LOUIS S. KORNICK Morphology, Ontogeny,

and Intraspecific

Variation of

Spinacopia, A

a New Genus of

Myodocopid Ostracod

(Sarsiellidae)

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • 1969 NUMBER 8

SMITHSONIAN CONTRIBUTIONS TO

ZOOLOGY

NUMBER 8

Louis s. Komicker Morphology, Ontogeny,

and Intraspecific

Variation of Spinacopia,

a New Genus of

Myodocopid Ostracod

(Sarsiellidae)

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ABSTRAC T

Morphology, biology, and variability of a new genus with four new species are

described from collections of deep-sea ostracods obtained by the Lamont Greological

Observatory and Woods Hole Biological Laboratory in the Atlantic, Antarctic, and

Indian Oceans. Adult females far outnumber males in collections, but juvenile males

and females are present in equal numbers indicating that adult males are short lived.

Microtome sections of male and female genitalia document that the male transfers

sperm to the female in ovoid spermatophores which are attached externally. Examination of stomachs shows that members of the new genus are carnivores—feeding on

copepods, ostracods, and nematodes. Apparently adult males do not eat. A key is

presented for identification of early instar stages by means of examination of sixth and

seventh limbs.

Introduction

Collections of deep-sea ostracods obtained by the

Lamont Geological Observatory, Columbia University,

and the Woods Hole Marine Biological Laboratory

contained a new genus belonging to the family

Sarsiellidae in samples from five localities (Figure 1).

Data concerning localities and collections follow:

Station

V-14-24

V-15-131

V-18-13

V-16-15

118A

Latitude-Longitude

56°37' S, 34°48' W

40° 14.6' S, 55°24.7' W

47°10' S, 61°02' W

45°00' S, 45°46' E

32° 19.2' N, 64°36.8' W

Ocean

Antarctic

South Atlantic

South Atlantic

southern Indian

North Atlantic

Depth {meters)

3500*

1475*

135 •

1622 •

1135-1153b

Date

7-8 March 1958

3 April 1959

17 February 1962

8 January 1960

18 August 1966

Number of specimens

1

76

1

1

353

• Small bottom trawl.

 b Epibenthic trawl.

Since three of the samples contained only one specimen of the new genus and the specimens at the remaining stations showed great variation, it was difficult to

determine whether differences between them were individual or specific. In order to establish a basis for

such a judgment, a detailed analysis was made of the

specimens from station 118A, which clearly belonged

to a single species. Using the variation found in this

species as a guide, it was determined that the collections

contained four new species, which are described herein.

I wish to thank Dr. Horton H. Hobbs, Jr., for help

in interpreting the anatomy of genital organs from both

whole mounts and microtome sections, and Drs. Robert J. Menzies, Meredith L. Jones, Neil C. Hulings for

supplying specimens upon which this study was based.

The specimens were collected on vessels of the Lamont

Geological Observatory, Columbia University, and the

Louis S. Kornicker, Department of Invertebrate Zoology,

Smithsonian Institution, Washington, D.C. 20560.

Woods Hole Marine Biological Laboratory. Criticisms

of parts of the manuscript by Drs. Thomas E. Bowman

and Roger F. Cressey, Jr., are most appreciated. I also

thank Mrs. Carolyne Bartlett Gast for final preparation of figures from my camera lucida pencil drawings

and for entire preparation of Plates 1 and 6, and

Mrs. Vernetta Williams for preparing stained sections.

Methods

IDENTIFICATION OF EARLY INSTAR STAGES.—The

usual method for determining the number of instars

in the ontogeny of a species of ostracod in a collection

is to make a scattergram of carapace length versus

carapace height on arithmetic graph paper. Normally,

instars of the same developmental stage form a cluster

of points sufficiently distant from clusters formed by

other instar stages to be able to determine the number

of stages in the sample. It is generally possible to rec1
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 1.—Stations of research vessels Vema and Atlantis II, where ostracods reported herein

were collected.

ognize that an instar is missing from a collection if

the spacing between any two clusters is inordinately

wide, compared to spacings between other clusters. On

the other hand, it is very difficult to determine whether

the population in nature contains earlier instar stages

than those represented in the collection. This is a problem because the small size of the earlier instars often

results in their being missed by the sampling device or

overlooked in the picking operation.

If the number of instar stages of a species is known,

it can be established whether all stages are present in

a collection. This is not possible, however, in many

groups, including myodocopid ostracods, in which the

number of instar stages seems to vary from species to

species and is known with certainty for few species.

During a study of variation of morphology of instars of S. sandersi, it was observed that the morphology

of the 6th and 7th limbs developed in a consistent and

predictable manner while progressing from instar I

to instar IV. A key was then constructed for use in

identifying early instar stages. This key, when tested

against other myodocopids reported in the literature,

was found also to apply to them with three exceptions

(to be discussed later). Use of the key, given below,
NUMBER 8

Key to Early Myodocopid In stars

1. 6th limb without bristles, 7th limb absent Instar I

6th limb with one or more bristles, 7th limb present 2

2. 6th limb with one bristle Instar II

6th limb with more than one bristle (usually many) 3

3. 7th limb without bristles • Instar III

7th limb with bristles Instar IV-Instar N

• In some genera of Sarsiellidae the males, which are relatively sparce, do not have bristles on

the 7th limb during any developmental stage. For these forms it is necessary to use other criteria such

as the morphology of the endopodite of the 2nd antenna to determine whether the specimen belongs

to instar III or IV.

should save an investigator considerable time and effort by permitting him to identify the stage of development of specimens without having to resort to

scattergrams.

Data from the literature presented in Table 1

strengthen the assumption that the above key may be

applied to myodocopid genera other than Spinacopia.

This table shows that Cypridina pectinata, Philomedes

globosus, and Sarsiella zostericola apparently do not fit

in the above key. Consideration of the evidence upon

which the authors based their interpretation of the

number of instars in these three species leads me to

believe that they are in error and that the key does

indeed also apply. For example, Skogsberg (1920)

found his earliest stage of P. globosus within the brood

chamber of a female, the next stage was not present in

his collection and its presence is based on theoretical

growth factors, and the following stage is according to

Skogsberg (p. 139) ".. . the youngest freely living stage

I found." I believe that Skogsberg's "earliest stage" is

an embryo and not an instar in the sense used in the

present paper, and the third stage, "youngest freely

living stage," is actually instar I (Skogsberg numbered

his instars in reverse to the system used herein so that

my instar I is his instar VII). Strong support for this

interpretation comes from the work of Elofson (1941),

who raised Philomedes globosus in aquaria and found

only five juvenile instar stages. He stated (p. 369) that

he did not find Skogsberg's stages VIII-VI (the two

earliest stages reported by Skogsberg). Certainly, the

best method for determining instar stages is by raising

ostracods in aquaria. Considerable weight must be

given to the conclusion by Elofson that Philomedes

globosus has five juvenile instar stages, which is the

same number derived by using the above key.

The only argument to support my contention that

the two earliest instars of Cypridina pectinata described by Skogsberg (1920) should both be included

in the instar I stage is that it seems unlikely that the

6th and 7th limbs would be identical in two early

instars; some development should take place. Additional data for this species as well as other myodocopid

species are needed to test the validity of the key.

The third species in Table 1 that does not fit the

key is Sarsiella zostericola. Kornicker (1967) estimated

that instars I and II were missing from his sample and

described instars III, IV, and V, as well as the adult

According to the above key, only instar I was missing

from the sample and his descriptions are of instars II,

III, IV, and the adult. In order to estimate the number of growth stages missing from his sample, Kornicker divided the average shell length of the earliest

stage in the sample by 1.26 (Przibram's theoretical

growth factor for a linear dimension). The resulting

dimensions were concluded to be the approximate

average length of the next earlier growth stage. This

procedure was repeated until an instar length was obtained approaching the length of an embryo acquired

from the brood chamber of a female. The method is in

common usage and similar to that used by Skogsberg

(1920) for determining early growth stages for Philomedes globosus. Concerning the estimate that instars

I and II were missing from the sample, Kornicker

(p. 7) stated, "The conclusion must be considered

tentative because of the many factors that cause the

growth rate to deviate from the theoretical (Tessier,

1960, p. 541)." The evidence now indicates that only

instar I was missing from the sample. Additional support for this conclusion comes from Elofson (1941, p.

