A Systematic Revision of the 

Ostracode Species Described by 

Ulrich and Bassler and by Malkin 

from the Chesapeake Group in 

Maryland and Virginia
A Systematic Revision of the 

Ostracode Species Described by 

Ulrich and Bassler and by Malkin 

from the Chesapeake Group in 

Maryland and Virginia

By RICHARD M. FORESTER

GEOLOGICAL SURVEY PROFESSIONAL PAPER 112

Describes new ostracode genera and species 

and systematically updates those species 

previously described from the Calvert, 

Choptank, St. Marys, Eastover, and 

Yorktown Formations

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1980
UNITED STATES DEPARTMENT OF THE INTERIOR 

CECIL D. ANDRUS, Secretary

GEOLOGICAL SURVEY 

H. William Menard, Director

Library of Congress Cataloging in Publication Data

Forester, Richard M.

A systematic revision of the ostracode species described by Ulrich and Bassler and by Malkin from the 

Chesapeake Group in Maryland and Virginia.

(Geological Survey Professional Paper 1128)

Bibliography: p. 21

1. Ostracode, Fossil. 2. Paleontology Tertiary. 3. Paleontology Maryland. 4. PaleontologyVirginia. I. Title. II. Series: United States Geological Survey Professional Paper 1128.

QE817.08F67 56s'.33 79-4081

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

Washington, D.C. 20402 

Stock Number 024-001-03179-5
CONTENTS

Page

Abstract..................................................... ..................... 1

Introduction ................................................. ..................... 1

Acknowledgments ............................................ ..................... 1

Previous ostracode work ...................................... ..................... 2

Stratigraphic setting ......................................... ..................... 2

Procedures......................................................................... 3

Systematic paleontology ............................................................ 3

Systematics........................................................................ 3

References cited .................................................................... 21

Index.............................................................................. 23

ILLUSTRATIONS

[Plates follow index]

PLATE 1. Cytheridea, Hulingsina, Peratocytheridea*

2. Hulingsina, Cytheropteron?, Cytherura.

3. Murrayina, Actinocythereis.

4. Henryhowella, Actinocythereis, Pterygocythereis, Echinorythereis, Pseudocytheretta.

5. Pseudocytheretta.

6. Otikocythere, Pseudocytheretta, Protocytheretta.

1. Microcytherura, Muellerina, Otikocythere, Bensonocyther 2, Paracytheridea, Thaerocy there.

TABLES

TABLE 1. Ulrich and Bassler's (1904) and Malkin's (1953) species .............................................................. 4

2. Stratigraphic distribution of discussed species ..................................................................... 5

in
A SYSTEMATIC REVISION OF THE OSTRACODE SPECIES

DESCRIBED BY ULRICH AND BASSLER AND BY MALKIN FROM

THE CHESAPEAKE GROUP IN MARYLAND AND VIRGINIA

By RICHARD M. FORESTER

ABSTRACT

Those ostracode species described by Ulrich and Bassler (1904) 

and Malkin (1953) from the Chesapeake Group of early Miocene to 

early Pleistocene age are treated systematically. Lectotypes are 

designated for all species which have syntypic suites and the lectotypes, holotypes, or hypotypes for all but two species are illustrated. A new genus Otikocythere is proposed, with Cythere 

punctistriata Ulrich and Bassler 1904 as the type species. A new 

species, Hulingsina calvertensis, is also proposed. All of the species 

are placed in an updated biostratigraphic framework.

INTRODUCTION

Ulrich and Bassler (1904) and Malkin (1953) described ostracode species from the Chesapeake Group 

(lower Miocene to lower Pleistocene) of Maryland and 

Virginia. In ascending order, the Chesapeake Group 

consists of the Calvert, Choptank, St. Marys, Eastover, Yorktown, and Croatan Formations (Clark and 

Miller, 1906; Blackwelder and Ward, 1976; Ward and 

Blackwelder, in press). The Ulrich and Bassler work 

was particularly important to ostracode systematics 

because the forms proposed were the first ostracodes 

described from the North American upper Tertiary. 

The taxa formed a nucleus for subsequent ostracode 

systematic and biostratigraphic studies dealing with 

upper Tertiary, Quaternary, and modern sediments of 

the Atlantic and Gulf Coasts. The majority of these 

and, to a lesser extent, the Malkin species, were in need 

of detailed systematic revision.

In Ulrich and Bassler (1904), many sexual dimorphs 

and juvenile instars were proposed as distinct species. 

Conversely, the authors also combined several distinctive (by modern standards) species under a single 

binomen that are represented by syntypic suites. Both 

practices, particularly the latter, have led to instability 

in taxonomic nomenclature because more than one 

species can be, and often have been, selected as the 

representatives for a binomen. Furthermore, many 

subsequent studies have erroneously identified other

species as being conspecific with those from the formations of the Chesapeake Group. This has led to a compounding of some of the original problems, thus 

hampering the utility of these species for systematic 

and biostratigraphic studies. The seven new species 

described by Malkin (1953) are also represented by 

syntypic suites and some of the same problems exist.

The primary purpose of this study has been to examine all of the species described by Ulrich and 

Bassler (1904) and Malkin (1953) in order to (1) classify 

them taxonomically, (2) designate lectotypes for all 

syntypic suites, in keeping with Article 74 of the 1961 

International Code of Zoological Nomenclature, and (3) 

provide adequate illustrations for the lectotypes and 

holotypes, thereby stabilizing the nomenclature of 

these ostracode species.

A few of Ulrich and Bassler's (1904) holotypes have 

been either lost or crushed. Where possible, these 

species are illustrated herein, using specimens that I 

feel are consistent with the original authors' concept. 

Hazel (1977; in press) has already illustrated a few of 

the Pliocene species in this category and these are not 

treated in this paper. I have attempted to preserve as 

many of the original trivial and varietal names as 

possible. However, this has occasionally meant 

synonymizing some commonly but erroneously used 

names. Synonymies are provided and a brief differential diagnosis is given for most species in order to indicate a few of the morphologic features I regard as 

particularly characteristic.

ACKNOWLEDGMENTS

This study represents part of a research topic completed while the author was a National Research Council Postdoctoral Associate with the U.S. Geological 

Survey. I would especially like to thank Joseph E. 

Hazel who proposed this study and generously provided space and equipment. I would also like to thank
REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

M. J. Mann and W. Brown of the U.S. National 

Museum for taking the scanning electron micrographs.

PREVIOUS OSTRACODE WORK

Howe and others (1935) identified a number of Ulrich 

and Bassler (1904) species and described several new 

forms, mostly from Florida correlatives of the 

Chesapeake Group. McLean (1957; 1966) outlined the 

stratigraphic distribution of some of these ostracode 

species. Swain (1948) studied ostracodes from the subsurface Chesapeake Group of the Maryland Eastern 

Shore. Hazel (1967) discussed some of these species in 

context with a study of the Holocene Hemicytheridae 

and Trachyleberididae of the North Atlantic, and also 

dealt with the biostratigraphy and systematics of the 

ostracodes from the Yorktown Formation (Hazel, 

1971; 1977; in press). Swain (1974) treated several 

ostracode species from the Yorktown and St. Marys 

Formations. In addition to the study by Howe and 

others (1935), other important works in which the 

species of Ulrich and Bassler (1904) have been identified, or thought to have been identified, from other 

geographic areas are Edwards (1944), Puri (1954) and 

Swain (1968). In some cases these studies have helped 

to clarify the taxonomic confusion associated with the 

Ulrich and Bassler material; however, with the exception of the work by Sandberg (1964) on Peratocytheridea subovata (Ulrich and Bassler, 1904), none of 

the original material seems to have been studied in any 

detail.

STRATIGRAPHIC SETTING

In 1904, Shattuck divided the Calvert, Choptank, 

and St. Marys Formations into 24 units that he called 

"zones." The Yorktown Formation, which crops out in 

nearby Virginia, was not treated by Shattuck; it is, 

however, normally included in the Chesapeake Group. 

Shattuck's divisions were based on a variety of criteria 

(lithology, occurrence or non-occurrence of fossil shells, 

and others) and, using today's terminology, the divisions are usually not valid lithostratigraphic or 

biostratigraphic units, but are only beds or groups of 

beds. His zones 1-15 make up the Calvert Formation, 

16-20 the Choptank Formation, and 21-24 the St. 

Marys Formation. The Calvert Formation was further 

divided by Shattuck (1904) into the Fairhaven 

Diatomaceous Earth (zones 1-3) and the Plum Point 

Marl Members (zones 4-15). Zone 1 crops out at Lyons 

Creek on the west side of Chesapeake Bay (Deale 

7 1/2-minute quadrangle), and the other zones appear 

successively as one proceeds south along the bay. 

Gernant (1970), in a study of the Choptank Formation,

concluded that beds 16-20 were distinctive enough to 

be assigned member status and proposed the names 

Calvert Beach, Drum Cliff, St. Leonard, Boston Cliffs, 

and Conoy Members, respectively.

Blackwelder and Ward (1976) have utilized the informal designation of Little Cove Point unit for bed 21 of 

the St. Marys Formation, because it has a distinctive 

lithology and fauna. They have also proposed (Ward 

and Blackwelder, in press) the Eastover Formation to 

incorporate those sediments that were known as the 

"Virginia St. Marys." The Eastover Formation includes the Claremont Manor and Cobham Bay 

Members (also new names), that were once recognized 

as formations by Blackwelder and Ward (1976).

To facilitate discussion I will refer to the Little Cove 

Point unit, the St. Marys Formation (as restricted to 

beds 22-24), and the Claremont Manor and Cobham 

Bay Members of the Eastover Formation as units A, 

B, C, and D respectively. Work in progress suggests 

that these units represent important biostratigraphic 

and lithology units.

Gibson (1971) states that, on the basis of planktic 

foraminifers, "zone" 10 is referable to planktic zone N8 

or N9 of Blow (1969). N8 is considered to be of latest 

early Miocene age and N9 is earliest middle Miocene 

(Berggren and Van Couvering, 1974). Well-preserved 

specimens of the foraminifer Praeorbulina glomerosa 

circularis (Blow, 1956) have been identified by me (and 

confirmed by T. G. Gibson, U.S. Geological Survey) 

from zone 12. This subspecies is indicative of an N9 

age for zone 12. The lower Miocene-middle Miocene 

boundary, therefore, very probably falls in zone 10 or 

11 of the Calvert Formation. It is not clear how much 

of the lower Miocene is represented by the lower 

Calvert. The similarity of the ostracode and mollusc 

faunas of the lower zones of the Calvert to zone 10 suggests that only the upper part of the lower Miocene is 

present. The middle Miocene-late Miocene boundary 

has been tentatively placed between units B and C. 

This is based on a K/Ar radiometric date of 12.5 m.y. 

on glauconite from the restricted St. Marys Formation 

(unit B), coupled with a faunal change in molluscs at 

that level (Blackwelder and Ward, 1976). Berggren and 

Van Couvering (1974), indicate that radiometrically 

the middle Miocene-upper Miocene boundary is at 

about 11.0 m.y. It is possible, however, that the faunally distinct unit C is also middle Miocene; it contains 

no diagnostic planktic organisms and no known radiometrically dateable minerals.

Hazel (1977; in press), using various lines of 

evidence, concluded that the basal beds of the 

Yorktown Formation are early Pliocene in age (N19 of 

Blow, 1969) and that the youngest beds legitimately 

assigned to the Yorktown are probably no younger
SYSTEMATICS

than the N20 zone. Paleontologic and radiometric data 

summarized by Hazel (1977; in press) and Blackwelder 

and Ward (1976) suggested that unit D (Cobham Bay 

Member of Eastover Formation) is of late, but not 

latest, Miocene age.

Most of the Ulrich and Bassler (1904) ostracode 

specimens came from "zone" 10 of the Calvert Formation at Plum Point on Chesapeake Bay. Other localities 

included Church Hill, Md. (Calvert Formation), 

Peachblossom Creek and Paw Paw Point, Md. (Choptank Formation), and outcrops on the James River in 

Virginia (Yorktown Formation). Malkin's (1953) 

material came from zones 4-6, 9, 10, 14, 19, 22 in 

Maryland and from the Yorktown Formation along the 

York and James Rivers, Va. The author has examined 

ostracode material from the above localities (except 

Church Hill and Paw Paw Point) and from numerous 

other localities which have ample comparative 

material. In the strictest sense exact original Ulrich 

and Bassler localities along Chesapeake Bay no longer 

exist due to erosion of the cliffs since 1904.

PROCEDURES

When species from either the Ulrich and Bassler 

(1904) or the Malkin (1953) collections were 

represented by syntypes, lectotypes and occasionally 

paralectotypes have been designated and illustrated 

for each species. If a species is represented only by a 

holotype, it has been illustrated if it was extant in the 

collection (some are not). All illustrations are scanning 

electron micrographs of gold- or gold-palladium-coated 

specimens. The known stratigraphic range in the 

Maryland and Virginia region is given for each species 

and is based primarily upon studies in progress by 

Forester on the Miocene part of the Chesapeake Group 

and by Hazel (1971; 1977; in press) and Valentine 

(1971) for the younger deposits. When none of the 

original specimens exist, or where additional illustrations of non-type material were needed for clarification, samples from U.S. Geological Survey collections 

have been used. These hypotypes, where possible, were 

selected from topotype material, recognizing that true 

topotype material is no longer available, in most cases, 

due to the erosion of the cliffs along Chesapeake Bay.

All of the illustrated specimens and the remaining 

Ulrich and Bassler and Malkin specimens are 

deposited in the collections of the National Museum of 

Natural History.

SYSTEMATIC PALEONTOLOGY

The left hand column of table 1 lists in alphabetical 

order, under their original generic assignments, the

species described by Ulrich and Bassler (1904) and 

Malkin (1953). The right hand column of the table 

gives my interpretation of the modern generic and 

species assignment. Each species is discussed in the 

following section under its updated binomen. Of the 

original 49 species-group taxa proposed, I feel that 

only 35 are valid.

The Ulrich and Bassler material has provided the 

type species for four previously described genera 

(Henryhowella evax, Murrayina howei, Puriana 

rugipunctata, and Orionina vaughani). One Ulrich and 

Bassler species, Cythere punctistriata, is made the 

type species of the new genus Otikocythere.

Table 2 is a generalized occurrence chart showing the 

distribution in the Chesapeake Group of the 35 valid 

taxa. See Hazel (1977) for a more detailed biostratigraphy for the Pliocene. A biostratigraphic treatment of the Miocene forms is in preparation by the 

author. Occurrence data are given for each species in 

the following section.

SYSTEMATICS

Class OSTRACODA Latreille, 18O6 

Order PODOCOPIDA G. W. MuUer, 1894

Suborder FODOCOFA Sars, 1866

Superfamily CYTHERACEA Baird, 185O

Family CYTHERIDEIDAE Sars, 1925

Genus Cytheridea Bosquet, 1852

Type-species.—Cythere mulleri Munster, 1830

Cytheridea diagonalis (Malkin, 1953)

Plate 1, figures 3, 6

Clithrocytheridea diagonalis Malkin, 1953, p. 782, pi. 79, figs. 18,

19, 21, 22, 24. 

Not Clithrocytheridea diagonalis Malkin. McLean, 1957, p. 74, pi. 8,

figs, la, b.

Diagnosis.—Greatest length near the ventral margin 

and greatest height through central muscle scar 

region; posterior half of valve drawn out, posteroventral corner extending below ventral margin in females; 

normal pores (in punctae) irregularly distributed over 

valve surface; two prominent concentric rows of 

punctae that form two furrows along anterior margin 

of valve; larger than Cytheridea virginiensis (Malkin, 

1953).

Lectotype.—A female valve (Malkin, 1953, pi. 79; fig. 

19), USNM 256018, from the Calvert Formation 

(locality MD 13-3 of Malkin, 1953) is herein 

designated the lectotype (pi. 1, fig. 6).

Measurements.—The lectotype is 900 pm (micrometers) in length and 500 f-tm in height. The illustrated
4 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

TABLE I.—A listing of all of the Ulrich and Bassler (1904) and Malkin (1953) ostracode species by their original designation and by their

present (this report) designation

Ulrich and Bassler (1904) or Malkin (1953) taxa Present assignment

Clithrocytheridea diagonalis Malkin...................................... Cytheridea diagonalis (Malkin).

virginiensis Malkin ................................................. virginiensis (Malkin).

Cy there burnsi Ulrich and Bassler........................................ Pseudocytheretta burnsi (Ulrich and Bassler).

calverti Ulrich and Bassler........................................... Bensonocy there calverti (Ulrich and Bassler).

clarkana Ulrich and Bassler.......................................... Echinocythereis clarkana (Ulrich and Bassler).

var. miniscula Ulrich and Bassler................................. miniscula (Ulrich and Bassler).

dorsicornis Ulrich and Bassler ....................................... Murrayina martini (Ulrich and Bassler).

var. bicornis Ulrich and Bassler .................................. howei (Ulrich and Bassler).

evax Ulrich and Bassler ............................................. Henryhowella evax (Ulrich and Bassler).

var. oblongula Ulrich and Bassler................................. Do.

exanthemata Ulrich and Bassler ..................................... Actinocythereis exanthemata (Ulrich and Bassler).

francisca Ulrich and Bassler ......................................... Otikocy therepunctistriata (Ulrich and Bassler).

inaequivalvis Ulrich and Bassler ..................................... Protocytheretta inaequivalvis (Ulrich and Bassler).

lienenklausi Ulrich and Bassler ...................................... Muellerina lienenklausi (Ulrich and Bassler).

martini Ulrich and Bassler........................................... Murrayina martini (Ulrich and Bassler).

micula Ulrich and Bassler ........................................... Muellerina micula (Ulrich and Bassler).

nitidula Ulrich and Bassler .......................................... Pseudocytheretta burnsi (Ulrich and Bassler).

var. calvertensis Ulrich and Bassler............................... Do.

paucipunctata Ulrich and Bassler .................................... Do.

planibasalis Ulrich and Bassler ...................................... Echinocythereis planibasalis Ulrich and Bassler).

plebeia Ulrich and Bassler ........................................... Pseudocytherettaplebeia (Ulrich and Bassler).

var. capax Ulrich and Bassler .................................... Do.

var. modica Ulrich and Bassler ................................... Do.

porcella Ulrich and Bassler .......................................... Do.

producta Ulrich and Bassler ......................................... Murrayina howei (Ulrich and Bassler).

punctistriata Ulrich and Bassler ..................................... Otikocytherepunctistriata (Ulrich and Bassler).

rugipunctata Ulrich and Bassler ..................................... Puriana rugipunctata (Ulrich and Bassler).

