (1953) point out that 

the male of Trachyleberis lytteltonensis shows asymmetry of the first thoracic legs. This asymmetry is apparently not imparted to the carapace, for none of the 

specimens of T. lytteltonensis I have observed nor specimens of other New Zealand species of the genus show 

valve asymmetry.

Blake (1933) notes that the fifth through seventh 

thoracic legs of Actinocythereis dawsoni (Brady, 1870) 

are unlike on the two sides of the body. The second 

and third pairs of legs on Trachyleberis lytteltonensis 

are symmetrical (Harding and Sylvester-Bradley, 

1953). Cushman (1906) describes the first thoracic leg 

(the illustrated specimen appears to be a right leg) as 

"* * * 2-jointed, outer joint very long, swollen in the 

middle, with a short stout strongly curved claw." 

Harding and Sylvester-Bradley (1953) show the right 

first thoracic leg of T. lytteltonensis to be composed of 

four segments and a claw. Thus there are several anatomical differences between at least two species of 

Trachyleberis and one of Actinocythereis.

Important from a paleontologic standpoint is the fact 

that the anatomical asymmetry in the males of Actinocythereis is manifest in the carapace. All adult males of 

Actinocythereis that I have examined show asymmetry 

of the valves. The area on the venter behind the middle 

on right valves is characteristically indented. This can 

be seen both in lateral and ventral views.

Two species of Actinocythereis occur in several samples, of the more than 400 examined, from off northeastern North America. In the literature covering the Kecent ostracodes of this area, only two species of 

Actinocythereis seem to have been described. One is 

Oythere dawsoni Brady, 1870, described from the Gulf 

of St. Lawrence and reported later from marine Pleistocene deposits at Montreal, Canada, and Portland, Maine, 

(Brady and Crosskey, 1871), from the Gulf of Maine

(Blake, 1933), and from Vineyard Sound (Cushman, 

1906). The second species is Oythereis vineyardensis 

Cushman, 1906, described from Vineyard Sound.

The two species found in my samples are superficially 

very similar, but separation is easy when attention is 

paid to details of ornamentation. Unfortunately, the 

illustrations of Brady (ISTOa) and Cushman (1906) 

do not show such detail. However, one of the species 

I have found is considerably larger than the other, females of the larger species measuring about 0.90 mm in 

length and those of the smaller species about 0.76 mm.

Brady (1870a) gives a length of one thirty-fifth of 

an inch ( = 0.74 mm) for a female or his Oythere 

daivsonij and Brady and Crosskey (1871) illustrate a 

male of the species that is (measured from the plate) 

0.64 mm in length. Cushman (1906) gives a length of 

0.9 mm for his male specimen of Oythereis vineyardensis. These measurements plus the fact that my specimens came from areas where Brady's and Cushman's 

species were reported give me almost complete confidence in the identification of my smaller species as 

Oythere dawsoni and the larger as Oythereis vineyardensis.

Actinocythereis dawsoni (Brady, 1870) 

Plate 5, figures 12-15, 17; plate 11, figure 6

1870. Cythere dawsoni Brady, Annals and Mag. Nat. History, 

4th ser., v. 6, p. 453, pi. 19, figs. 8-10.

1871. Cythere dawsoni Brady. Brady and Crosskey, Geol. Mag., 

v. 8, p. 64, pi. 2, figs. 10,11.

1878. Not Cythere dawsoni?. Brady, Zool. Soe. London Trans., 

v. 10, pt. 8, p. 393, pi. 66, figs. 3a, b.

1889. Cythere dawsoni Brady. Brady and Norman, Royal Dublin Soc. Sci. Trans., 2d, ser., v. 4, no. 2, p. 166, pi. 16, 

figs. 19, 20.

1906. Cythere dawsoni Brady. Cushman, Boston Soc. Nat. History Proc., v. 32, n. 10, p. 372, pi. 35, figs. 84, 85.

1933. Cythereis dawsoni (Brady). Blake, Biol. Survey Mount 

Desert region, pt. 5, p. 238.

Diagnosis. Small; spines of middle row elongated 

parallel to valve length.

Description. Laterally subquadrate to subrectangular; anterior broadly obliquely rounded, posterior 

bluntly rounded. Double row of denticles around anterior and posterior, anterior inside row more prominent, 

posterior outside row more prominent. Valves ornamented with three rows of spines; three spines of middle 

row elongated parallel to valve length, nearly coalescing ; anterior spine separated with slight gap from high 

muscle node; dorsal row consists of three spines all 

elongated normal to valve length, anterior tAvo spines 

form an inverted U with closed end of U slanted towards 

posterior. Curved riblet running to muscle node from 

glassy eye tubercle; anterior rim solid in dorsal half, 

breaks up into about four large spines in the lower half;
SYSTEMATIC PALEONTOLOGY 33

ventral row of spines composed of six to eight blunt 

spines; V-shaped arrangement of riblets connecting 

short spines located in anterocentral area, V pointed 

towards posterior, legs of V angled slightly towards 

anterodorsal area. In dorsal view, left valve overlaps 

right at cardinal angles; rim and double row of anterior 

denticles are of equal size; elongation of spines of middle row prominent in dorsal view. In ventral view, 

interior row of spines at anterior comes farther back 

upon the ventral surface than does outer row; double 

row of spines at posterior very prominent in ventral 

view, inner row much smaller and more numerous, outer 

row on ventral surface changes to solid ridge that runs 

to the central depression. Internally, marginal areas 

rather wide with about 30 to 40 radial canals around 

anterior and very slight vestibule at anterior; about 15- 

20 radial canals 'around posterior. Hinge holamphidont; both teeth of right valve rounded and high, 

posterior tooth larger; socket behind anterior tooth 

small; groove leading to posterior tooth very narrow; 

hinge of left valve complementary; selvage moderately 

strong, some list grooves inside of selvage; selvage of 

right valve at outer margin. Muscle scars consist of 

curved row of four rounded adductor scars, top and bottom scars set forward; frontal scar U-shaped, open 

toward anterodorsal area. 

Measurements in mm. 

Female: 

L. ......

H. ..................

Male: 

L.. ....... .

H. ..................

N

7

7

g

g

M

0.771

.429

.774

402

Sd

0.021

.021

.024

.027

OR

0

7cnn (2io

400- 462

. 738- . 812

V

2.7

4 9

Q 1

6.7

Discussion. Actinocythereis dawsoni is smaller than 

A. vineyardensis, and the females are relatively shorter 

and wider than in that species. The surface between 

the spines is relatively free of riblets in contrast to A. 

vineyardensis.

Specimens found. 18.

Occurrence. Gulf of Maine, Vineyard Sound, and 

Gulf of St. Lawrence. Pleistocene of Maine and Quebec. In the present study the species was found in the 

Gulf of Maine, on Browns Bank, and at two localities on 

the Atlantic Shelf at about 40° N., 70° W.

Repository. USNM 112700, 112779-112783.

Actinocythereis vineyardensis (Cushman, 1906) 

Plate 5, figures 16,18; plate 11, figure 4

1906. Cythereis vineyardensis Cushman, Boston Soc. Nat. History, Proc., v. 32, p. 380, pi. 37, figs. 110-114.

Diagnosis. Large; small sinuous coalescing riblets 

connect spines of middle row to those of dorsal and 

ventral rows.

231-538 O 67 4

Description. Subrectangular to subquadrate in lateral view; anterior broadly, obliquely rounded; posterior bluntly, evenly rounded. Double row of denticles 

around anterior; interior row more prominent, denticles 

largest in anteroventural area; strong anterior rim present; rim solid and sharp from eye tubercle halfway 

around anterior, then breaks up into three to four bladetype spines; posterior denticulate with two rows of 

denticles, outside row more prominent. Curved riblet 

runs from eye tubercle to muscle node; muscle node 

ornate as result of the junction of several riblets. Surface ornamented with three major rows of spines connected by coalescing riblets. In anterocentral area are 

four small spines with low riblets connecting the posterior two to each other and to anterior two, but anterior 

two not connected. Ventral row of spines formed by 

two large spines below muscle node which are oriented 

with their greatest length parallel to valve length and 

three large spines behind these which are elongate 

nearly normal to valve length. Dorsal row made up of 

three spines; anterior spine complex forms an inverted 

U with a riblet coming off anterior leg, angling forward 

and then down, connecting at muscle node with riblet 

from eye tubercle; two posterior spines blunt, oriented 

with greatest length normal to length of valve, large 

gap between anterior spine of median row which is set 

below other two, and muscle node. In dorsal view, left 

valve overlaps right at cardinal angles; middle row of 

spines prominent as are anterior rim and double row of 

anterior denticles; clump of about four small spines at 

posterior cardinal angle of left valve. In ventral view, 

inner row of double row of anterior denticles is composed of many small slightly elongated spines, whereas 

outer row is composed of much larger blade spines which 

flare at ends; denticles in the posterior double row are of 

approximate equal size. Hinge liolamphidont; posterior tooth of right valve rather small; anterior tooth 

large, rounded; 20-25 radial canals around anterior, 

about 15 in posterior and posteroventral areas; marginal 

areas rather narrow; vertical row of four adductor scars, 

second from top set farthest back; lowest set farthest 

forward; frontal scar not seen. See Cushman (1906) 

for description of soft parts.

Measurements in mm. 

Female: 

L.. .................

H.. .................

Male: 

L. .. ................

H. ..................

N

6 

6

2 

2

M

0.887 

.490

Sd

0.024 

.015

OR

0. 862-0. 925 

. 462- . 500

. 888- . 912

. 462- . 475

V

2.7 

3.1

Discussion. These species is closely related to Actinocythereis dawsoni (Brady, 1870) from which it can
34 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

be distinguished by its larger size and small riblets 

connecting the major spines. Actinocythereis mundorffi (Swain, 1951) also possesses the connecting riblets, tout they are much better developed and that species 

is much smaller. Actinocythereis vineyardensis is also 

closely related to the often misidentified Actinocythereis 

exanthemata, the extinct type species of the genus. 

The differences between them are minor, but consistent. 

Actmocytheseis exanthemata does not possess the riblets connecting the major spine as does A. vineyardensis 

and the shapes of the individual spines, particularly, of 

the middle row are different, being oriented with the 

greatest length parallel to valve length.

Brady and Crosskey (1871) describe a species, Cythere cuspidata, from Pleistocene deposits on the banks 

of the Saco River, Maine, which may well be an Actinocythereis. It is the same size and has an outline in 

lateral and dorsal views as Actinocythereis vineyardensis. The illustrations of Cythere cuspidata are 

poor and the description minimal. From its locality 

and what morphological data are available, I suspect 

that Brady and Crosskey's specimen is conspecific with 

Cushman's Cythere vineyardensis and therefore would 

have priority. However, I am more sure that my specimens belong to the same species as Cushman's and will 

use his name until Brady and Crosskey's type specimen 

can be examined.

Specimens found. 8.

Occurrence. Known previously from Vineyard 

Sound. In the present study it was found in the Gulf 

of Maine, on the Geoj-ges Bank, and on the Atlantic 

Shelf at 40°02' N., 69°24' W.

Repository. USNM, 112698, 112784, 112785.

Genus ACANTHOCYTHEKEIS Howe, 1963

Type species, Acanthocythereis amneosa Howe, 1963.

Diagnosis. Elongate subtriangular or subquadrate 

in lateral view; elliptic in dorsal view; surface spinose 

and coarsely reticulate; spines may be arranged in rows; 

eye tubercle well developed; muscle node usually indistinct; marginal areas narrow to moderately wide; 

radial canals moderately numerous, simple; hinge 

holamphidont; four adductor muscle scars with single 

J- or U-shaped antennal scar.

Discussion. In 1963 Swain erected the genus Cletocythereis. He had in his Pleistocene arctic fauna one 

species which he referred to Cletocythereis, C. noblissimus Swain, 1963 ( = Cythere dunelmensis Norman, 

1865); however, he selected as the type species Cythere 

rastromarginata Brady, 1880, a tropical species from the 

Pacific. I have examined Pacific specimens of Cythere 

rastromarginata and consider this species closely related 

to if not congeneric with the type species of Hermanites.

Cletocythereis noblissimus on the basis of its shape and 

reticular ornamentation seems, at least tentatively, 

more closely related to species of the trachyleberidid 

genus Acanthocythereis than to Cythere rastromarginata.

Stratigraphic range. Campanian( ?), Paleocene to 

Recent.

Acanthocythereis? dunelmensis (Norman, 1868)

1865. Cythere dunelmensis Norman, British Assoc. Adv. Sci.,

rept. 34th Mtg., p. 193. 

1941. Cythereis dunelmensis (Norman). Blofson (partim),

Zool. Bidrag fran Uppsala, v. 19, p. 296 (gives full

synonymy 1865-1941). 

1941. Not Cythereis dunelmensis (Norman). Tressler, U.S.

Geol. Survey, Prof. Paper 196-C, p. 100, pi. 19, fig. 21. 

1943. Cytnereis dunelmensis (Norman). Elofson (partim),

Arkiv Zoologi, v. 35A, no. 2, p. 10. 

1963. Cletocythereis noblissimus Swain, Jour. Paleontology, v.

37, no. 4, p. 824, pi. 98, fig. 5; pi. 99, figs. 15a, b; text

fig. lOa. 

1965. Cletocythereis dunelmensis minor Bassiouni, Dansk

Geol. F6ren. Medd., v. 15, pt. 4, no. 4, p. 513, pi. 2,

fig. 9. 

1965. Cletocythereis dunelmensis dunelmensis (Norman).

Bassiouni idem, pi. 2, fig. 8. 

1965. Cletocythereis elofsoni elofsoni Bassiouni, idem, p. 514, pi.

2, figs. 4,5.

Discussion. Although reported several times from 

the area of this study, I have not found the species in 

any of my study-area samples. I have had an opportunity to study specimens of the species found in 

Recent samples from the Greenland Sea and Beaufort 

Sea.

Elofson (1941), in his study of the ostracodes of the 

Skagerrak, found two morphologic types both of which 

he referred to Cythereis dunelmensis, calling one the 

large form and the other the small form.

Swain (1963) makes no mention of Cythere dunelmensis in his discussion of Cletocythereis noblissimus, 

yet the similarity of his illustrations and specimens, 

which I have examined, with the illustrations of Brady 

(1868a), Brady, Crosskey, and Robertson (1874), and 

Elofson (1941) cannot be denied. Cletocythereis 

noblissimus would seem to be a junior synonym of Cythere dunelmensis (the large form of Elofson, 1941).

Bassiouni (1965) considers both the large and small 

forms of Elofson to represent not Cythere dunelmensis 

but a new species which he names Cletocythereis elofsoni. Bassiouni divides C. elofsoni into two subspecies, 

C. elofsoni elofsoni, the large form Elofson, and C. elofsoni abbreviata, the small form of Elofson. Cletocythereis elofsoni abbreviata may represent a new species, 

but C. elofsoni elofsoni seems to be only the male of 

Cythere dunelmensis. Bassiouni seems not to have correctly sexed his specimens as all four of his illustrations
SYSTEMATIC PALEONTOLOGY 35

of Gletocythereis elofsoni are of males and the two illustrations of 0. dunelmemsis are of females.