367) who listed the length of the egg (carried within

the brood chamber) of Philomedes globosus as 0.49-

0.56 mm and the length of the freshly hatched larva

as 0.80 mm. By dividing larval length by the length

of the smallest egg and then the largest egg, a "growth"

factor range of 1.63-1.57 is obtained. If the estimated
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

TABLE 1.—Number of bristles on 6th and 7th limbs of juvenile instars

Juvenile

ins tar

stage

I

II

III

IV

V

VI

VII

Total estimated by

original author

Total estimated herein

Gigmtocypris

agassizi •

6th limb 7th limb

0 limb

absent

instar missing

1+ 0

1+ 1 +

1+ 1 +

instar missing

6

6

Gigantocypris

muelleri •

6th limb 7th limb

0 limb

absent

1 0

1+ 0

1+ 1 +

1+ 1 +

1+ 1 +

6

6

Gigantocypris

danae »

6th limb 7th limb

0 limb

absent

1 0

instar missing

1+ 1 +

1+ 1 +

instar missing

6

6

Macrocypridina

castanea •

6th limb 7th limb

0 limb

absent

1 0

1+ 0

1+ 1 +

1+ 1 +

5

5

Juvenile

stage

I

II

III

IV

V

VI

VII

Total estimated by

original author

Total estimated herein

Cypridina

pectinata b

6th limb 7th limb

0 limb

absent

0 absent

1 0

1+ 0

1+ 1 +

1+ 1 +

6

5

Philomedes

globosus b

6th limb 7th limb

limb limb

absent absentd

instar missing

0 absent

1 0

1+ 0

1+ 1 +

1+ 1 +

7

5

Sarsiella

zoster kola c

6th limb 7th limb

instar missing

1 0

1+ 0

1+ 1 +

5

4

Spinacopia

sander si

6th limb 7th limb

0 limb

absent

1 0

1+ 0

1+ 1 +

4

Spinacopia

variabilis

6th limb 7 th limb

instar missing

1 0

instar missing

1+ 1 +

4

* E. Poulsen, 1962.

b

 T. Skogsbcrg, 1920.

• L. S. Komicker, 1967.

d

 Instar removed from brood chamber of female.

length of the missing instar I listed by Kornicker

(1967, p. 7) is divided by the embryo length (obtained

from within brood chamber of female) a "growth"

factor of 1.09 is the result. The factor of 1.09 may be

much too small. If the average "growth" factor (1.52)

of Philomedes globosus is applied to the S. zostericola

embryo, a dimension of 0.48 mm results, which is close

to instar II (0.44 mm) of Kornicker (p. 7). It is, of

course, hazardous to apply factors obtained from one

species to another, but the data help to arrive at the

conclusion that only instar I was absent from the

samples studied by Kornicker.

The data used herein indicate that the total number

of juvenile instars in the myodocopa is four to six,

with four instars in the Sarsiellidae (N=3 species),

five in the Philomedinidae (N= l species), and five

or six in the Cypridinidae (N=5 species) (Table 2).

It is suggested by the present study that the total

number of instars in a species does not affect appendage

morphology of the first three stages.
NUMBER 8

TABLE 2.—Number of juvenile stages

Taxon

Cypridinidae

Gigantocypris agassizi

" muelleri

" danae

Macrocypridina castanea

Cypridina pectinata

Philomedinidae

Philomedes globosus

Sarsicllidae

Sarsiella zostericola

Spinacopia sandersi

" variabilis

Juvenile instars

6

6

6

5

5

PREPARATION OF SPECIMENS.—Standard microtome

sections stained with Mallory's triple stain were used

in the study of genitalia. In these preparations the

head of sperm stains yellow orange and the midpiece

from which the flagellum arises stains light blue. Secretion in the seminal vesicle of the male and in the

spermatophore attached to the female stains red. Smear

preparations were made of testes, seminal vesicle, and

spermatophores by mashing them in aceto-carmine under a cover glass. In these, the head of sperm stains

pink and the midpiece is without color.

Biology

RELATIVE ABUNDANCE OF MALES AND FEMALES.—

Adult males are generally sparce among the Sarsiellidae. Miiller (1894) pointed out that the maxilla and

5th limb of the male are unsuitable for gathering food.

Sample 118A contains 32 adult males and 123 adult

females of S. sandersi; adult females outnumber males

by 3.8 to 1. I examined the gut of three males and

found them empty, thus supporting Miiller's contention that adult males do not eat. If this is so, it seems

likely that males are less abundant than females because of having a shorter life span. Probably, they die

soon after fertilizing the female.

Data concerning the relative abundance of sexes

among juvenile instars might be useful in establishing

the reason for adult males being sparce in nature. For

example, if males are also sparce in juvenile stages,

as suggested by the few data presented by Kornicker

(1967, p. 7) for Sarsiella zostericola, the sex-ratio pattern would have been established prior to the male's

reaching the adult stage, and, therefore, length of the

life of the male could not be a major reason for its

being sparse. Data in the literature concerning the

distribution of sexes in juvenile instars of the Sarsiellidae are lacking, except for that of Kornicker and Wise

(1962) and Kornicker (1967), in which samples were

too small to have statistical value; therefore, the sex

was determined herein for 35 specimens of S. sandersi

at the instar IV stage of development.

In order to be able to treat the results statistically,

seven subsamples of four to six specimens each were

picked at random from the collection and the percent

of males calculated (Table 3). The average percentage

of males in all subsamples is 54.5. The percent of males

in the population at 0.95 probability is within the range

40-68.

The presence of about the same number of males

and females at the instar IV stage of development supports the hypothesis that adult males are short lived.

An alternate hypothesis that adult males might live in

a different locality than adult females is discounted

because of the absence of records of collections of sarsiellids in which males are more abundant than

females.

TABLE 3.—Distribution of sexes in instar IV

Subsample

1

2

3

4

5

6

7

Total

specimens

6

4

5

5

5

5

5

Males

4

3

2

2

2

2

4

Females

2

1

3

3

3

3

1

Percent of

males

66.7

75.0

40.0

40.0

40.0

40.0

80.0

Average percent of males (x) = 54.5

N=7

S. D. = 18.52

2S. E. m=±1 4

Percent of males in population at 95% confidence 40-68

REPRODUCTIVE SYSTEM (Figure 2).—Because the

collections contain adult males only of S. sandersi the

study of the reproductive system was made on this

species. A similarity between the spermatophores attached to adult females of S. sandersi and the remaining three species studied indicates that the system

described for S. sandersi probably also applies to the

other species.

In brief, sperm is produced in two testes located on

each side of the male above the penis. The sperm

is transferred through a tubular vas deferens to a large

bilobed seminal vesicle which also contains a secretion

that stains red with Mallory's. A single penis with a
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

spermatophores

FIGURE 2.—Spinacopia sandersi, genitalia, adult $ : a, copulation system, specimen 3; b, same,

specimen 43; c, same, with furca, and outline of gut, specimen 3; d, detail of c; e, right copulatory

organ, medial view, specimen 3; /, same, lateral view; g, detail of /; h, left copulatory organ,

specimen 3, medial view; i, detail of h; j , section of right testis; k, section of seminal vesicle.

Adult $, specimen 66, 4 eggs in marsupium: /, section through spermatophore; m, sections

through specimen showing both spermatophores; n, section through end of spermatophore.

(Same scale in microns: c; a, b, d, e; f, h; g, i-n.)
NUMBER 8

short curved ejaculatory duct hangs between the lobes

of the seminal vesicle. On either side of the penis is a

long complex clasping organ consisting of three lobes,

one of which bears a terminal sclerotized hook and a

triangular ridged tooth.

Two oval spermatophores each consisting of a sheath

of secretion and containing sperm are found on most

adult females; each is attached to a genital opening

located on the left and right sides of the body above

the furca. Presumably these have been extruded

through the ejaculatory duct of the male and deposited

on the female.

The spermatophores of Spinacopia resemble more

closely spermatophores of Cypridina mediterranea described by Ramsch (1906) than the elongate spermatophores observed by Poulsen (1965, p. 116) entering

the "receptaculum seminis" of Eusarsiella longicornis

Poulsen.

The oviduct of the female of one specimen examined

contained sperm only in the immediate vicinity of the

spermatophore, suggesting that eggs are fertilized as

they leave the oviduct. Additional studies are necessary

to confirm this, however, because the proximal portion

of the oviduct was not visible on the specimen, and the

oviduct was obscure on several other specimens sectioned. The gravid females of S. sandersi contain up to

four eggs in the marsupium, and some also have the

same number in the ovaries. Females of S. variabilis

contain as many as six eggs in the marsupium and seven

in the ovaries. The single female of S. menziesi in the

collection contains nine unextruded eggs in the ovaries.

The single specimen of S. bisetula contains five eggs in

the marsupium and four in the ovaries. Spermatophores

are attached to females having eggs both in the

marsupium and ovaries. This suggests that part of the

genital opening is sufficiently free from the attached

spermatophore to permit passage of eggs; however, it is

also possible that new spermatophores are attached to

the female after she deposits the first clutch of eggs in

the marsupium.

A more detailed description of genitalia is presented

in the description of males and females of S. sandersi.