? shattucki Ulrich and Bassler ....................................... Microcytherura shattucki (Ulrich and Bassler).

spiniplicata Ulrich and Bassler....................................... Henryhowella evax (Ulrich and Bassler).

subovalis Ulrich and Bassler ......................................... Cytheridea subovalis (Ulrich and Bassler).

toumeyi Ulrich and Bassler .......................................... Pseudocytheretta burnsi (Ulrich and Bassler).

vaughani Ulrich and Bassler ......................................... Orionina vaughani (Ulrich and Bassler).

Cythereis alaris Ulrich and Bassler....................................... Actinocythereis sp. (Ulrich and Bassler).

cornuta var. americana Ulrich and Bassler ............................ Pterygocythereis americana (Ulrich and Bassler).

Cytheridea ? chesapeakensis Ulrich and Bassler........................... Pseudocytheretta plebeia (Ulrich and Bassler).

subovata Ulrich and Bassler ......................................... Peratocytheridea subovata (Ulrich and Bassler).

Cytherideis ashermani Ulrich and Bassler ................................ Hulingsina ashermani (Ulrich and Bassler).

echolsae Malkin .................................................... rugipustulosa (Edwards).

cylindrica Ulrich and Bassler ........................................ cylindrica (Ulrich and Bassler).

longula Ulrich and Bassler........................................... semicircularis (Ulrich and Bassler).

semicircularis Ulrich and Bassler..................................... Do.

subaequalis Ulrich and Bassler....................................... subaequalis (Ulrich and Bassler).

Cytheropteron nodosum Ulrich and Bassler ............................... Paracytheridea altila (Edwards).

Cytherura coryelli Malkin ............................................... Cytherura coryelli Malkin.

Eocytheropteron yorktownensis Malkin .................................. Cytheropteron ? yorktownensis (Malkin).

Hemicythere schmidtae Malkin .......................................... Thaerocythere schmidtae (Malkin).

Paracytheridea shattucki var. curta Malkin ............................... Microcytherura curta (Malkin).

similis Malkin ...................................................... similis (Malkin).

Trachyleberis radiata Malkin ............................................ Murrayina radiata (Malkin).

paralectotype (pi. 1, fig. 3), USNM 256019, is 950 pan in 

length and 460 /urn in height.

Remarks.—Cytheridea diagonalis (Malkin, 1953) exhibits strong sexual dimorphism, with the males being 

more elongate and lower than the females.

Occurrence.—Malkin (1953) reported this species 

from the Calvert and Choptank Formations. However, 

in our collections it occurs throughout the Calvert Formation, but is not present in the Choptank Formation. 

The specimens reported by Malkin (1953) from the 

Choptank Formation are all juveniles and their assignment to C diagonalis is questionable. As far as is 

known Cytheridea diagonalis is restricted to the 

Calvert Formation. 

Stratigraphic range. Lower to middle Miocene.

Cytheridea virginiensis (Malkin, 1953)

Plate 1, figure 7

Haplocytheridea sp. aff. H. israelsky (Stephenson). Swain, 1951,

p. 20, pi. 1, figs. 15-17. 

Clithrocytheridea virginiensis Malkin, 1953, p. 783, pi. 79, figs. 27,

28; McLean, 1957, p. 74, pi. 8, figs. 2a-g.
SYSTEMATICS

TABLE 2.—Stratigraphic distribution of the Ulrich and Bossier (1904) 

and Malkin (1953) ostracode species within the Maryland and 

Virginia Miocene and Pliocene formations

[Leaders ( ) indicate not found]

Miocene

St. Marys Eastover 3 

Formation Formation 1

Taxa

Actinocythereis exanthemata . 

Bensonocythere calverti ......

Cytheridea diagonalis ........

subovalis ................

virgimensis

Cytheropteronf yorktownensis 

Cytherura coryelli 

Echinocythereis Hchinocythei cl

miniscula .. 

planibasalis

X

X X

X

clarkana

Henryhowella evax 

ashermani .... 

cylindrica ..... 

rugipustulosa . 

semicircularis . 

subaequalis ...

Microcytherura curta ...

shattucki ..........

similis .............

Muellerina lienenklausi

micula.............

Murrayina howei.........

martini ..............

radiata ..............

Orionina vaughani .......

Otikocythere punctistriata

Paracytheridea altila ........

Peratocytheridea subovata... 

Protocytheretta inaequivalvis 

Pseudocytherftta burnsi .....

plebeia .................

x

X -- X -- -- 

XXX---

Pterygocythereis americana.. 

Puriana rugipunctata........

Thaerocythere schmidtae ....

X 

X 

X

X

X

X

..

X

X

„

.-

X

X

..

X

X

..

X

"

„

X

-

..

..

X

X

..

X

"

„

..

"

"

„

X

X

..

X

~

„

..

-

X

„

X

-

X

X

"

„

..

"

~

„

X

..

X

X

"

„

..

-

X

„

..

..

X

X

"

X

..

X

XXX 

XXX

'identification uncertain.

Not Clithrocytheridea virginiensis Malkin, 1953, p. 783, pi. 79, figs. 

23, 25 (= Cytheridea campwallacensis Hazel, 1977).

IHaplocytheridea sp. aff. H. blanpedi (Stephenson). Swain, 1968, 

p. 8, pi. 1, figs. 6a, b.

Cytheridea sp. A Swain, 1974 (partim), p. 13, pi. 1, figs. 6, 7; not 

Cytheridea sp. A Swain, 1974, p. 13, pi. 1, fig. 8 (= Peratocytheridea bradyi (Stephenson, 1938)).

Cytheridea muelleri (Munster) subspecies Swain, 1974, p. 14, pi. 1, 

fig. 5.

Cytheridea virginiensis (Malkin). Hazel, 1977, p. 382, fig. g.

Diagnosis.—Greatest length about midvalve and 

greatest height just anterior of the central muscle scar

field; normal pores (in punctae) forming somewhat 

regular V-shaped patterns in medial area of the valve; 

three concentric rows of punctae forming concentric 

furrows along both the anterior and posterior ends of 

the valve; smaller than Cytheridea diagonalis (Malkin, 

1953).

Lectotype.—A male left valve (Malkin, 1953, pi. 79, 

fig. 28), USNM 256020, from the Yorktown Formation 

(locality VA-10 of Malkin, 1953) is herein designated as 

the lectotype (pi. 1, fig. 7).

Measurements.—The lectotype is 770 /mi in length 

and 420 /mi in height.

Remarks.—Cytheridea virginiensis (Malkin, 1953) 

and a closely related species are illustrated in Hazel 

(1977; in press). Both species are morphologically 

similar except that C. virginiensis is always smaller 

and has a somewhat different punctae-normal pore 

pattern on the lateral surface of the valve. The larger 

species occurs in units C and D of the Eastover Formation (upper Miocene) and the lower (lower Pliocene) 

Yorktown Formation. Cytheridea virginiensis occurs 

throughout the Yorktown Formation and also occurs 

in upper Pliocene and lower Pleistocene units in the 

Atlantic Coastal Plain (Hazel, 1977).

Stratigraphic range. Pliocene to lower Pleistocene.

Cytheridea subovalis (Ulrich and Bassler, 19O4)

Plate 1, figures 1, 8

Cythere subovalis Ulrich and Bassler, 1904, p. Ill, pi. 38, figs. 14, 

15.

Diagnosis.—Sub triangular to oval valve outline; 

greatest length just below the midheight; greatest 

height just anterior of central muscle scar field; normal 

pores (in punctae) form a poorly defined V-shaped pattern on the medial area of the valve; three concentric 

rows of punctae form three furrows along the anterior 

margin of the valve, concentric furrows present but 

poorly defined at the posterior margin of the valve.

Measurements.—The holotype (pi. 1, fig. 8), USNM 

35439, is 840 /mi in length and 540 /mi in height. The illustrated specimen (pi. 1, fig. 1), USNM 256021, is 

850 /mi long and 510 /mi in height.

Remarks.— The species concept of Cytheridea 

subovalis (Ulrich and Bassler, 1904) is based upon a 

single poorly preserved valve (pi. 1, fig. 8). This specimen (the holotype) was collected at their Paw Paw 

Point locality near Leonardtown, Md., from the Choptank Formation. Due to the poor preservation, cogent 

placement of other specimens in this species is difficult. In my studies of the Choptank Formation no 

adult Cytheridea has yet been found. Specimens of a 

Cytheridea from the Calvert Formation at Plum Point 

(Bed 10) are similar in size and shape to the holotype of 

C. subovalis and are tentatively placed in this species.
REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

One of these specimens is illustrated in plate 1, figure 

1. This specimen and the others from the Plum Point 

locality form the material upon which the diagnosis of 

C. subovalis is based.

Occurrence.—Calvert (see remarks) and, the Choptank Formations.

Stratigraphic range.—Lower to middle Miocene.

Genus Peratocytheridea Hazel, in press

Type-species. Cytheridea setipunctata Brady, 

1869.

Peratocytheridea subovata (Ulrich and Bassler, 19O4)

Plate 1, figure 4

Cytheridea subovata Ulrich and Bassler, 1904, p. 124, pi. 37, figs.

1-8. 

Not Haplocytherideaf cf. H.I subovata (Ulrich and Bassler). Swain,

1951, p. 22, pi. 1, figs. 19, 20. 

Haplocytheridea subovata (Ulrich and Bassler). Malkin, 1953, p. 782,

pi. 79, figs. 15, 17; Sandberg, 1964, p. 359, pi. 1, figs. 1-9 (gives

more complete synonymy).

Diagnosis.—Subovate valve outline; greatest length 

along midvalve and greatest height in central muscle 

scar area; finely punctate lateral surface with punctae 

containing the normal pores; posterior acute.

Measurements.—The illustrated paralectotype (pi. 1, 

fig. 4), USNM 648513, is 880 ^m in length and 480 urn 

in height. The lectotype, USNM 35445, is 870 frni in 

length and 490 /um in height.

Remarks.—Peratocytheridea subovata (Ulrich and 

Bassler, 1904) comprises a complex group of sizes and 

morphologies. The lectotype and paralectotype (Sandberg, 1964, chose the lectotype from Ulrich and 

Bassler's syntype suite) are from bed 10 of the Calvert 

Formation at Plum Point, Md. The Calvert forms are 

generally small specimens ranging in size from 750 to 

900 jLon in length, and the females are smaller than the 

males. In contrast, specimens from the Choptank Formation are usually within a range of from 920 to 1,200 

jLon in length, the females again being smaller. Units A 

and B of the St. Marys Formation contain forms intermediate in size (ranging from 850 to 930 nm (between the Calvert and Choptank specimens. This sizetime relationship has also been observed in correlative 

sediments in Florida (Sandberg, 1964).

Sandberg's (1964) illustrated adults were all from 

the Shoal River Formation of Florida. These specimens 

represent the large version of P. subovata (Ulrich and 

Bassler) common to the Choptank Formation. At present no obvious explanation can be advanced for these 

size differences.

Occurrence.—Ulrich and Bassler (1904) reported this 

species from the Calvert Formation. Malkin (1953) 

notes the occurrence of this species in both the Calvert

and Choptank Formations. I have found Peratocytheridea subovata occurring commonly in the Calvert, 

Choptank and units A and B of the St. Marys Formations. 

Stratigraphic range.—Lower to middle Miocene.

Family NEOCYTHERIDEIDAE Puri, 1957 

Genus Hulingsina Puri, 1958

Type-species.—Hulingsina tuberculata Puri, 1958.

Hulingsina calvertensis new species

Plate 1, figures 2, 5

Cytherideis ashermani Ulrich and Bassler, 1904, p. 126, pi. 37,

fig. 15. 

Cushmanidea fabula (Howe and Dohm). Swain, 1974, p. 15, pi. 1,

fig. 20; pi. 8, figs. 4a, b. 

Not Cytherideis ashermani Ulrich and Bassler, 1904, p. 126, pi. 37,

figs. 11-14, 16; Howe and others, 1935, p. 14, pi. 3, figs. 8-10;

Malkin, 1953, p. 778, pi. 78, figs. 1-13; Puri, 1954, p. 286, pi. 9,

figs. 4-8. (= Hulingsina spp., primarily H. semicircularis

(Ulrich and Bassler, 1904)). 

Not Cushmanidea ashermani (Ulrich and Bassler). McLean, 1957,

p. 77, pi. 18, figs. 5a-f. (= Hulingsina sp.) 

Not Pontocythere ashermani (Ulrich and Bassler). Swain, 1968,

p. 10, pi. 2, figs. la-d. (= Hulingsina sp.) 

Not Pontocythere (Hulingsina) ashermani (Ulrich and Bassler).

Swain, 1974, p. 16, pi. 1, figs. 21, 24; pi. 2, figs. 1-3; pi. 9, figs.

12a, b. (= Hulingsina sp.)

Diagnosis.— Subquadrate shape; very oblique 

anterodorsal margin; predominantly smooth valves 

(particularly in the anterior); diagnostic punctae pattern in the posteromedial area of the valve where the 

pattern consists of five punctae forming an isosceles 

triangle that points toward the posterior, with three 

additional punctae located posterodorsally from the 

posterior-most point of the triangle.

Etymology.— The trivial name is after the Calvert 

Formation in which the holotype occurs.

Holotype.—A female left valve (pi. 1, fig. 2), USNM 

256022, from "zone" 10 of the Calvert Formation, 0.5 

miles north of Randle Cliffs, 10 feet above the water 

level on the west side of Chesapeake Bay, Calvert 

County, Md.

Measurements.—The holotype is 775 jum in length 

and 375 /um in height.

Remarks.—The syntype suite of four specimens 

(only one was illustrated by Ulrich and Bassler, 1904) 

for Cytherideis ashermani Ulrich and Bassler, 1904, 

represents three species. There are two poorly preserved juvenile specimens, which, in my opinion, represent Hulingsina subaequalis (Ulrich and Bassler, 

1904). A third specimen, also poorly preserved, is conspecific with H. semicircularis (Ulrich and Bassler, 

1904) (see discussion under that species). The fourth 

specimen represents a valid species that is a common
SYSTEMATICS

constituent of assemblages in the Miocene part of the 

Chesapeake Group. It was illustrated by Ulrich and 

Bassler (1904, plate 37, figure 15), and subsequently by 

Swain (1974), where it was erroneously classified under 

Cushmanidea fabula (Howe and Dohm, 1935) in Howe 

and graduate students (1935). There were other specimens illustrated by Ulrich and Bassler (1904), but 

these have apparently been lost.

I had originally planned to designate the specimen illustrated by Ulrich and Bassler (1904, pi. 37, fig. 15) as 

the lectotype of Cytherideis ashermani Ulrich and 

Bassler, and thereby conserve that trivial name. Unfortunately, the Ulrich and Bassler specimen was lost 

after the scanning electron micrograph shown on plate 

1, figure 5 (this report) was taken. As noted above, the 

other specimens of the syntype suite were not illustrated and are either juveniles or clearly another 

described species (Hulingsina semicircularis). Furthermore, the trivial name ashermani has never been consistently used for any valid taxon occurring in the 

Chesapeake Group. In fact, the name ashermani has 

been used for several distinctive species of Hulingsina 

occurring in sediments ranging in age from early 

Miocene to Holocene. Hulingsina ashermani 

represents a group of species sharing a generally 

similar ornament rather than any one species.

In view of the situation outlined above, I feel that it 

is best to: (1) propose a new species that would include 

the lost specimen illustrated by Ulrich and Bassler as 

part of their Cytherideis ashermani, (2) designate as 

the lectotype of C. ashermani the unillustrated adult 

specimen from the syntype suite (this specimen is 

cataloged as USNM 35446), and (3) subjectively suppress Cytherideis ashermani by placing it in synonymy 

with Hulingsina semicircularis. This action is further 

warranted because the Ulrich and Bassler (1904) illustrations (pi. 37; figures 11-16) indicate that their 

concept of Cytherideis ashermani involved at least 

Hulingsina calvertensis and several poorly preserved 

specimens of H. semicircularis. If later workers disagree with this assessment that the lectotype of 

Cytherideis ashermani is synonymous with Hulingsina 

semicircularis, the trivial name ashermani can be 

revived.

Occurrence.—Hulingsina calvertensis occurs 

throughout the Miocene part of the Chesapeake 

Group.

Stratigraphic range.— Lower to upper Miocene.

Hulingsina rugipustulosa (Edwards, 1944)

Plate 2, figure 1

Cytherideis rugipustulosa Edwards, 1944, p. 514, pi. 86, figs. 5-7. 

Cytherideis echolsae Malkin, 1953, p. 778, pi. 78, figs. 14-17.

^Cushmanidea echolsae (Malkin). McLean, 1957, p. 78, pi. 9, figs.

la-c, 2a-d. 

Pontocythere rugipustulosa (Edwards). Swain, 1968, p. 9, pi. 1,

fig. 10. 

Hulingsina rugipustulosa (Edwards). Valentine, 1971, pi. 3, figs. 17,

18, 21, 22, 25, 26, 29, 30. 

Pontocythere (Hulingsina) rugipustulosa (Edwards). Swain, 1974,

p. 17, pi. 1, fig. 18; pi. 2, figs. 4-7.

Diagnosis.— Distinguished by its generally small 

size, elongate subrectangular valve outline, rugose 

nature of the primary ornament (often leaving the appearance of the valve surface being wrinkled), and 

variation with respect to the presence of pustules 

along the carinae.

Lectotype.—A male right valve (Malkin, 1953, pi. 78, 

fig. 15), USNM 256023, from the Yorktown Formation 

(locality VA-12 of Malkin, 1953) is herein selected as 

the lectotype of Cytherideis echolsae Malkin, 1953 (pi. 

2, fig. I).

Measurements.—The lectotype is 650 pan in length 

and 250 pan in height.

Remarks.—Hulingsina rugipustulosa (Edwards, 

1944) is typically represented by two morphologies 

(also see Valentine, 1971), a pustulose form described 

by Edwards (1944) as Cytherideis rugipustulosa and a 

nonpustulose form described by Malkin (1953) as 

Cytherideis echolsae. The carinae and normal pores of 

both forms seem identical in pattern. Occurrence data 

suggest that the nonpustulose form tends to be a more 

cryophilic form, whereas the pustulose form is more 

thermaphilic. Both forms commonly occur in the same 

modern samples in the subtropical Carolinian Paunal 

Province, but only the nonpustulose form occurs north 

of Cape Hatteras in the mild temperate Virginian 

Province (J. E. Hazel, written commun., 1976).