Occurrence. Greenland Sea, Beaufort Sea, Iceland, 

Spitzbergen, Franz Josef Land, Kara Sea, Barents Sea, 

Norwegian Sea, western Baltic Sea, North Sea, several 

localities off England, Scotland, and Ireland, Shetland 

Islands, Cumberland Sound, Gulf of St. Lawrence, Gulf 

of Maine, and Vineyard Sound. Pleistocene of Alaska, 

Maine, England, Scotland, Ireland, and Denmark.

Genus B.OBERTSONITES Swain, 1963

Type species, Robertsonites gubikensis Swain, 1963 

(= Cythereis tuberculata Sars, 1865).

Diagnosis. Subquadrate to subrectangular in lateral 

view; anterior broadly rounded; posterior more bluntly, 

obliquely rounded; surface irregularly pitted or 

reticulate and nodose; hinge holamphidont; U-shaped 

frontal muscle scar; four adductor scars.

Stratigraphic range. Pleistocene to Recent.

Robertsonites tuberculata (Sars, 1865) 

Plate 6, figures 1-3

1865. Cythereis tuberculata Sars, Vidinsk. Selsk. Christiania,

Forh., p. 37. 

1871. ICytTiere loaani Brady and Crosskey, Geol. Mag., v. 8, p.

63, pi. 2, figs. 8,9. 

1874. Cythere logani Brady and Crosskey. Brady, Crosskey, and

Robertson, A monograph of the Post-Tertiary Entomostraca * * *, p. 165, pi. 15, figs. 17, 18. 

1878. Cythere logani Brady and Crosskey. Brady, in Nares,

Narrative of a trip to the Polar Sea during 1875-6 * * *,

v. 2, No. 7, p. 254. 

1906. Cythereis tuberculata Sars. Cushman, Boston Soc. Nat.

History Proc., v. 32, no. 10, p. 376, pi. 36, figs. 108, 109. 

1941. Cythereis tuberculata Sars. Elofson, Zool. Bidrag fran

Uppsala, v. 19, p. 294 (gives full synonymy 1865-1941). 

1941. Not Cythereis tuberculata. Tressler, U.S. Geol. Survey

Prof. Paper 196-C, p. 100, pi. 19, fig. 20. 

1943. Cythereis tuberculata Sars. Elofson, Arkiv Zoologi v. 35A,

no. 2, p. 9. 

1963. Robertsonites aubikensis Swain, Jour. Paleontology, v. 37,

no. 4, p. 821 pi. 98, figs. 8a, b; pi. 99, fig. 12; text fig. 9b. 

1963. Robertsonites tuberculatina Swain, idem, p. 822, pi. 98,

fig. 10; pi. 99, fig. 1; text fig. 9c.

Diagnosis. Surface reticulate, with smaller reticules 

or pits inside the larger ones; two prominent nodes 

posterodorsally and posteroventrally; sulcus behind 

muscle swelling.

Measurements in mm. 

Female: 

L.. .................

ff-. ..............

Male: 

L... ................

H.- ... .. ... .

N

3

3

4

4

M

1.117

.638

1.122

.566

Sd

0.029

.013

.028

.012

OR

1. 100-1. 150

. 625- . 650

1. 088-1. 150

. 550- . 575

V

2.6

2.0

2.5

2.1

Discussion. Blake (1933) reported this species from 

the Mount Desert region of Maine, and Cushman (1906) 

reported it from Vineyard Sound. I have not found the 

species in my material from off New England, although 

it is a common constituent of my samples from further 

north. Cushman's (1906) report of Robertsonites 

tuberculata could be based on a misidentification, as he 

illustrates an antennule having only five podomeres, 

whereas Sars (1925) shows that the species has sixjointed anternmles. The joint between the fourth and 

fifth podomeres on the antennules of trachyleberidids is 

not always easily seen, and Cushman's illustration of 

only five podomeres could easily be an error in observation.

Swain (1963) describes Robertsonites gubikensis and 

R. tuberculatina; he makes no comparison of his species 

with the often described Cythereis tuberculata Sars, although he may have been indicating some relationship 

with the use of the trivial name tuberculatina. After 

comparison of the types of R. tuberculatina and R. gubikensis with each other and with many specimens of Cythereis tuberculata Sars, found in the present study, I 

can only conclude that Swain's R. gubikensis and R. 

tuberculatina are junior synonyms of R. tuberculata.

The holotype of Robertsonites gubikensis appears to 

be a female, whereas that of R. tuberculatina is the male 

of the species.

The variability of R. tuberculata is great. Brady 

(1868a, p. 407) states that "there is great variety in the 

different forms of the carapace * * *." Brady, Crosskey, and Eobertson (1874, p. 165) said that R. tuberculata "exhibits much variation in outline and in surface-marking, and * * * the tubercular elevations are 

much more conspicuous in very young than in old specimens, though the contrary holds good with regard to 

the pitting or excavation of the shell."

Specimens found. 42.

Occurrence. Baltic Sea, North Sea, Norwegian Sea, 

many localities in the British Isles, Barents Sea, Franz 

Josef Land, Spitzbergen, Iceland, Kane Basin, Godhavn Harbor, Hunde Islands, Davis Strait, Holsteinsborg Harbor, Gulf of St. Lawrence, Gulf of Maine, and 

Vineyard Sound. Pleistocene of England, Scotland, 

Wales, Ireland, and Alaska. In the present study the 

species was found in samples from near North Wolstenholme Island, the Vaigat Strait, Frobisher Bay, Kneeland Bay, and Ungava Bay.

Repository. USNM 112786-112788.

Genus CARINOCYTHEREIS Ruggieri, 1956

Type species, Cytherina carinata Roemer, 1838.
36 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Carinocythereis whiteii (Baird, 1850)

1850. Cythereis whiteii Baird, * * * British Entomostraca, 

p. 175, pi. 20, fig. 3.

1868. Cythere whitei (Baird). Brady, Linnean Soc., London 

Trans., v. 26, p. 416, pi. 30, figs. 21-24.

1870. Cytherel whiteii (Baird). Brady, Annals and Mag. Nat. 

History, 4th ser., v. 6, p. 450.

1874. Cythere whiteii (Baird). Brady, Crosskey and Robertson, A monograph of the Post-Tertiary Entomostraca 

* * *, p. 169, pi. 12, figs. 1-3.

1889. Cythere whitei (Baird). Brady and Norman, Royal 

Dublin Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 169.

Discussion. This species was identified from the 

Gulf of St. Lawrence by Brady (1870a). I have not 

found it in any of my material. Euggieri (1956) considers Cythereis whiteii Baird to belong to his genus 

Carinocythereis.

Occurrence. Several localities in the British Isles, 

Shetland Islands, Mediterranean, and Gulf of St. Lawrence. Pleistocene of Ireland.

Subfamily ECHINOCYTHEREIDINAE new subfamily

Diagnosis. Carapace subovate in lateral view; ovate 

in dorsal view, widest at middle; anterior broadly 

rounded, denticulate, posterior obliquely to bluntly 

rounded to truncate, denticulate; surface concentrically 

reticulate with or without concentrically arranged 

spines; eye tubercles well developed; no muscle node; 

marginal areas of moderate width, inner margin and 

line of concrescence coincident; radial canals moderately 

numerous, usually simple; hinge amphidont, terminal 

teeth smooth; near-vertical row of four adductor muscle scars; two frontal scars; normal canals open. AJItennules with six podomeres, setae at anterodistal ends 

of podomeres very elongate; setae and terminal claws 

of antennae very elongate; exopodites of antennae moderately developed; chitinous supports in knees of thoracic legs.

Discussion. The genera of the Echinocythereidinae 

are distinguished from the Trachyleberidinae by their 

subovate shape in lateral view, by tumidity in dorsal 

view, and by the presence of two frontal scars. The 

shape is somewhat the same as in the Buntoniinae and 

Cytherettinae, but the genera of these subfamilies 

possess a single J-shaped antennal scar in addition to 

other hard and soft-part morphological differences.

Van Morkhoven (1963) considers Echinocythereis as 

a transitional form between the Hemicytheridae and 

Trachyleberididae. Echinocythereis has two antennal 

muscle scars and chitinous thoracic knee supports, both 

of which are common in the Hemicytheridae, but it has 

six-jointed antennules and complex mandibular branchial plates which are trachyleberidid characters. 

Echinocythereis is morphologically intermediate between the two families; however, I believe that the type 

of antennules and branchial plates are more important 

taxonomic criteria at the family level than the knee supports or antennal scars. Although Echinocythereis is 

interemediate morphologically, I do not think it is 

transitional in a phyletic sense. Thus, the double 

frontal scars and chitinous knee supports of the 

Echinocythereidinae parallel development of these 

characters in the Hemicytheridae.

Ho we and Laurencich (1958) assign two Cretaceous 

species to Echinocythereis. Although much smaller 

than Tertiary representatives of the genus, they are very 

similar in shape and ornamentation. The internal features of these two species are as yet poorly known. No 

data are available on their muscle scars. Howe and 

Laurencich's assignation of the Cretaceous taxa to 

Echinocythereis is provisionally accepted. The Cretaceous species of Howe and Laurencich are in need of 

study to ascertain if they are Echinocythereis or, at 

least, Echinocythereidinae. If they are, then the range 

of the subfamily is Campanian to Eecent.

The following genera are placed in the Echinocythereidinae :

Echinocythereis Puri, 1954, Campanian (?), Paleocene to

Recent

Rabilimis n. gen., Pleistocene to Recent 

Bosquetina Keij, 1957, Eocene to Recent

Genus ECHINOCYTHEREIS Furi, 1953

Type species, Cythereis garretti Howe and McGuirt, 

1935 ( = Cythere margaritifera Brady, 1870).

Diagnosis. Subovate to quadrate in lateral view; 

elliptic in dorsal view, widest at or just behind middle; 

eye tubercle well developed; surface ornamented with 

concentrically arranged spines and, generally, reticules; 

hinge holamphidont; two frontal muscle scars; four 

adductor muscle scars.

Stratigraphic range. Campanian (?), Paleocene to 

Eecent.

Echinocythereis margaritifera (Brady, 1870) 

Plate 6, figures 6, 7, 9

1870. Cythere margaritifera Brady, Fonds de la Mer, v. 1, p.

192, pi. 27, figs. 3, 4. 

1935. Cythereis garretti Howe and McGuirt, in Howe and others,

Florida Geol. Survey Bull. 13, p. 20, pi. 3, figs. 17-19;

pi. 4, figs. 5,15. 

1951. Buntonia sp. cf. B.I garretti (Howe and McGuirt).

Swain, U.S. Geological Survey Prof. Paper 234-A, p.

39, pi. 3, fig. 6; pi. 4, figs. 4-6. 

1954. Echinocythereis garretti (Howe and McGuirt). Puri,

Florida Geol. Survey Bull. 36, p. 260, pi. 12, figs. 2-5;

text figs. 9a, b; [1953d]. 

1958. Echinocythereis garretti (Howe and McGuirt). Brown,

North Carolina Div. Mineral Resources Bull. 72, p. 65,

pi. 6, fig. 12.
SYSTEMATIC PALEONTOLOGY 37

I960. Echinocythereis margaretifera (Brady). Curtis, Am.

Assoc. Petroleum Geologists Bull., v. 44, no. 4, p. 480, pi.

1, fig. 19. 

1963. Echinocythereis garrctti (Howe and McGuirt). Benson

and Coleman, Kansas Univ. Paleont. Contr., Arthropoda,

art, 2, p. 46, pi. 4, fig. 4, 5 ; text fig. 30.

Diagnosis. Quadrate (females) to elongate quadrate 

(males); thick shelled; spines broad based, and short. 

Measurements in mm. 

Female: 

L. ..................

H.. .................

Male: 

L. ..................

H...................

N

4

4

2

2

M

1.006 fiOK

Sd

0.071

nAt)

OR

0. 900-1. 050

. 562- . 650

Q7C.1 A1O

. 525- . 575

V

7.1

7.7

--..-.....

Discussion. In 1963 I had an opportunity to examine 

the types of the species described by G. S. Brady 

(1870b) in "Les Fonds de la Mer." One of the specimens examined was the holotype of Cythere margaritifera Brady, 1870, described from off Vera Cruz, Mexico. 

I compared Recent specimens of an Echinocythereis 

found off the Mississippi Delta with Brady's type and 

judged them to be conspecific with Cythere margaritifera, an identification already correctly made by Curtis 

(1960). I have since examined specimens of Gythereis 

garretti Howe and McGuirt, 1935, from the type horizon and judge them to be conspecific with Cythere margaritifera. Thus, in my opinion, the type species of 

Echinocythereis becomes Cythere margaritifera Brady, 

1870.

Echinocythereis margaritifera is distinguished from 

most other species of the genus, particularly those found 

in North America, both fossil and Recent, by its more 

quadrate outline in lateral view.

Specimens found. 12.

Occurrence. Gulf of Mexico, Miocene of North Carolina and Florida. In the present study the species was 

found on the Georges Bank and at three localities on 

the Atlantic Shelf at approximately 40° N., 70° W.

Repository. USNM 112792-112794.

Echinocythereis planisbalis (Ulrich and Bassler, 1904) 

Plate 6, figures 4, 5, 8

1904. Cythere planisbalis Ulrich and Bassler, Maryland Geol. 

Survey, Miocene [volume], p. 99, pi. 38, figs. 1-3.

1929. Cythereis procteri Blake, Biol. Survey Mount Desert region, pt. 3, p. 13, fig. 6.

1933. Cythereis procteri Blake. Blake, idem, pt. 5, p. 239.

1951. Buntonial planisbalis (Ulrich and Bassler). Swain, U.S. 

Geol. Survey Prof! Paper 234-A, p. 39, pi. 3, figs. 4, 5.

1958. Not Echinocythereis planisbalis. Brown, North Carolina 

Div. Mineral Resources Bull. 72, p. 65, pi. 8, fig. 11.

Diagnosis. Spinose ventrolateral rib developed in 

posterior half of valve; one spine particularly well developed at posterior end of rib; tendency for clump of 

several spines to form at posteroventral angle.

Measurements in mm. 

Female: 

L.. .................

H. ... ... ... ... ...

N

5

5

M

1.022

.612

Sd

0.047

.013

OR

0.975-1.100

. 600- . 625

V

4.6

2.1

Discussion. Echinocythereis planisbalis is distinguished from E. echinata and other species of the genus 

with similar carapace shapes by the presence of a short 

ventrolateral ridge in the posterior part of the valves. 

On some specimens, such as that illustrated by Swain 

(1951), the ridge is very pronounced.