FOOD AND DIGESTION.—Darby (1965) presented photographs of copepod remains in the gut of Sarsiella

greyi Darby (1965, pi. 27: fig. 8). He also reported

(1965, p. 35) several copepods in the stomach of Sarsiella pilipollicus Darby. Kornicker (1967, p. 32) reported a complete harpacticoid copepod in the gut of a

juvenile female of Sarsiella zostericola, and the presence of a whole harpacticoid copepod, several arthropod appendages and a diatom in one specimen of Sarsiella disparalis, and two nematodes in another (p. 44).

Organisms found in the gut of several specimens of

Spinacopia are shown on Plate 2 and are listed below:

Species

S. bisetula adult

S. variabilis adult

Stage

S. sandersi

adult

adults (3 spec.)

instar I

instar II

instar IV

Sex Gut content

9 copepod fragments

9 3 harpacticoid copepods, 1 nematode,

3 pellets

9 1 polycopid ostracod,

copepod fragments

cf empty

? 1 polycopid ostracod,

3 copepods

? 1 copepod

? 1 podocopid ostracod

9 1 polycopid ostracod

d" copepod remains

These data indicate that adult males of Spinacopia

do not eat, and that juveniles of both sexes and adult

females are extremely voracious. Their diet consists

mainly of small arthropods (copepods, polycopid and

podocopid ostracods) and worms (free living nematodes) . The presence of foreign fecal pellets in the midgut and foregut region of a specimen suggests that

Spinacopia swallows objects and organisms on the basis

of size rather than type. The gut contains relatively

little fine-grained material.

Apparently food is pushed into the mouth of Spinacopia by the coxale endite of the mandible and the

spines and bristles of the maxilla. The size of organisms

in the gut shows that the esophagus is capable of considerable dilation. Copepods, ostracods, and nematodes

in the gut often are whole, indicating that Spinacopia

does not have an internal mechanism for grinding

food. Whole specimens in the gut appear to be cleaned

of internal protoplasm, suggesting that digestive

enzymes produced by Spinacopia do not affect the

chitinous exoskeleton of arthropods or nematodes. The

calcified shells of ingested ostracods remain brittle and

do not seem to have been decalcified during.the digestive process.

In one specimen a whole copepod was observed

partway out the anus. Apparently, intact organisms

with their viscera digested pass through the gut of

Spinacopia. Finely divided material filled the rectal

area of another specimen. This loose aggregation was

roughly cylindrical but did not form a distinct pellet
8

such as that formed by Cypridopsis vidua (see Kesling,

1951, p. 7, fig. 3).

Although the data are few, they suggest that the

Sarsiellidae are voracious carnivores that feed upon

small benthic arthropods and worms. When sarsiellids are abundant—they are the dominant species in

some localities—the effect of their voraciousness on

the community must be considerable.

Family SARSIELLIDAE Brady and Norman, 1896

Spinacopia, new genus

TYPE-SPECIES.—Spinacopia sandersi Kornicker, described herein.

ETYMOLOGY.—The generic name "Spinacopia,"

from the Latin "spina" = thorn and "copia" =

abundance. Gender: feminine.

DIAGNOSIS OF GENUS.—Shape: Carapace oval with

greatest height near middle in female and posterior to

middle in male; shallow incisur present on both male

and female; rostrum of male more prominent than on

female.

Ornamentation: Punctate or smooth and with

abundant hairs and scattered normal pores.

Infold: Infold of female characterized by having 5

stout spinous bristles forming row in front of caudal

process (6 bristles observed on single valve of 1 specimen) ; 3-8 smaller spinous bristles present below larger

bristles; infold in front of caudal process of single male

observed with only 4 large spinous bristles and 2 or 3

smaller bristles; both female and male with single

bristle below rostrum.

Size: Length of mature females of 4 species ranges

from 1.71 to 2.75 mm; height as percent of length

ranges from 80.2 to 94.1. Male slightly smaller and

much narrower than female; height as percent of

length 69.4.

First antenna: Second joint with 1 dorsal bristle, 3rd

joint with usual ventral and dorsal bristles; 4th joint

with 1 dorsal and 2 or 3 ventral bristles; sensory bristle

of 5th joint on both male and female normal for family; medial bristle of 6th joint of female minute and

missing on some specimens, same bristle longer on

male; bristles of joints 7 and 8 normal for family.

Second antenna: Protopodite without medial bristle;

expodite normal for family, with 2 bristles on 9th joint;

endopodite of female 2-jointed with 2 or 3 bristles on

1st joint and 1 (rarely 2) long bristle on 2nd joint;

endopodite of male (S. sandersi) 3-jointed with 3rd

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

joint recurved: 1st joint with 2 bristles, 2nd with 3,

4th with 2.

Mandible: Considerable sexual dimorphism usually

present in family; coxale endite with bifurcate tip

present in female, absent in male; ventral margin of

coxale on female fringed with hairs; basale of female

with 1 spine near middle of dorsal margin and 2 distally, ventral margin with total of 8 or 9 spines and

bristles; exopodite of both male and female prominent

and with bristle reaching one-fourth to one-third the

length of 1st endopodite joint; basale of male (S. sandersi) with 3 bristles on dorsal margin and 7 short

bristles and 1 extremely long bristle on ventral margin.

Endopodite of male: 1st joint with 1 long and 2 short

distoventral bristles; 2nd joint with 2 stout bristles near

middle of dorsal margin and 1 long and 1 medium

bristle on terminal end near ventral margin; 3rd joint

with short a-bristle, stout clawlike b-bristle, short clawlike c-bristle, and long d-bristle. Endopodite of female:

joints 1-3 with large claws normal for family; joint 1

with 2 medial spines at base of main claw and 1 distodorsal spine; joint 2 with 2 dorsal spines and 1 lateral

spine at base of main claw; joint 3 with 2 ventral spines

and 1 small spine medially near base of main claw.

Maxilla: Normal for family. Exopodite with 3

bristles.

Fifth limb: Endite with 1 bristle; 1st joint with 3

bristles; 2nd joint with 6 bristles; 3rd joint with 1

(rarely 2) bristle on outer lobe and 3 or 4 bristles on

inner lobe; 4th and 5th joints with 4-6 bristles.

Sixth limb: All species in the genus with at least 3

distinct endites; in 3 species, S. menziesi, S. variabilis,

and S. bisetula, 4 endites evident, but in S. sandersi the

4th endite not separated from end joint by indentation

in margin. First endite with 1-3 bristles; 2nd endite

with 2 or 3 bristles; 3rd endite with 3 or 4 bristles;

4th endite with 3-5 bristles; end joint with 2-4 (rarely

5) anterior bristles, 1 or 2 (rarely 3) middle bristles,

and 1-3 hirsute posterior bristles.

Seventh limb: Well developed in both male and female; proximal group with 4-10 bristles; distal group

with 6 bristles, 3 on each side; each bristle spinous

distally; terminus with opposing combs; each comb

with 9-12 teeth in female and 2 or 3 in male.

Furca: Each lamella with 7 or 8 claws; claw 3

shorter than claw 4; claw 1 continuous with lamella.

Eyes: Lateral eyes absent. Medial eye large. (Lateral

eyes are generally present in sarsiellids, most of which

have been reported from shallow water.)
NUMBER 8

Rod-shaped organ: 1 - or 2-jointed and with rounded

or pointed tip.

Brush-like bristles: Consisting of 7 or 8 minute

bristles above genitalia of female.

COMPARISONS.—Genera having only claw 1 continuous with the lamella are Sarsiella Norman, 1869,

and Parasarsiella Poulsen, 1965. The claws of these

two genera decrease gradually in length and strength

proximally on the lamella, whereas on Spinacopia the

3rd claw is shorter and weaker than the 4th. Genera

having species with weaker claws placed between

stronger claws are Chelicopia Kornicker, 1959, and

Muelleriella Poulsen, 1965. These genera differ from

Spinacopia in having more than one claw continuous

with the lamella. The remaining genus in the family,

Scottiella Poulson, 1965, has more than one claw continuous with the lamella and does not have weak claws

between stronger claws.

Of particular interest is the well-developed exopodite

of the mandible on Spinacopia. The only species having a similar exopodite, but with a shorter bristle is

Muelleriella zealandica Poulsen, 1965.

Key to Species of Spinacopia

1. Carapace longer than 2.50 mm; 4th joint of 1st antenna with 3 ventral bristles

S. menziesi, new species

Carapace shorter than 2.25 mm; 4th joint of 1st antenna with 2 (rarely 3) ventral bristles . . 2

2. Carapace with large punctae S. sandersi, new species

Carapace smooth 3

3. Endopodite of 2nd antenna of 9 with 2 bristles on 1st joint and ridge-like hirsute ventral

margin on posterodorsal bulge of carapace S. bisettda, new species

Endopodite of 2nd antenna of 9 w*

m

 3 bristles on first joint and without hirsute ridge on

carapace S. variabilis, new species

Spinacopia menziesi, new species

FIGURES 3, 4; PLATES \C, Za-c

HOLOTYPE.—USNM 122086, 9 with unextruded

eggs, carapace length 2.75 mm; carapace and some

appendages in alcohol, remaining appendages on slides.