Occurrence. Malkin (1953) reported this species 

from the Yorktown Formation in Virginia. In my 

samples from the Chesapeake Group the nonpustulose 

form is found in units C and D of the Eastover Formation and in the Yorktown Formation.

Stratigraphic range.—Upper Miocene to Holocene.

Hulingsina cylindrica (Ulrich and Bassler, 19O4)

Plate 2, figure 2

Cytheridea cylindrica Ulrich and Bassler, 1904, p. 126, pi. 37, fig. 

17.

Diagnosis.— Quadrate valve outline; sulcus along the 

line of the central muscle scar field; prominent 

reticulum.

Measurements.—The holotype (pi. 2, fig. 2), USNM 

35447, is 890 pan in length and 370 jum in height.

Remarks.—Hulingsina cylindrica is similar to many 

other reticulate species of Hulingsina; however, it is
8 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

usually more coarsely reticulate, with a reticulum that 

covers the entire lateral surface, except for the medial 

dorsal part of the valve. The species, taken in a strict 

sense, may be confined to the Calvert Formation and 

represent a very rare component of the ostracode 

fauna. There is, however, a very similar but somewhat 

larger form in the Choptank and St. Marys Formations. The Choptank forms average 1,030 jLtm in length; 

the St. Marys form averages 900 /mi in length. This 

younger form is probably conspecific with the Calvert 

form because an increase in size of several species from 

the Calvert to the Choptank Formations has been 

noted.

Occurrence.— Calvert Formation and probably the 

Choptank Formation, as well as units A and B of the 

St. Marys Formation.

Stratigraphic range. Lower to middle Miocene.

Hulingsina semicircular is (Ulrich and Bassler, 19O4)

Plate 2, figure 5

Cytherideis semicircularis Ulrich and Bassler, 1904, p. 127, pi. 37,

figs. 18-20. 

Cytherideis languid Ulrich and Bassler, 1904, p. 128, pi. 37, figs.

21-27. 

Cytherideis ashermani Ulrich and Bassler, 1904, partim, p. 126,

pi. 37, figs. 11-13; Howe and others, 1935, p. 14, pi. 3, figs.

8-10; Malkin, 1953, partim, p. 778, pi. 78, figs. 1-11, 13?; Puri,

1953, partim, p. 286, pi. 9, figs. 4, 5, 7, 8.

Diagnosis.— This species is distinguished by its 

somewhat semicircular valve outline, greatest length 

below midheight, greatest height (midvalve) behind 

the adductor muscle scar field, prominent large 

punctae containing normal pores.

Lectotype.—A female right valve, USNM 35449 a, is 

designated as the lectotype. This specimen is probably 

that illustrated by Ulrich and Bassler (1904) on plate 

37, figure 18. The syntype series is from the Calvert 

Formation at Plum Point, Md.

Measurement—The lectotype is 760 /-tin in length 

and 350 /mi in height.

Remarks.— The specimens assigned to Cytherideis 

semicircularis by Ulrich and Bassler (1904) are all 

females (as has been noted by many authors). I believe 

the male of the species was described by Ulrich and 

Bassler as Cytherideis longula and therefore, 

synonomize the two species, retaining the trivial name 

semicircularis. A left valve, which is probably the 

specimen illustrated by Ulrich and Bassler (1904) on 

plate 37, figure 25, USNM 35448 a, is designated as the 

lectotype of Hulingsina longula (Ulrich and Bassler, 

1904). The lectotype is illustrated herein on plate 2, 

figure 3 and a paralectotype is illustrated in plate 2, 

figure 4. The lectotype is 940 pan in length and 380 /mi 

in height, while the illustrated paralectotype, USNM 

35448 b, is 850 /mi in length and 330 /mi in height.

My concept is, however, that H. semicircularis 

(Ulrich and Bassler) is equivalent in part to 

Cytherideis ashermani of some authors. The C ^ashermani syntype series represents three species (see 

discussion under Hulingsina calvertensis), and it is not 

clear what their concept of the species was. The C. 

semicircularis series contains only one species, in my 

opinion; at least for the females, Ulrich and Bassler's 

concept of them is clear. One of the specimens in the 

syntype series of Cytherideis ashermani, herein 

designated the lectotype of that species, is placed in 

synonymy of H. semicircularis.

Hulingsina semicircularis is a common constituent 

of Calvert, Choptank and St. Marys (units A and B) 

assemblages, becoming somewhat rarer in the younger 

Miocene (Eastover Formation) sediments (units C and 

D). As with several other ostracode species occurring 

in both the Calvert and Choptank Formations, the 

mean size of the Choptank form is larger.

Hulingsina semicircularis (Ulrich and Bassler) is 

morphologically similar to H. americana (Cushman, 

1906). Pleistocene and Holocene specimens of the latter species are readily distinguished from H. semicircularis by their narrower murae, prominent normal 

pores, and slight differences in valve outline. However, 

Pliocene specimens are morphologically somewhat 

gradational, exhibiting only slightly greater morphologic similarity with H. americana. My concept of H. 

semicircularis restricts the species to the Miocene; 

however, considerable difficulty is encountered in trying to classify some specimens from the lower part of 

the Yorktown Formation.

Occurrence.—Calvert, Choptank, and St. Marys and 

Eastover Formations.

Stratigraphic range. Lower to upper Miocene.

Hulingsina subaequalis (Ulrich and Bassler, 19O4)

Plate 2, figure 6

Cytherideis subaeqaMs Ulrich and Bassler, 1904, p. 127, pi. 37, fig. 28; 

Malkin, 1953, partim, p. 779, pi. 78, fig. 18.

Diagnosis.—This species is distinguished by its 

quadrate shape; height approximately half the length; 

few, scattered punctae with normal pores.

Measurements.—The holotype USNM 35450 (female 

left valve, pi. 2, fig. 6), is 840 jum, in length and 420 

Mm in height.

Occurrence.—Ulrich and Bassler (1904) reported this 

species from the Calvert Formation. Malkin (1953) 

reported it from the Calvert and Choptank Formations, but her illustrated specimens are all from the 

Calvert Formation.. In my samples, Hulingsina subaequalis occurs in the Calvert below "zone" 11.

Stratigraphic range.—Lower Miocene.
SYSTEMATICS

Family CYTHERURIDAE G. W. Muller, 1894 

Subfamily CYTHERURINAE G. W. MuUer, 1894

Genus Cytherura Sars, 1866

Type-species. —Cytherura gibba O. F. Muller, 1785. 

Cytherura coryelli Malkin, 1953

Plate 2, figure 8 

Cytherura coryelli Malkin, 1953, p. 788, pi. 80, figs. 20, 21, 25.

Diagnosis.— Height to length ratio of 0.5 or greater, 

greatest height just posterior to the adductor muscle 

scar field; punctation that covers the entire valve surface and forms concentric rows along the dorsal and 

ventral margins; hingement consisting of an anterior 

socket, crenulate tooth, crenulate bar, and another 

crenulate tooth in the left valve.

Lectotype.—A female left valve (Malkin, 1953, pi. 

80, fig. 25), USNM 256024, from the Choptank Formation (locality 14-5 of Malkin, 1953) is herein designated 

as the lectotype (pi. 2, fig. 8).

Measurements.—The lectotype is 450 pun in length 

and 250 jum in height.

Occurrence.— Malkin (1953) reported this species 

from the Choptank Formation. It also occurs in unit B 

of the St. Marys Formation in my collections, as well 

as in the Choptank Formation.

Stratigraphic range. Middle Miocene.

Subfamily CYTHEROPTERINAE Hanai, 1957 

Genus Cytheropteron Sars, 1866

Type-species.—Cythere latissima Norman, 1865

Cytheropteron? yorktownensis (Malkin, 1953)

Plate 2, figure 7

Eocytheropteront species Swain, 1951, p. 47, pi. 7, fig. 16. 

Eocytheropteron yorktownensis Malkin, 1953, p. 780, pi. 79, figs.

1-4. 

Cytheropteron leonensis Puri, 1954, p. 242, pi. 4, figs. 11, 12; figs.

6c, d. 

Cytheropteron yorktownensis (Malkin). Swain, 1968, p. 13, pi. 4,

figs. 7a-c, 11. 

Shattuckocythere yorktownensis (Malkin). Swain, 1974, p. 22, pi. 3,

figs. 9-12, 14, 15. 

Not Shattuckocythere yorktownensis (Malkin). Swain, 1974,

p. 22, pi. 3, fig. 13; pi. 9, figs. 9a, b (^Microcytherura similis

(Malkin)).

Diagnosis.—Small size; subtrapezoidal valve outline; 

in having the greatest height anterior to the adductor 

muscle scar field; ventral medial portion of the valve 

inflated and overhanging ventral valve margin; prominent ornamentation pattern consisting of a subdued 

reticulum with numerous fine punctae covering the 

solum of each fossa.

Lectotype.—A female left valve (Malkin, 1953, pi. 

79, fig. 3), USNM 256025, (locality VA-4, of Malkin,

1953), is herein designated as the lectotype (pi. 2, 

fig. 7).

Measurements.—The lectotype is 390 ^m in length 

and 220 ^m in height.

Remarks.—Cytheropteron! yorktownensis (Malkin, 

1953) is a very distinctive and common species in 

Pliocene sediments along the Atlantic Coastal Plain. It 

is probably sufficiently distinctive from the Cytheropteron to be placed in a new genus, although its 

familial assignment is uncertain at present. Swain 

(1974) assigned C? yorktownensis to his new genus 

Shattuckocythere. However, Shattuckocythere is not a 

useful taxon because the type species selected by 

Swain (Cytherel shattucki Ulrich and Bassler, 1904) is 

a typical member of the genus Microcytherura 

Mueller, 1894.

Occurrence.—In the Chesapeake Group the species 

has been found only in the Yorktown Formation. It 

also occurs in Atlantic Coastal Plain deposits of early 

Pleistocene age.

Stratigraphic range.—Pliocene to lower Pleistocene.

Family TRACHYLEBERIDIDAE Sylvester-Bradley, 1948

Subfamily TRACHYLEBERIDINAE Sylvester-Bradley,

1948

Tribe TRACHYLEBERIDINI Sylvester-Bradley, 1948 

Genus Murrayina Puri, 1954

Type-species.—Murrayina howei Puri, 1954.

Remarks.— The genus Murrayina is comprised of a 

group of reticulate Trachyleberidini closely related to 

Actinocythereis. The morphologic bounds of the 

species within this genus, for the most part, are poorly 

understood, particularly when populations are examined that are geographically or temporally disjunct 

from the type area of the species in question. Murrayina either consists of a few species with a great deal 

of morphologic variability or numerous species with 

little variability (or perhaps both). The genus has a 

known range of early Miocene to early Pleistocene and 

is recognized by its rectangular shape (i.e., Actinocythereis), its usually distinctive reticulum, and the 

presence of a denticular structure on the ventral inner 

margin of the right valve (also developed to varying 

degrees in Actinocythereis). The close relationship of 

Murrayina to Actinocythereis is exemplified by Murrayina radiata (Malkin, 1953), which has certain 

features that are practically intermediate between 

typical Actinocythereis and typical Murrayina.

The confusion associated with the morphologic 

definition of the various species of Murrayina is further compounded by the preservational states of Murrayina. In surface morphology, specimens may range 

from strongly reticulate to completely smooth; 

however, smooth exterior surfaces seem to be the
10 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

result of post-mortem processes. Diagenetic changes 

(the causes of which are poorly understood at present) 

seem to have progressively removed some or all of the 

reticulation, resulting in a smooth-valved specimen as 

an end product. I have observed specimens of several 

species of Murrayina in various states of alteration, 

with the reticulum "exfoliating" off the valve. Murrayina is in need of extensive morphologic study; this 

is beyond the scope of the present work.

Murrayina howei Purl, 1954

Plate 3, figure 3

Cythere producta Ulrich and Bassler, 1904, p. 115, pi. 36, fig. 17;

pi. 38, figs. 28-30. 

Cythere dorsicornis Ulrich and Bassler, 1904, p. 113, pi. 36, fig.

13. 

Not Cythereis producta Howe and others, 1935, p. 22, pi. 1, figs.

31, 32, 35-37; pi. 4, figs. 11, 12 (?= male of Murrayina gunteri). 

Not Murrayina howei Puri, 1954, p. 255, pi. 12, figs. 9, 10; figures

8g, h; McLean, 1957, p. 85, pi. 10, figs. 4a-e.

Diagnosis,— Rectangular valve outline; very prominent reticulum, with narrow murae forming each fossa; 

broad smooth areas concentric with the anterior and 

posterior of the valve; large size.

Lectotype.—A male right valve, which is probably 

the specimen illustrated by Ulrich and Bassler (1904) 

on pi. 38, fig. 30, USNM 35433 a, is designated the lectotype (pi. 3, fig. 3). This specimen occurs at the Plum 

Point locality (Ulrich and Bassler, 1904) of the Calvert 

Formation.

Measurements.—The lectotype measures 980 pm in 

length and 400 pan in height.

Remarks.—Murrayina howei is very similar to M. 

martini (Ulrich and Bassler, 1904), but the former is 

larger and has polygonal fossae, whereas the fossae in 

M. martini are elliptical in outline and are relatively 

smaller.

The nomenclatural history of this species is quite 

complex. Ulrich and Bassler's Cythere producta is a 

junior homonym of C. producta Brady, 1866. Puri 

(1954) recognized this and renamed the species Murrayina howei, making it the type species of that genus. 

In my opinion, it is quite possible that the form identified by Puri (1954) and Howe and others (1935) as 

Ulrich and Bassler's Cythere producta may be the 

male of Murrayina gunteri (Howe and Chambers, 

1935). Hazel (1967, p. 22) thought that Murrayina 

gunteri and M. howei were synonyms and therefore the 

former would have priority over Puri's (1954) name M. 

howei. However, work by the author on the genus Murrayina has led to the conclusion that M. gunteri is a 

distinct species and M. howei is retained for Cythere 

producta Ulrich and Bassler, 1904.

The juveniles of the species differ from the adults in 

shape and possess two prominent spines in the 

posterior of the valves. Cythere dorsicornis Ulrich and 

Bassler, 1904, is a typical juvenile of M. howei Puri, 

1954. The holotype of C. dorsicornis Ulrich and 

Bassler, 1904, is illustrated in plate 3, figure 5 and is 

670 pan in length and 360 /mi in height.

Occurrence.— This species was reported from the 

Calvert Formation by Ulrich and Bassler (1904). It has 

been reported from younger sediments by other 

authors, but I believe that these reports represent 

other species. Murrayina howei occurs throughout the 

Calvert Formation in my collections, but has not been 

observed in younger units.

Stratigraphic range.—Lower to middle Miocene.

Murrayina martini (Ulrich and Bassler, 19O4)

Plate 3, figures 2, 4

Cythere martini Ulrich and Bassler, 1904, p. 112, pi. 36, figs. 11-15. 

iCy there dorsicornis var. bicornis Ulrich and Bassler, 1904, p. 114,

pi. 38, figs. 32, 33. 

Not Trachyleberisl martini (Ulrich and Bassler). Swain, 1951, p. 29,

pi. 3, figs. 8, 15; Malkin, 1953, p. 793, pi. 82, figs. 6-13. 

Not Murrayina martini (Ulrich and Bassler). Puri, 1954, p. 256,

pi. 12, figs. 8e, f, 11-13; McLean, 1957, p. 86, pi. 11, figs, la-c,

2a-b, 3a-d.

Diagnosis.— Valve outline quadrate; prominent 

reticulum with fairly wide murae and oval-shaped 

fossae; narrow smooth areas concentric to the anterior 

and posterior margins.

Lectotype.—A male right valve illustrated by Ulrich 

and Bassler (1904, pi. 36, fig. 13), USNM 35423 a, from 

the Calvert Formation at Plum Point, Md., is selected 

as the lectotype (pi. 3, fig. 2).

Measurements.—The lectotype is 710 jum in length 

and 310 /^m in height. The illustrated paralectotype, 

USNM 35423 b, (pi. 3, fig. 4), a female left valve, is 

710 (Jim in length and 410 ^m in height.

Remarks.—Hazel (1967) deals with the complicated 

nomenclatural history of Murrayina martini. The majority of the species referred to M. martini by various 

authors represent several species of the genus 

Muellerina of the family Hemicytheridae.

Murrayina martini as defined herein has not been 

reported from sediments younger than the Choptank 

Formation. In fact, in my collections of Choptank 

sediments M. martini only occurs in "zones" 16 and 17 

of the Choptank Formation. Morphologically similar 

forms, occurring in younger sediments, could easily be 

confused with M. martini; I regard them as being one 

or more undescribed species.

Cythere dorsicornis var. bicornis Ulrich and Bassler, 

1904, like C. dorsicornis sensu stricto, represents a
SYSTEMATICS 11

Murrayina instar. The holotype USNM 35416, illustrated here (pi. 3, fig. 6; 430 /mi in length and 250 /-on 

in height), comes from the Choptank Formation at the 

"Paw Paw Point" locality of Ulrich and Bassler (1904). 

The reticulation is developed in a manner most similar 

to that seen in adults of Murrayina martini and 

therefore M. bicornis is placed in synonymy with M. 

martini.

Occurrence.—This species occurs commonly in collections from the Calvert and Choptank Formations.

Stratigraphic range.—Lower to middle Miocene.

Murrayina radiata (Malkin, 1953)

Plate 3, figure 1

Trachyleberis radiata Malkin, 1953, p. 791, pi. 81, figs. 12, 13. 

Not Trachyleberis radiata Malkin, 1953, p. 791, pi. 81, fig. 14 

(= Murrayina howei (Ulrich and Bassler)).

Diagnosis.— Valve outline quadrate; prominent 

reticulum, with polygonal to irregularly shaped fossae; 

large carinae radiating from the central muscle node 

toward the posterior margin and medial ventral area, 

terminating in blunt denticles; prominent dorsal 

carina, which overhangs the dorsal margin; smooth 

area concentric to the anterior margin.

Lectotype.—A female right valve illustrated by 

Malkin (1953, pi. 81, fig. 12), USNM 256026, from the 

Kirkwood Formation of New Jersey (locality NJ-9 of 

Malkin, 1953) is designated the lectotype (pi. 3, fig. 1).