Blake (1929, 1933), apparently unaware of the work 

of Ulrich and Bassler (1904), described the species 

under the name Cythereis procteri.

Specimens found. 7.

Occurrence. Gulf of Maine, Miocene of Virginia and 

North Carolina. In the present study the species was 

found in samples from the Gulf of Maine,,

Repository USNM. 112789-112791.

Echinocythereis echinata (Sars, 1865) 

Plate 6, figures 10, 11

1865. Cythereis echinata Sars., Vidensk. Selsk. Christiania, 

Fb'rh., p. 44.

1941. Cythereis echinata Sars. Elofson, Zool. Bidrag fran Uppsala, v. 19, p. 295 (gives full synonmy 1865-1941).

1941. Cythereis echinata Sars. Tressler, U.S. Geol. Survey Prof. 

Paper 196-C, p. 100, pi. 19, fig. 24.

1943. Cythereis echinata Sars. Elofson, Arkiv Zoologi, v. 35A, 

no. 2, p. 9.

1952. Not "Cythereis" echinata (Sars). Crouch, Am. Assoc. 

Petroleum Geologists Bull., v. 36, no. 5, pi. 7, fig. 17.

Diagnosis. Large; very numerous thin elongate 

spines cover unreticulated surface.

Measurements in mm. 

Female?: 

L.. .................

H..... ..............

N

2

2

M Sd

0.017

.022

OR

1. 125-1. 150

. 650- . 662

V

Speciments found. 2.

Occurrence. North Sea, Norwegian Sea, several localities in the central North Atlantic and one in the 

South Atlantic near Tristan da Cunha. In the present 

study the species was found on the Stout Swell.

Repository. USNM. 112795,112796.
38 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Genus RABILIMIS n. gen.

Type species, Gy there mirdbilis Brady, 1868.

Etymology. An anagram constructed from letters 

in the trivial name of the type species.

Diagnosis. Large; subovate in lateral view; ovate in 

dorsal view, valves greatly inflated; surface ornamented 

with concentrically arranged reticulae, pits and ridges; 

no prominent surface spines; hinge strong holamphidont; two frontal muscle scars; four adductor muscle 

scars.

Discussion. Rabilimis is similar to but larger and 

more inflated than Echinocythereis and is without the 

prominent surface spines of that genus. The smallest 

known species of Rabilimis, R. mirabilis, is 10 percent 

larger than the largest known species of Echinocythereis, E. echinata. The anatomy of Rabilimis is like 

that of Echinocythereis, including the chitinous thoracic knee supports. The two genera are very closely related, and Rabilimis is most probably descended from 

Echinocythereis.

Rabilimis is proposed for Cythere mirabilis Brady, 

1868, Cythere septentrionalis Brady, 1866, and Pseudocythereis paramirabilis Swain, 1963.

Rabilimis is virtually synonymous with Pseudocythereis as used by Swain (1963). Skogsberg (1928) 

described Pseudocythereis', the type species, P. spinifera, is from off the island of South Georgia. Skogsberg considers the anatomy of Pseudocythereis, particularly the thoracic legs, to compare favorably with 

those of the type species of Cytheretta, C. rubra. He 

states that Pseudocythereis does not have chitinous supports in the knees of the thoracic legs. Puri (1958b) 

feels that the hingement and carapace shape of Pseudocythereis is similar to Cytheretta, and he places Pseudocythereis in the Cytherettinae.

Swain (1963) places two new arctic Pleistocene species in Pseudocythereis, P. paramirabilis and P. simpsonensis ( = Cythere septentrionalis Brady, 1866). By 

implication Swain also includes Cythere mirabilis 

Brady, 1868, in Pseudocythereis. Swain's species and 

Cythere mirabilis are shaped and ornamented similar to 

Echinocythereis, and the anatomy of Cythere mirabilis 

is like that of Echinocythereis. The affinity of Cythere 

mirabilis to species of Echinocythereis is also noted by 

van Morkhoven (1963) who places Cythere mirabilis in 

Echinocythereis.

The hard parts of Rabilimis mirabilis are described 

by Brady (1868a), Brady, Crosskey, and Eobertson 

(1874), Elofson (1943), and Akatova (1946). Soft 

parts are described and illustrated by Elofson (1943) 

and Akatova (1946). Rabilimis mirabilis is known 

from approximately 157° E. to 25° W. (East Siberian 

Sea to Greenland Sea), and approximately 58° N. to

80° N. (Lewis Island, Scotland to Franz Josef Land). 

In addition to the localities given by Elofson and Akatova, I have studied specimens of the species found in 

a' sample taken between Shannon Island and Hochstetter Foreland off eastern Greenland.

Rabilimis septentrionalis is known from the Hunde 

Islands, Disko Bay (Brady, 1866, 1868b), approximately 69° K, 53° W., west Greenland, and off Point 

Barrow, Alaska (approx. 71° K, 156° W.). Rabilimis 

paramirabilis is also known to occur from off Point 

Barrow. The genus, therefore, is circumarctic and extends only as far south as 50° N. It occurs in waters 

where the mean annual temperature is less than 10°C.

Rabilimis mirabilis is known from the Pleistocene of 

Scotland and England (Brady and others, 1874), and 

R. paramirabilis and R. septentrionalis are known from 

the Pleistocene of Alaska (Swain, 1963).

Stratigraphic range. Pleistocene to Recent.

Rabilimis septentrionalis (Brady, 1866)

1866. Cythere septentrionalis Brady, Zool. Soc. London Trans.,

v. 5, p. 375, pi. 60, figs. 4a-f. 

1889. Cythere septentrionalis Brady. Brady and Norman,

Royal Dublin Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 149,

pi. 16, figs. 13,14. 

1963. Pseudocythereis simpsonensis Swain, Jour. Paleontology,

v. 37, no. 4, p. 825, pi. 97, figs. 4, 12, 16, 20; pi. 98, figs.

12a-d; pi. 99, figs. lOa-c; text fig. 12a.

Discussion. This species was described from the 

Hunde Islands of southwestern Greenland. I have not 

identified the species from any of my samples.

Swain (1963) described Pseudocythereis simpsonensis and stated that the species "is close to l Cythere* 

septentrionalis Brady in outline, hingement and general surface ornamentation, but in that species the concentrate ridges are more prominent marginally and the 

terminal margins are more spinose." Swain's specimens are abraded and the denticles most probably have 

been worn off. Brady's (1866) original illustrations do 

not emphasize the concentric anterior ornamentation as 

do those of Brady and Norman (1889), yet the specimens came from the same locality and the two sets of 

illustrations may be based on the same specimen. 

After examination of Swain's types and specimens of 

the species found in Recent samples off Point Barrow, 

Alaska, I can see no justification for separating his 

Pseudocythereis simpsonensis from Cythere septentrionalis.

Occurrence. Reported only from the Hunde Islands 

and the Pleistocene of Alaska. I have seen the species 

in Recent samples from off Point Barrow, Alaska.

Subfamily PTERYGOCYTHEREIDINAE Puri, 1957.

Diagnosis. Subrectangular to subpyriform in lateral 

view; triangular in dorsal view; valves alate; hinge
SYSTEMATIC PALEONTOLOGY 39

hemiamphidont to holamphidont; single J-shaped antennal muscle scar; four adductor muscle scars, the 

dorsal scar sometimes divided.

Discussion. The strongly alate valves of the Pterygocythereidinae serve to distinguish the subfamily from 

most other subfamilies of the Trachyleberididae. The 

Brachycytherinae are similar in being swollen ventrally 

and are, in some specimens, alate but differ in the type 

of adductor muscle scars. The Pterygocythereidinae 

have four adductor scars; the upper scar is usually heart 

shaped and sometimes divided. The Brachycytherinae 

generally have both the upper and dorsomedian adductor scars divided.

The following is a list of the Upper Cretaceous and 

Cenozoic genera that seem referable to the Pterygocythereidinae :

Pterygocythereis Blake, 1933, Eocene to Recent 

Pterygocythere Hill, 1954, Turonian to Eocene 

Alatacythere Murray and Hussey, 1942, Albian to Oligocene 

Incongruellina Ruggieri, 1958, Pliocene to Recent 

Ruggieria Keij, 1957, Miocene to Recent 

Kingmaina Keij, 1957, Maestrichtian to Eocene

Genus PTERYGOCYTHEREIS Blake, 1933

(=Fimbria Neviani, 1928) 

Type species, Oythereis jonesi Baird, 1850. 

Diagnosis. Subrectangular in lateral view; valves 

strongly alate, alae may be broken up into row of 

spines; hinge holamphidont; dorsal adductor muscle 

scare may be heart shaped or divided. 

/Stratigraphic range. Eocene to Recent.

Pterygocythereis americana

(Ulrich and Bassler, 1904)

Plate 4, figures 14, 15

1904. Oythereis cornuta var. americana Ulrich and Bassler,

Maryland Geol. Survey, Miocene [volume], p. 122, pi. 37,

figs. 29-33. 

1904. Oythereis alaris Ulrich and Bassler, idem., p. 123, pi. 38,

figs. 34-36. 

1929. Oythereis inexpectatus Blake, Biol. Survey Mount Desert

region, pt. 3, p. 12, fig. 7. 

1933. Oythereis (Pterygocythereis) inexpectata Blake. Blake,

idem, pt. 5, p. 240. 

1935. Not Cythereis (Pterygocythereis) cornuta var. americana

Ulrich and Bassler. Howe and others, Florida Geol.

Survey Bull. 13, p. 26, pi. 2, figs. 19, 21-24. 

1946. Not Cythereis (Pterygocythereis) cornuta var. americana

Ulrich and Bassler. Van den Bold, Contributions to the

study of Ostracoda * * *, p. 100, pi. 10, figs. 17a, b. 

1948. Not Cythereis (Pterygocythereis) cornuta var. americana

Ulrich and Bassler. Swain, Maryland Dept. Geology,

Mines and Water Resources, Bull. 2, p. 206, pi. 13, fig. 4. 

1950. Pterygocythereis americana (Ulrich and Bassler). Van,

den Bold, Jour. Paleontology, v. 24, no. 1, p. 83.

1951. IPterygocythereis cornuta americana (Ulrich and 

Bassler). Swain, U.S. Geol. Survey Prof. Paper 234-A, 

p. 41.

1953. Pterygocythereis americana (Ulrich and Bassler). 

Malkin, Jour. Paleontology, v. 27, no. 6, p. 795, pi. 80, 

fig. 26-29.

1954. Pterygocythereis americana (Ulrich and Bassler). Hill,

Jour. Paleontology, v. 28, no. 6, p. 814, pi. 99, fig. 7a. 

1954. Pterygocythereis cornuta americana (Ulrich and Bassler).

Puri (partim), Florida Geol. Survey Bull 36, p. 261, pi.

13, fig. 1, [1953d]. 

1957. Pterygocythereis americana (Ulrich and Bassler).

McLean, Bull. Am. Paleontology, v. 37, no. 167, p. 80,

pi. 9, figs. 5a-d, 6a-e. 

1960. 1 Pterygocythereis cf. P. americana (Ulrich and Bassler).

Curtis, Am. Assoc. Petroleum Geologists Bull., v. 44, no.

4, pi. 1, fig. 33. 

1963. Pterygocythereis sp. afE. P. americana (Ulrich and

Bassler). Benson and Coleman (partim), Kansas Univ.,

Paleont. Contr., Arthropoda, art. 2, p. 22, pi. 5, fig. 1;

text fig. 10. 

1965. Pterygocythereis americana (Ulrich and Bassler).

Pooser, Kansas Univ. Paleont. Contr., Arthropoda, art.

8, p. 34, pi. 13, figs. 3, 7, 11-14; pi. 14, fig. 12.

Diagnosis. Subrectangular in lateral view; fluted, 

divided, dorsal crest; spine at posterior cardinal angle 

of left valve.

Measurements in mm. 

Female: 

L.. .................

H-.-.-.-..-. ..-

Male: 

L.. .................

H. ..................

N

6

5

4

4

M

1.096

.585

1.172

.562

Sd

0.034

.024

.065

.037

OR

1. 050-1. 125

. 550- . 612

1. 075-1. 212

. 512- . 600

V

3.1

4.1

5.5

6.5

Discussion. At least three species of Pterygocythereis in Oligocene to Recent deposits of the United 

States and Caribbean area have been referred to P. 

americana.

The first report subsequent to Ulrich and Bassler 

(1904) was by Howe and others (1935) who placed 

forms from the Miocene of Florida in the species. In 

1946 van den Bold placed forms from the Miocene of 

Cuba and Guatemala in the species. In 1950 van den 

Bold reported P. americana from the Miocene of 

Venezuela. In this paper he questionably removes his 

1946 specimens and those of Howe and others (1935) 

from the species because they do not have the fluted 

divided dorsal crest described by Ulrich and Bassler 

(1904).

Swain (1948) places a form from the subsurface Miocene of Maryland in P. americana. However, Swain's 

specimen does not seem to have the dorsolateral crest, 

and Hill (1954) places Swain's form in his new species 

P. howei. Hill does not include the specimens of Howe
40 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

and others (1935) in P. howei, but they seem to be conspecific. Hill (1954) considers the identifications of P. 

americana by van den Bold (1950) and Malkin (1953) 

as correct. The species seems to have also been correctly identified by McLean (1957) and Pooser (1965) 

who illustrate specimens from the Neogene of Virginia 

and South Carolina, respectively. McLean states that 

Cythereis alaris Ulrich and Bassler, 1904, is a juvenile 

and very probably a synonym of Pterygocythereis 

americana.

Butler (1963) points out that most of what Puri 

(1953d) illustrates as P. americana from the Neogene 

of Florida is actually P. howei Hill. Curtis (1960) 

illustrates an uncrested form from the Recent off 

Louisiana as Pterygocythere sp., and a juvenile as 

Pterygocythereis cf. P. americana. Benson and Coleman (1963) refer crested and uncrested forms to P. aff. 

P. americana. The uncrested forms of Curtis and Benson and Coleman probably represent an undescribed 

species, whereas the crested forms probably are P. 

americana.

In 1929 Blake described the species Cythereis inexpectata from the Gulf of Maine, and later referred the 

species to his genus Pterygocythereis. Blake was apparently unaware of the work of Ulrich and Bassler 

(1904). My specimens of P. inexpectata, some of which 

were collected from the general area of Blake's localities, have been compared with the types of P. americana 

and judged to be conspecific.

Material studied. 25 specimens.

Occurrence. Previously known from the Gulf of 

Maine and Gulf of Mexico and the Neogene of the 

Atlantic Coastal Plain, Florida, and Venezuela. In the 

present study the species was found in samples from the 

Gulf of Maine and at the edge of the Atlantic Shelf 

north of Hudson Canyon.

Repository. USNM 112767,112768.