TYPE-LOCALITY.—Antarctic Ocean, Lamont Geological Observatory No. 48, station V-14-24, 3500

meters, lat. 56°37'S, long. 34°48'W, Abyssal Hills,

eastern Scotia Sea southeast of South Georgia Island,

collected 7-8 March 1958 in small bottom trawl

(SBT).

ETYMOLOGY.—The species is named in honor of

Dr. Robert J. Menzies, who has collected many of the

ostracods described herein and has contributed greatly

to the knowledge of the abyssal fauna.

DESCRIPTION OF FEMALE.—Shape (Figures 3a, b;

Plates \c, 3a): Carapace oval in lateral view with

greatest height near middle; anterior produced in area

of rostrum and with shallow but distinct incisur; posterior with short caudal process below valve middle;

carapace globose in dorsal view with greatest width

posterior to middle; dorsoposterior part of shell inflated.

Ornamentation (Figures 3d, g, h) : Surface smooth

with abundant hairs, and scattered normal pores.

Infold (Figures 3c, e, f): Infold broad behind rostrum and in front of caudal process, narrower elsewhere; infold below incisur with single bristle near

inner margin; infold in front of caudal process with 5

spinous bristles forming row in middle near dorsal margin of process; 3 or 4 small spinous bristles present

below the 5 larger bristles; about 14 minute bristles

present along inner margin of infold in front of and

dorsal to caudal process.

Selvage: Wide lamellar prolongation with smooth

outer margin present along anterior, ventral, and posterior margins of both valves; prolongation continuous

across incisur (Figure 3/).

Muscle scars (Figure 3»): Central muscle scars consisting of about 16 oval scars (not visible through shell;

scars estimated by examining ends of muscles after

removing shell).

Pore canals (Figures 3d-f): Normal pore canals

scattered over valve surface. Radial pore canals numerous around anterior, ventral, and posterior margins.

Size: Holotype length 2.75 mm, height 2.29 mm

(measurements include caudal process) ; height as percent of length 83.3.

First antenna (Figures 3;-/) : Dorsal bristle of 2nd

joint fairly long and with long spines near middle and

short spines distally; lateral surface, ventral and dorsal

margins of 2nd joint with clusters of short spines;

ventral bristle of 3rd joint longer than spinous dorsal

bristle, and with a few faint spines near middle; 4th
10

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 3.—Spinacopia menziesi, $ holotype, carapace: a, left lateral view; b, dorsal view,

anterior to left. Caudal process left valve: c, medial view, d, lateral view. Caudal process right

valve: e, medial view. Anterior margin right valve: /, medial view. Surface hairs: g, on left

valve dorsal to central muscle scars. Hairs along rostral margin left valve: h, medial view.

Muscle scars right valve: i, lateral view. First antenna: ;', small bristle on 6th joint of left limb,

medial view; k, bases of bristles on joints 5-8 of right limb, medial view; I, right limb, lateral

view. Right 2nd antenna, medial view: m, joints 2—9 of exopodite (bristles shown only on

joints 2, 7, 9); n, endopodite and joints 1, 2 of exopodite. Right mandible: o, lateral view;

p, coxale endite, medial view; q, expodite, medial view; r, joints 1—3 of endopodite, medial view;

s, ventral bristles on basale, medial view. Right maxilla: t, lateral view (all bristles of endites

not shown); u—w, 3 endites; x, medial view of 2nd joint of endopodite (marginal spines not shown

on bristles). Same scale in microns: a, b; I, o; c-g, i, m, n, t-x; h, j , k, q-a.)
NUMBER 8 11

joint with 1 spinous dorsal bristle, ventral margin with

3 spinous bristles, 1 long, 1 medium, 1 short; sensory

bristle of 5th joint with 2 short filaments; 6th joint

with minute medial bristle on left limb, and without

bristle, but with minute projection on medial distal

margin of right limb where bristle is generally located;

7th joint with a-, b-, and c-bristles: a-bristle with spines

distally and reaching more than one-half length of

sensory bristle of 5th joint; b-bristle shorter than abristle and with 1 short filament near middle; c-bristle

about same length as sensory bristle and with 3 short

filaments; 4 bristles of 8th joint bare, similar in length,

slightly shorter than c-bristle.

Second antenna (Figures 3m, n; Plate 36): Protopodite bare and without distomedial bristle. Endopodite weakly 2-jointed: 1st joint with 3 short bare

bristles, 2nd joint with 1 long spinous terminal bristle.

Exopodite 9-jointed: distal margin of joint 1 with short

curved medial spine; bristle of joint 2 with few natatory hairs distally and without ventral spines; joint 9

with 1 short spinous bristle and 1 long bristle with sparse

natatory hairs; bristles of joints 3-8 without marginal

spines, and with sparse natatory hairs; distal margins of

joint 1-A or 2-5 with comb of short spines.

Mandible (Figures 3o~s) : Ventral margin of coxale

hirsute; coxale endite with bifurcate tip and several

spines near base. Basale: dorsal margin with 1 spine

near middle and 2 distally; ventral margin with total of

8 or 9 spines and bristles, 3 in proximal group and 5 or

6 in distal group: proximal group with 2 short medial

spines and 1 longer marginal bristle; distal group with

1 medial spine, 1 very long medial bristle and 3 or 4

shorter lateral bristles forming row; a U-shaped

gladular? opening present on lateral side between proximal and distal groups. Exopodite large with blunt tip

and ventral bristle about one-third length of 1st endopodite joint. Endopodite: 1st joint with short terminal spine on dorsal margin, 2 medial spines near

base of main ventral claw, and short spines in 2 rows

distally on medial surface; 2nd joint with 2 subterminal spines on dorsal margin and 1 lateral spine proximal to base of main ventral claw; 3rd joint with 1

dorsal and 2 ventral spines, and short spines in row at

base of main claw.

Maxilla (Figures 3t-x) : Coxale with anterior bristle

with faint marginal spines distally; basale with 1 bare

bristle near exopodite; exopodite with 2 short bare

bristles and 1 long bristle with marginal spines distally;

1st and 3rd endites each with 6 bristles, 2nd endite

with 5; 1st endopodite joint with spinous alpha- and

beta-bristles, and a few short spines distally on anterior

margin; 2nd endopodite joint with 2 spinous a-bristles

laterally, 1 bare c-bristle medially, and usually 5 pectinate terminal bristles; distal inner margin of posterior

terminal bristle with closely spaced teeth in row.

Fifth limb (Figure 4a): Epipodial appendage with

45 or 46 hirsute bristles; single endite with 1 bare

bristle. Exopodite: 1st joint with 3 spinous bristles,

2 long, 1 short; 2nd joint with 6 spinous bristles, 5

terminal and 1 proximal,, latter bristle shorter than

others; 3rd joint with 3 bristles on inner lobe and 1

on outer lobe; 4th and 5th joints with 4 spinous bristles;

surface of exopodite joints hirsute.

Sixth limb (Figures Ah, c) : Four endites present:

1st endite with 1 bristle, 2nd with 2 or 3, 3rd with

4, 4th with 3, all bristles spinous. End joint with 4

spinous anterior bristles, 2 spinous bristles near middle,

and 2 stout hirsute posterior bristles; clusters of hairs

present on medial surface of limb, and along margin of

end joint on each side of posterior bristles.

Left 7th limb (Figure Ad) : Proximal group with 8

bristles, 4 on each side; distal group with 6 bristles, 3

on each side; each bristle with 3-6 bells, and with

long marginal spines distally; terminus with opposing

combs, each with about 9 faint teeth.

Right 7th limb: Similar to left limb except for having 10 bristles in proximal group, 6 on one side, 4 on

other.

Furca (Figures Ae, f; Plate 3c): Each lamella with

8 claws: claw 1 continuous with lamella, remaining

claws separated from lamella by suture; claw 3 more

slender and shorter than claw 4, all claws slender and

with pointed tip; most claws with teeth in row along

posterior margin and short hairs along anterior margin ; clusters of spines present along anterior margin of

each lamella and at base of claw 1.

Eyes: Lateral eyes absent. Medial eye large elongate (Figure Ah).

Rod-shaped organ (Figure Ah): Elongate, single

jointed, with triangular process at tip.

Genitalia (Figure Ae) : Oval amber-colored spermatophore present on each side in vicinity of genital

opening.

Brush-like organ (Figures Ae, g) : Consisting of

about 7 minute ringed bristles posterior to and above

genitalia.