Measurements.—The lectotype is 780 /mi in length 

and 380 /mi in height.

Remarks.—Murrayina radiata exhibits a transitional 

morphology between Actinocythereis and Murrayina 

(see remarks above under Murrayina). This species is 

morphologically similar in reticulation pattern to the 

other species of Murrayina occurring in the Calvert 

Formation (compare pi. 3, figs. 1-4). These taxa differ 

from each other only in a few morphologic 

characteristics such as size or expression of a carina. 

Murrayina presumably originated in the Oligocene or 

early Miocene and thus the strong morphologic 

similarity of these lower to middle Miocene species (M. 

radiata, M. howei, and M. martini) may be because of 

the limited morphologic radiation from a common 

ancestor.

Occurrence.— Malkin (1953) reported this species 

from the Kirkwood and Calvert Formations. It 

represents a fairly rare component of the Calvert 

fauna.

Stratigraphic range.—Lower to middle Miocene.

Genus Actinocythereis Puri, 1954

Type-species.—Cythere exanthemata Ulrich and 

Bassler, 1904.

Actinocythereis exanthemata (Ulrich and Bassler, 19O4)

Plate 3, figures 7, 8 

Cy there exanthemata Ulrich and Bassler, 1904, p. 117, pi. 36,

figs. 1-3, 5. 

Not Cythere exanthemata Ulrich and Bassler, 1904, p. 117, pi. 36,

fig. 4 (= Actinocythereis marylandica (Howe and Hough,

1935)). 

Not Trachyleberis exanthemata (Ulrich and Bassler). Swain, 1951,

p. 37, pi. 6, fig. 5; Malkin, 1953, p. 791, pi. 81, fig. 19. 

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

p. 791, pi. 81, fig. 19. 

Not Actinocythereis exanthemata (Ulrich and Bassler). Puri, 1954,

p. 252, pi. 13, figs. 6-13 (= Actinocythereis spp.); McLean,

1957, p. 82, pi. 10, figs, la-c (= Actinocythereis spp.); Swain,

1968, p. 14, pi. 2, figs. 5a-f, 12 (= Actinocythereis capitonis

Hazel); Swain, 1974, p. 30, pi. 4, figs. 23, 24; pi. 5, figs. 1, 2;

pi. 10, figs, la-g (= Actinocythereis spp.)

Diagnosis.—Distinctive arrangement of various surface spines: a posterodorsally oriented row of five 

spines occur along a weakly developed ridge located 

near the ventral margin; the two anterior-most of these 

clavate spines are located directly below the central 

muscle node, the posterior three are bullate in shape 

and positioned spines in the medial ventral area of the 

valve; the valve midline is marked by a longitudinal 

curved row of four spines, directly posterior of the central muscle node. The geometric relationship of these 

nine spines to each other is constant and unique for 

this species.

Lectotype.—A female left valve (Ulrich and Bassler, 

1904, pi. 36, fig. 3), USNM 35419 a, from the Calvert 

Formation at Plum Point, Md., is selected as the lectotype (pi. 3, fig. 8).

Measurements.—The lectotype is 850 /mi in length 

and 400 /mi in height; the illustrated paralectotype, 

USNM 35419 b (pi. 3, fig. 7), is 800 /mi in length and 

400 /mi in height.

Remarks.—Actinocythereis exanthemata is most 

frequently confused with the lower Miocene to 

Holocene species A. marylandica (Howe and Hough, 

1935). Actinocythereis marylandica is a larger and 

more robust form that has a slightly different arrangement of the nine spines discussed above.

Occurrence.—Actinocythereis exanthemata occurs 

throughout the Calvert Formation and is also known 

from the lower part of the Choptank Formation 

("zone" 17) in my collections.

Stratigraphic range.—"Lower to middle Miocene.

Actinocythereis alaris (Ulrich and Bassler, 19O4)

Plate 4, figure 3

Cythereis alaris Ulrich and Bassler, 1904, p. 123, pi. 38, figs. 34,

35, 36.

Measurements.—The holotype, USNM 35451, is 

730 /mi in length and 390 /mi in height.
12 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

Remarks. —Cythereis alaris Ulrich and Bassler, 1904 

represents a rather early instar of a species of Actinocythereis from the Yorktown Formation. However, 

it cannot be specifically differentiated with certainty 

and therefore the binomen Cythereis alaris is considered to be nomen dubium.

Genus Henryhowella Purl, 1957

Type-species.—Cythere evax Ulrich and Bassler, 

1904.

Henryhowella evax (Ulrich and Bassler, 19O4)

Plate 4, figures 1, 2

Cythere evax Ulrich and Bassler, 1904, p. 119, pi. 36, figs. 6-8. 

Cy there evax var. oblongula Ulrich and Bassler, 1904, p. 119, pi.

36, figs. 9, 10. 

Cythere spiniplicata Ulrich and Bassler, 1904, p. 120, pi. 38, fig.

18. 

Trachyleberis evax (Ulrich and Bassler). Swain, 1951, p. 28, pi. 3,

figs. 2, 3; Malkin, 1953, p. 792, pi. 82, figs. 4, 5. 

ITrachyleberis evax (Ulrich and Bassler). Swain, 1951, p. 28, pi. 3,

fig. 1. 

Not Echinocythereis evax (Ulrich and Bassler). Puri, 1954, p. 260,

pi. 12, fig. 1; fig. 9c. 

Not Howella evax (Ulrich and Bassler). Puri, 1956, p. 275, pi. 35,

figs. 1-8. 

IHenryhowella evax (Ulrich and Bassler). Pooser, 1965, p. 59,

pi. 19, fig. 1; pi. 20, figs. 2, 7, 9-13.

Diagnosis.— Large valve size; characteristic 

quadrate shape; three primary longitudinal carinae; 

numerous small bifurcating spines; development of a 

reticulum from the central muscle area of the valve to 

the valve anterior.

Lectotype.—A female left valve illustrated by Ulrich 

and Bassler (1904, pi. 36, fig. 7), USNM 35417 a, from 

the Calvert Formation, Plum Point, Md., is selected as 

the lectotype (pi. 4, fig. 2).

Measurements.—The lectotype is 770 ptm in length 

and 450 pirn in height.

Remarks.—Henryhowella species are usually morphologically quite similar to each other. Carapace size 

and minor details of the ornament appear to be important characteristics for differentiating the various 

species. The species identified by Puri (1954, 1956) 

from upper Miocene and Pliocene sediments as Henryhowella evax is smaller and has a slightly different 

shape than specimens from the Calvert Formation. 

Cythere evax var. oblongula Ulrich and Bassler, 1904 

is the male of Henryhowella evax. A left valve (Ulrich 

and Bassler, 1904, pi. 36, fig. 10), USNM 35418 a, from 

the Calvert Formation, Plum Point, Md., is selected as 

the lectotype. The lectotype is 860 pirn in length and 

450 /^m in height.

Only a fragment of the holotype of Cythere spiniplicata Ulrich and Bassler, 1904, USNM 35438, exists. 

The fragment is part of the valve just behind the central muscle node. This fragment appears to be a 

Henryhowella, probably H. evax, and thus this species 

is synonymized under H. evax.

Occurrence.— Ulrich and Bassler (1904) reported this 

species from the Calvert Formation and from the 

Yorktown Formation; however, subsequent authors 

have not found the genus in the Yorktown Formation 

(Hazel, 1971). I have only found this species in the 

Calvert Formation. Pooser (1965) reports this species 

from the upper part (upper Oligocene) of the Cooper 

Formation in South Carolina.

Stratigraphic range.—Upper Oligocene to middle 

Miocene.

Tribe PTERYGOCYTHEREIDINI Puri, 1957 

Genus Pterygocythereis Blake, 1933

Type-species.—Cythereis jonesii Baird, 1850

Pterygocythereis americana (Ulrich and Bassler, 1904)

Plate 4, figure 4

Cythereis cornuta var. americana Ulrich and Bassler, 1904, p. 122,

pi. 37, figs. 29-33. 

Not Cythereis (Pterygocythereis) cornuta var. americana (Ulrich

and Bassler). Howe and others, 1935, p. 26, pi. 2, figs. 19, 21-24;

pi. 4, fig. 24. 

^Pterygocythereis cornuta americana (Ulrich and Bassler, 1904).

Puri, 1954, partim, p. 261, pi. 13, %. 5. 

Pterygocythereis americana (Ulrich and Bassler, 1904). Malkin,

1953, partim, p. 795, pi. 80, fig. 29. 

Not Pterygocythereis americana (Ulrich and Bassler, 1904). McLean,

1957, p. 80, pi. 9, figs, 5a-d, 6a-e; Swain, 1974, p. 23, pi. 2, fig.

11; pi. 9, fig. 5; pi. 13, figs. 2a-c (= Pterygocythereis inexpectata

Blake, 1933).

Diagnosis.—Distinguished by its quadrate valve 

outline, valve size, details of the dorsal crests, and the 

position and nature of the ala. The two dorsal crests 

are approximately equidimensional and generally nonplicated; ala parallels and overhangs the ventral 

margin and is usually wide enough that it is not 

plicated; ala is connected to the posteroventral area of 

the valve by a short, but prominent, posterodorsally 

oriented ridge.

Lectotype.—A female left valve (Ulrich and Bassler, 

1904, pi. 37, fig. 31 (?)), USNM 35452 a, from the 

Calvert Formation at Plum Point, Md., is selected as 

the lectotype.

Measurements.—The lectotype (pi. 4, fig. 4) is 

950 pm in length and 530 pan in height.

Remarks.—Pterygocythereis americana appears to 

represent an intermediate morphologic stage between 

P. howei Hill, 1954 (from the Oligocene) and P. inexpectata Blake, 1933, an upper Miocene to Holocene 

species. Pterygocythereis howei differs from P. 

americana in having dorsal crests of unequal length, 

where the posterior crest is longer than the anterior 

crest. The alae of P. howei are relatively thicker and
SYSTEMATICS 13

are located closer to the medial part of the valve 

(higher on the valve) than in P. americana, Pterygocythereis americana differs from P. inexpectata in 

having relatively thicker alae that are located more 

medially (higher) on the valve surface. The dorsal 

crests of both species are about the same length, 

although those in P. americana are relatively thicker 

than those in P. inexpectata. The valve outline of the P. 

howei to P. inexpectata sequence also changes by becoming progressively less quadrate and more rectangular, where P. howei has a greater height to length 

ratio than P. inexpectata.

The upper Miocene (unit D of the Eastover Formation), Pliocene, and Quaternary specimens of P. inexpectata are readily distinguished from Calvert 

specimens of P. americana (lower to middle Miocene) 

by the characteristics noted above. However, there are 

a number of intermediate forms occurring in units B 

and C of the St. Marys Formation (upper middle and 

upper Miocene) that could be placed in either species. 

These morphologically intermediate specimens are 

herein arbitrarily placed in P. inexpectata. As yet no 

Pterygocythereis species have been found in the Choptank Formation, thus providing a slight and somewhat 

arbitrary morphologic gap to subdivide the species.

Occurrence.—Pterygocythereis americana is confined to the Calvert Formation in our collections.

Stratigraphic range.— Lower to middle Miocene.

Tribe ECHINOCYTHEREEDINI Hazel, 1967 

Genus Echinocythereis Purl, 1954

Type-species.—Cythereis garretti Howe and 

McGuirt, 1935 (= Echinocythereis margaritifera 

(Brady, 1840)).

Echinocythereis clarkana (Ulrich and Bassler, 1904)

Plate 4, figure 5

Cythere clarkana Ulrich and Bassler, 1904, p. 98, pi. 35, figs. 1-3,

5, 7-10. 

Not Cythere clarkana Ulrich and Bassler, 1904, p. 98, pi. 35, figs.

4, 6 (= Echinocythereis miniscula (Ulrich and Bassler, 1904)). 

ILeguminocythereisl clarkana (Ulrich and Bassler). Swain, 1951,

p. 43, pi. 6, fig. 18. 

Not Trachyleberis clarkana (Ulrich and Bassler). Malkin, 1953,

p. 792, pi. 82, figs. 1-3 (= Echinocythereis planibasalis (Ulrich

and Bassler, 1904)). 

Not Echinocythereist clarkana (Ulrich and Bassler). Swain, 1974,

p. 32, pi. 5, figs. 13-15 (figs. 13, 14 = juvenile Murrayina

macleani Swain, 1974; fig. 15 = Echinocythereis planibasalis

(Ulrich and Bassler, 1904)).

Diagnosis.—Large size; valve outline, quadrate; 

prominent reticulum with small spines along the 

murae; greatest length is midvalve; greatest height is 

anterior to the central muscle field.

Lectotype. A male left valve (Ulrich and Bassler, 

1904, pi. 35, fig. 5), USNM 35413 a, from the Calvert

Formation, Plum Point, Md., is selected as the 

lectotype.

Measurement—The lectotype is 1,200 /mi in length 

and 640 /mi in height.

Occurrence.—Echinocythereis clarkana occurs in the 

Calvert Formation, below bed 12.

Stratigraphic range.—Upper Oligocene to lower 

Miocene.

Echinocythereis miniscula (Ulrich and Bassler, 1904)

Plate 4, figure 8

Cythere clarkana var. miniscula Ulrich and Bassler, 1904, p. 99,

pi. 35, figs. 11-14. 

Cythere clarkana Ulrich and Bassler, 1904, partim, p. 98, pi. 35,

figs. 4, 6.

Diagnosis.—Small; valve outline quadrate to ovate; 

greatest length just ventral of midvalve; greatest 

height anterior of central muscle scar field; prominent 

reticulum (with generally thicker murae than E. 

clarkana} with spinelets along the murae.

Lectotype.—A female left valve (Ulrich and Bassler, 

1904, pi. 35, fig. 14), USNM 35414 a, from the Calvert 

Formation at Plum Point, Md., is selected as the 

lectotype.

Measurements. The lectotype is 900 /mi in length 

and 550 /mi in height.

Remarks.— Ulrich and Bassler, 1904, designated E. 

miniscula as a variety of E. clarkana, because of its 

smaller size. The syntype suite of E. miniscula contains three juvenile and one adult valves. Presumably 

Ulrich and Bassler's concept of E. miniscula was based 

primarily upon the three juveniles; however, the 

specimen they illustrated on plate 35, figure 14 is an 

adult female left valve. Material collected from various 

Calvert localities reveals that there is a polymodal 

distribution in size of Echinocythereis populations. 

One female mode is centered around about 937 /mi in 

length; the adult female selected as the lectotype of E. 

miniscula falls in this class. A second female mode is 

centered around 1,025 /mi in length, while the two male 

modes are centered around 1,062 /mi and 1,225 /mi in 

length. I have interpreted the smaller male and female 

modes as being E. miniscula and the larger two male 

and female modes as being E. clarkana. At present, 

size appears to be the only means of consistently 

distinguishing the two forms from each other. The two 

size groupings may represent two closely related 

species differing primarily in size, or they may be the 

same species exhibiting two sizes. The latter might 

result from seasonal breeding, wherein one size 

represents fall-winter population and the other a 

spring-summer population. Males and females of E. 

clarkana and E. miniscula occur commonly in the same 

samples, and both have the same Stratigraphic range.
14 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

It is impossible to be certain whether or not there is 

one or two species in this case; I have elected to conserve both names and recognize two species at this 

time.

Occurrence.—Echinocythereis miniscula (Ulrich and 

Bassler, 1904) occurs in the pre-"zone" 12 units of the 

Calvert Formation in our collections.

Stratigraphic range. Lower Miocene.

Echinocythereis planibasalis (Ulrich and Bassler, 19O4)

Plate 4, figure 7

Cythere planibasalis Ulrich and Bassler, 1904, p. 99, pi. 38, figs.

1-3. 

Buntonial planibasalis (Ulrich and Bassler). Swain, 1951, p. 39,

pi. 3, figs. 4, 5. 

Trachyleberis clarkana (Ulrich and Bassler). Malkin, 1953, p. 792,

pi. 82, figs. 1-3. 

Echinocythereis clarkana (Ulrich and Bassler). McLean, 1957, p. 84,

pi. 10, figs. 3a-c. 

Echinocythereis planibasalis (Ulrich and Bassler). Hazel, 1967,

p. 37, pi. 6, figs. 4, 5,8. 

Echinocythereis"? clarkana (Ulrich and Bassler). Swain, 1974, p. 32,

pi. 5, fig. 15. 

Not Echinocythereis'? clarkana (Ulrich and Bassler). Swain, 1974,

p. 32, pi. 5, figs. 13, 14 (= juvenile Murray ma macleani Swain,

1974).

Diagnosis. Valve outline ovoid; massive reticulum; 

greatest length about midvalve; greatest height just 

anterior of central muscle scar field; prominent ventral 

carinae with numerous stubby spines on the males.

Measurements.—The holotype, a male right valve, 

USNM 35428, is 1,020 jmi in length and 570 ^m in 

height.

Remarks.—Echinocythereis planibasalis (Ulrich and 

Bassler, 1904) was originally described from the 

Yorktown Formation. In the present collections I have 

assigned individuals from the Calvert, Choptank, and 

Eastover Formations to E. planibasalis. The Miocene 

forms (particularly those from the Calvert Formation) 

are somewhat smaller than their Pliocene and younger 

counterparts; Miocene males, for example, will usually 

fall in the 950 to 1,000 ^m length size class. There does 

appear to be a general size increase through time. 

Other than size, however, the Miocene individuals 

seem nearly identical with the Pliocene and younger 

forms.

The males of E. planibasalis have a characteristic 

ventral rib with numerous blunt spines that is lacking 

in the females. The females often have a "braided" sequence of murae in the same area of the valve.

Occurrence.— Ulrich and Bassler (1904) found this 

species in the Yorktown Formation. I have found this 

species in the Calvert, Choptank, and Eastover (unit C) 

Formations. Hazel (1967) and Valentine (1971) report 

this species from modern sediments.

Stratigraphic range.—Lower Miocene to Holocene.

Tribe CYTHEBETTINI Triebel, 1952 

Genus Pseudocytheretta Cushman, 19O6

Type-species.—Pseudocytheretta edwardsi 

Cushman, 1906.

Pseudocytheretta burns! (Ulrich and Bassler, 19O4)

Plate 4, figure 6; Plate 5, figures 2, 3, 6, 7, 8.

Cythere burnsi Ulrich and Bassler, 1904, p. 103, pi. 36, figs. 35-39. 