Subfamily CYTHERETTINAE Triebel, 1952

Diagnosis. Carapace generally large; surface 

smooth to reticulate or ribbed; hinge very strong 

holamphidont; inner lamella extremely wide, inner 

margin sinuous; most anterior radial canals initiate in 

area of small anterior vestibule; single antennal scar; 

four adductor muscle scars.

Discussion. The following genera are considered to 

belong to the Cytherettinae.

Cytheretta Muller, 1894, Eocene to Recent 

Flexus Neviani, 1928, Oligocene to Miocene 

Paracytheretta Triebel, 1941, Senonian to Paleocene 

Protocytheretta Puri, 1958, Oligocene to Recent 

Neocytheretta van Morkhoven, 1963, Miocene to Recent 

Pseudocythereis Skogsberg, 1928, Recent

Genus CYTHERETTA Muller, 1894

(=Pseudocytheretta Cushman, 1906; Cylindrus Neyiani, 1928; 

Prionocytheretta Mehes, 1941)

Type species, Cytheretta rubra Mueller, 1894 (= Cytherina subradiosa Koemer, 1838).

Diagnosis. Carapace ovate to elongate ovate in lateral view; posterior upturned; left valve overlaps right 

strongly at cardinal angles; hinge strong holamphidont; 

inner lamella extremely broad; inner margin sinuous; 

single J-shaped antennal scar; four adductor scars; first 

thoracic legs of males asymmetrical.

Discussion. Cytheretta has a troubled history. 

Three names seem to have been proposed for the genus; 

one (Cylindrus} is a homonym. Three names are 

available for the type species.

The genus and type species, Cytheretta rubra, were 

described by Mueller (1894) from the Gulf of Naples. 

Both the soft and hard parts are described and illustrated. On Mueller's plate 8, Cytheretta rubra, is represented by four illustrations. Two of these, figures 13 

and 16, are lateral views, and they seem to be of two 

species. The soft parts of a male and female, and an 

internal view of a male left valve are illustrated on 

Mueller's plate 39. The male valve on plate 39 would 

seem to belong to the same species as that of figure 16 

on plate 8. I assume that the male soft parts are also 

of this species. Van Morkhoven (1963) also recognizes 

that Mueller had two species and points out that 

Ilyobates ? judaea Brady, 1868, from the Mediterranean 

may be a senior synonym. Brady's illustrations do seem 

to be of the same species as shown on Mueller's plate 8, 

figure 16, and plate 39, figure 24. Kuggieri (1950) 

synonymizes Cytheretta rubra with Cytherina subradiosa Koemer, 1838, a species originally described 

from the Pliocene of Italy. Puri (1958b) describes and 

illustrates Cytherina subradiosa from the Recent of the 

Adriatic Sea. At least part of what Puri illustrates as 

Cytherina subradiosa seems to be the same species as 

part of what Mueller illustrates (pi. 8, fig. 16; pi. 39, 

fig. 24, and probably the male soft parts on pi. 39) as 

Cytheretta rubra.

The soft parts of Cytheretta subradiosa ( = Cytheretta rubra (part) and Ilyobates^. judaea} are well 

illustrated by Mueller. The salient anatomical characters emphasized by Mueller are the three-jointed exopodite of the second antennae, absence of a seta on the 

posterior border of the protopodite of the first thoracic 

legs, and asymmetry of the first pair of thoracic legs in 

the male. The asymmetry is not particularly strong.

Cushman (1906) described the genus Pseudocytheretta; the type species, P. edivardsi Cushman, is from 

Vineyard Sound and Buzzards Bay. The shell and most
SYSTEMATIC PALEONTOLOGY 41

anatomical characters are said to be virtually the same 

as in Cytheretta, but Pseudocytheretta is said to differ 

by having very strong asymmetry of the first thoracic 

legs in the males. The last joint of the first right leg 

is elongated and greatly broadened on the inner border. 

This asymmetry is really very pronounced when compared with that shown in Mueller's illustration for 

Cytheretta subradiosa.

Blake (1929) describes a species from the Gulf of 

Maine that also shows this asymmetry. Blake does not 

recognize Cushman's genus and places his species in 

Cytheretta without comment, probably following Mueller (1912) who considered Pseudocytheretta to be a 

synonym of Cytheretta because it can not be distinguished on shell structure. Puri (1952) states that from 

the standpoint of paleontology Mueller's conclusions are 

sound. This may be a practical solution for paleontologists but perhaps not logically sound. Many paleontologists have been critical of neontologists for not recognizing taxonomically useful shell characters when the 

anatomies of groups of species, genera, or higher taxa 

are similar. If the anatomical difference between Cytheretta and Pseudocytheretta is such to warrant their 

recognition as separate taxa, then it seems inconsistent 

for paleontologists not to recognize anatomically distinguished genera which unfortunately cannot be distinguished by hard parts alone, particularly when many 

genera are recognized by paleontologists which neontologists claim cannot be recognized by soft parts.

The question is how taxonomically important is the 

difference in the magnitude of asymmetry in Cytheretta 

and Pseudocytheretta. The fact that both Mueller and 

Blake, neontologists, considered the two genera synonymous seems to indicate that the anatomical differences is 

not of generic importance. Unfortunately, Pseudocytheretta edwardsi, Cytheretta subradiosa (~C. rubra] 

and Cytheretta tracyi Blake, 1929, seem to be the only 

three species of Cytheretta for which the soft parts have 

been described.

As far as the carapace is concerned, Cytheretta subradiosa and Pseudocytheretta edwardsi are very similar. 

They differ in the amount of overlap of the left valve 

over the right at the posterior cardinal angle, that of P. 

edwardsi being greater and therefore showing a slightly 

greater posterior upswing. Both species are virtually 

without surface ornamentation, though on some specimens of P. edwardsi the normal pore pits tend to be 

alined longitudinally. Pseudocytheretta edwardsi is 

more than 30 percent larger than Cytheretta subradiosa. 

Further, the average specimen of Cytheretta subradiosa 

is 25 percent smaller than the average of all the smallest 

measurements given for several species of Cytheretta

by Puri (1952, 1958b), and the largest measurement 

given for what appears to be a true representative of 

C. subradiosa is 0.794 mm (Puri, 1958b) the larger 

specimens illustrated by Puri also have a different 

carapace shape and may not be conspecific with the 

smaller ones and this is nearly 8 percent smaller than 

the lowest measurement I could find for a Neogene 

Cytheretta. Size, in general, is a poor taxonomic criterion to use in ostracodes, particularly at the generic 

level; and I do not advocate its use here. However, the 

fact that the specimens of Neogene Cytheretta described 

by Puri (1952) in general bear a closer resemblance to 

Pseudocytheretta edwardsi than to Cytheretta subradiosa, in addition to being approximately the same 

size, certainly calls for an investigation of the living 

species assigned to Cytheretta to see if strong first 

thoracic leg asymmetry is concomitant with larger size. 

It is known to hold for at least two species, Pseudocytheretta edwardsi and Cytheretta tracyi. 

Stratigraphic range. Eocene to Recent.

Cytheretta edwardsi (Cushman, 1906)

1906. Pseudocytheretta edicardsi Cushman, Boston Soc. Nat.

History Proc., v. 32, p. 382, pi. 38, figs. 119-132. 

1958. Cytheretta edwardsi (Cushman). Puri, Gulf Coast Assoc. Geol. Socs. Trans., v. 8, p. 187, pi. 2, figs. 6-11. 

1963. Not Cytheretta edwardsi (Cushman). Swain, Jour.

Paleontology, v. 37, no. 4, p. 832, pi. 95, fig. 11; pi. 99,

figs. 13a-c ; text figs. 9a, 13b.

Diagnosis. Highest at posterior; surface essentially 

smooth except for small pits at normal pore canal exits.

Measurements. Two adult made specimens measure 

1.275 and 1.325 mm in length and 0.625 and 0.650 mm in 

height.

Discussion. Puri (1958b) has described and illlustrated specimens of the species from samples taken at 

the original stations of Cushman (1906). Swain 

(1963) reports Cytheretta edwardsi from the Pleistocene of Alaska. However, his specimens have a very 

different carapace shape than Cytheretta edwardsi, 

being relatively much higher at the anterior. Swain's 

specimens probably represent a new species.

Material studied. Two adult males and several juveniles (Recent), plus many adults and juveniles found 

in Pleistocene samples taken from the subsurface at 

Sandy Hook, N.J.

Occurrence. Previously known from Vineyard 

Sound and Buzzards Bay. In the present study the 

species was found in a sample from off Lower New York 

Bay. Also known from subsurface Pleistocene deposits 

at Sandy Hook, N.J.

Repository. USNM 112799.
42 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Cytheretta tracyi Blake, 1929

1929. Cytheretta tracyi Blake, Biol. Survey Mount Desert region, pt. 3, p. 18, fig. 9. 

1933. Cytheretta tracyi Blake. Blake, idem, pt. 5, p. 233.

Discussion. Blake (1929) described this species from 

near Mount Desert Island, Maine. I have not found 

the species in my samples. Blake distinguishes Cytheretta tracyi from C. edwardsi by the more acute posterior 

cardinal angle and shallower "depression in the inner 

shell margin below the adductor muscle."

Subfamily Indeterminate 

Genus Indeterminate

Cythereis phalaropi Cushman, 1906

1906. Cythereis phalaropi Cushman, Boston Soc. Nat. History 

Proc. v. 32, no. 10, p. 378, pi. 35, figs. 86-94; pi. 36, figs. 

95, 96.

Discussion. I have not been able to modernize the 

taxonomy of Cythereis phalaropi described by Cushman 

(1906). No specimens were found that I could refer to 

the species. The soft parts are well illustrated, but the 

illustrations of the carapace are minimal. The soft 

parts are trachyleberidid.

Occurrence. Known only from Buzzards Bay.

REFERENCES

Akatova, N. A., 1946, K faune Ostracoda Novosibirskogo melkovod'ya [Ostracodes from the New Siberian Islands shelf 

waters], in Dreifuyushchei ekspeditsii glavsevmorputi na 

ledokol'nom parokode "G. Sedov," 1937-1940 g.g., Trudy: 

Vsesoyusnyy Arkticheskiy Nauchno-IssledovatePskiy Inst. 

[Leningrad], v. 3, p. 224-230.

Apostolescu, Vespasin, 1961, Contribution a 1'etude paleontologique (Ostracodes) et stratigraphique des bassins cretaces et tertiaires de 1'afrique occidentale: Inst. Frangais 

Petrole Rev., v. 16, no. 7, p. 779-867.

Baird, William, 1850, The natural history of the British Entomostraca: London, Ray Soc., 364 p.

Bassiouni, M. A. A., 1962, Ostracoden aus dem Mittelmiozan in 

NW-Deutschland: Romeriana, no. 3, 99 p.

 1965, tiber einige Ostracoden aus dem Interglazial von

Esbjerg: Dansk Geol Foren., Medd., v. 15, no. 4, p. 507-518. 

Bate, R. H., 1963, Middle Jurassic Ostracoda from north

Lincolnshire: British Mus. (Nat. History), Geology, Bull,

v. 8, no. 4, p. 175-219. 

Benson, R. H., 1964, Recent cytheracean ostracodes from McMurdo Sound and the Ross Sea, Antarctic: Kansas Univ.

Paleont. Contr., Arthropoda, art. 6, 1-36. 

Benson, R. H., and Coleman, G. L., II, 1963 Recent marine

ostracodes from the eastern Gulf of Mexico: Kansas Univ.

Paleont. Contr., Arthropoda, art. 2, p. 1-52. 

Benson, R. H. and Tatro, J. O., 1964, Faunal description of the

Ostracoda of the Marlbrook Marl (Campanian), Arkansas:

Kansas Univ. Paleont. Contr., Arthropoda, art. 7, p. 1-32. 

Blake, C. H., 1929, New Crustacea from the Mount Desert region:

Biol. Survey Mount Desert Region, pt. 3, p. 1-34.

 1933, Order Ostracoda: Biol. Survey Mount Desert region, pt. 5, p. 229-241.

Blake, D. B., 1950, Gosport Eocene Ostracoda from Little Stave 

Creek, Alabama: Jour. Paleontology, v. 24, no. 2, p. 174-184.

Bold, W. A. van den, 1946, Contribution to the study of Ostracoda 

with special reference to the Tertiary and Cretaceous 

microfauna of the Caribbean region: Amsterdam, DeBussy, 167 p.

 1950, Miocene Ostracoda from Venezuela: Jour. Paleontology, v. 24, no. 1- p. 76-88.

 1960, Eocene and Oligocene Ostracoda of Trinidad: 

Micropaleontology, v. 6, no. 2, p. 145-196.

 1963a, The ostracode genus Orionina and its species: 

Jour. Paleontology, v. 37, no. 1, p. 33-50.

 1963b, Upper Miocene and Pliocene Ostracoda of Trinidad: Micropaleontology, v. 9, no. 4, p. 361-424.

1964, Ostracoden aus der Oberkreide van Abu Rawash,

Agypten: Paleontographica, v. 123, pt. A. p. 111-136.

Bosquet, J., 1852, Description des Entomostraces fossiles des 

terrains tertiaires de la France et de la Belgique: Acad. 

Royale des Sci. Belgique, Mem. Cour. et Mem. savants 

 Strangers, v. 24,142 p.

Bowen, R. N. C., 1953, Ostracoda from the London Clay: Geol. 

Assoc. London Proc., v. 64, no. 4, p. 276-292.

Brady, G. S., 1866, On new or imperfectly known species of marine Ostracoda: Zool. Soc. London Trans., v. 5, p. 359-393.

 1868a, A monograph of the Recent British Ostracoda: 

Linnean Soc. London Trans., v. 26, no. 2, p. 353-495.

 1868b, Ostracoda from the Arctic and Scandinavian Seas: 

Annals and Mag. Nat. History, 4th ser., v. 2, p. 30-35.

 1868c. Entomostraces, C6te de Sicile: Fonds de la Mer, 

v. 1, pt. 1, chap. 19, p. 93-94.

 1870a, Recent Ostracoda from the Gulf of St. Lawrence:

Annals and Mag. Nat. History, 4th ser., v. 6, p. 450-454.

 1870b, Appendice (ostracodes), Vera-Cruz et Carmen: 

Fonds de la Mer, v. 1, pt. 2, chap. 2, p. 191, 192.

 1878a, Notes on the Ostracoda, in Nares, G. S., Narrative 

of a trip to the polar sea during 1875-6 in H. M. ships 

'Alert' and 'Discovery': London, S. Lowe, Marston, Searle 

and Rivington, v. 2, no. 7, p. 253-255.

 1878b, A monograph of the Ostracoda of the Antwerp 

Crag: Zool. Soc. London Trans., v. 10, p. 379-409.

 1880, Report on the Ostracoda dredged by H.M.S. 

Challenger during the years 1873-76; Report on the scientific results of the voyage of H.M.S. Challenger, Zoology, v. 

1, pt. 3, p. 1-184.