Posterior (Figure Ai) : Posterior margin of thorax

above furca with clusters of long hairs.
12

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 4.—Spinacopia mtnziesi, 9 holotype: a, 5th limb; b, c, 6th limbs; d, left 7th limb (all

proximal bristles not shown); e, furca, brush-like organ and spermatophore, viewed laterally from

right side; /, left furcal lamella, lateral view (marginal spines not shown); g, brush-like organ;

h, rod-shaped organ and medial eye in front of 1st joint of left 1st antenna; i, posterior; ;', anterior

of animal, showing position of coxale endite relative to upper lip; k, 2 eggs from marsupium.

(Same scale in microns: a-c, h-j; d, g; e, f, k.)
NUMBER 8 13

Upper lip (Figure 4;'): Simple curvature, surface

bare. Triangular process present on each side between

lip and 1st antenna.

Eggs (Figure 4k) : About 9 unextruded oval eggs

present in holotype.

Spinacopia variabilis, new species

FIGURES 5-9; PLATES Id, 3e, f

ETYMOLOGY.—The specific name is derived from

the Latin "variabilis" = changeable, in reference to

the variability of appendages among specimens in the

species.

HOLOTYPE.—USNM 122191, 9 with eggs in brood

chamber, carapace length 1.92 mm; carapace and

some appendage in alcohol, remaining appendages on

slides; sta. V-15-131, specimen no. 4.

PARATYPES.—USNM 122192, 9 from sta. V-18-

13; USNM 122193, 9, specimen no. 5 from sta.

V-15-131; USNM 122195, juvenile $, instar IV,

specimen no. 1 from sta. V-15-131; USNM 122196,

juvenile & , instar IV, specimen no. 204 from sta.

V-15-131; USNM 122194, 9 with eggs, specimen no.

8 from sta. V-15-131; USNM 122547, 9 with eggs,

specimen no. 3 from sta. V-15-131; USNM 122548,

9 , specimen no. 2, sta. V-15-131; USNM 122549, 9

specimen no. 6, sta. V-15-131; USNM 122550, 67

adult 9 9 and juvenile 9 9 and $ $ , sta. V-15-131;

USNM 122691, adult female carapace figured on Plate

Id, sta. V-15-131.

MATERIAL.—Adult females: 27 inflated, 13 noninflated; instar IV, 36; instar II, 1.

TYPE-LOCALITY.—Lamont Geological Observatory

Sta. V-15-131, South Atlantic along western slope of

Argentine Basin, lat. 40°14.6'S, long. 55°24.7'W, 1475

meters; collected in small bottom trawl on bottom 45

minutes, 3 April 1959.

OTHER LOCALITIES.—LGO Sta. V-18-13, South Atlantic on Falkland Rise north of Falkland Islands, lat

47°10'S, long. 61°02'W, 135 meters; collected in small

bottom trawl 17 February 1962.

DISTRIBUTION.—South Atlantic on Falkland Rise

north of Falkland Islands and along western margin of

the Argentine Basin between latitudes 40°14.6'S and

47°10'S, and longitudes 55°24.7/W and 61°02'W, at

depths of 135 to 1475 meters.

DISCUSSION OF VARIATION WITHIN THE SPECIES.—

This species includes specimens collected at station

V-15—131 on the western margin of the Argentine Basin at a depth of 1475 m, and 1 specimen from station

V-18-13 from the Falkland Rise at a depth of 135 m.

The latter specimen differs somewhat from those collected at greater depth in having a carapace with a

slightly greater height-to-length ratio and in having a

different distribution and number of claws on one

lamella of the caudal furca, but is tentatively considered herein to be conspecific with the deeper water

specimens.

The species contains many individual variants, and

it is difficult to be certain that the collection does not

contain more than one species. The presence of 2

bristles on the end joint of the endopodites on the second antennae of specimen number 4 from station

V-15-131 suggests that it might belong to a different

species than the many specimens with only 1 bristle;

however, 2 specimens in the collection with 1 bristle

on one end joint of the endopodite and 2 on the endopodite of the opposite limb seem to be intermediate

forms. Therefore, this presence of 2 bristles is considered to be due to individual variation within the

species. The 6th limb of specimen 4 also differs from

other specimens in having 5 bristles on the 4th endite

of one limb and 4 bristles on the other. Other specimens in the species have 3 bristles on this endite with

the exception of one specimen which has 3 bristles on

the endite of one limb and 4 on the other. The linkage

of this difference with differences on the 2nd antennae

noted above strengthens the possibility of specimen 4

being another species. However, the 2 specimens having "intermediate" endopodites on the 2nd antennae

have "normal" 6th limbs. Therefore, the 4th endite

of the 6th limb of specimen 4 is considered herein to

be an individual variant.

Specimens 3 and 6a, both from station V-15-131,

have 3 posterior bristles on the end joints of the 6th

limbs, whereas 5 specimens (and all specimens of the

other 3 species of the genus) have only 2. This also

suggests that 2 species are in the sample; however,

2 specimens have 3 posterior bristles on one limb and

2 on the other. Therefore, the presence of 3 posterior

bristles on the end joint of the 6th limb is considered

herein to be the result of individual variation.

Specimen 3 in addition to having 3 posterior bristles

on the end joint of the 6th limb also has 2 bristles on

the outer lobe of the 3rd joint on the 5th limb; other

specimens have only 1. This linkage strengthens the
14 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

possibility of specimen 3 being another species; however, specimen 6a, which also had 3 posterior bristles

on the end joint of the 6th limb, has the "normal"

number of bristles on the outer lobe of the 3rd joint

of the 5th limb. Therefore, the presence of 2 bristles

on the outer lobe of the 3rd joint is considered herein

to be an individual variant.

Considerable variability was also noted in the frontal

organ: some have a pointed tip, some a rounded tip,

and others have a rounded tip with small protuberances. Most are 1-jointed, but on one specimen the

frontal organ is 2-jointed. The frontal organ of specimen 4 is bifurcate. All these are considered here to

be individual variants.

The number of bristles in the proximal group on the

7th limb varies from 4 to 7, but as differences could

not be linked to differences on other appendages, this,

too, is considered herein to be, due to individual

variation.

The sample from station V-15-131 is from a trawl

which was dragged on the bottom for 45 minutes. It

is possible that specimens from many different habitats

and populations are included in the sample. Additional

collections from the area sampling smaller areas may

elucidate whether more than one species or population

is included in S. variabilis.

DESCRIPTION OF FEMALE (adult male unknown).—

Shape (Figures 5a-g; Plate Id), ornamentation, selvage, muscle scars, and pore canals: Similar to S.

menziesi.

Infold: Infold below incisur with single bristle near

inner margin as in S. menziesi; infold in front of

caudal process with 5 spinous bristles forming row in

middle near dorsal margin of process (Figures 5h-l);

4 to 8 small spinous bristles present below the 5 larger

bristles; numerous minute bristles present along inner

margin of infold in front of and dorsal to caudal

process. The distribution of spinous bristles forming

row on infold in front of caudal process of six adult

females is tabulated below:

Left valve Right valve

Station

(specimen no.)

V-18-13

V-15-131 (5)

(4)

" (6a)

(10)

(11)

Large

bristles

5

5

5

5

5

5

Small

bristles

5

4

4

6

5

8

Large

bristles

5

5

5

5

5

5

Small

bristles

5

4

5

7

4

5

Size: Length of adult females 1.76-1.92 mm, average 1.84 mm. Dimensions of twelve adult females are

tabulated below:

Station

(specimen no.)

V-18-13

V-15-131 (5)

(4)

(6a)

(6)

(3)

(2)

(8)

(9)

(10)

(11)

" (12)

Length mm

(includes caudal

process)

. 9 0

.81

. 9 2

. 8 5

.81

. 9 0

. 7 6

. 8 3

. 8 3

. 7 9

. 8 5

. 8 4

Height

TflTTl

.57

. 5 9

. 6 4

.74

. 6 2

.71

. 5 0

. 6 3

. 5 5

. 6 0

. 5 8

. 5 5

Height as

percent of

length

82.6

87.8

85.4

94. 1

89.5

90.0

85.2

89. 1

84.7

89.4

85.4

84.2

First antenna (Figures 5m-o): Bristles of joints

1-3 similar to S. menziesi; joint 4 with single dorsal

bristle and 2 ventral bristles, 1 long, 1 medium; sensory bristle of 5th joint with 2 short filaments; 6th

joint without bristle or with minute medial bristle;

7th joint with a-, b-, and c-bristles: a-bristle with

spines distally and one-half length of sensory bristle of

5th joint; b-bristle longer than a-bristle and with short

filament near middle; c-bristle about same length as

sensory bristle and with 3 short filaments near middle;

bristles of 8th joint shorter than sensory bristle of 5th

joint; d- and e-bristles bare, f- and g-bristles each

with 3 short filaments near middle.