Not Cythere burnsi Ulrich and Bassler, 1904, p. 105, pi. 38, fig. 34

(= Pseudocytheretta n. sp.). 

Cythere paucipunctata Ulrich and Bassler, 1904, p. 105, pi. 38,

figs. 7-9.

Cythere nitidula Ulrich and Bassler, 1904, p. 107, pi. 36, figs. 21-23. 

Cythere nitidula var. calvertensis Ulrich and Bassler, 1904, p. 108,

pi. 36, fig. 24.

Cythere toumeyi Ulrich and Bassler, 1904, p. 105, pi. 38, figs. 5, 6. 

Cytheretta burnsi (Ulrich and Bassler). Howe and others, 1935,

p. 33, pi. 2, figs. 12-14,17, 20; pi. 4, figs. 14, 21; Malkin, 1953, p.

789, pi. 81, figs. 7, 8,10,11; Puri, 1954, p. 282, pi. 7, figs. 1, 2.

Diagnosis.—Extreme asymmetry between the 

valves; small "tab" like extension of the valve margin 

in the posterodorsal corner of the left valve; fine to 

coarse punctation posterior of the central muscle scar 

field that is ovate in outline; greatest length along the 

medial portion of the valve.

Lectotype.—A male left valve (Ulrich and Bassler, 

1904, pi. 36, fig. 37 (?)), USNM 35411 a, from the 

Calvert Formation at Plum Point, Md., is selected as 

the lectotype (pi. 4, fig. 6).

Measurements.—The lectotype is 1,130 /^m in length 

and 570 jmi in height.

Remarks.—Pseudocytheretta burnsi has a complicated nomenclatural history. Like other species of 

the genus, P. burnsi exhibits extreme asymmetry between the valves (compare pi. 4, fig. 6 with pi. 5, fig. 3). 

This feature, coupled with strong sexual dimorphism 

and normal individual variation in size, results in 

populations of valves represented by numerous sizes 

and shapes. These factors are compounded when the 

instar sequence is considered. Ulrich and Bassler 

(1904) did not recognize these features and proposed 

several species based on juveniles as well as one based 

on an adult (P. paucipunctata). Pseudocytheretta paucipunctata (Ulrich and Bassler) differs from P. burnsi 

primarily in the nature of the punctae; P. paucipunctata has a large ovate punctae as opposed to small fine 

punctae.

The holotype, USNM 35427, of Pseudocytheretta 

paucipunctata (Ulrich & Bassler, 1904) is illustrated in 

plate 5, figure 6. This specimen is a female left valve 

that is 1,050 /tfn in length and 580 jmi in height. The remaining species herein synonymized under Pseudocytheretta burnsi (Ulrich and Bassler, 1904) are all 

juveniles. A left valve, which is probably the specimen 

illustrated by Ulrich and Bassler (1904) in plate 36, 

figure 21, is herein designated the lectotype of
SYSTEMATICS 15

Pseudocytheretta nitidula (UMch and Bassler, 1904). 

This specimen, USNM 35425 a, was collected from the 

Plum Point locality of Ulrich and Bassler (1904), in the 

Calvert Formation. It is illustrated in plate 5, figure 2 

and is 860 jion in length and 460 jion in height.

A left valve (UMch and Bassler, 1904, pi. 36, fig. 24), 

USNM 35426 a, from the Calvert Formation at Plum 

Point, Md., is selected as the lectotype of Pseudocytheretta calvertensis (Ulrich and Bassler, 1904). The 

lectotype (pi. 5, fig. 8) is 780 jum in length and 410 jum in 

height. The lectotype is one of two specimens in the 

syntype suite; the other (Ulrich and Bassler, 1904, pi. 

36, fig. 25) is a juvenile of Pseudocytheretta plebeia 

(UMch and Bassler, 1904).

A right valve (UMch and Bassler, 1904, pi. 38, fig. 5), 

USNM 35440, from the Peachblossom Creek locality 

in the Choptank Formation, is selected as the lectotype 

of Pseudocytheretta toumeyi (UMch and Bassler, 

1904). The lectotype (pi. 5, fig. 7) is 600 jum in length 

and 320 jum in height. The P. toumeyi syntype suite 

originally contained juveniles of two species of Pseudocytheretta. One of the species is from the Yorktown 

Formation and the other is from the Choptank Formation. The specimen from the Yorktown Formation is 

lost and was probably conspecific with Pseudocytheretta burnsi sensu McLean (1957), Swain (1974), 

and Hazel (1971). However, the Yorktown species does 

not appear to be conspecific with P. burnsi (UMch and 

Bassler, 1904), as noted above.

Pseudocytheretta burnsi is known from the Calvert, 

Choptank, and St. Marys (units A and B) Formations. 

I do not believe that the specimens reported from the 

Pliocene (Swain, 1974) are conspecific with P. burnsi. 

The younger forms possess a punctation that covers 

the whole valve and are much more equivalved (and 

thus more symmetrical) than P. burnsi.

Occurrence.—Pseudocytheretta burnsi (UMch and 

Bassler, 1904) occurs in the Calvert, Choptank, and St. 

Marys (units A and B) Formations in my collections.

Stratigraphic range.—Lower to middle Miocene.

Pseudocytheretta plebeia (Ulrich'and Bassler, 19O4)

Plate 5, figures 1, 4, 5; Plate 6, figures 5, 6, 7

Cythere plebeia Ulrich and Bassler, 1904, p. 102, pi. 35, figs. 20-29. 

Cythere plebeia var. capax Ulrich and Bassler, 1904, p. 103, pi. 35,

figs. 30-33. 

Cythere plebeia var. modica Ulrich and Bassler, 1904, p. 103, pi. 35,

figs. 18,19. 

Cytherideal chesapeakensis Ulrich and Bassler, 1904, p. 125, pi. 37,

fig. 9.

Cythere porcella Ulrich and Bassler, 1904, p. 106, pi. 36, figs. 26-33. 

Not Cytheretta porcella (Ulrich and Bassler). Swain, 1951, p. 45,

pi. 4, fig. 7; Swain, 1974, p. 24, pi. 2, figs. 19, 20. 

Not Cytherettat sp. aff. C. plebeia (Ulrich and Bassler). Swain,

1951, p. 45, pi. 6, fig. 17. (= Pseudocytheretta n. sp.) 

Cytheretta paucipunctata (Ulrich and Bassler). Puri, 1952, p. 204,

pi. 39, figs. 1, 2, text figs. 3, 4.

Not Cytheretta ulrichi Puri, 1952, p. 204, pi. 39, fig. 3, text figs.

5-7 (= Pseudocytheretta burnsi (Ulrich and Bassler, 1904));

McLean, 1957, p. 92, pi. 12, figs. 3a-d. 

Cytherettaplebia (Ulrich and Bassler). Malkin, 1953, p. 790, pi. 81,

figs. 1-6, 9.

Diagnosis.—Valves asymmetrical; left valve ovoid in 

outline; right valve with a medial portion of the valve 

overhanging the ventral margin; dorsal margin of right 

valve arched; the few punctae are generally circular in 

outline.

Lectotype.—A male left valve (UMch and Bassler, 

1904, pi. 35), USNM 35429 a, from the Calvert Formation at Plum Point, Md., is selected as the lectotype.

Measurement—The lectotype (pi. 5, fig. 4) is 

1,025 pan in length and 550 jum in height.

Remarks.—Pseudocytheretta plebeia (UMch and 

Bassler, 1904), like P. burnsi, has a complicated 

nomenclatural history. Puri (1952) pointed out that 

Cythere (Bairdia) plebeia was used in 1859 by Jones 

and proposed the new name Cytheretta ulrichi for P. 

plebeia. Puri (1954) later realized that the name 

Pseudocytheretta porcella (UMch and Bassler, 1904) 

was available and advised that his name P. ulrichi be 

dropped. Swain (1974) followed this suggestion and 

used P. porcella for a species of Pseudocytheretta from 

the Yorktown Formation. Sohn (1960) has provided the 

nomenclatural history of Bairdia plebeia, which was 

originally described by Reuss (1854) and subsequently 

transferred to Cythere (Bairdia) plebeia by Jones 

(1859). Vine (1884) transferred the species from the 

genus Cythere back to the genus Bairdia. Therefore, 

Cythere plebeia (UMch and Bassler, 1904) is not a 

homonym of Cythere (Bairdia) plebeia, and the trivial 

name is valid.

UMch and Bassler (1904) described two variants of 

P. plebeia and two juvenile species that are all 

synonymous with P. plebeia. The species ascribed to P. 

porcella by Swain (1974) differs from P. plebeia by 

having greater valve symmetry in the right valve.

A right valve, which is probably the specimen illustrated by UMch and Bassler, 1904, pi. 35, fig. 32, 

USNM 35430 a, from the Plum Point locality (UMch 

and Bassler, 1904) of the Calvert Formation is 

designated as the lectotype of Pseudocytheretta capax 

(UMch and Bassler, 1904). The lectotype (pi. 5, fig. 5) is 

990 jion in length and 530 jum in height. As noted by 

UMch and Bassler (1904) this form is a variety of P. 

plebeia, although in my opinion it may be more of a 

preservational variant than a biologic one.

A left valve (Ulrich and Bassler, 1904, pi. 35, fig. 18), 

USNM 35431 a, from the Calvert Formation at Plum 

Point, MD., is selected as the lectotype of Pseudocytheretta modica (UMch and Bassler, 1904). The lectotype (pi. 6, fig. 5) is 900 jum in length and 500 jum in 

height and is a typical specimen of P. plebeia. The
16 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

distinctions made by Ulrich and Bassler, based on 

ornamentation or valve shape, are gradational within 

the population of P. plebeia. The remark made by 

Ulrich and Bassler, about having only left valves of P. 

modica, is curious because one of their syntype 

specimens is a carapace.

Cytherideal chesapeakensis Ulrich and Bassler, 

1904, is a well-preserved, very ornate, juvenile of 

Pseudocytheretta plebeia (Ulrich and Bassler). The 

holotype, USNM 35444, is 770 /LOD in length and 

410 fjm. in height and is illustrated in pi. 6, fig. 7.

A left valve (Ulrich and Bassler, 1904, pi. 36, fig. 27), 

USNM 35432 a, from the Calvert Formation at Plum 

Point, Md., is selected as the lectotype of Pseudocytheretta porcella (Ulrich and Bassler, 1904). The lectotype (pi. 6, fig. 6) is 770 jum in length and 420 /LOD in 

height. P. porcella is a poorly preserved, weakly ornamented juvenile of P. plebeia (Ulrich and Bassler, 

1904).

Occurrence.—Pseudocytheretta plebeia occurs 

throughout the Calvert Formation in our collections.

Stratigraphic range.—Lower to middle Miocene.

Genus Protocytheretta Puri, 1958 

Type-species.—Cythere daniana Brady, 1869. 

Frotocytheretta inaequivalvis (Ulrich and Bassler, 19O4)

Plate 6, figure 8

Cythere inaequivalvis Ulrich and Bassler, 1904, p. 101, pi. 35,

figs. 15,16. 

Not Cythere inaequivalvis Ulrich and Bassler, 1904, p. 101, pi. 35,

fig. 17 (= Pseudocytheretta burnsi (Ulrich and Bassler, 1904)). 

ICytheretta inaequivalvis (Ulrich and Bassler). Puri, 1954, p. 284,

pi. 8, fig. 9.

Diagnosis.—Strong valve asymmetry; prominent 

sinuous ventral margin; distinct caudal process; two 

prominent carinae, one paralleling the dorsal margin 

and the other running anterior-posterior through the 

medial part of the valve.

Lectotype.—A. right valve (Ulrich and Bassler, 1904, 

pi. 35, fig. 16), USNM 35421 a, from the Calvert Formation at Plum Point, Md., is selected as the lectotype 

(pi. 6, fig. 8).

Measurements.—The lectotype is 1,125 /LOD in length 

and 480 /LOD in height.

Remarks.— Protocytheretta inaequivalvis is extremely rare in the Chesapeake Group sediments. The 

only known specimens are those illustrated by Ulrich 

and Bassler (1904).

Occurrence.—Protocytheretta inaequivalvis was 

reported from the Calvert Formation by Ulrich and 

Bassler (1904) at their Plum Point locality. It does not 

occur in our collections.

Stratigraphic range.—Lower. Miocene.

Family HEMICYTHERIDAE Puri, 1953

Subfamily HEMICYTHERINAE Puri, 1953

Tribe AURILINI Puri, 1973

Genus Otikocythere New Genus

Type-species.—Cythere punctistriata Ulrich and 

Bassler, 1904.

Etymology.—Otikos (Greek), of ears, in reference to 

the somewhat ear-shaped outline.

Diagnosis.—Low height to length ratio; valves compressed; anterior margin rounded; prominent caudal 

process; valve surface smooth to reticulate; holamphidont hinge; central muscle scar pattern with three frontal scars linearly arranged, split dorsal and dorsomedian adductor scars and two complete (unsplit) ventral 

and ventromedian adductor scars.

Comparisons.—Otikocythere is very similar to both 

Aurila and Heterocythereis, undoubtedly reflecting 

their close relationship. Otikocythere differs from 

Heterocythereis in possessing a prominent caudal 

process and in having an aurilid-shaped right valve. 

Otikocythere differs from Aurila in having an unsplit 

ventromedial adductor muscle scar and a "cauditid"- 

shaped left valve.

Remarks.—Three species can be presently assigned 

to Otikocythere with confidence; they are Cythere 

punctistriata Ulrich and Bassler, 1904, Hemicythere 

dalli Howe and Brown, 1935, and Hemicythere redbay ensis Howe and Brown, 1935. These taxa all occur 

in Miocene sediments in the Atlantic Coastal Plain or 

Florida. Aurila petricola Hartmann, 1974, described 

from the southwestern coast of Africa, may also 

belong to Otikocythere, despite its disjunct geographic 

and temporal position from the other species. 

However, I have not examined specimens of that 

species.

Stratigraphic range.—Lower to upper Miocene; 

Holocene(?).

Otikocythere punctistriata (Ulrich and Bassler, 1904) 

Plate 6, figures 1-4; Plate 7, figure 5

Cythere punctistriata Ulrich and Bassler, 1904, p. 108, pi. 38, figs.

22-24. 

Cythere francisca Ulrich and Bassler, 1904, p. 110, pi. 38, figs. 19,

20. 

Hemicythere punctistriata (Ulrich and Bassler). Malkin, 1953,

p. 796, pi. 82, fig. 15.

Diagnosis.— Large; reticulum weakly to strongly 

developed in the medial to posterior portion of the 

valve; greatest length ventral of valve midline; 

greatest height at anterior cardinal angle; crescent 

shape of a medioanterior depression on the valve.

Paratype.—A female left valve (Ulrich and Bassler, 

1904, pi. 38, fig. 24), USNM 35435, from the Calvert
SYSTEMATICS 17

Formation at Church Hill, Md., is illustrated (pi. 6, fig. 

3), being the only whole specimen remaining in the 

type suite. The holotype, USNM 35434, is partially 

destroyed, with only the anterior and posterior part of 

the valve remaining.

Measurements.—The paratype is 600 jum in length 

and 310 jum in height.

Remarks.—Ulrich and Bassler (1904) designated a 

specimen of O. punctistriata from their Peachblossom 

Creek locality in the Choptank Formation as the holotype. Otikocythere punctistriata occurs abundantly in 

some parts of the Choptank Formation, but rarely 

throughout the formation as a whole. Based upon the 

study collections, the Choptank specimens always are 

typified by the specimens illustrated on pi. 6, figs. 1,2, 

4 (USNM 256029, 256030, 256031). The Choptank 

form, however, appears to represent an end member of 

a morphologic cline starting in the Calvert Formation.

Otikocythere punctistriata is currently known from 

two localities in the Calvert Formation: (1) from the 

Ulrich and Bassler locality at Church Hill, Md., and (2) 

from well cuttings near Denton, Md. Specimens from 

the latter locality exhibit a continuous gradation from 

a completely smooth form (similar to the slightly 

larger O. dalli (Howe and Brown)) to an ornate version 

represented by the specimen illustrated on pi. 6, fig. 3 

(the paratype). Each step of this gradation basically involves the addition of more reticulae starting in the 

posterior of the valve and progressing toward the 

anterior. The only morphologic gap occurs between 

specimens from the upper Calvert Formation and the 

lower Choptank Formation, as illustrated on pi. 6 (compare figs. 3 and 4). I currently regard the entire sequence as a gradually changing population of a single 

species (including specimens from both the Calvert and 

Choptank Formations).

The smooth specimens of Otikocythere punctistriata 

from the well cuttings near Denton, Md., are quite 

similar to O. dalli (Howe and Brown), differing from O. 

dalli primarily in its slightly smaller size. Howe and 

Brown (in Howe and graduate students, 1935) noted 

that their H. dalli varies morphologically from a 

smooth version to a slightly ornate version, where 

their more ornate ribbed specimens are regarded as a 

separate species, O. redbayensis. The size differences 

do not appear to be significant and may simply represent geographic variation. Thus O. dalli (Howe and 

Brown) may be a junior synonym of O. punctistriata 

(Ulrich and Bassler).

Otikocythere punctistriata differs from O. redbayensis (Howe and Brown) in its larger size, 

somewhat different shape and in details of the ornament. O. redbayensis occurs in upper Miocene

sediments in Florida (Red Bay Formation of Puri and 

Vernon, 1964) and in the eastern shore of Chesapeake 

Bay.

Otikocythere punctistriata generally occurs abundantly along the present edges of the depositional 

basins for the Choptank and Calvert Formations. It 

appears to become very rare to nonexistent towards 

the center of those basins. Thus, I would surmise that 

O. punctistriata favors shallow marine to possibly 

polyhaline conditions. Aurila petricola Hartmann, 

1974 was also collected from a near shore locality.

Ulrich and Bassler (1904) proposed Cythere francisca 

based upon a single specimen, USNM 35420, the 

holotype. This specimen has been lost; however, from 

Ulrich and Bassler's (1904) description, illustrations, 

and locality data, this species seems to be a juvenile of 

Otikocythere punctistriata (Ulrich and Bassler, 1904). 

A juvenile of O. punctistriata from the Choptank Formation at Peachblossom Creek, is illustrated (pi. 7, fig. 

5, USNM 256032) for comparison purposes.

Occurrence.—Otikocythere punctistriata occurs in 

the Calvert and Choptank Formations.

Stratigraphic range.—Lower to middle Miocene.