 1890, On Ostracoda collected by H. B. Brady, Esq., 

LL.D., F.R.S., in the South Sea Islands: Royal Soc. Edinburgh Trans., v. 35, pt. 2, no. 14, p. 489-525.

 1898, On new or imperfectly-known species of Ostracoda,

chiefly from New Zealand: Zool. Soc. London Trans., v. 14, 

p. 429-452.

Brady, G. S., and Crosskey, H. S. 1871, Notes on fossil Ostracoda from the post-Tertiary deposits of Canada and New 

England: Geol. Mag., v. 8, p. 60-65.

Brady, G. S., Crosskey, H. W., and Robertson, D., 1874, A monograph of the post-Tertiary Entomostraca of Scotland including species form England and Ireland: London, Palaeontographical Soc., 274 p.

Brady, G. S., and Norman, A.M., 1889, A monograph of the marine and fresh-water Ostracoda of the North Atlantic and 

of Northwestern Europe. Section I, Podocopa: Royal 

Dublin Soc. Sci. Trans., 2d ser., v. 4, no. 2, p. 63-270.

Brady, G. S., and Robertson, D., 1869, Notes of a week's dredging in the west of Ireland: Annals and Mag. Nat. History, 

4th ser., v. 3, p. 353-374.
REFERENCES 43

Brown, P. M., 1957, Upper Cretaceous Ostracoda from North 

Carolina: North Carolina Div. Mineral Resources Bull. 70, 

29 p.

 1958, Well logs from the Coastal Plain of North Carolina : North Carolina Div. Mineral Resources Bull. 72, 68 p.

Butler, E. A., 1963, Ostracoda and correlation of the upper and 

middle Frio from Louisiana to Florida: Louisiana Geol. 

Survey Bull. 39,100 p.

Butler, E. A., and Jones, D. E., 1957, Cretaceous Ostracoda of 

Prothro and Rayburns salt domes Bienville Parish, Louisiana : Louisiana Geol. Survey Bull. 32, 65 p.

Chernysheva, N. E., ed., 1960, Osnovy paleontologii, spravochnik 

dlya paleontologov i geologov SSSR; [v. 8], Chlenistonogie, 

trilobitoobraznye i rakoobraznye: [Basic paleontology 

* * *Arthropods, Trilobites, Crustaceans]: Moscow, 

Gosudarstvennoe Nauchno-Tekhnicheskoe Izdatel'stvo Literatury Geologii i Okhrane Nedr, 515 p.

Coryell, H. N. and Fields, S., 1937, A Gatun ostracode fauna 

from Cativa, Panama: Am. Museum Novitates, no. 959,19 p.

Crouch, R. W., 1952, Significance of temperature on Foraminifera from deep basins off southern California coast: Am. 

Assoc. Petroleum Geologists Bull., v. 36, no. 5, p. 807-843.

Curtis, D. M., 1960, Relation of environmental energy levels and 

ostracod biofacies in east Mississippi delta area: Am. Assoc. 

Petroleum Geologists Bull., v. 44, no. 4, p. 471-494.

Cushman, J. A., 1906, Marine Ostracoda of Vineyard Sound and 

adjacent waters: Boston Soc. Nat. History, Proc., v. 32, no. 

10, p. 359-385.

Deroo, G., 1962, Mauritsininae, Nouvelle sous-famille de Cytheridae (Ostracodes) dans le Cr6tac6 Sup6rieur de la region de Maastricht, Pays-Bas: Revue de MicropalSontologie, 

v. 4, no. 4, p. 203-210.

Edwards, R. A., 1944, Ostracoda from the Duplin Marl (upper 

Miocene) of North Carolina: Jour. Paleontology, v. 18, no. 

6, p. 505-528.

Elofson, Olof, 1938, Neue und wenig bekannte Cytheriden von 

der SchwedisChen Westkiiste: Arkiv Zoologi, v. 30A, no. 

21, p. 1-22.

 1941, Zur Kenntnis der marinen Ostracoden Schwedens, 

mit besonderer Berucksichtigung des Skagerraks: Zool. 

Bidrag fran Uppsala, v. 19, p. 215-534.

 1943, Neuere Beobachtungen fiber die Verbreitung der 

Ostracoden an den skandinavischen Kusten: Arkiv Zoologi, 

V. 35A, no. 2, p. 1-26.

Emery, K. O., and Schlee, J. S., 1963, The Atlantic Continental 

Shelf and Slope, a program for study: U.S. Geol. Survey 

Circ. 481,11 p.

Grekoff, Nicolas and Moyes, Jean, 1955, Un nouveau genre d'ostracode du bassin d'Aquitaine. Falunia girondica, n.g., n. 

sp.: Soc. Geol. France Bull., 6th ser., v. 5, p. 331-335.

Harding, J. P., and Sylvester-Bradley, P. C., 1953, The ostracod 

genus Tracliyleberis: British Mus. (Nat. History), Bull. 

Zoology, v. 2, no. 1, p. 1-15.

Hartmann, Gerd, 1959, Zur Kenntnis der lotischen Lebensbereiche der pazifischen Ktiste von El Salvador unter besonderer Berucksichtingung seiner Ostracoden fauna, [pt.] 

3 of Beitrag zur Fauna El Salvadors: Kieler Meeresforschungen, v. 15, no. 2, p. 187-241.

 1962, Ostracoden des Euliterals, in Hartmann-Schroder, 

G. und Hartmann, G., Zur Kenntnis des Eulittorals der 

chilenischen Pazifikkuste und der argentinischen Kiiste 

Siidpatagoniens unter besonderer Berucksichtingung der 

Polychaeten und Ostracoden: Hamburg Zool. Mus. Inst., 

Mitt., pt. 3, p. 169-270.

Hartmann, Gerd, 1964, Zur Kenntnis der Ostracoden des Roten

Meeres: Kieler Meeresforschungen, v. 20, spec, pub., p.

31-127. 

Haskins, C. W., 1963, Revision of the ostracode genus Trachyleberidea Bowen: Micropaleontology, v. 9, no. 1, p. 71-74. 

Hazel, J. E., 1962, Two new hemicytherid ostracods from the

lower Pleistocene of California: Jour. Paleontology, v. 36,

no. 4, p. 822-836.

 1965a, Notes on the ostracode genus Trachyleberidea 

Bowen: Jour. Paleontology, v. 39, no. 3, p. 501-503.

 1965b. Ostracoda: Woods Hole Oceanographic Inst.,

Summary Invest. (1964), p. 73.

Hazel, J. E. and Paulson, O. L., Jr., 1964, Some new ostracode 

species from the Austinian and Tayloran (Coniacian and 

Campanian) rocks of the East Texas Embayment: Jour. 

Paleontology, v. 38, no. 6, p. 1047-1064.

Hill, B. L., 1954, Reclassification of winged Cythereis and winged 

Brachycythere: Jour. Paleontology, v. 28, no. 6, p. 804-826.

Holden, J. C., 1964, Upper Cretaceous ostracods from California: 

Palaeontology, v. 7, pt. 3, p. 393-429.

Hornibrook, N. de B., 1952, Tertiary and Recent marine Ostracoda of New Zealand. Their origin, affinities, and distribution : New Zealand Geol. Survey Palaeont. Bull. 18, 82 p.

Howe, H. V., 1951, New Teritary ostracode fauna from Levy 

County, Florida: Florida Geol. Survey Bull. 34, pt. 1, 

p. 1-43.

 1962, Ostracod taxonomy: Baton Rouge, Louisiana State 

Univ. Press, 366 p.

Howe, H. V., and Chambers, Jack, 1935, Louisiana Jackson 

Eocene Ostracoda: Louisiana Geol. Survey, Geol. Bull. 5, 

65 p.

Howe, H. V., and Laurencich, Laura, 1958, Introduction to the 

study of Cretaceous Ostracoda: Baton Rouge, Louisiana 

State Univ. Press, 536 p.

Howe, H. V., and Law, John, 1936, Louisiana Vicksburg Oligocene Ostracoda: Louisiana Geol. Survey Geol. Bull. 7, 

96 p.

Howe, H. V., and others, 1935, Ostracoda of the Area zone of the 

Choctawhatchee Miocene of Florida: Florida Geol. Survey 

Bull. 13, 47 p.

Howe, R. C., 1963, Type Saline Bayou Ostracoda of Louisiana: 

Louisiana Geol. Survey Geol. Bull. 40, 62 p.

Israelsky, M. C., 1929, Upper Cretaceous Ostracoda of Arkansas: 

Arkansas Geol. Survey Bull. 2,28 p.

Jones, T. R., 1857, A monograph of the Tertiary Entomostraca 

of England: London, Palaeontographical Soc., 68 pKeij, A. J., 1957, Eocene and Oligocene Ostracoda of Belgium: 

Inst. Royal Sci. Nat. Belgique Mem. 136, 210 p.

Krutak, P. R., 1961, Jackson Eocene Ostracoda from the Cocoa 

Sand of Alabama: Jour. Paleontology, v. 35, no. 4, p. 769- 

788.

Loeblich, A. R., Jr., and Tappan, H. N., 1953, Studies of Arctic 

Foraminifera: Smithsonian Misc. Coll., v. 121, no. 7, 150 p.

McLean, J. D., Jr., 1957, The Ostracoda of the Yorktown Formation in the York-James Peninsula of Virginia: Bulls. Am. 

Paleontology, v. 38, no. 167, p. 57-103.

Malkin, D. S., 1953, Biostratigraphic study of Miocene Ostracoda 

of New Jersey, Maryland, and Virginia : Jour. Paleontology, 

v. 27, no. 6, p. 761-799.

Mandelstam, M. L, and others, 1957, Novye rody ostrakod v 

semeistvakh Cypridae i Cytheridae [New genera of Ostracoda in the families Cypridae and Cytheridae]: Vsesoyuznogo Poleont. Obshchestva Ezhegodnik, v. 16 (1955-56), 

p. 166-185.
44 RECENT HEMICYTHERIDAE, TRACHYLEBERIDIDAE OFF NORTHEASTERN NORTH AMERICA

Moore, R. C., ed., 1961, Treatise on invertebrate paleontology ;

Pt. Q, Arthropoda 3, Ostracoda : New York and Lawrence,

Bans., Geol. Soc. America and Univ. Kansas Press, 442 p. 

Morkhoven, F. P. C. M. van, 1962, Post-Paleozoic Ostracoda;

their morphology, taxonomy, and economic use : Amsterdam,

Elsevier, v. 1 (general) , 204 p.

 1963, Post-Paleozoic Ostracoda, their morphology, taxonomy, and economic use : Amsterdam, Elsevier, v. 2 (generic descriptions) , 478 p.

Mueller, G. W., 1894, Die Ostracoden des Golfes von Neapel und 

der angrenzenden Meeresabschnitte : Naples Sta. Zool., 

Fauna und Flora des Golfes von Neapel, Monographic 21, 

p, 1-404.

 1908, Die Ostracoden der Duetschen Sudpolar-Expedition 

1901-1903: Wiss. Ergebn. d. Deutschen Sudpolar-Expedition, v. 10, Zoology 2, p. 51-181.

 1912, Ostracoda in Das Terreich : Auftrage Kgl. Preussische Akad. Wiss., v. 31, p.

1931, Die Ostracoden des arktischen Gebietes: Fauna

Arctica, v. 6, no. 1, p. 21-32.

Neale, J. W., 1959, Normanicy'there Gen. Nov. (Pleistocene and 

Recent) and the division of the ostracod family Trachyleberididae: Palaeontology, v. 2, pt. 1, p. 72-93.

 1961, Normanicythere leioderma (Norman) in North

America : Palaeontology, v. 4, pt. 3, p. 424. 

Neviani, A., 1928, Ostracodi fossili d'ltalia; [pt.] l, Vallebiaja

(Calabriano) : Pontifica Accad. Sci., M6m., ser. 2, v. 11, p.

1-120. 

Norman, A. M., 1865, Report on the Crustacea, in Brady, G. S.,

Deep-sea dredging on the coasts of Northumberland and

Durham in 1864: British Assoc. Adv. Sci., rept. 34th Mtg.,

p. 189F-193F.

 1869, Shetland final dredging report, Pt. 2.; On the 

Crustacea, Tunicata, Polyzoa, Echinodermata, Actinozoa, 

Hydrozoa, and Porifera: British Assoc. Adv. Sci., rept. 38th 

Mtg., p. 247-336.

1877, Crustacea, Tunicata, Polyzoa, Echinodermata,

Actinozoa, Foraminifera, Polycystina, and Spongida (of the

Valorous Cruise, 1875) : Royal Soc. London Proc., v. 25, p.

202-215. 

Oertli, H. J., 1956, Ostrakoden aus der Oligozanen und Miozanen

Molasse der Schweiz: Schweizen Palaont. Gesell. Abb.., v.

74, no. 1,119, p. 

Pokorny, Vladimir, 1955, Contribution to the morphology and

taxonomy of the subfamily Hemicytherinae Puri, 1953

(Crust, Ostrac.) : Carolinae Univ. acta, Geologica, v. 3,

p. 1-35.

 1958, Grundziige der zoologischen Mikropalaontologie: 

Berlin, Deutscher. Verlag Wiss., v. 2, 453 p.

 1964a, The taxonomic delimitation of the subfamilies 

Trachyleberidinae and Hemicytherinae (Ostracoda, 

Crustacea) : Carolinae Univ. acta, Geologica, v. 3, p. 275- 

384.

 1964b, Oertliella and Spinicythereis, new ostracod genera

from the Upper Cretaceous: Ustrednlho Ustavu Geol.

VSstnlk [Czechoslovakia], v. 39, no. 4, p. 281-284. 

Pooser, W. K., 1965, Biostratigraphy of Cenozoic Ostracoda from

South Carolina: Kansas Univ. Paleont. Contr., Arthropoda,

art. 8, p. 1-80. 

Puri, H. S., 1952, Ostracode genera Cytheretta and Paracytheretta in America: Jour. Paleontology, v. 26, no. 2, p.

199-212.

Puri, H. S., 1953a, The ostracode genus Trachyleberis and its 

ally Actinocythereis: Am. Midland Naturalist, v. 49, no. 1, 

p. 171-181.

 1953b, Taxonomic comment on: "Ostracoda from wells 

in North Carolina Part I: Cenozoic Ostracoda" by F. M. 

Swain: Jour. Paleontology, v. 27, n. 5, p. 750-752.

 1953c, The ostracode genus Hemicythere and its allies: 

Washington Acad. Sci. Jour., v. 43, no. 6, p. 169-179.

 1953d, Contribution to the study of the Miocene of the 

Florida panhandle; Part 3, Ostracoda: Florida Geol. Survey Bull. 36, p. 217-345[1954].

 1955, Hermanites, new name for Hermania Puri, 1954: 

Jour. Paleontology, v. 29, no. 3, p. 558.