Second antenna (Figures 5p~t; Plate 3e, f):

Exopodite similar to S. menziesi except comb of short

spines present on distal margins of joints 2-8. Endopodite distinctly 2-jointed: 1st joint with 2-4 (generally

3) short bristles; 2nd joint with 1 or 2 (usually 1)

long bristles. Distribution of bristles on endopodite

of fourteen adult females is tabulated below:

1st joint 2nd joint

Station

(specimen no.)

V-18-13

V-15-131 (5)

(4)

" (6a)

" (6)

(3)

(2)

" (8)

" (203)

(9)

" (10)

(11)

(12)

" (203)

Left

limb

3»

4

3

3

3

3

3

3

3

3

3

3

3

3

Right

limb

3

3

3

3

3

3

2

3

3

3

3

3

3

3

Left

limb

1

2

2

Right

limb

1

1

2

1

1

1

1

1

1

2

I

1

1

1

• 1 of the bristles bifurcate (see Figure 5r).
NUMBER 8 15

FIGURE 5.—Spinacopia variabilis, 9 adult carapace, station V-15-131, specimen 24, L=1.81

mm: a, lateral view; b, dorsal view; c, posterior view. Specimen 27, L=1.85 mm: d, lateral

view; e, dorsal view; /, posterior view. Specimen from station V-18-13, L—1.90: g, lateral

view showing eggs; k, caudal process left valve, medial view; i, caudal process right valve, medial

view. Caudal process left valve: ;, specimen 4, station V-15-131, medial view; k, specimen 11,

station V-15-131, medial view. Caudal process right valve, specimen 4: /, medial view. First

antenna, specimen from station V-18-13: m, right limb showing rod-shaped organ, medial view;

n, distal posterior corner of 4th joint; o, end joints. Second antenna: p, endopodite and 1st

joint of exopodite of left limb, specimen 5, station V-15-131, medial view; q, endopodite of

right limb, specimen 5, medial view; r, endopodite of left limb, specimen from station V-18-13,

medial view; s, endopodite and 1st joint of exopodite of left limb, specimen 4, medial view;

t, endopodite of right limb, specimen from station V-18-13, medial view. (Same scale in

microns: a-g; j-l, p, q, s, t; h, i; n, o, r.)

331-394 O-69—2
16

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

10

FIGURE 6.—Spinacopia variabilis, $ adult, mandible: a, basale and exopodite of right limb,

specimen from station V—18—13, lateral view; b, 1st endopodite joint and exopodite, same limb;

c, end joint of endopodite, left limb, specimen 4, station V-15-131, medial view. Sixth limb:

d, limb from specimen 3, station V-15-131; e, limb of specimen from station V-18-13; /, limb

from specimen 4, station V-15-131. Furca: g, limbs, specimen from station V-18-13; h, limb

from specimen 4 showing hairs of posterior (spines of furcal claws not shown). Rod-shaped

organ: i, limb from specimen 3, station V—15—131; j , limb from specimen 6, same station; k, tip

of limb from station V-18-13; /, limb from specimen 4; m, limb from specimen 8, station,

V-15—131. Posterior region: n, brush-like organ, spermatophore, Y-shaped sclerite of furca.

Embryo: o, specimen from station V-18-13. (Same scale in microns: h, o; b, d—g, n; a, c, i, j ,

I, m; Jfc.)
NUMBER 8 17

Mandible (Figures 6a-c): Similar to S. menziesi

with following exceptions: 3 short bristles form row on

lateral surface near ventral margin of basale on both

limbs; bristle of exopodite only about one-fourth length

of ventral margin of 1st endopodite joint.

Maxilla: Similar toS. menziesi.

Fifth limb: Epipodial appendage with 40-42 hirsute bristles; single endite with bristle. Expodite: 1st

joint with 3 bristles; 2nd joint with 6 bristles; 3rd

joint with bristles on inner lobe and 1 or 2 bristles on

outer lobe; 4th and 5th joints with 4 or 5 bristles; surface of exopodite joints hirsute. The distribution of

bristles on limbs of ten adult females is tabulated below:

Exopodite

M l

(specimen no.)

V-18-13

V-15-131

<<

u

«

«

«

M

«

((

(4)

(3)

(6a)

(203)

(2)

(5)

(8)

(9)

(6)

Endite

1

1

1

1

1

frag.

1

1

1

1

1

1

1

frag.

1

1

1

1

1st joint

3

3

3

3

3

3

3

3

3

3

4

3

3

3

4

3

3

3

2nd joint

6

6

6

6

6

6

6

6

6

6

6

5

6

6

5

6

6

6

Inner lobe

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3

3rd joint

Outer lobe

1

1

0

1

2

2

1

1

1

1

1

1

1

1

1

1

1

1

4th + 5th joints

4

5

4

4

4

4

5

5

4

4

5

4

4

4

4

4

4

4

Epipodite

frag.

frag.

40

42

frag.

42

42

42

frag.

42

frag.

frag.

frag.

frag.

frag.

frag.

frag.

frae.

Sixth limb (Figures 6d-f): 4 endites present, but

on some specimens 3rd endite only slightly separated

from end joint: 1st endite with 3 bristles, 2 short and

1 medium; 2nd endite with 2 long terminal bristles;

3rd endite with 4 bristles; 4th endite with 3-5 bristles.

End joint with 3 or 4 anterior bristles, 1 or 2 bristles

near middle, and 2 or 3 hirsute posterior bristles;

medial surface of limb with clusters of hairs. The

distribution of bristles on limbs of ten adult females

is tabulated below:

ototUrn

(specimen no.)

V-18-13

V-15-131

M

"

i t

i t

"

i (

(4)

(6)

(3)

(6a)

(203)

(2)

(5)

(8)

(9)

Short

2

2

1

2

2

3

2

2

2

2

2

3

2

2

2

2

2

2

2

2

Endite 1

Medium

1

1

1

1

2

1

1

1

1

1

1

1

1

1

1

1

1

0

1

1

Endite II

2

2

2

2

2

3

2

2

2

2

2

2

2

2

2

frag.

2

3

2

2

£w/ite // /

4

4

4

4

4

4

4

4

3

4

4

4

4

4

frag.

4

3

4

4

EiK/ifc IV

3

3

5

4

3

3

3

3

3

3

3

3

3

3

3

3

3

4

3

3

Anterior

3

4

4

4

4

4

4

4

4

3

4

5

5

4

4

4

4

4

4

3

End joint

Middle

2

2

2

2

frag.

2

1

(>

2

2

2

1

1

I

Posterior

2

2

2

2

3

2

3

3

3

3

2

2

2

2

2

frag.

3

2

2

2
18

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

Seventh limb: Proximal group with 4-7 bristles

(usually 4-6); distal group with 6 bristles, 3 on each

side; each bristle with 2-6 bells, and with long marginal spines distally; terminus with opposing combs,

each with 9-12 teeth. Numbers of bristles in proximal

group on left and right limbs of seven adult females

are tabulated below:

Station

(specimen no.)

V-18-13

V-15-131 (5)

(4)

(6a)

(6)

(3)

(2)

Left limb

frag.

6

4

4

6

5

7

Right limb

5

6

5

4

6

5

5

Furca (Figures 6g, h) : Each lamella with 7-9 claws

(usually 8) : claw 1 continuous with lamella, remaining claws separated by suture; claw 3 more slender

and shorter than claw 4, remaining claws decreasing

gradually in length proximally on lamella (an exception is left lamella of specimen from station V-18-13

on which both claws 3 and 5 are smaller than claw 4,

apparently an aberrant form (Figure 6g)); spines and

hairs as in S. menziesi, but with some variation between

specimens. The number of claws on each lamella of

eight adult females is tabulated below:

Station

(specimen no.)

V-18-13

V-15-131 (5)

" (4)

(6a)

" (6)

" (3)

(2)

(203)

Left lamella

9»

7

8

8

8

8

8

8

Right lamella

7

8

8

8

7

8

7

8

* Claw 3 smaller than claw 4, claw 5 smaller than claw 6.

Eyes: Lateral eyes absent. Medial eye similar to

S. menziesi.

Rod-shaped organ: Generally 1-jointed with

pointed tip adjacent to rounded flap (Figure 6k);

sclerotized pit present at end of tip. Variations observed included a 2-jointed organ (Figure 6i), one

with 2 branches (Figure 6/), and some with rounded

tip, or with rounded tip and protuberances (Figures

Sj,m). The number of joints and shape of tip of eight

adult females are given in tabular form below:

Station

(specimen no.)

V-18-13

V-15-131 (5)

" (4)

(6a)

" (6)

(3)

(12)

(8)

Number of joints

1

1

bifurcate with

both branches

1-jointed

1

1

2

1

1

Shape of tip

pointed

pointed

pointed

with

protuberance

with

protuberance

rounded with

protuberances

pointed

pointed with

protuberances

Genitalia (Figure 6n) : Oval amber-colored spermatophore present on each side over genital pore.