Subfamily THAEROCYTHERINAE Hazel, 1967

Tribe THAEROCYTHERINI Hazel, 1967

Genus Thaerocythere Hazel, 1967

Type-species.—Cythereis crenulata Sars, 1865.

Thaerocythere schmidtae (Malkin, 1953)

Plate 7, figure 8

Trachyleberist cf. T.I reesidei (Swain). Swain, 1951, p. 30, pi. 3,

fig. 13.

Hemicythere schmidtae Malkin, 1953, p. 796, pi. 82, figs. 19-23. 

Hemicythere schmidtae Malkin. McLean, 1957, p. 92, pi. 12, figs.

2a-d. 

Thaerocythere schmidtae (Malkin). Swain, 1974, p. 40, pi. 6, fig. 1.9;

pi. 7, figs. 9-15; pi. 9, figs. la-d.

Lectotype.—A female left valve (Malkin, 1953, pi. 

82, fig. 2), USNM 256033, from the Yorktown Formation (locality VA-9 of Malkin (1953)), is selected as the 

lectotype (pi. 7, fig. 8).

Measurements.—The lectotype is 700 jum in length 

and 410 jum in height.

Remarks.—Thaerocythere schmidtae occurs frequently in upper Miocene (Eastover Formation, units 

C and D), Pliocene, and lower Pleistocene sediments in 

North Carolina, Virginia, and Maryland, but it has not 

been found in equivalent age sediments in Florida. On 

this basis it would appear to be a temperate species, as 

is the type, Thaerocythere crenulata (Sars, 1865) (see 

Hazel, 1967). Hazel (1977; in press) illustrated and 

discussed this taxon.
18 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

Occurrence.—Thaerocy there schmidtae occurs in the 

Eastoyer (units C and D) and Yorktown Formations in 

my collections.

Stratigraphic range.— Upper Miocene to lower 

Pleistocene.

Genus Puriana Coryell and Fields, 1937

Type-species. —Favella puella Coryell and Fields, 

1937 ( = Puriana rugipunctata var. gatunensis Coryell 

and Fields, 1937).

Puriana rugipunctata (Ulrich and Bassler, 19O4)

Cythere rugipunctata Ulrich and Bassler, 1904, p. 118, pi. 38, figs.

16, 17. 

Cythereis rugipunctata (Ulrich and Bassler). Howe and others,

1935, p. 23, pi. 1, figs. 18, 20-22; pi. 4, figs. 22, 23. 

Trachylebereisl rugipunctata (Ulrich and Bassler). Swain, 1951,

p. 38, pi. 6, fig. 8. 

Favella rugipunctata (Ulrich and Bassler). Malkin, 1953, p. 797,

pi. 82, fig. 24. 

Puriana rugipunctata (Ulrich and Bassler). McLean, 1957, p. 89,

pi. 11, figs. 5a-d. 

IPuriana rugipunctata (Ulrich and Bassler). Swain, 1968, p. 18,

pi. 5, figs. 8a-c; pi. 7, fig. 4; text figs. 16,17. 

Puriana rugipunctata (Ulrich and Bassler). Swain, 1974, p. 41, pi.

7, figs. 19, 20.

Remarks.—-The holotype of P. rugipunctata (Ulrich 

and Bassler, 1904), USNM 35436, has been crushed 

and most of the fragments are lost. At present, only 

two small fragments of the holotype are left. Hazel 

(1977; in press) has illustrated this species and 

discusses some of the problems associated with it.

Occurrence.—Puriana rugipunctata occurs in the 

Eastover (units C and D) Formation, and is common in 

Pliocene to Holocene deposits along the Atlantic 

Coast.

Stratigraphic range.—Upper Miocene to Holocene.

Subfamily COQUIMBINAE Ohmert, 1968 

Genus Muellerina Bassiouni, 1965

Type-species.—Cythere latimarginata Speyer, 1863.

Muellerina lienenklausi (Ulrich and Bassler, 19O4)

Plate 7, figure 4

Cythere lienenklausi Ulrich and Bassler, 1904, p. 114, pi. 38, fig. 31. 

Not Orionina lienenklausi (Ulrich and Bassler). Puri, 1954, p. 254,

pi. 12, fig. 14; text fig. 8d (= Neocaudites sp.). 

Not Muellerina lienenklausi (Ulrich and Bassler). Swain, 1968,

p. 16, pi. 3, figs. 2a-h, 3a-b, 4a-b; text fig. 15 (= Muellerina

spp.). 

Not Muellerina micula (Ulrich and Bassler). Swain, 1974, p. 38,

pi. 7, figs, 1-8 (= Muellerina spp.).

Diagnosis.—Small; rectangular valve outline; welldeveloped reticulum; details of fossae arrangement 

characteristic, such as the anterior-most (ventral to

dorsal) row of fossae consisting of two small rounded 

fossae, one dorsal to the other, followed dorsally by 

two other rounded fossae, one anterior to the other; 

these in turn are followed dorsally by two more fossae, 

with one fossa dorsal to the other and sometimes fused 

to form one elongate fossa; prominent carina extends 

subparallel to the valve margin, originating at the 

anterodorsal corner and proceeding to the posterodorsal corner. These carina become slightly broader 

just posterior of the ventral concavity and contain five 

to six small fossae (relationship of these fossae to one 

another are characteristic); the carina splits and encircles several more fossae in the posteroventral region 

of the valve.

Measurements.—-The holotype, USNM 35422, from 

the Calvert Formation at Plum Point, Md., is 590 j^trn in 

length and 290 jmi in height. The illustrated specimen, 

a female right valve, USNM 256034, from the type 

locality, is 620 jum in length and 330 j^trn in height.

Remarks.—The holotype, a male left valve, is 

crushed. However, the specimen is still sufficiently intact to use it as a means of recognizing complete 

specimens from the type locality at Plum Point, bed 

10, of the Calvert Formation. There are only two 

species of Muellerina known from Bed 10. One of these 

species appears to be the adult of Cythere micula 

Ulrich and Bassler, 1904 and is illustrated on pi. 7, fig. 

2. The other species is morphologically identical with 

the holotype of M. lienenklausi. The two species are 

easily distinguished from one another by several characteristics, such as arrangement of the anterior-most 

row of fossae, where M. micula has a row of several circular fossae, one dorsal to the other.

Hazel (1967) discusses the nomenclatural confusion 

associated with various Neogene species of Muellerina. 

Most of these species of Muellerina have been identified as Murrayina martini (Ulrich and Bassler, 1904), 

even though Murrayina and Muellerina are in different 

families. Hazel (1967) argued that what was identified 

as Murrayina martini by many authors should be referred to Muellerina lienenklausi. Subsequently, Hazel (in 

press) and the author (in studies in progress) have 

recognized numerous species of Muellerina in the 

Chesapeake Group sediments. Thus, what at one time 

was regarded as a single species is now believed to be 

several. Swain (1974) also discusses this problem and 

argues that the holotype of Muellerina lienenklausi is 

too badly damaged to be recognized. He believes that 

the juveniles in the M. micula syntype collection are 

more representative of what was referred to in the past 

as Murrayina martini. In my opinion, most of the 

Muellerina species referred to Murrayina martini by 

various authors are conspecific with Muellerina species 

from post-Miocene deposits. The Muellerina micula
SYSTEMATICS 19

syntype slide contains two species of Muellerina, a 

juvenile of M. lienenklausi (Ulrich and Bassler, 1904), 

and the specimen selected as the lectotype of M. 

micula (Ulrich and Bassler, 1904). The latter specimen 

is believed to be the juvenile of the specimen illustrated on plate 7, figure 2. Many of the specimens illustrated by Swain (1968; 1974) as Muellerina micula 

and Muellerina lienenklausi are M. ohmerti Hazel, 

1977.

The majority of Muellerina species are superficially 

quite similar to each other. However, each can be readily distinguished by fossae pattern, size, and valve 

outline. When the fossae patterns of numerous 

Muellerina species have been studied, distinctive 

species groups can be recognized, and some of these 

complexes can be traced from the Calvert Formation at 

least into the Pliocene.

Occurrence.—I have found Muellerina lienenklausi in 

bed 10 and older beds within the Calvert Formation.

Stratigraphic range.—Lower Miocene.

Muellerina micula (Ulrich and Bassler, 19O4)

Plate 7, figures 2, 3

Cy there micula Ulrich and Bassler, 1904, p. 116, pi. 36, figs. 19, 20. 

Not Cy there micula Ulrich and Bassler, 1904, p. 116, pi. 36, fig. 18

(= Muellerina lienenklausi (Ulrich and Bassler, 1904)). 

Trachyleberis martini (Ulrich and Bassler). Malkin, 1953, p. 793,

pi. 82, figs. 9, 13. 

Not Muellerina micula (Ulrich and Bassler). Swain, 1974, p. 38, pi. 7,

figs. 1-8 (= Muellerina spp.).

Diagnosis.— Large; strong reticulum; details of the 

fossae pattern characteristic, such as a continuous 

anterior-most row of round fossae subparallel to the 

anterior margin; murae thin relative to M. lienenklausi; ventral carinae are subparallel to ventral 

margin terminating just posterior of ventral concavity.

Lectotype.—A juvenile left valve illustrated by 

Ulrich and Bassler, 1904, plate 36, figure 20, USNM 

35424 a, from the Calvert Formation at Plum Point, 

Md., is selected as the lectotype.

Measurements.— The lectotype (pi. 7, fig. 3) is 500 jion 

in length and 270 jum in height. The illustrated specimen (pi. 7, fig. 2), a female left valve, USNM 256035, is 

640 jion in length and 350 jion in height.

Remarks.—Muellerina micula was represented by a 

syntypic suite of three valves. The specimen illustrated on plate 36, figure 19 of Ulrich and Bassler 

(1904) has been destroyed and lost except for a small 

fragment. Ulrich and Bassler (1904) note that the 

specimen illustrated in figure 18 is smaller than normal, suggesting that it was not what they regarded as 

typical. The latter specimen, in my opinion, is a 

juvenile of Muellerina lienenklausi, and is not conspecific with the specimen illustrated in figure 20. The 

specimen illustrated in figure 20 and chosen here as the 

lectotype of M. micula, appears to be a juvenile conspecific with the specimen illustrated herein on plate 7, 

figure 2. The latter specimen is representative of the 

dominant Muellerina species in the Calvert Formation 

and is regarded by the author as M. micula. The 

Muellerina micula ornament pattern varies, often due 

to the merging of two or more fossae or the degree of 

expression of the carinae. However, this variation 

never overlaps with the ornamentation pattern seen in 

M. lienenklausi, although the two species are apparently closely related.

There is an undescribed species of Muellerina occurring in the Choptank Formation that is morphologically disjunct from M. micula, but very similar to it.

Occurrence. Ulrich and Bassler (1904) reported this 

species from the Calvert and Yorktown Formations. 

The Yorktown occurrence represents another species 

of Muellerina. Mullereina micula occurs throughout 

the Calvert Formation in our collections.

Stratigraphic range. Lower to middle Miocene.

Subfamily ORIONININAE Puri, 1973 

Genus Orionina Puri, 1954

Type-species.—Cy there vaughani Ulrich and 

Bassler, 1904.

Orionina vaughani (Ulrich and Bassler, 19O4)

Cy there vaughani Ulrich and Bassler, 1904, p. 109, pi. 38, figs.

25-27. 

Cythereis vaughani (Ulrich and Bassler). Howe and others, 1935,

p. 25, pi. 3, figs. 24-26; pi. 4, fig. 13. 

1'Trachyleberis vaughani (Ulrich and Basssler). Swain, 1951, p. 37,

pi. 6, figs. 6, 7. 

Trachyleberis vaughani (Ulrich and Bassler). Malkin, 1953, p. 794,

pi. 82, fig. 14. 

Orionina vaughani (Ulrich and Bassler). Puri, 1954, p. 254, pi. 12,

fig. 16; McLean, 1957, p. 88, pi. 11, figs. 6a-b; Swain, 1968, p.

21, pi. 4, figs. 4a-e; text fig. 19; Swain, 1974, p. 39, pi. 7, fig. 17;

pi. 12, figs. 2a-h.

Remarks.— Ulrich and Bassler's (1904) holotype, 

USNM 35442, the only deposited specimen, is lost. 

However, Hazel (in press) has recently treated this 

species and the reader is referred to that study.

Occurrence.—Orionina vaughani occurs commonly 

in Pliocene to Holocene sediments in the Atlantic 

coastal plain and Florida.

Stratigraphic range.—Pliocene to Holocene.

Subfamily CAMPYLOCYTHERINAE Puri, I960

Tribe LEGUMINOCYTHERINI Howe, 1961

Genus Bensonocythere Hazel, 1967

Type-species.— Leguminocythereis whitei Swain, 

1951.
20 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

Bensonocythere calverti (Ulrich and Bossier, 19O4)

Plate 7, figure 6

Cythere calverti Ulrich and Bassler, 1904, p. 100, pi. 38, figs. 11-13.

Diagnosis.—Large; prominent reticulum; absence of 

carinae; rectangular valve outline.

Measurements.—The holotype, USNM 35412, from 

the Calvert Formation at Plum Point, Md., is 800 jum in 

length and 430 /-on in height.

Remarks.—Bensonocythere calverti is an extremely 

rare component of the Chesapeake Group sediments. 

As with several other ostracodes in these sediments, B. 

calverti increases in overall size through time so that 

the Yorktown Formation individuals are larger but 

otherwise morphologically similar to those from the 

Calvert Formation.

Occurrence.—Bensonocythere calverti occurs in the 

Calvert, Eastover (units C and D), and Yorktown Formations in our collections.

Stratigraphic range.—Lower Miocene to Lower 

Pliocene.

Family FARACYTHERIDEIDAE Puri, 1957 

Genus Paracytheridea G. W. Muller, 1894

Type-species.— Paracytheridea depressa G. W. 

Muller, 1894.

Paracytheridea altila Edwards, 1944

Plate 7, figure 7

Cytheropteron nodosum Ulrich and Bassler, 1904, p. 129, pi. 38,

figs. 37-40.

Not Cytheropteron nodosum Brady, 1868, p. 448, pi. 34, figs. 31-34. 

Paracytheridea nodosum (Ulrich and Bassler). Howe and others,

1935, p. 37, pi. 3, fig. 7; Swain, 1951, p. 51, pi. 3, figs. 19-22. 

Paracytheridea altila Edwards, 1944, p. 512, pi. 85, figs. 20, 21;

Swain, 1974, p. 20, pi. 1, fig. 17. 

Paracytheridea vandenboldi Puri, 1953, p. 751 (new name); Malkin,

1953, p. 780, pi. 79, fig. 5; Puri, 1954, p. 238, pi. 3, fig. 7; text

figs. 5a, b; McLean, 1957, p. 75, pi. 8, figs. 4a-b. 

^Paracytheridea cf. P. vandenboldi Puri. Swain, 1968, p. 11, pi. 2,

figs. 4a, b.

Measurements.—The holotype (C. nodosum Ulrich 

and Bassler, 1904), USNM 35443, is 650 jum in length 

and 300 /mi in height.

Remarks.—Cytheropteron nodosum Ulrich and 

Bassler, 1904 is a junior homonym of C. nodosum 

Brady, 1868. Puri (1953) recognized this and renamed 

the species Paracytheridea vandenboldi. However, van 

den Bold (1968) has shown that P. altila Edwards, 1944 

is conspecific with P. nodosum (Ulrich and Bassler) 

and therefore is the valid name for the species.

Occurrence.—Ulrich and Bassler (1904) found this 

species in the Yorktown Formation (see also Hazel, 

1971); Edwards (1944) reported it in the Duplin Marl of

South Carolina. The species occurs in the Eastover 

(unit C) and Yorktown Formations in our collections. It 

has also been reported from Pleistocene and modern 

sediments (Valentine, 1971). 

Stratigraphic range.—Upper Miocene to Holocene.

Genus Microcytherura G. W. Mueller, 1894

Type-species.— Microcytherura nigrescens G. W. 

Muller, 1894.

Microcytherura shattucki (Ulrich and Bassler, 19O4)

Plate 7, figure 1

Cythere(7) shattucki Ulrich and Bassler, 1904, p. 121, pi. 38, fig. 10. 

Not Paracytheridea shattucki (Ulrich and Bassler). Malkin, 1953,

p. 780, pi. 79, figs. 6-9. (? = Microcytherura n. sp.) 

Not Shattuckocythere shattucki (Ulrich and Bassler). Swain, 1974,

p. 21, pi. 1, fig. 14; pi. 8, fig. 9 (? = Microcytherura similis

(Malkin, 1953)).

Diagnosis.— Triangular to subtriangular valve shape 

with a broad anterior and a surface ornamentation consisting of a weak reticulum superimposed on a finely 

punctate surface; punctae are very numerous and 

small, densely distributed in each solum.

Measurements.—The illustrated specimen, USNM 

256036, (pi. 7, fig. 1) is 600 jwm in length and 300 jum 

in height.

Remarks.—The anterior half of the holotype of 

Microcytherura shattucki, USNM 35437, is all that remains intact; the posterior portion of the valve consists of several fragments. The type locality of this 

species is at Ulrich and Bassler's Paw Paw Point, in 

the Choptank Formation. Based on our collections, 

only one species of Microcytherura occurs in the Choptank Formation, and this appears to be conspecific 

with the holotype. It also conforms to Ulrich and 

Bassler's description and illustration of M. shattucki. 

The illustrated specimen (pi. 7, fig. 1) comes from bed 

17 of the Choptank Formation at Scientist's Cliffs on 

the Western Shore of Chesapeake Bay.

Swain (1974) selected this species as the type of his 

genus Shattuckocythere. In my opinion, this species is 

congeneric with the type species of Microcytherura (M. 

nigrescens G. W. Mueller, 1894). The diagnostic 

criteria given by Swain (1974) for Shattuckocythere do 

not differentiate it from Microcytherura except in the 

type of hingement, which Swain describes as being antimerodont (Microcytherura being hemimerodont). All 

of Swain's (1974) Shattuckocythere species have a 

hemimerodont hinge except for the species Eocytheropteront yorktownensis Malkin, 1953 which he 

also places in Shattuckocythere and which has an antimerodont hinge. I do not consider Eocytheropteron? 

yorktownensis to be a Microcytherura.
REFERENCES CITED 21

Occurrence.— Microcytherura shattucki occurs only 

in the Choptank Formation in our collections. 

Stratigraphic range. Middle Miocene.