 1956, Two new Tertiary ostracode genera from Florida: 

Jour. Paleontology, v. 30, no. 2, p. 274-277.

 1957a, Postscript notes on the ostracode subfamily 

Brachycytherinae: Washington Acad. Sci. Jour., v. 47, no. 

9, p. 306-308.

 1957b, Stratigraphy and zonation of the Ocala Group: 

Florida Geol. Survey Bull. 38,248 p.

 1957c, Henryhowelto, new name for Howella Puri, 1956: 

Jour. Paleontology, v. 31, no. 5, p. 982.

 1958a, Ostracode genus Cushmanidea: Gulf Coast Assoc. 

Geol. Socs. Trans., v. 8, p. 171-181.

 1958b, Ostracode subfamily Cytherettinae: Gulf Coast 

Assoc. Geol. Socs. Trans., v. 8, p. 183-195.

 1960, Recent Ostracoda from the west coast of Florida:

Gulf Coast Assoc. Geol. Socs. Trans., v. 10, p. 107-149. 

Reyment, R. A., 1960, Studies on Nigerian Upper Cretaceous and 

Lower Tertiary Ostracoda, Pt. 1; Senonian and Maestrichtian Ostracoda : Stockholm Contr. Geology, v. 7, 38 p., 23 pis.

 1963, Studies on Nigerian Upper Cretaceous and Lower 

Tertiary Ostracoda, Pt. 2; Danian, Paleocene, and Eocene 

Ostracoda : Stockholm Contr. Geology v. 10, 286 p., 23 pis.

Roemer, F. A., 1838, Die Cytherinen des Molasse-Gebirges: 

Neues Jahrb. Mineralogie, Geologic, Palaontologie, p. 514- 

519.

Ruggieri, Giuliano, 1950, Gli Ostracodi delle sabbie grigie 

Quaternarie (Milazziano) di Imola, Pt. 1: Gior. Geologia, 

ser. 2, v. 21, p. 1-57.

 1955, Tyrrhenocythere, a new Recent ostracode genus 

from the Mediterranean: Jour. Paleontology, v. 29, no. 4, p. 

698-699.

 1956, La subdivisione degli ostracodi gi£ compresi nel 

genere Cythereis proposta da Neviani nel 1928: Soc. Italiana Sci. Nat. Atti., v. 95, no. 2, p. 161-175.

 1962, Gli Ostracodi marini del Tortoniano (Miocene

medio superiore) di Enna, Nella Sicilia centrale: Palaeontographia Italica, v. 56, (n. ser., v. 26), Mem. no. 2, p. 1-68.

Sars, G. O., 1865, Oversigt af Norges marine ostracoder: 

Vidensk.-Selsk. Christiania, Forh., p. 1-130.

 1922-28, An account of the Crustacea of Norway: Bergen 

Mus. (Norway), v. 9, Ostracoda, 277 p.

Sharpe, R. W., 1908, A further report on the Ostracoda of the 

U.S. National Museum: U.S. Natl. Mus. Proc., v. 35, p. 399- 

430.

Simpson, G. G., 1961, Principles of Animal Taxonomy: New 

York, Columbia University Press, 247 p.

Skogsberg, Tage, 1928, Studies on marine ostracods, [pt.]2. 

External morphology of the genus Cythereis with descriptions of 21 new species: California Acad. Sci., Occasional 

Paper, no. 15,154 p.
REFERENCES 45

Sonmez-Gokgen, N., 1964, Notice sur le nouvel age determine par 

les Ostracodes de la s6rie a Congeria du Neogene des environs 

de Catalca (Thrace) : Turkey Mineral Research and Explor. 

Inst. Bull, no. 63, p. 47-59.

Speyer, Oscar, 1863, Die Ostracoden der Casseler Tertiarbildungen: Ver. Naturkunde Kassel Ber., v. 13, p. 1-63.

Swain, F. M., 1948, Ostracoda from the Hammond well: Maryland Dept. Geology, Mines and Water Resources Bull. 2, p. 

187-212.

 1951, Ostracoda from wells in North Carolina; Pt. 1, 

Cenozoic Ostracoda: U.S. Geol. Survey Prof. Paper 234-A, 

58 p.

 1955, Ostracoda of San Antonio Bay, Texas: Jour. Paleontology, v. 29, no. 4, p. 561-646.

 1963, Pleistocene Ostracoda from the Gubik Formation,

Arctic Coastal Plain, Alaska: Jour. Paleontology, v. 37, no.

4, p. 798-834. 

Sylvester-Bradley, P. C., 1948, The ostracode genus Cythereis:

Jour. Paleontology, v. 22, no. 6, p. 792-797. 

Tressler, W. L., 1940, Ostracoda from Beaufort, North Carolina,

sand beaches: Am. Midland Naturalist, v. 24, no. 2, p. 365- 

368.

Tressler, W. L., 1941, Geology and biology of North Atlantic 

deep-sea cores between Newfoundland and Ireland; Pt. 4, 

Ostracoda: U.S. Geol. Survey Prof. Paper 196-C, p. 95-104.

Tressler, W. L., and Smith, E. M., 1948, An ecological study of 

seasonal distribution of Ostracoda, Solomons Island, Maryland, region: Maryland, Chesapeake Biol. Lab., Pub. no. 71, 

57 p.

Triebel, Erich, 1940, Die Ostracoden der deutschen Kreide, pt. 

3; Cytherideinae und Cytherinae aus der Unteren Kreide: 

Senckenbergiana, v. 22, no. 1-6, p. 160-227.

 1952, Ostracoden der Gattung Cytheretta aus dem Tertiar des Mainzer Beckens: Hess. Landesamt Bodenforschung Notizbl., v. 6, no. 3, p. 15-30.

Ulrich, E. O. and Bassler, R. S., 1904, Systematic paleontology, 

Miocene Arthropoda: Maryland Geol. Survey, Miocene 

[volume], p. 98-130.

Wagner, C. W., 1957, Sur les ostracodes du Quaternaire R6cent 

des Pays-Bas et leur utilization dans 1'etude geologique des 

dep6ts holocenes: The Hague, Mouton and Co., 259 p.

INDEX

[Italic page numbers Indicate major references and descriptions]

Page

abbreviata, Cletocythereis elofsoni _ 34 

Absonocytheropteron _____ 10, 12, 13, 14 

abyssicola, Cythere _______________ 22

Cythereis ________________ 22

Muellerina ______ 4, 21, 22, 23; pi. 3

Acanthocythereis _________________ 31, 34

araneosa ___________ 34

dunelmensis ____________ 4, 34

Actinocythereis _________ 3.1, 32, 34 

allisoni _________________ 31

dawsoni ________ 4, 32, 33; pis. 5, 11

exanthemata _________________ 34

mundorffl ________________ 34

twieyardewsts _ 4, 32, S3, 34 ; pis. 5, 11 

Actinocythereis-Trachyleberis group _ 31 

Acuticythereis _______________ 26

Adductor muscle scars________ 8 

alaris, Cythereis __________________ 39, 40

Alatacythere _____________________ 30, 39

albomaculata, Cythere_____________ 23

Cythereis ____________________ 23

allisoni, Actinocythereis____________ 31

Ambostracon_____________ 8, 10, 12, 14, 16

americana, Bensonocythere ___ 1, 4, 27, 28,

29; pis. 5, 11

Cythereis cornuta _____________ 39

(Pterygocythereis) cornuta- 39 

Ptervgocythereis______ 4, 39, 40; pi. 4

corwMta ____________ 39 

Amphicythere ____________________ 30

angulata, Cythereis_____________ 2, 18, 19

Cythereis (Eucythereis) _______ 19

Finmarchinella _______________ 19

Hemicythere _________________ 19

Hemicytherinae ____________ 19

Nereina__________ 4, 18, 19; pis. 1, 11

Trachylebris ______________ 19, 25, 26

Antarctica, Patagonacythere longiducta _______________ 19

Awticytftereis_________ 7, 8, 11, 26, 27 

b&paensis ______________ 26 

reticulata ____________________ 27

AgwitawieMa______________ 1, 9, 24 

arachoides, Velarocythere________ 27

araweosa-, Acanthocythereis_______ 34

Archicythereis ____________________ 6

arenicola, Bensonocythere______ 4, 28, 29 ;

pis. 5, 11

Cythereis ______________ 27, 29 

(Hemicythere) ___________ 29

Awr«a 10, 11, 12, 13, 14, 23 

laevicula ____________________ 23

sp ______ 4,23; pi. 1 

Auris _______________________ 23

Australicythere________________ 10, 12, 14

Bafflnicythere_________ 1, 11, 12, 14, 16, 17

costata___________ 4, 17, 18; pis. 2, 8

emarginata--_____ 4, 17, 18 ; pis. 2, 9 

baremsovoen,sis, Nereina____________ 18, 19

Basslerites ________________ 26, 27 

bellula, Hemicythere_______________ 10

Page 

Bensonocythere________ 1, 7, 13, 26, 27, 29

americawa___ 1, 4, 27, 28, 29; pis. 5, 11 

arewicoZa_____ 4, 28, 29 ; pis. 5, 11 

caZverti ________________ 28 

whitei_____ 4, 27, 28, 29; pis. 5, 10, 11

bermudezi, Cythereis______________ 31

bollii, Trachyleberis________________ 31

bopaensis, Anticythereis __________ 26

borealis, Cythere____________ 14,15

Hemicythere_______ 4, 14, J5 ; pi. 2

Bosquetina ________________ 1,36

Brachycythere _____________ 11, 30

ogboni ________________ 10, 30

Brachycytheridae __________ 30

Brachycytherinae____ 8, 11, 29, 30, 31, 39

Bradleya_______________ 1, 7, 9, 24

lactea pakaurangia________ 7

semivera _____________ 7

Bwwfowia __________________ 9, 26

garretti _______________ 36

planisbalis _____________ 37

Buntoniinae__________ 11, 30, 31, 36

cacumenata, Velarocythere

calhounensis, Hemicythere-.

calverti, Bensonocythere_.

Cythere ________.

__ 27 

__ 13 

__ 28 

___ 27 

Gampylocythere _____________ 26, 27 

conoinnoidea ____________ 27 

Campylocytherinae- 7, 8, 9, 11, 13, 14, 26, 27 

canadensis, Cythere__________ 22

Cythereis ______________ 22

Muellerina___ 4, 21, 22, 23; pis. 3, 7

carinata, Cytherina _______ 35

Carinocythereis__________ 31, 35, 36 

whiteii _____________ 4, 36

Cativella _______________ 31

Caudites_____________ 10, 12, 14, 16 

Chrysocythere ________________ 26, 27

citrusensis, Trachyleberis______ 31 

clathrata, Cythere___________ 2

Cletocythereis ______________ 34

dunelmensis ___ _ __ 35

dunelmensis _________ 34

minor _____ __ ___ 34

elofsoni ________________ 34, 35

abbreviata ___ __ 34

elofsoni ____ _ ___ 34

noblissimus ______ ____ 34

Climacoidea _______ 31

concinella, Normanicythere_ ___ 23, 24

concinna concinna, Elofsonella___ 15, 16

Cythere ______________ 15, 16

Cythereis (Paracythereis) ____ 15

Elofsonella_____ 4, 14, 15, 16; pi. 4

concinna ______ ___ 15,16

neoconcinna, Elofsonella __ 16 

concinnoidea, Campylocythere __ 27 

convexa, Cythere____________ 23 

cookei, Leguminocythereis_______ 27 

cornuta americana, Cythereis_____ 39 

americana, Cythereis (Pterygocythereis) _______ 39

Pterygocythereis ______ 39

Page

Costa_____ 7, 8, 31

costata, Bafflnicythere-- 4, 17, 18; pis. 2, 8

Cythere______ _ 2, 16, 17

crassus, Legwminocythereis 27

crenulata, Cythereis 1, 25

Cythereis (Eucythereis) 25

Thaerocythere___ 4, 25, 26; pis. 4, 9

cribraria, Hemicythere _ 10

cuspidata, Cythere 34

Cylindrus _ 40

Cypridacea - 6

Cyprididae 6

Cytheracea 6, 13 

Cythere 16, 25

abyssicola - 22

albomaculata 23 

borealis 14,15

calverti 27 

canadensis 22

clathrata 2 

cemciwwa _ 15,16 

convexa 23 

costata _____-__ 2, 16, 17 

cuspidata 34 

dawsoni ---------- 32

dubia 19,20

dunelmensis _ 34 

exanthemata --------------- 31

flnmarchica 18 

latimarginata 20, 23 

leioderma 23 

lienenklausi - 21, 22 

logani __ 35 

margaritifera _ 36, 37 

martini 21. 22 

micula 21,22 

mirabilis _ - 1. 38 

oedichilus 25 

planisbalis -- 37 

producta 21, 22 

pulchella -- 14,15

punctata - 23 

rastromarginata - 34 

rw&ida __ 14 

scabrocuneata ----------- 31

septentrionalis 2, 38 

ventricosa ------------------ 10

whitei --- - - 36

whiteii 36

wyvillethompsoni 19

Cythereis 5, 30. 31

abyssicola 22

alaris -________ - - -- 39, 40

albomaculata 23 

angulata . - 2, 18, 19 

arenicola - - 27, 29 

bermudesi -- -- - 31

canadensis 22 

corrMta americana _- 39 

crenulata 1» 25 

davidwhitei -- - 31 

dawsoni 32 

dunelmensis -------------- 34

echinata 37 

emarginata -- -- 16,17

flnmarchica 18

47
48 INDEX

Cythereis Continued Page 

garretti _____________________ 36, 37

gunteri ____________ 21, 22

inexpectata ____________ 40 

inexpectatus _____________ 39

jonesi _______________________ 39

midwayensis _________________ 24

montgomeryensis _____________ 31

phalaropi ____________________ 4, 42

procteri _____________________ 37

quadrataspinata ____________ 31

saratogana ______________ 27

tuberculata __________________ 2,35

verricula ____________________ 24

villosa ----- -- - _ 14

vineyardensis ________________ 32, 33

whiteii ______________________ 36

(Eucythereis), angulata________ 19

emarginata ______________ 17

villosa ---------- ________ 14

(Hemicythere) arenicola_______ 29

(Paracythereis) concinna ______ 15

latimarginata _________ 23

(Pterygocythereis) c o rn u ta

americana ___________ 39

inexpectata ___________ 39

Cytheretta______________ 38, 40, 41 

edwardsi__________________ 4, 41, 42

rubra __________________ 38, 40

subradiosa ___________________ 40, 41

*racj/i _________ 4, 41, 42

Cytherettinae_____ 11, 30, 31, 36, 38, 40 

Cytheridae _____________ 5, 6, 30 

Cytherideidae ______________ 8 

Cytherina carinata________________ 35

subradiosa ___________________ 40

D

davidwhitei, Cythereis_____________ 31

dawsoni, Actinocythereis________ 4, 32, 33 ;