Brush-like organ (Figure 6n) : Consisting of about

8 minute ringed bristles posterior to and above

genitalia.

Posterior: Clusters of long hairs present on posterior margin of thorax above furca.

Upper lip: Similar to S. menziesi.

Eggs (Figure 6o) : Gravid females contain 2-6 eggs

in the marsupium. Some specimens with eggs in the

marsupium also have as many as 7 eggs in the ovaries.

The number of eggs in the marsupium and ovaries of

twelve adult females is tabulated below (eggs in ovaries obscure in some specimens):

Station

(specimen no.)

V-18-13

V-15-131 (5)

" (4)

' (6a)

' (6)

(3)

(2)

(8)

' (9)

(10)

(11)

' (12)

In brood chamber

6

3

3

0

3

2

0

4

3

4

4

0

In ovaries

7

4

0

0

0?

7

1?

0

5

0

5

0

Food (Plate 2e) : Gut of specimen 4 from station

V-15-131 contained remains of 3 harpacticoid copepods, 1 nematode, and 3 pellets. Two of the pellets are

oval and dark brown and are probably fecal pellets,

1 is rectangular and yellowish. Their position in the

gut suggests that they were ingested. The gut of specimen 28, an adult female from station V-15-131, contained a polycopid ostracod and copepod fragments.
NUMBER 8 19

The polycopid carapace was closed and contained undisturbed appendages which appeared cleaned of

protoplasm.

DISCUSSION OF DIMORPHISM IN SHELLS OF ADULT

FEMALES.—Thirteen of the adult females in the collection are not inflated in the posterodorsal region, but

instead are evenly rounded as in juveniles (Figures

5a-c). The dimensions of three carapaces are as

follows:

Station

(specimen no.)

V-15-131 (15)

(16)

(24)

Length mm

(includes caudal

process)

1.86

1.75

1.81

Height

mm

1.60

1.55

1.50

Height as

percent of

length

86.0

88.6

82.9

The appendages of the 3 specimens are similar to

specimens with inflated posterodorsal regions (Figures

5d-f) with the exception that specimens 15 and 16

have 3 ventral bristles on the 4th joint of the 1st antenna; this number was present only rarely on inflated

forms. All inflated forms examined have attached spermatophores, whereas only specimen 24 of the noninflated forms has them. The above 3 specimens do not

contain eggs in either the ovaries or carapace. All specimens contained harpacticoid copepods in their gut,

and in addition specimen 24 had 1 free living nematode, showing that the diet of the inflated and noninflated forms are similar.

The reason for the observed dimorphism is not clear.

The similarity in lengths and heights of both types

make it unlikely that the noninflated forms are juveniles, although it is a possibility; for example, when

preadult males of some sarsiellids molt to form adults,

the resulting carapace has a different shape than the

preadult, but has about the same length and height.

Another possibility is that the preadult female molted

to form adults not having all characters of mature

females. The absence of eggs in the few specimens examined supports either hypothesis.

DESCRIPTION OF INSTAR n (sex undetermined)

(Figure 7).—Shell (Figure la) : Shell similar in lateral

outline to adult female but without inflated posterodorsal region; infold below shallow sinus with single

bristle; infold in front of caudal process with 2 long

spinous bristles and 1 shorter bristle. Dimensions of

single specimen (no. 20) in collection is as follows:

length 1.11 mm, height 0.94 mm, height as percent of

length 84.6.

First antenna: Similar to adult female except for

having on 2nd and 4th joints only 1 dorsal bristle and

no ventral bristles.

Second antenna (Figure 76): Protopodite and exopodite similar to adult; endopodite 2-join ted; 1st joint

with short bristle; 2nd joint with long distal bristle.

Mandible, maxilla, 5th limb: AH well developed

and similar in general morphology to adult female.

Sixth limb (Figure 7 c): Outer margin divided into

2 hirsute lobes; 1 long bristle present anterior to

middle.

Seventh limb (Figure 7/): Short, bare.

Furca (Figure 7d): Each lamella with 4 claws decreasing in length posteriorly; claw 1 continuous with

lamella; spines present posterior to claw 4.

Rod-shaped organ (Figure 7e): Elongate, with restriction about one-third distance from terminal end.

FIGURE 7.—Spinacopia variabilis, instar II, specimen 20, station V-15-131; a, carapace, lateral view, L=l.ll; b, endopodite right 2nd antenna, medial view; c, 6th limb; d, right

furcal lamella, lateral view; e, rod-shaped organ; /, 7th limb.

(Same scale in microns: a; b—f.)

DESCRIPTION OF FEMALE INSTAR rv (Figure 8).—

Shell (Figure 8a): Shape of carapace similar to adult

female but not globose in posterodorsal region. Infold

below shallow sinus with single bristle; infold in front

of caudal process with 3 or 4 large and 3 small spinous

bristles forming row near middle and additional bare

bristles along inner margin. Dimensions of specimen

23, station V-15-131, are as follows: length 1.59 mm,

height 1.29 mm, height as percent of length 81.1.

First antenna, mandible, maxilla, 5th and 6th limbs:

Well developed, similar in general morphology to adult

female.

Second antenna: Protopodite and exopodite similar

to adult female; endopodite 2-jointed (Figure 86) : 1st

joint with 2 or 3 short bristles; 2nd joint with 2 bristles,

1 long and 1 medium.

Seventh limb: Proximal group with 5 bristles; distal

group with 4 bristles; bristles tapering distally, each
20 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

with 2-5 bells; terminus with opposing combs, each

having about 10 teeth.

Furca: Each lamella with 7 claws; claw 1 continuous

with lamella; claw 3 shorter than claw 4, clusters of

hairs medially at base of claw 1.

Rod-shaped organ: Elongate, single jointed with

rounded tip.

Genitalia: Undeveloped.

FIGURE 8.—Spinacopia variabilis, 9 ins tar IV, specimen 23,

station V—15—131: a, carapace, lateral view, L—1.59 mm;

b, endopodite, 2nd antenna.

DESCRIPTION OF MALE INSTAR rv (Figure 9).—Shell

(Figures 9a, b): Shape of carapace in lateral view similar to adult female but not globose in posterodorsal

region. Infold below shallow sinus with single bristle;

infold in front of caudal process with 4 or 5 large

spinous bristles and several smaller spinous bristles

forming row near middle of infold and about 12 bare

slender bristles along inner margin. Distribution of

spinous bristles is listed below:

Left valve Right valve

Station

(specimen no.)

V-15-131 (1)

" (2)

" (21)

(204)

(22)

Large

bristles

4

4

4

4

4

Short

bristles

5

4

3

5

3

Large Short

bristles bristles

5 4

Dimensions of measured specimens are listed as follows:

Station

(specimen no.)

V-15-131 (1)

" (2)

(21)

" (204)

(22)

Length mm

(includes

caudal process)

1.72

1.65

1.56

1.48

1.58

Height

mm

.56

.28

.32

.24

.27

Height

as percent

of length

90.7

75.6

84.6

83.8

80.4

First antenna, mandible, maxilla, 5th and 6th limbs,

rod-shaped organ, posterior: Well developed, similar

in general morphology to adult female.

Second antenna: Protopodite and exopodite similar

to adult female. Endopodite quite variable, 2- or 3-

jointed (Figures 9c-e); number of joints and bristles

per joint are listed below for specimens studied:

Station

(specimen no.)

V-15-131(1)

" (2)

" (21)

1st joint 2nd joint 3rd joint

left right left right left right

3 2 2P», IT* 2P, IT no third joint

3 3 3P 3P 2T 2T

3 3 2P, IT IP, IT no third joint

(204) 3 3 3P

" (22) 3

* Proximal bristles.

b

 Terminal bristles.

3 3P

3P

3P

2T 2T

IT 2T

Seventh limb (Figures 9/, g) : Proximal group with

3-5 bristles, distal group with 4-6, each with 2-5 bells

distally; terminus with opposing combs with few to

many teeth. The number of bristles on proximal and

distal groups of specimens studied is as follows:

Proximal

group

Distal

group

(specimen no.) Left Right Left Right Remarks

V-15-131 (1) 4 5 6 5 (not tapered)

(2) 4 4 4 4 (tapered)

(21) 6 5 4 4

(204) 5 4 4 4

(22) 4 4 4 4

Furca: Each lamella with 7 or 8 claws; claw 1 continuous with lamella; claw 3 shorter than claw 4. The

number of claws on each lamella of specimens studied

is listed below:

Station

(specimen no.)

V-15-131 (1)

(2)

" (21)

(204)

(22)

Copulatory organ: Very weakly developed (Figure 9»).