Microcytherura curta (Malkin, 1953)

Plate 7, figure 10

Paracytheridea shattucki curta Malkin, 1953, p. 791, pi. 79, figs. 

10-12.

.Diagnosis. Trapezoidal right valve in the female, 

subtrapezoidal left valve in the female, and both valves 

in the male; a subdued reticulum superimposed over 

fine punctation that tends to occupy the entire solum.

Lectotype.—A male left valve illustrated by Malkin 

(1953, pi. 79, fig. 11), USNM 256037, from the 

Yorktown Formation (Malkin, 1953, locality VA-10) is 

selected as the lectotype.

Measurements.—The lectotype (pi. 7, fig. 10) is 

600 /urn in length and 300 /urn in height.

Remarks.—Malkin (1953) originally proposed Microcytherura curta as a subspecies of M. shattucki 

However, M. curta differs from M. shattucki in having 

fewer and larger punctae and a different valve outline. 

Further, the two species are not known from the same 

or even adjacent stratigraphic horizons. Microcytherura curta, however, does appear to be closely 

related to M. similis, based upon general morphologic 

similarity.

Occurrence.—Microcytherura curta occurs only in 

the Yorktown Formation in our collections.

Stratigraphic range. Pliocene.

Microcytherura similis (Malkin, 1953) 

Plate 7, figure 9

Paracytheridea similis Malkin, 1953, p. 781, pi. 79, figs. 13, 14. 

^.Shattuckocythere similis (Malkin). Swain, 1974, p. 22, pi. 9, fig. 14. 

Not Shattuckocythere similis (Malkin). Swain, 1974, p. 22, pi. 1,

fig. 19a (= Microcytherura curta (Malkin, 1953)). 

Shattuckocythere shattucki (Ulrichand Bassler). Swain, 1974, p. 21,

pi. 1, fig. 14; pi. 8, fig. 9. 

Shattuckocythere yorktownensis (Malkin). Swain, 1974, p. 22, pi. 3,

fig. 13; pi. 9, figs. 9a, b.

Diagnosis. Subtrapezoidal valve outline; subdued 

reticulum with wide murae; prominent punctae usually 

located mainly along the edge of the murae in the 

solum.

Lectotype.—A female right valve illustrated by 

Malkin (1953, pi. 79, fig. 13), USNM 256038, is 

selected as the lectotype. This specimen is from the 

Yorktown Formation (Malkin, 1953, locality VA-10).

Measurements.—The lectotype is 550 /-im in length 

and 280 /urn in height.

Occurrence.—Microcytherura similis occurs commonly in the Pliocene and lower Pleistocene formations in the Atlantic Coastal Plain (Hazel, 1977).

Stratigraphic range.—Pliocene to lower Pleistocene.

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pis. 23-41.

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Zoologisches Museum und Institut, Mitteilungen, v. 70, 

p. 7-73.

Hazel, J. E., 1967, Classification and distribution of the Recent 

Hemicytheridae and Trachyleberididae (Ostracoda) off northeastern North America: U.S. Geological Survey Professional 

Paper 564, 49 p.

___1971, Ostracode biostratigraphy of the Yorktown formation 

(upper Miocene and lower Pliocene) of Virginia and North 

Carolina: U.S. Geological Survey Professional Paper 704, 13 p.

___1977, Distribution of some biostratigraphically diagnostic 

Ostracodes in the Pliocene and lower Pleistocene of Virginia and 

northern North Carolina: U.S. Geological Survey Journal of Research, v. 5, no. 3, p. 373-388.

___in press, Age and correlation of the Yorktown (Pliocene) 

and Croatan (Pliocene and Pleistocene) Formations at the Lee 

Creek, North Carolina, open pit mine: Smithsonian Contributions in Paleobiology.
22 REVISION OF OSTRACODE SPECIES, CHESAPEAKE GROUP, MARYLAND AND VIRGINIA

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zone of the Choctawhatehee Miocene of Florida: Florida Department of Conservation Bulletin no. 13, 47 p.

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in Kirkby, J. W., Permian Entomostraca from the shelllimestone of Durham: Newcastle-upon-Tyne, Tyneside 

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of New Jersey, Maryland, and Virginia: Journal of Paleontology, 

v. 27, no. 6, p. 761-799.

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in the York-James Peninsula of Virginia: Bulletins of American 

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___1966, Miocene and Pleistocene Foraminifera and Ostracoda 

of southeastern Virginia, Part II: Virginia Division of Mineral 

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Geological Societies, v. 22, p. 241-251.

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South Carolina, m Arthropoda, University of Kansas Paleontological Contributions, no. 38, Article 8: Lawrence, 80 p.

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in America: Journal of Paleontology, v. 26, no. 2, p. 199-212.

___1953, Taxonomic comment on "Ostracoda from Wells in 

North Carolina, Part I Cenozoic Ostracods" by F. M. Swain: 

Journal of Paleontology, v. 27, p. 750-752.

___1954, Contributions to the study of the Miocene of the Florida 

panhandle: Florida Department of Conservation Geological 

Bulletin, v. 36, p. 216-345. 

_1956, Two new Tertiary Ostracode genera from Florida:

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Puri, H. S., and Vernon, R. O., 1964, Summary of the geology of

Florida and a guidebook to the classic exposures: Tallahassee,

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the Ostracode genus Haplocytheridea: Micropaleontology, v.

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with a review of earlier investigations: Maryland Geological

Survey, XXXIII-CXXVII, 7 pis.

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U.S. Geological Survey Professional Paper 330-A, p. 1-105.

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in Anderson, J. L., and others, Ostracoda from the Hammond 

well [Md.]: Maryland Department of Geology, Mines and Water 

Resources Bulletin 2, p. 187-212.

___1951, Ostracoda from wells in North Carolina, Part 1 Cenozoic Ostracoda: U.S. Geological Survey Professional Paper 

234-A, 58 p.

_____1968, Ostracoda from the upper Tertiary Waccamaw Formation of North Carolina and South Carolina: U.S. Geological 

Survey Professional Paper 573-D, p. D1-D37.

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Text, p. 98-130.

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ostracode assemblage from southeastern Virginia: U.S. Geological Survey Professional Paper 683-D, 28 p.

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Geological Survey publication.
INDEX

[Italic page numbers indicate major references]

A 

Abstract ............. ...

Actinocythereis .......... ...

sp. ...................................

spp. .................................

altila, Paracytheridea ........... ... 4

americana, Cythereis cornuta . . ...

B

Bairdia plebeia ...........................

(Bairdia) plebeia, Cythere .................. 

Bensonocythere ..........................

calverti ............................. 4, 

bicornis, Cythere dorsicornis ............... 

Murrayina ...........................

dorsicornis .......................

blanpedi, Haplocytheridea .................

Boston Cliffs Member, Choptank Formation

Buntonia planibasalis ..................... 

burnsi, Cythere ...........................

Cytheretta ...........................

C

Calvert Beach Member, Choptank Formation 

Calvert Formation ..... 7, 2, 3, 4, 8, 11, 13, 14

Pseudocytheretta ......................

Page

1

9

1 -t

. 77; pi. 4

11

5, 11; pi. 3

11

. 11; pi. 4

5,20;pl.7

5, 12; pi. 4

5 Q

1 £

15

15 

19

5, 20; pi. 7 

4, 10 

11

pi. 3

5

2

14 

4, 14

14 

6; pis. 4, 5

2 

15, 16, 20

7, 8; pi. 1

5, 20; pi. 7

1Q

pi. 5

7

11

7

Dl. 6

9, 10, 13,

Church Hill, Md., Calvert Formation .....

circularis, Praeorbulina glomerosa ........

Page 

1, 2, 4, 6, 8, 

14, 20; pi. 2

... 3; pi. 6

2

Claremont Manor Member, Eastover Formation ............................ 2

Echinocythereis ................. 4, 5

Clithrocytheridea diagonalis .............

virginiensis ........................

Cobham Bay Member, Eastover Formation 

Conoy Member, Choptank Formation ....

cornuta americana, Cythereis ............

Thaerocythere ......................

Croatan Formation .....................

curta, Microcytherura ...................

Paracytheridea shattucki ............

Cushmanidea ashermani ................

cylindrica, Cytheridea ...................

Henryhowella ......................

daniana ............................

bicornis ........................

latissima ...........................

martini ............................

(Bairdial plebeia ....................

4,13

13, 14; pi. 4 

13

4, 13

... 13,14

3,4

4

2, 3 

2

12

78

4,12

12

4, 5, 9; pi. 2

17

17

1

4, 5, 21; pi. 7 

4, 21

6

7

6,7

7

5

.. 4, 7; pi. 2

4, 14

4, 20

4, 13

16

4, 10 

4, 12

4, 12

4, 16, 17 

4, 16

18

9

4, 10 

... 4, 18, 19

3

4, 14

4, 14

4, 14

4,14

4,15

4,15

4,15

4, 15

4, 10

. . 1, 3, 4, 16

4, 18

... 4, 9, 20

4,12

... 4, 5, 6

4,14

4, 19

15

Page 

Cythereis alaris ............................. 4, 11

cornuta americana ...................... 4, 12

crenulata............................... 17

garretti ................................ 13

jonesii ................................. 12

producta ............................... 10

(Pterygocythereis) ...................... 12

Cytheretta burnsi ........................... 14

inaequivalvis ........................... 16

paucipunctata .......................... 15

plebia .................................. 15

porcella ................................ 15

ulrichi ................................. 15

Cytherettini................................ 14

Cytheridea ................................. 3

chesapeakensis ......................... 4, 15, 16

cylindrica .............................. 7

diagonalis ........................... 3, 4, 5; pi. 1

muelleri ................................ 5

setipunctata ............................ 6

subovalis .............................. 4, 5;pl. 1

subovata ............................... 4, 6

virginiensis .......................... 3, 4, 5; pi. 1

sp...................................... 5

Cytherideidae .............................. 3

Cytherideis ashermani...................... 4, 6, 7, 8

cylindrica .............................. 4

echolsae ................................ 4, 7

longula ................................ 4, 8

rugipustulosa .......................... 7

semicircularis .......................... 4, 8

subaequalis ............................ 4, 8

Cytheropteron leonensis ..................... 9

nodosum ............................. 4, 20; pi. 7

yorktownensis ....................... 4,5, 9;pl. 2

Cytherura.................................. 9

coryelli .............................. 4, 5,9; pi. 2

gibba .................................. 9

Cytheruridae ............................... 9

Cytherurinae ............................... 7

D

da//i, Hemicythere .......................... 16

Otikocythere ........................... 17

daniana, Cythere ........................... 16

Denton, Md., well cuttings .................. 17

depressa, Paracytheridea .................... 20

diagonalis, Clithrocytheridea ................ 3, 4

Cytheridea ........................... 3, 4, 5; pi. 1

Diatomaceous Earth Member, Calvert Formation ............................ 2

dorsicornis, Cythere ........................ 4, 10

bicornis, Cythere ........................ 4

Murrayina ............................. pi. 3

Drum Cliff Member, Choptank Formation .... 2

Duplin Marl, South Carolina ................. 20

E

Eastover Formation ...................... 7, 2, 14, 17

Unit C .............................. 7, 17, 18, 20

Unit D ........................ 3, 7, 13, 17, 18, 20

Echinocythereidini ......................... 13

Echinocythereis ............................ 13

clarkana ........................ 4, 5, 13, 14; pi. 4

23
24 INDEX

Echinocythereis—Continued

evax ...................................

margaritifera ...........................

miniscula ....................... 4, 5, 13,

planibasalis ..................... 4, 5, 13,

echolsae, Cushmanidea......................

Cytherideis.............................

edwardsi, Pseudocytheretta .................

Electron micrographs .......................

Eocytheropteron ...........................

yorktownensis ...........................

evax, Cythere ..............................

Echinocythereis ........................

Henrykowella .................... 3, 4, 5,

Howella................................

oblongula, Cythere ......................

Trachyleberis ...........................

exanthemata, Actinocythereis ........... 4, 5,

Cythere ................................

Trachyleberis ...........................

F, G

12

13

14; pi. 4

14; pi. 4

7

4, 7

14

2,3

9

4, 9, 20

4, 12

12

12; pi. 4 

12

4, 12 

12

11; pi. 3

4, 11

11

fabula, Cushmanidea..................

Fairhaven Member, Calvert Formation . 

Favella puetta ........................

rugipunctata .... .................

6,7 ' 2 

18 

18 

francisca, Cythere .......................... 4, 16, 17

garretti, Cythereis ...............

gatunensis, Puriana rugipunctata . 

gibba, Cytherura ................

glomerosa circularis, Praeorbulina. 

gunteri, Murraying ..............

H

Haplocytheridea blanpedi ................... 5

israelsky ............................... 4

subovata ............................... 6

sp...................................... 4, 5

Hemicythere dalli........................... 16

punctistriata ........................... 16

redbayensis ............................ 16

schmidtae .............................. 4, 17

Hemicytheridae ............................ 2, 10, 16

Hemicytherinae ............................ 16

Henryhowella .............................. 12

ashermani .............................. 5

cylindrica .............................. 5

evax ............................. 3,4, 5, 12; pi. 4,

oblongata .......

rugipustulosa ...

semicircularis ...

subaequalis ..... 

Heterocythereis ..... 

Hilingsina cylindrica .

pi. 4

5

5

5

16

pi. 2

howei, Murrayina ................ 3, 4, 5, 9, 10, 1 1; pi. 3

Ptergocythereis ......................... 12

Howella evax ............................... 12

Hulingsina ................................. 6

americana .............................. 8

ashermani .............................. 4, 7

calvertensis ....................... 1, 6, 7, 8; pi. 1

cylindrica .............................. 4, 7

longula ................................ 8, pi. 2

rugipustulosa .......................... 4, 7; pi. 2

semicircularis ...................... 4,6,7, 8;pl. 2

subaequalis .......................... 4, 6, 8; pi. 2

tuberculata ............................. 6

sp. ..................................... 6

spp. ................................... 6

I, J, K

inaequivalvis, Cythere ...................... 4, 16

Cytheretta ............................. 16

Protocytheretta ..................... 4, 5, 16; pi. 6

inexpectata, Pterygocythereis ............... 12, 13

israelsky, Haplocytheridea .................. 4

Page 

James River, Va, Yorktown Formation ....... 3; pi. 4

Kirkwood Formation, N. J. .................. 11; pi. 3

L

latimarginata, Cythere ...................... 18

latissima, Cythere .......................... 9

lectotypes ................................. 1

Leguminocythereis clarkana................. 13

whitei ................................. 19

Leguminocytherini ......................... 19

Leonardtown, Md., Choptank Formation ..... 5

leonensis, Cytheropteron .................... 9

lienenklausi, Cythere ........................ 4, 18

Muellerina ...................... 4, 5,18, 19;pl.l

Orionina ............................... 18

Little Cove Point unit, St. Marys Formation .. 2

longula, Cytherideis ........................ 4, 8

Hulingsina ............................. 8; pi. 2

Lyons Creek ............................... 2

M

macleani, Murrayina ........................ 13

margaritifera, Echinocythereis ............... 13

martini, Cythere ............................ 4, 10

Murrayina ...................... 4, 5, 10, 11; pi. 3

Trachyleberis ........................... 10, 19

marylandica, Actinocythereis ................ 11

Microcytherura............................. 20

curta. .............................. 4, 5,27;pl. 7

nigrescens ............................. 20

shattucki ........................ 4, 5,20, 21; pi. 7

simi/is ........................ 4, 5, 9, 20, 21 ;pl. 7

sp...................................... 20

micula, Cythere ............................. 4,18, 19

Muellerina ...................... 4, 5, 18, 79; pi. 7

miniscula, Cythere clarkana ................. 4, 13

Echinocythereis ................. 4, 5,13, 14; pi. 4

modica, Cythere plebeia ..................... 4, 15

Pseudocytheretta .................... 15, 16; pi. 6

muelleri, Cytheridea ........................ 5

Muellerina ................................. 10, 18

lienenklausi ..................... 4, 5, 78, 19; pi. 7

micula .......................... 4, 5, 18, 79;pl. 7

ohmerti ................................ 19

spp. ................................... 18, 19

mulleri, Cythere ............................ 3

Murrayina ................................. 9, 11

bicornis ................................ 11

dorsicornis ............................. pi. 3

bicornis ............................ pi. 3

gunteri................................. 10

noii>et....................... 3, 4, 5, 9, 70, 11; pi. 3

macleani ............................... 13

martini .......................... 4,5,10, 11; pi. 3

radiata ........................... 4,5,9, ll;pl. 3

N

Neocaudites sp. ...........

Neocytherideidae ..........

nigrescens, Microcytherura . 

nitidula, Cythere ..........

calvertensis, Cythere ...