pis. 5, 11

Cythere ______________ 32

Cythereis _____________ 32

deltoides, Jugosocythereis __________ 9

devexa, Patagonacythere___________ 19

Dictyocythere 30

Diffmocythere ________________ 11, 30

dubia, Cythere____________________ 19, 20

Patagonacythere___ 4, 19, 20; pis. 4, 9

dunelmensis, Acanthocythereis___ 4, 34

Cletocythereis ________________ 35

dunelmensis ______________ 34

Cythere _____________________ 34

Cythereis ______________ 34 

dunelmensis, Cletocythereis_____ 34

minor, Cletocythereis _______ 34

E 

echinata, Cythereis________________ 37

Echinocythereis ______ 4, 37, 38; pi. 6

Echinocythereidinae ___________ 1,

8, 11, 24, 29, 30, 31, 36

Echinocythereis___________ 1, 8, 36, 37, 38

echinata____________ 4, 37, 38; pi. 6

garretti _____________________ 36, 37

margaritifera________ 4, 36, 37 ; pi. 6

planisbalis____________ 4, 37; pi. 6

edwardsi, Cytheretta____________ 4, 41, 42

Pseudocytheretta _____________ 40, 41

eikonata, Velarocythere____________ 27

Elofsonella__________ 10, 12, 14, 15, 16 

concinna _____ 4, 14, 15, 16; pi. 4

concinna _____________ 15, 16

neoconcinna _____________ 16

elofsoni abbreviata, Cletocythereis___ 34 

Cletocythereis ________________ 34, 35

elofsoni ______________ 34

elofsoni, Cletocythereis_______ 34

Page 

emarginata, Bafflnicythere______ 4, 17, 18;

pis. 2, 9 

Cythereis - 16,17

(Eucythereis) __ 17

(Eucythereis) angulata, Cythereis__ 19

crenulata, Cytheris_ 25

emarginata, Cythereis__________ 17

villosa, Cythereis 14

exanthemata, Actinocythereis 34

Cythere - 31

F 

Falunia 30, 31

Faluniinae ________ 30 

Fimbria 39

ftnmarchica, Cythere__ 18 

Cythereis 18

Hemicythere 18

Nereina 4, 18; pis. 1, 11

Finmarchinella _ 18

angulata _ ___ 19

ftssispinata, Puriana 9

Plexus 40

Frontal muscle scars 7

G

garretti, Buntonia 36

Gythereis 36, 37

Echinocythereis _ 36, 37

gubikensis, Robertsonites 35

gunteri, Cytherete 21, 22

Murrayina _______ 22

H

Hemicythere 5, 6, 7, 10, 12, 13, 14, 15 

angulata ____ 19

borealis__________ 4, 14, 15, pi. 2

calhounensis __ 13 

cribraria _ 10 

ftnmarchica 18

lienosa 10 

mota ________________ 10

phrygionia --------------- 10

pulchella _____ _ 4,15

schmidtae _____ 25

viZZosa___________ 4,14,15 ; pi. 2

(Hemicythere) arenicola, Cythereis 29

Hemicytheria ____ 10,12,14

Hemicytheridae__ 4, 6, 7, 8, 11, 13, 27, 36 

Hemicytheridae-Trachyleberididae

group _ 7, 8, 9 

Hemicytherides _ 25 

Hemicytherinae 6, 7, 8, 9,10,11,14,24, 25 

Hemicytherinae angulata_ _ 19 

Henryhowella ______ 31 

Hermanites__________ 1, 9, 24, 25, 34 

Heterocythereis_________ 10, 12, 14, 23 

Hirsutocythere _______ 31 

H.M.S. Valorous expedition. 2 

howei, Murrayma______ 21, 22 

Pterygocythereis _________ 39,40

Idiocythere ________________ 31

Ilyobates judaea___________ _ 40

Incongruellina ___________ 39

inexpectata, Cythereis- 40

Cythereis (Pterygocythereis) 39

Pterygocythereis ____ 40

inexpectatus, Cythereis 39

J

jonesi, Cythereis _ 39

judaea, Ilyobates______ 40

Jugosocythereis_________ 1, 7, 9, 24, 25

deltoides _ ___ 9

K Page

Kingmaina ___ ____ 39 

Kikliocythere_____________ 7, 11, 30

lactea pakaurangia, Bradleya 7 

ZaeviCMZa, Aurila_____________ 23 

latimarginata, Cythere______ 20, 23 

Cythereis (Paracythereis) 23 

Hemicythere __ 23 

Muellerina _ 21 

legrandi, Velarocythere_______ 27 

Leguminocythereididae ____ 26 

Leguminocythereis_________ 11, 26, 27 

cookei __ ____ - 27 

crassus _ 27 

whitei_______________ 1, 27, 28 

leioderma, Cythere___________ 23 

Normanicythere____ 4, 5, 23, 24 ; pi. 1 

Leniocythere - ______-_ 26, 27 

lienenklausi, Cythere_________ 21, 22 

Muellerina __ 4, 21, 22, 23; pis. 3, 7 

Orionina _______________ 21 

lienosa, Hemicythere 10 

limbata, Pokornyella 10 

Limnocytheridae _ 8 

logani, Cythere ____________ 35 

longiducta antarctica, Patagonacythere __________ 19 

longiducta, Patagonacythere___ 20 

Loxoconcha postdecliva_______ 27 

lytteltonensis, Trachyleberis- 31, 32

M

Macrodentina ____ _ 30 

margaritifera, Cythere________ 36, 37 

Echinocythereis_____ 4, 36, 37 ; pi. 6 

martini, Cythere- _____ 21, 22 

Murrayina _____________ 21 

Trachyleberis ___________ 21 

Mauritsina_______________ 7, 11, 30 

Mauritsininae _ 8, 30, 31 

micula, Cythere______________ 21, 22 

Trachyleberis ____________ 21 

midwayensis, Cythereis________ 24 

minor, Cletocythereis dunelmensis__ 34 

mirabilis, Cythere 1, 38 

Rabilimis _____________ 38 

montgomeryensis, Cythereis--__ 31 

Morphologic features used in delimitation __________ 6 

mota, Hemicythere_______ 10 

Muellerina_____ 10,11,12,13,14, 20, 21 

abyssicola_______ 4, 21, 22, 23 ; pi. 3 

canadensis___ 4, 21, 22, 23; pis. 3, 7 

latimarginata _ 21 

lienenklausi___ 4, 21, 22, 23 ; pis. 3, 7 

parallelokladia ___________ 11, 21 

mundorffl, Actinocythereis__ 34 

Murrayina______________ 21, 22, 31 

gunteri _______________ 22 

feotoe* __________________ 21, 22 

martini _______________ 21 

Muscle scars in relation to phylogeny_ 9 

Mutilus 10, 12, 14

N

Neocaudites _ 31 

neoconcinna, Elofsonella concinna_ 16 

Neocytheretta _ _ - 40 

Nephokirkos 10,12,13,14 

Nereina 10,12,14,16,18 

angulata 4,18, 19; pis. 1,11 

barenzovoensis 18, 19 

finmarchica _ 4,18; pis. 1, 11 

(Nigeria), Veenia.__ 27 

noblissimus, Cletocythereis 34
INDEX 49

Page 

Normanicythere__________ 10,12, 13,14, 23

concinella ____ _ 23, 24 

leioderma___________ 4, 5, 23,24 ; pi. 1

O 

Occultocythereis ______ 31

oedichilus, Cythere______ __ 25

Thaerocythere ______ 25, 26

Oertliella___________________ 9, 24, 31

ogboni, Brachycythere_____________ 10

Oligocythereis ___________________ 5

Orionina_____________ 10,11,12,13,14, 16

lienenklausi ___ 21 

Ostracoda 13

pakaurangia, Bradleya lactea_______ 7

Palaciosa_________ 6,10, 12, 14

Paracythereis ___ __ __ 15

(Paracythereis) concinna, Cythereis- 15

latimarginata, Cythereis_______ 23

Paracytheretta ___ 40 

parallelokladia, Muellerina_________ 11, 21

paramirabilis, Pseudocythereis______ 38

Rabilimis __________________ 38

Patagonacythere____ 7,10,12,14,16, 19, 20

devexa ____ _ __ 19

dubia______________ 4, J9, 20 ; pis. 4, 9

longiducta antarctica--_ __ 19 

longiductus _____ _ _ 20

tricostata -_ 19 

phalaropi, Cythereis_______ __ 4, 42

phrygionia, Hemicythere __ 10 

planisbalis, Buntonia_____ __ 37

Cythere _________ __ 37

Echinocythereis___________ 4, 37; pi. 6

Platycosta _____________ __ 31

Platycythereis ___________________ 31

Pneumatocythere _______ _ _ 7

Podocopida _ __ 13 

Podocopina _______________ 13

Pokornyella_____________ 10,11,12,13,14

limbata _____________________ 10

Polydentina __________________ 30

postdecliva, Loxoconcha_________ 27

Prionocytheretta ______________ 40

procteri, Cythereis______________ 37

Procythereis_____________ 12, 13, 14 

producta, Cythere_________________ 21, 22

Progonocytheridae __________ 7

Protocytheretta _______________ 40

Pseudocythereis __________________ 38, 40

paramirabilis ______________ 38

reticulata ___________________ 26

simpsonensis ___________ 38 

spinifera ____________________ 38

Pseudocytheretta _________________ 40, 41

edwardsi ____________________ 40, 41

Pterygocy there ___________________ 30, 39

sp _____________ 40 

Pterygocythereidinae__ 11, 29, 30, 31, 38, 39

Page 

Pterygocythereis_______________ 30, 39, 40

americana____________ 4, 39,40 ; pi. 4

cornuta americana---_________ 39

howei _ 39,40

inexpectata ___ 40

cornuta americana, Cythereis___ 39

inempectata, Cythereis - ___ 39

pulchella, Cythere_________ 14, 15

Hemicythere ________ __ 4, 15 

punctata, Cythere_________ __ 23

Puriana________________________ 1, 9, 24

flssispinata _________ 9

Q

Quadracythere ___________ _ 1, 9, 24, 25

quadrataspinata, Cythereis________ 31

R

RaMlimis______________________ 1, 36, 38

miraMlis ___________________ 38

paramirabilis __________ __ 38

septentrionalis __________ 4, 38 

rastromarginata, Cythere_________ 34

reesidei, Trachyleberis _ _ 25

reticulata, Anticythereis____ __ 27

Pseudocythereis _____ ___ 26

Reticulocythereis ____ ___ 31

Robertsonites _______________ 31, 35

guoikensis ________ __ 35

tuberculata _____ 4, 35; pi. 6

tuberculatina ___________ 35

rubida, Cythere_____________ 14

rubra, Cytheretta____________ 38,40

Ruggieria ________ __ 39

saratogana, Gythereis_

scabrocuneata, Gythere 

Trachyleberis _____

schmidtae, Hemicythere.

____ 27 

_____ 31 

_____ 32

_____ 25 

Thaerocythere ___________ 25,26 

scuffeltonensis, Velarocythere____ 27 

semivera, Bradleya___________ 7 

septentrionalis, Cythere________ 2, 38 

Rabilimis _______________ 4, 38 

ximpsonensix, Pseudocythereis ___ 38 

Soft parts______________ __ 8 

spinifera, Pseudocythereis______ 38 

Spongicytfiere _____________ 31

subradiosa, Cytheretta________ 40, 41 

Cytherina ____________ 40

Systematic paleontology________ 13

Thaerocythere____________ 1, 9, 24, 25

crenulata _____ 4, 25, 26; pis. 4, 9

oedichilus _____________ 25, 26

schmidtae ______________ 25, 26

Thaerocytherinae___ 1, 8, 9, 11, 14, 24, 25

Thalmannia ________________ 26

thomsoni, Trachyleberis____ _ 31

Page

Trachyleberidea _____________ 31 

Trachyleberididae_ 4, 6, 7, 8, 9, 11, 25, 29,

30, 36, 39 

Trachyleberididae-Hemicytheridae

group __ __ 7, 8, 9 

Trachyleberidinae_ 6, 8, 9, 11, 21, 24, 29, 30,

31, 36

Trachyleberis_________ 5, 9, 30, 31, 32 

angulata____________ 19, 25, 26 

bollii _________________ 31 

citrusensis ______________ 31 

lytteltonensis ___________ 31, 32

martini _ ____ _ 21 

micula _______________ 21

reesidei _______-___-___ 25

scabrocuneata ___________ 32

thomsoni ___ ___ __ 31

tridens _________ ___ 31

Trachyleberis-Actinocythereis group- 31

tracyi, Cytheretta__________ 4, 41, 42

tricofttata, Patagonacythere____ 19

tridens, Trachyleberis_ _ -__ 31

Triginglymus _________ ____ 26, 27

whitei ________________ 28

tuberculata, Cythereis ______ _ 2, 35

Robertsonites____ 4, 35; pi. 6

tuberculatina, Robertsonites_____ 35

Tyrrhenocythere__________ 11, 12, 14

U

Urocythere__________ 10, 11, 12, 13, 14 

Urocytherels_____ 10, 12, 13, 14, 20, 21

Veenia (Nigeria)_____________ 27,31

(Veenia) __________ __ 31

(Veenia), Veenia ____________ 31

Velarocythere _____ __ 26, 27

arachoides _________ ___ 27

cacumenata _______ __ 27

eikonata __________ __ 27 

legrandi _______ __ 27

scuffeltonensis ____ _ __ 27 

venrricosa, Cythere_____ ___- 10

verricula, Gythereis__ _ ___ 24

Verrucocythereis-______ _ 1, 9, 24

villosa, Cythereis____ _ __ 14

Cytherew (Eucythereis) __ 14

Hemicythere______ 4, 14, 15; pi. 2

vineyardensis, Actinocythereis 4, 32, 33,

34 ; pis. 5, 11 

Cythereis _______________ 32, 33

W

whitei, Bensonocythere___ 4, 27, 28, 29 ;

pis. 5, 10, 11

Cythere ______________ 36 

Leguminocythereis 1, 27, 28 

Triginglymus _____ _ 28

whiteii, Carinocythereis_ ___ 4, 36 

Cythere _______________ 36 

Cythereis _________ 36

wyvillethompsoni, Cythere 19

PLATES 1-11
PLATE 1

[All figures X 60]

FIGURES 1-4, 6. Nereina finmarchica (Sars, 1865) (p. 18).

1. Lateral view carapace, female. Sample 42. TJSNM 112703.

2. Lateral view right valve, female. Sample 42. TJSNM 112704.

3. Dorsal view carapace, female. Sample 42. USNM 112705.

4. Lateral view carapace, male. Sample 42. USNM 112706.

6. Lateral view left valve, male. Sample 42. USNM 112707. 

5. Aurila sp. (p. 23).

Lateral view, juvenile. Sample 39. USNM 112708. 

7-11. Nereina angulata (Sars, 1865) (p. 19).