........... 18

........... 6

........... 20

........... 4,14

........... 4, 14

Pseudocytheretta ....................... 15; pi. 5

nodosum, Cytheropteron................... 4, 20; pi. 7

Paracytheridea ......................... 20

nomen dubium ............................. 12

nomenclature .............................. 7

O

oblongata, Henryhowella .................... pi. 4

oblongula, Cythere evax ..................... 4, 12

ohmerti, Muellerina ......................... 19

Orionina ................................... 79

lienenklausi ............................ 18

Orionina Continued Page 

vaughani.............................. 3, 4,5,19

Orionininae ................................ 79

Otikocythere ................................ 1,3, 16

dalli ................................... 17

punctistriata ................. 4,5,16,11; pis. 6, 7

redbayensis ............................ 17

Paracytheridea ............................. 20

ato'to............................... 4, 5, 20; pi.7

depressa ............................... 20

nodosum ............................... 20

shattucki .............................. 20

eurta ............................... 4, 21

similis ................................. 4, 21

vandenboldi ............................ 20

Paracytherideidae .......................... 20

paucipunctata, Cythere ..................... 4, 14

Cytheretta ............................. 15

Pseudocytheretta ....................... 14; pi. 5

Paw Paw Point, Md., Choptank Formation.. 3, 5; pis. 1,3 

Peachblossom Creek, Md., Choptank Formation .................... 3, 15, 17; pis. 5,6

Peratocytheridea ........................... 6

bradyi ................................. 5

subovata .......................... 2, 4, 5, 6;pi. 1

petricola, Aurila ............................ 16, 17

planibasalis, Buntonia ...................... 14

Cythere ................................ 4, 14

Echinocythereis ................. 4, 5, 13, 14; pi. 4

plebeia, Bairdia............................. 15

Cythere ................................ 4, 15

(Bairdia) ............................ 15

Cytheretta ............................. 15

Pseudocytheretta.......... 4,5,14,15, 16; pis. 5,6

capax, Cythere.......................... 4, 15

modica, Cythere ........................ 4, 15

Plum Point, Md., Calvert Formation.......... 6, 10,

12, 16, 18; pis. 1, 2, 3, 4, 5 

fossil locality ........................... 6

Plum Point Marl Member, Cajvert Formation . 2 

Pontocythere ashermani..................... 6

rugipustulosa .......................... 1

(Hulingsina) ashermani.................. 6

(Hulingsina} rugipustulosa............... 1

porcella, Cythere ............................ 4, 15

Pseudocytheretta .................... 15, 16; pi. 6

Praeorbulina glomerosa circularis ............ 2

Procedures................................. 3

producta, Cythere .......................... 4, 10

Protocytheretta ............................ 16

inaequivalvis ....................... 4, 5, 16; pi. 6

Pseudocytheretta........................... 14

burnsi.................... 4, 5,14, 15, 16; pis. 4, 5

calvertensis ............................ 15; pi. 5

capax .................................. pi. 5

chesapeakensis ......................... pi. 6

edwardsi ............................... 14

modica .............................. 15, 16; pi. 6

nitidula ................................ 15; pi. 5

paucipunctata .......................... 14; pi. 5

plebeia ................... 4, 5, 14, 15, 16; pis. 5, 6

porcella ............................. 15, 16; pi. 6

toumeyi ................................ 15; pi. 5

ulrichi ................................. 15

sp...................................... 14

Pterygocythereidini ........................ 12

Pterygocythereis ........................... 12

americana .......................... 4, 5, 12; pi. 4

cornuta americana ...................... 12

howei .................................. 12

inexpectata ............................ 12, 13

puelld, Favella.............................. 18

punctistriata, Cythere............... ..... 1,3, 4,16

Hemicythere ........................... 16

Otikocythere ................. 4, 5,16, 17; pis. 6, 7

Puriana .................................... 18

rugipunctata .......................... 3, 4, 5, 18

gatunensis ......................... 18
INDEX 25

R Page

radiata, Murrayina .................... 4, 5, 9, 11 ;pl. 3

Trachyleberis ........................... 4, 11

Handle Cliffs, Md., Calvert Formation........ 6

Red Bay Formation, Florida ................. 17

redbayensis, Hemicythere ................... 16

Otikocythere ........................... 17

reesidei, Trachyleberis ...................... 17

rugipunctata, Cythere ....................... 4, 18

Favella ................................ 18

Puriana .................................. 3, 4, 5

Trachylebereis .......................... 18

gatunensis, Puriana..................... 18

rugipustulosa, Cytherideis ................... 7

Henryhowella .......................... 5

Hulingsina ............................ 4, 7 ;pl. 2

Pontocythere ........................... 7

(Hulingsina) ........................ 7

St. Leonard Member, Chop tank Formation.... 2

St. Marys Formation .......................... 1, 2, 9

Unit A ................................. 6, 15

Unit B ................................. 6,13, 15

Unit C ................................. 13

schmidtae, Hemicythere ..................... 4, 17

Thaerocythere ................... 4, 5, 17, 18; pi. 7

Scientist's Cliffs, Md., Choptank Formation... 20 

semicircularis .............................. 8

Cytherideis ............................. 4, 8

Henryhowella .......................... 5

Hutingsina ........................ 4, 6, 7, 8;pi. 2

setipunctata, Cytheridea .................... 6

Shattucki, Cythere ........................... 4,9, 20

Microcytherura .................. 4, 5, 20, 21; pi. 7

Paracytheridea ......................... 20

Shattuckocythere ....................... 20, 21

curta, Paracytheridea ................... 21

Page

Shattuckocythere........................... 20

shattucki .............................. 20, 21

similis ................................. 21

yorktownensis .......................... 9, 21

Shoal River Formation ...................... 6

similis, Microcytherura .............. 4, 9, 20, 21; pi. 7

Paracytheridea ......................... 4, 21

Shattuckocythere ....................... 21

spiniplicata, Cythere ........................ 4, 12

Stratigraphic setting ....................... 2

subaequalis, Cytherideis .................... 4, 8

Hulingsina .......................... 4, 6, 8; pi. 2

subovalis, Cythere .......................... 4, 6

Cytheridea ............................. 4,5

subovata, Cytheridea ....................... 4, 6; pi. 1

Haplocytheridea ........................ 6

Peratocytheridea................... 2, 4, 5,6;pl. 1

Systematics................................ 3

Thaerocythere .............................. 17

crenulata............................... 17

schmidtae ....................... 4, 5,17, 18; pi. 7

Thaerocytherinae........................... 17

Thaerocytherini ............................ 17

toumeyi, Cythere ........................... 4, 14

Pseudocytheretta ....................... 15; pi. 5

Trachyleberididae .......................... 9

Trachyleberidinae .......................... 9

Trachyleberidini............................ 9

Trachyleberis clarkana ...................... 13, 14

evax ................................... 12

exanthemata ........................... 11

martini ................................ 10, 19

radiata ................................. 4, 11

reesidei ................................ 17

rugipunctata ........................... 18

vaughani............................... 19

tuberculata, Hulingsina .

U, V

ulrichi, Cytheretta .......................... 15

Pseudocytheretta ....................... 15

Unit A, Little Cove Point unit, St. Marys

Formation ....................... 2, 6, 15

Unit B, St. Marys Formation............ 2, 6, 9,13,15

Unit C, Claremont Manor Member, Eastover

Formation ............. 2, 7, 13, 17, 18, 20

Unit D, Cobham Bay Member, Eastover Formation ............... 2, 3, 7,13,17,18, 20

vandenboldi, Paracytheridea ................. 20

vaughani, Cythere .......................... 4, 19

Orionina .............................. 3, 4, 5, 19

Trachyleberis ........................... 19

Virginia St. Marys .......................... 2

virginiensis, Clithrocytheridea ............... 4

Cytheridea ........................... 3, 4, 5; pi. 1

W, Y, Z 

whitei, Leguminocythereis ..... 19

Yorktown Formation.... 1,2,5,7, 9,12,15, 20; pis. 1, 2

yorktownensis, Cytheropteron ............ 4, 5, 9; pi. 2

Eocytheropteron ......................... 4, 9, 20

Shattuckocythere ....................... 9, 21

Zones 1-15, Calvert Formation .... 

Zones 16-20, Choptank Formation . 

Zones 21-24, St. Marys Formation.
PLATES 1-7

Contact photographs of the plates in this report are available, at cost, from the U.S. Geological Survey 

Photographic Library, Federal Center, Denver, Colorado 80225.
PLATE 1

FIGURES 1, 8. Cytheridea subovalis (Ulrich and Bassler, 1904).

1. Lateral view, left valve, female; Plum Point, Md., Calvert Formation. USNM 256021. X 95.

8. Lateral view, Left valve, female, Ulrich and Bassler's Paw Paw Point, Md., Choptank Formation. USNM 35439. X 105. 

Holotype.

2. 5. Hulingsina calvertensis new species.

2. Lateral view, left valve, female; 0.8 km north of Randle Cliffs Beach, North Beach 7 Vis-minute quadrangle, Maryland;

Calvert Formation. USNM 256022. X 100. Holotype. 

5. Lateral view, left valve, female, Plum Point, Md., Calvert Formation. USNM 35446. X 120.

3. 6. Cytheridea diagonalis (Malkin, 1953).

3. Lateral view, right valve, male; Malkin locality 13-3, Calvert Formation. USNM 256019. X 100. Paralectotype.

6. Lateral view, right valve, female; Malkin locality 13-3, Calvert Formation. USNM 256018. X 100. Lectotype. 

4. Peratocytheridea subovata (Ulrich and Bassler, 1904).

Left valve, male; Plum Point, Calvert Formation. USNM 648513. X 90. Paralectotype. 

7. Cytheridea virginiensis (Malkin, 1953).

Lateral view, left valve, female; Malkin locality VA-10, Yorktown Formation. USNM 256020. X 125. Lectotype.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1128 PLATE 1

CYTHERIDEA, HULINGSINA, AND PERATOCYTHERWEA
PLATE 2

FIGURE 1. Hulingsina rugipustutosa (Edwards, 1944).

Lateral view, right valve, male; Malkin locality VA-12, Yorktown Formation. USNM 256023. (Lectotype of H. echolsae

(Malkin, 1953)). X 150. 

2. Hulingsina cylindrica (Ulrich and Bassler, 1904).

Lateral view, left valve, male (?); Ulrich and Bassler's Plum Point locality, Calvert Formation. USNM 35447. X 110.

Holotype. 

3-5. Hulingsina semicircularis (Ulrich and Bassler, 1904).

3. Lateral view, right valve, male; Ulrich and Bassler's Plum Point locality, Calvert Formation. USNM 35448 a. (= lectotypeofH longula (Ulrich and Bassler, 1904)). X 100.

4. Lateral view, left valve, male; Ulrich and Bassler's Plum Point locality, Calvert Formation. USNM 35448 b. (= paralectotypeofK longula (Ulrich and Bassler, 1904)). X 110.

5. Lateral view, right valve, female; Ulrich and Bassler's Plum Point locality, Calvert Formation. USNM 35449 a. X 120. 

Lectotype.

6. Hulingsina subaequalis (Ulrich and Bassler, 1904).

Lateral view, female; Ulrich and Bassler's Plum Point locality, Calvert Formation. USNM 35450. X 110. Holotype.

7. Cytheropteront yorktownensis (Malkin, 1953).

Lateral view, left valve, female; Malkin locality VA-4, Yorktown Formation. USNM 256025. X 250. Lectotype.

8. Cytherura coryelli Malkin, 1953.

Lateral view, left valve, female; Malkin locality 14-5, Choptank Formation. USNM 256024. X 200. Lectotype.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1128 PLATE 2

HULINGSINA, CYTHEROPTERON, AND CYTHERURA
PLATE 3

FIGURE 1. Murrayina radiate (Malkin, 1953).

Lateral view, right valve, female; Malkin locality NJ-9, Kirkwood Formation. USNM 256026. X 110. Lectotype.

2. 4. Murrayina martini (Ulrich and Bassler, 1904).

2. Lateral view, right valve, male; Plum Point, Md., Calvert Formation. USNM 35423 a. X 110. Lectotype. 

4. Lateral view, left valve, female; Plum Point, Calvert Formation. USNM 35423 b. X 120. Paralectotype.

3. 5. Murrayina howei (Ulrich and Bassler, 1904).

3. Lateral view, right valve, male; Plum Point, Calvert Formation. USNM 35433 a. X 100. Lectotype.

5. (Holotype of M. dorsicornis (Ulrich and Bassler, 1904)). Lateral view, left valve, juvenile; Plum Point, Calvert Formation.

USNM 35415. X 145. 

6. Murrayina martinil (Ulrich and Bassler, 1904).

(= holotype of M. dorsicornis bicornis (Ulrich and Bassler, 1904)). Lateral view, left valve, juvenile; Ulrich and Bassler's

Paw Paw Point, Md., Choptank Formation. USNM 35416. X 210. 

7, 8. Actinocythereis exanthemata (Ulrich and Bassler, 1904).

7. Lateral view, right valve, female; Plum Point, Calvert Formation. USNM 35419 b. X 120. Paralectotype.

8. Lateral view, right valve, female; Plum Point, Calvert Formation. USNM 35419 a. X 110. Lectotype.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1128 PLATE 3

MURRAYINA AND ACTINOCYTHEREIS
PLATE 4

FIGURES 1, 2. Henryhowella evax (Ulrich and Bassler, 1904).

1. Lateral view, left valve, male (H. oblongata); Plum Point, Md., Calvert Formation. USNM 35418 a. X 100. Lectotype.

2. Lateral view, left valve, female; Plum Point, Calvert Formation. USNM 35417 a. X 110. Lectotype.

3. Actinocythereis alaris (Ulrich and Bassler, 1904).

Lateral view, left valve, juvenile; James River, Va., Yorktown Formation. USNM 35451. X 120. Holotype.

4. Pterygocythereis americana (Ulrich and Bassler, 1904).

Lateral view, left valve, female; Plum Point, Calvert Formation. USNM 35452 a. X 95. Lectotype.

5. Echinocythereis clarkana (Ulrich and Bassler, 1904).

Lateral view, left valve, male; Plum Point, Calvert Formation. USNM 35413 a. X 80. Lectotype.

6. Pseudocytheretta burnsi (Ulrich and Bassler, 1904).

Lateral view, left valve, male; Plum Point, Calvert Formation. USNM 35411 a. X 90. Lectotype.

7. Echinocythereis planibasalis (Ulrich and Bassler, 1904).

Lateral view, right valve, male; James River, Yorktown Formation. USNM 35428. X 95. Holotype.

8. Echinocythereis miniscula (Ulrich and Bassler, 1904).

Lateral view, left valve, female; Plum Point, Calvert Formation. USNM 35414 a. X 100. Lectotype.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1128 PLATE 4

HENRYHOWELLA, ACTINOCYTHEREIS, PTERYGOCYTHEREIS, ECHINOCYTHEREIS, AND PSEUDOCYTHERETTA
PLATE 5

FIGURES 1, 4, 5. Pseudocytherettaplebeia(Uliichand'Bassler, 1904).

1. Lateral view, right valve, female; Plum Point, Md., Calvert Formation. USNM 256028. X 80.

4. Lateral view, left valve, female; Plum Point, Calvert Formation. USNM 35429 a. X 85. Lectotype.

5. Lateral view, right valve, female (lectotype of P. capax (Ulrich and Bassler, 1904)); Calvert Formation. USNM 35430 a.

X85. 

2, 3, 6, 7, 8. Pseudocytheretta burnsi (Ulrich and Bassler, 1904).

2. Lateral view, left valve, juvenile (lectotype of P. nitidula (Ulrich and Bassler, 1904)), Plum Point, Calvert Formation. 

USNM 35425 a. X 105.

3. Lateral view, right valve, female, Bed 10, 0.8 km north of Plum Point, Calvert Formation. USNM 256027. X 80.

6. (Holotype of P. paucipunctata (Ulrich and Bassler, 1904)). Lateral view, left valve, female; 4.8 km southwest of Easton, 

Md., Choptank Formation. USNM 35427. X 85.

7. (Lectotype of P. toumeyi (Ulrich and Bassler, 1904)). Lateral view, right valve, juvenile; Peachblossom Creek, Trappe 

7 1/2-minute quadrangle, Maryland; Choptank Formation. USNM 35440. X 160.

8. (Lectotype of P. calvertensis (Ulrich and Bassler, 1904)). Lateral view, left valve, juvenile; Plum Point, Calvert Formation. USNM 35426 a. X 120.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1128 PLATE 5

PSEUDOCYTHERETTA
PLATE 6

FIGURES 1-4. Otikocy'therepunctistriata (Ulrich and Bassler, 1904). New genus

1. Lateral view, left valve, interior, female; Peachblossom Creek, Md., Choptank Formation. USNM 256029. X 135.

2. Lateral view, right valve, interior, female; Peachblossom Creek, Choptank Formation. USNM 256030. X 135.

3. Lateral view, left valve, female; Church Hill, Md., Calvert Formation. USNM 35435. X 155. Paratype.

4. Lateral view, left valve, female; Peachblossom Creek, Choptank Formation. USNM 256031. X 160. 

5-7. Pseudocytherettaplebeia (Ulrich and Bassler, 1904).

5. (Lectotype of P. modica (Ulrich and Bassler, 1904)). Lateral view, left valve, female; Plum Point, Md., Calvert Formation. 

USNM3543 la. X 100.

6. (Lectotype of P. porcella (Ulrich and Bassler, 1904)). Lateral view, left valve, juvenile; Plum Point, Calvert Formation. 

USNM 35432 a. X 130.

7. (Holotype of P. chesapeakensis (Ulrich and Bassler, 1904)). Lateral view, right valve, juvenile; Plum Point, Calvert Formation. USNM 35444. X 130. 

8. Protocytheretta inaequivalvis (Ulrich and Bassler, 1904).

Lateral view, right valve; Plum Point, Calvert Formation. USNM 35421 a. X 85. Lectotype.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1128 PLATE 6

OTIKOCYTHERE, PSEUDOCYTHERETTA, AND PROTOCYTHERETTA
PLATE 7

FIGURE 1. Microcytherura shattucki (Ulrich and Bassler, 1904).

Lateral view, left valve, female, Bed 17, Scientists Cliffs, Md., Choptank Formation. USNM 256036. X 135. 

2, 3. Muellerina micula (Ulrich and Bassler, 1904).

2. Lateral view, left valve, female, Calvert Formation. USNM 256035. X 125.

3. Lateral view, left valve, Juvenile, Plum Point, Md., Calvert Formation. USNM 35424 a. X 180. Lectotype.

4. Muellerina lienenklausi (Ulrich and Bassler, 1904).

Lateral view, left valve, female, Plum Point, Calvert Formation. USNM 256034. X 120.

5. Otikocy therepunctistriata (Ulrich and Bassler, 1904).

Lateral view, left valve, juvenile, Peachblossom Creek, Md., Choptank Formation. USNM 256032. X 160.

6. Bensonocythere calverti (Ulrich and Bassler, 1904).

Lateral view, left valve. Plum Point, Calvert Formation. USNM 35412. X 115. Holotype.

7. Paracytheridea altila Edwards, 1944.

(= holotype of Cytheropteron nodosum Ulrich and Bassler, 1904). Lateral view, right valve, James River, Va., Yorktown 

Formation. USNM 35443. X 145.

8. Thaerocythere schmidtae (Malkin, 1953).

Lateral view, left valve, female, Malkin (1953) locality VA-9, Yorktown Formation. USNM 256033. X 130. Lectotype.

9. Microcytherura similis (Malkin, 1953).

Lateral view, left valve, female, Malkin (1953) locality VA-10, Yorktown Formation. USNM 256038. X 170. Lectotype. 

10. Microcytherura curta (Malkin, 1953).

Lateral view, left valve, female, Malkin (1953) locality VA-10, Yorktown Formation. USNM 256037. X 160. Lectotype.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1128 PLATE 7

MICROCYTHERURA, MUELLERINA, OTIKOCYTHERE, BENSONOCYTHERE, 

PARACYTHERIDEA, AND THAEROCYTHERE

it U.S. GOVERNMENT PRINTING OFFICE: I960—677-129/35