7. Lateral view right valve, male. Sample 21. USNM 112709.

8. Lateral view right valve, female. Sample 22. USNM 112710

9. Lateral view carapace, female. Sample 24. USNM 112711.

10. Lateral view carapace, female. Sample 24. USNM 112712.

11. Lateral view right valve, male. Sample 30. USNM 112713. 

12-16. Normanicythere leioderma (Norman, 1869) (p. 23).

12. Lateral view right valve, male. Sample 26. USNM 112714.

13. Lateral view carapace, male. Sample 24. USNM 112715.

14. Dorsal view carapace, female. Sample 24. USNM 112716.

15. Lateral view carapace, female. Sample 24. USNM 112717.

16. Lateral view right valve, female. Sample 26. USNM 112718.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 1

NEREINA, AURILA, AND NORM A NICYTHERE
PLATE 2

[All figures X60]

FIGURES 1, 2, 8, 9. Baffinicythere emarginata (Sars, 1865) (p. 17).

1. Lateral view right valve, male. Sample 31. USNM 112719.

2. Dorsal view carapace, male. Sample 31. USNM 112720.

8. Lateral view left valve, female. Sample 31. USNM 112721.

9. Lateral view right valve, female. Sample 31. USNM

112722. 

3, 5, 6, 10, 11. Hemicythere borealis (Brady, 1868) (p. 15).

3. Dorsal view carapace, female. Sample 26. USNM 112723.

5. Lateral view left valve, female. Sample 26. USNM 112724.

6. Lateral view right valve, female. Sample 26. USNM 

112725.

10. Lateral view left valve, male. Sample 26. USNM 112726.

11. Lateral view left valve, female. Sample 26. USNM 112727. 

4. Hemicythere cf. H. villosa (Sars, 1865) (p. 14).

Lateral view left valve, female. Sample 31. USNM 112728. 

7, 12-15. Baffinicythere costata (Brady, 1866) (p. 17).

7. Dorsal view carapace, female. Sample 24. USNM 112729.

12. Dorsal view carapace, male. Sample 24. USNM 112730.

13. Lateral view left valve, female. Sample 31. USNM 112731.

14. Lateral view left valve, male. Sample 30. USNM 112732.

15. Lateral view right valve, female. Sample 30. USNM 

112733.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 1

NEREINA, AURILA, AND NORMANICYTHERE
PLATE 2

[All figures X60]

FIGURES 1, 2, 8, 9. Baffinicythere emarginata (Sars, 1865) (p. 17).

1. Lateral view right valve, male. Sample 31. USNM 112719.

2. Dorsal view carapace, male. Sample 31. USNM 112720.

8. Lateral view left valve, female. Sample 31. USNM 112721.

9. Lateral view right valve, female. Sample 31. USNM

112722. 

3, 5, 6, 10, 11. Hemicythere borealis (Brady, 1868) (p. 15).

3. Dorsal view carapace, female. Sample 26. USNM 112723.

5. Lateral view left valve, female. Sample 26. USNM 112724.

6. Lateral view right valve, female. Sample 26. USNM 

112725.

10. Lateral view left valve, male. Sample 26. USNM 112726.

11. Lateral view left valve, female. Sample 26. USNM 112727. 

4. Hemicythere cf. H. villosa (Sars, 1865) (p. 14).

Lateral view left valve, female. Sample 31. USNM 112728. 

7, 12-15. Baffinicythere costata (Brady, 1866) (p. 17).

7. Dorsal view carapace, female. Sample 24. USNM 112729.

12. Dorsal view carapace, male. Sample 24. USNM 112730.

13. Lateral view left valve, female. Sample 31. USNM 112731.

14. Lateral view left valve, male. Sample 30. USNM 112732.

15. Lateral view right valve, female. Sample 30. USNM 

112733.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 2

BAFFINICYTHERE AND HEMICYTHERE
PLATE 3

[All figures X 60]

FIGURES 1, 2, 7, 8, 10, 16. Muellerina abyssicola (Sars, 1865) (p. 22).

1. Lateral view left valve, male. Sample 34. USNM

112734.

2. Lateral view right valve, female. Sample 34. USNM

112735.

7. Lateral view right valve, male. Sample 34. USNM

112736.

8. Lateral view left valve, female. Sample 34. USNM

112737.

10. Dorsal view carapace, male. Sample 34. USNM 112738. 

16. Dorsal view carapace, female. Sample 34. USNM

112739. 

3-6, 11. Muellerina Henenklausi (Ulrich and Bassler, 1904) (p. 21).

3. Lateral view carapace, female. Sample 42. USNM

112740.

4. Lateral view left valve, female. Sample 42. USNM

112741.

5. Lateral view carapace, male. Sample 42, USNM 112742.

6. Lateral view carapace, male. Sample 42. USNM

112743.

11. Dorsal view carapace, female. Sample 42. USNM

112744. 

9, 12-15, 17-20. Muellerina canadensis (Brady, 1870) (p. 22).

9. Lateral view right valve, male. Sample 30. USNM

112745.

12. Lateral view left valve, male. Sample 30. USNM

112746.

13. Lateral view left valve, female. Sample 30. USNM

112747.

14. Lateral view right valve, male. Sample 34. USNM

112748.

15. Dorsal view carapace, female. Sample 30. USNM

112749.

17. Lateral view right valve, male. Sample 30. USNM

112750.

18. Lateral view right valve, female. Sample 34. USNM

112751.

19. Lateral view left valve, male. Sample 34. USNM

112752.

20. Lateral view left valve, female. Sample 34. USNM

112753.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 3

MUELLERINA
PLATE 4

[All figures X 60]

FIGURES 1, 6, 7, 9, 12. Patagonacythere dubia (Brady, 1868) (p. 19).

1. Lateral view carapace, female, appendages protruding. Sample 17. USNM 112754.

6. Lateral view carapace, female, appendages protruding. Sample 17. USNM 112755.

7. Lateral view carapace, female. Sample 24. USNM 112756. 

9. Lateral view right valve, male. Sample 24. USNM 112757. 

12. Dorsal view carapace, female. Sample 17. USNM 112758. 

2-5, 8. Thaerocythere crenulata (Sars, 1865) (p. 25).

2. Lateral view right valve, female. Sample 34. USNM 112759.

3. Lateral view left valve, male. Sample 34. USNM 112760.

4. Lateral view right valve, male. Sample 34. USNM 112761.

5. Lateral view left valve, female. Sample 34. USNM 112762. 

8. Dorsal view carapace, female. Sample 34. USNM 112763. 

10, 11, 13. Elofsonella concinna (Jones, 1857) (p. 15).

10. Lateral view right valve, female showing a type of ornamentation that some individuals possess. All 

the specimens found in the Gulf of Maine possessed this type; both this type of ornamentation 

and that shown on the other individuals of this plate were present in populations from other 

areas. Sample 31. USNM 112764.

11. Lateral view carapace, female. Sample 24. USNM 112765.

13. Lateral view carapace, male. Sample 24. USNM 112766. 

14, 15. Pterygocythereis americana (Ulrich and Bassler, 1904) (p. 39).

14. Lateral view left valve, female. Sample 30. USNM 112767.

15. Lateral view right valve, female. Sample 30. USNM 112768.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 4

PAT AGONACYTHERE, THAEROCYTHERE, ELOFSONELLA, AND PTEBYGUCYTHERE1S
PLATE 5

[All figures X 60]

FIGUEES 1, 4, 5. Bensonocythere americana n. sp. (p. 28).

1. Lateral view left valve, female. Sample 42. USNM 112697. 

(Holotype).

4. Dorsal view carapace, male. Sample 42. USNM 112770.

5. Lateral view carapace, female. Sample 42. USNM 112771. 

2, 3, 8-10. Bensonocythere whitei (Swain, 1951) (p. 27).

2. Lateral view left valve, male. Sample 42. USNM 112772.

3. Dorsal view carapace, female. Sample 42. USNM 112772.

8. Lateral view right valve, male. Sample 42. USNM 112773.

9. Lateral view left valve, female. Sample 42. USNM 112774.

10. Lateral view right valve, female. Sample 42. USNM 112775. 

6, 7, 11. Bensonocythere arenicola (Cushman, 1906) (p. 29).

6. Lateral view carapace, female. Sample 42. USNM 112776.

7. Lateral view carapace, male. Sample 42. USNM 112777.

11. Lateral view carapace, male. Sample 42. USNM 112778. 

12-15, 17. Actinocythereis dawsoni (Brady, 1870) (p. 32).

12. Lateral view right valve, female. Sample 48. USNM 112779.

13. Lateral view carapace, male. Sample 31. USNM 112780.

14. Lateral view right valve, female. Sample 30. USNM 112781.

15. Lateral view carapace, male. Sample 31. USNM 112782. 

17. Dorsal view carapace, female. Sample 30. USNM 112783. 

16, 18. Actinocythereis vineyardensis (Cushman, 1906) (p. 33).

16. Lateral view carapace, female. Sample 30. USNM 112784. 

18. Lateral view carapace, female. Sample 30. USNM 112785.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 5

BENSONOCYTHERE AND ACTINOCYTHEREIS
PLATE 6

[All figures X 60]

FIGURES 1-3. Robertsonites tuberculata (Sars, 1865) (p. 35).

1. Lateral view right valve, male. Sample 21. USNM 112786.

2. Lateral view left valve, male. Sample 24. USNM 112787.

3. Lateral view carapace, female. Sample 24. USNM 112788. 

4, 5, 8. Echinocythereis planisbalis (Ulrich and Bassler, 1904) (p. 37).

4. Lateral view right valve, female. Sample 30. USNM 112789.

5. Lateral view left valve, female. Sample 30. USNM 112790. 

8. Dorsal view carapace, female Sample 41. USNM 112791. 

6, 7, 9. Echinocythereis margaritifera (Brady, 1870) (p. 36).

6. Lateral view left valve, female. Sample 48. USNM 112792.

7. Lateral view left valve, male. Sample 44. USNM 112793.

9. Lateral view right valve, female. Sample 48. USNM 112794. 

10, 11. Echinocythereis echinata (Sars, 1865) (p. 37).

10. Lateral view right valve, matrix adhering to specimen. Sample 35. 

USNM 112795.

11. Lateral view left valve. Sample 35. USNM 112796.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 664 PLATE 6

ROBERTSONITES AND ECHINOCYTHEREIS
PLATE 7

FIGUEES 1, 4, 5, 7. Muellerina lienenklausi (TJlrich and Bassler, 1904) (p. 21).

1. Masticatory processes of maxilla, female. Sample 42. TJSNM 

112681. X640.

4. Antenna, female. Sample 42. USNM 112681. X 640.

5. Interior of right valve, female. Sample 31. TJSNM 112682.

X 115.

7. Antennule, female. Sample 42. USNM 112681. X 640. 

2, 3, 6, 8. Muellerina canadensis (Brady, 1870) (p. 22).

2. Antennule, female. Sample 42. USNM 112683. X 570.

3. Protopod and exopodite of antenna, male. Sample 30. USNM

112684. X 480. 

6. Interior of right valve, female. Sample 30. USNM 112685.

X 115. 

8. Antenna, female. Sample 30. USNM 112683. X 600.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 7

MUELLERINA
PLATE 8

Figures 1-8. Baffinicythere costata (Brady, 1866) (p. 17).

1. Antenna, male. Sample 17, USNM 112687. X 280.

2. Exopodite of maxilla, female. Sample 17. USNM 112686. X 350.

3. Antenna, female. Sample 17. USNM 112686. X 270.

4. Second? thoracic leg, female. Sample 17. USNM 112686. X 300.

5. Cutting edge of mandible, female. Sample 17. USNM 112686. 

X 600.

6. Antennule, female. Sample 17. USNM 112686. X 240.

7. Knee of third thoracic leg, female, showing chitinous supports. 

Sample 17. USNM 112686. X 390.

8. Interior of right valve, female. Sample 31. USNM 112688. X 115.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 8

BAFFINICYTHERE
PLATE 9

FIGURES 1, 3, 5, 6. Patagonacythere dubia (Brady, 1868) (p. 19).

1. Detail of surface ornament, female. Sample 17. USNM

112689. X 440. 

3. Antennule, female. Sample 17. USNM 112689. X 300.

5. Antenna, female. Sample 17. USNM 112689. X 390.

6. Interior of right valve, female. Sample 17. USNM 112690.

X115. 

2. Baffinicythere emarginata (Sars, 1865) (p. 17).

Interior of right valve, female. Sample 31. USNM 112691.

X 115. 

4. Thaerocythere crenulata (Sars, 1865) (p. 25).

Interior of right valve, female. Sample 34. USNM 112692. 

X 115.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 9

BAFFINICYTHERE, THAEROCYTHERE, AND PAT AGON ACYTHERE
PLATE 10

FIGURES 1-8. Bensonocythere whitei (Swain, 1951) (p. 27).

1. Furca, female. Sample 42. USNM 112693. X 250.

2. Knee of thoracic leg, female, showing chitinous supports. Sample 42. 

USNM 112693. X 400.

3. Antenna, male. Sample 42. USNM 112694. X 300.

4. Exopodite of maxilla, female. Sample 42. USNM 112693. X 170.

5. Cutting edge of mandible, male. Sample 42. USNM 122694. 

X 650.

6. Third thoracic leg, female. Sample 42. USNM 112693. X 250.

7. Antenule and antenna, female. Sample 42. USNM 112693. X 320.

8. Endopodite and exopodite of mandible, male. Sample 42. USNM 

122694. X 300.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 564 PLATE 10

BENSONOCYTHERE
PLATE 11

FIGURES 1, 2. Bensonocythere whitei (Swain, 1951) (p. 27).

1. Antennal and adductor muscle scars (composited from more than one 

specimen). X 300.

2. Interior of right valve, female. Sample 42. USNM 112696. 

X 115.

3. Bensonocythere americana n. sp. (p. 28).

Interior of left valve, female. Sample 42. USNM 112697. X 115.

4. Actinocgthereis vineyardensis (Cushman, 1906) (p. 33).

Interior of right valve, female. Sample 47. USNM 112698. X 115. 

5, 8. Nereina angulata (Sars, 1868) (p. 19).

5. Interior of left valve, female. Sample 8. USNM 112699. X 115. 

8. Antennal and adductor muscle scars (composited from more than one 

specimen). X 300.

6. Actinocythereis dawsoni (Brady, 1870) (p. 1870) (p. 32).

Interior of right valve, male. Sample 30. USNM 112700. X 115.

7. Nereina finmarchica (Sars, 1865) (p. 18).

Interior of left valve, female. Sample 42. USNM 112701. X 115. 

9. Bensonocythere arenicola (Cushman, 1906) (p. 29).

Interior of right valve, female (note body muscles attached to dorsal 

muscle platform). Sample 40. USNM 112702.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 664 PLATE 11

8

BENSONOCYTHERE, ACTINOCYTHEREIS, AND NEREINA