Brush-like organ (Figure 9h): Consisting of about

6 annulated bristles above copulatory organ (observed

only on specimen no. 1).

DISCUSSION OF SPECIMEN NUMBER I.—Although

this specimen has been included in the description of

instar IV, it differs from other specimens in this group

in many respects. In carapace size, number of furcal

claws, and absence of tapering bristles on the 7th limb,

the speciment resembles an adult. In shape of caraLeft lamella

8

7

7

7

7

Right lamella

8

7

7

7

7
NUMBER 8 21

50

FIGURE 9.—Spinacopia variabilis, $ instar IV, station V-15-131, carapace: a, lateral view,

specimen 1, L=1.72 mm; b, lateral view, specimen 204, L=1.48 mm. Endopodite 2nd antenna:

c, left limb, specimen 204; d, right limb, specimen 21; e, limb from specimen 1. Seventh limb:

/, limb from specimen 1; g, limb from specimen 204. Posterior region: h, brush-shaped organ;

i, copulatory organ. (Same scale in microns: a-b;i; c-h.)

pace, development of the 1st antenna, mandible, endopodite of the 2nd antenna, and copulatory organ, the

specimen resembles instar IV.

COMPARISONS.—The adult 9 of Spinacopia variabilis is much smaller than S. menziesi; the former 1.76—

1.92 mm long compared to 2.75 mm for the latter.

Another difference is that the 4th joint of the female

1st antenna of S. menziesi has 3 ventral bristles, whereas the 4th joint of S. variabilis rarely has more than 2.

Each 7th limb of S. variabilis has 4-7 bristles in the

proximal group compared to 8-10 for S. menziesi. The

epipodial appendage of the 5th limb of S. variabilis has

40-42 hirsute bristles compared to 45 or 46 for S.

menziesi.

Spinacopia bisetula, new species

FIGURE 10; PLATES 3d, 6

HOLOTYPE.—USNM 122545, 9 with eggs in brood

chamber, carapace length 2.03 mm; carapace and

some appendages in alcohol, remaining appendages

on slides; station V-16-15.

TYPE-LOCALITY.—Lamont Geological Observatory

Station V-16-15, lat. 45°00'S, long. 45°46'E, 1622
22 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

meters, southern Indian Ocean, Madagascar Rise; collected in small bottom trawl on bottom 20 minutes, 8

January 1960.

ETYMOLOGY.—The specific name is derived from

the Latin "bi" = two and "setula" = diminutive of seta,

in reference to the 2 small bristles on the 1st joint of

the endopodite of the 2nd antenna.

DESCRIPTION OF FEMALE.—Shape (Figure 10a;

Plates 3d, 6), ornamentation, muscle scars, selvage and

pore canals: Similar to S. menziesi except for posterodorsal bulge having ridgelike ventral margin outlined

by long hairs forming horizontal row.

Infold: Infold below incisur with single bristle near

inner margin; infold in front of caudal process with 5

spinous bristles forming row in middle near dorsal

margin of process (Figures 106, c); 3 or 4 smaller

bristles present below 5 larger bristles; minute bristles

present along inner margin of infold in front and

dorsal to caudal process.

Size: Holotype length 2.03 mm, height 1.81 mm;

height as percent of length 89.2.

First antenna: Similar to 1st antenna of S. menziesi

except both limbs have a short medial bristle on 6th

joint and only 2 ventral bristles on 4th joint.

Second antenna: Exopodite similar to S. menziesi

except combs of short spines present on joints 2-8.

Endopodite 2-join ted with 2 short bristles on 1st joint

and 1 long spinous bristle on 2nd joint.

Mandible (Figures \0d, e): Similar to S. menziesi

with the following exceptions: 3 short bristles form a

row on lateral surface near ventral margin of basale

on both limbs; bristle of exopodite reaches less than

one-fourth length of ventral margin of 1st endopodite joint.

Maxilla: Similar to S. menziesi.

Fifth limb (Figures 10/, g): Epipodial appendage

with 41 hirsute bristles; single endite with 1 or 2

bristles. Exopodite: 1st joint with 3 bristles; 2nd joint

FIGURE 10.—Spinacopia bisetula, $ holotype: a, carapace, right lateral view, L=2.03 mm; b,

caudal process right valve, medial view; c, caudal process left valve, medial view; d, right mandible, exopodite and 1st joint of endopodite, medial view; e, left mandible, end joint of endopodite,

lateral view; /, g, 5th limbs; h, rod-shaped organ; i, brush-shaped organ and spermatophore.

(Same scale in microns: b-d, f, g; e, h, i.)
NUMBER 8 23

with 6 bristles; 3rd joint with 4 bristles on inner lobe

and 1 on outer lobe; 4th + 5th joints with 4 or 5

bristles; surface of exopodite joint hirsute.

Sixth limb: Four endites present: 1st endite with

3 bristles, 2 short and 1 medium; 2nd endite with 2

long terminal bristles; 3rd endite with 3 or 4 bristles;

4th endite with 4 bristles. End joint with 3 or 4 anterior bristles; clusters of hairs present on medial surface

and in vicinity of posterior bristles of end joint.

Seventh limb: Proximal group with 4 bristles, 2

on each side; distal group with 6 bristles, 3 on each

side; each bristle with 3-6 bells, and with long spines

distally; terminus with opposing combs, each with

about 10 teeth.

Furca, eyes, rod-shaped organ (Figure 10h), brushlike bristles (Figure lOt), posterior, upper lip: Similar

to S. menziesi.

Genitalia: Oval amber-colored spermatophore present on each side in vicinity of genital pore (Figure lOi).

Eggs: 5 round eggs present in brood pouch, about 4

in ovaries.

Food: Gut contained copepod fragments.

COMPARISONS.—Spinacopia bisetula is smaller than

S. menziesi and larger than S. variabilis. The 1st joint

of the endopodite of the 2nd antenna of S. bisetula

has only 2 bristles compared to 3 on S. menziesi and S.

variabilis. The endite of the 5th limb of the latter two

species has only 1 bristle, whereas, one of the limbs of

the holotype of S. bisetula has 2 bristles, but whether

this character is consistent is not known. The inner

lobe of the 3rd joint of the exopodite of the 5th limb

of S. bisetula has 4 bristles compared to 3 on S. menziesi and S. variabilis. The shell of the species is characterized by having long hairs in a horizontal row along

the ventral margin of the inflated posterodorsal region.

Spinacopia sandersi, new species

FIGURES 2, 11, 13-20; PLATES la-b, 2a-c, 4, 5

HOLOTYPE.—USNM 122551, 9 with eggs in brood

chamber, carapace length 1. 77; carapace and some

appendages in alcohol, remaining appendages on

slides; station 118A, specimen no. 1. Allotype: USNM

122558, adult <$ specimen no. 3, carapace length

1.59 mm.

PARATYPES.—USNM 122557, $ specimen no. 2;

USNM 122559, 12 adult $ 9 ; USNM 122560, 9

specimen no. 6, figured on Plate lb; USNM 122561,

4 adult & $ ; USNM 122562, 5 specimens instar I, 12

specimens instar II and 12 of instar III; USNM

122563, 18 9 9 and 19 $ $ instar IV; USNM

122564, 260 whole specimens. USNM 122692, adult

$ no. 45, figured on Plate la.

MATERIAL.—Adult females with eggs, 75; adult females without eggs, 48; instar IV, 112; instar III, 39;

instar II, 26; instar I, 21; adult males, 32.

TYPE-LOCALITY.—Station 118A, RV Atlantis II,

cruise 24, near Bermuda, lat. 32°19.4'N, long. 64°34.9'

W to lat. 32°19.0'N, long. 64°38.8'W; dredge sample,

18 August 1966, depth 1135-1153 m. Collected by H.

Sanders and R. Hessler. All specimens from same epibenthic trawl.

Etymology.—The species is named in honor of Dr.

Howard Sanders, Woods Hole Oceanographic Laboratory, under whose direction the sample containing

the species was collected.

DESCRIPTION OF ADULT FEMALE (Figures 2l-n, 11;

Plates \b, 4a).—Shape (Figure lla ; Plates lb, 4a):

Similar to S. menziesi.

Ornamentation (Figures lid, e; Plate lb): Surface

with shallow punctations and scattered normal pores;

punctae with inwardly pointing spines in vicinity of

periphery; surface with scattered spines and hairs, the

latter especially abundant around margins.

Infold: Infold below incisur with single bristle near

inner margin as in S. menziesi; infold in front of caudal

process with 5 (rarely 4 or 6) spinous bristles forming

row in middle near dorsal margin of process; (Figures

ll/-t) ; 3 (rarely 2) small spinous bristles present below

the larger bristle; minute bristles present along inner

margin of infold in front of and dorsal to caudal

process. The distribution of large and small spinous

bristles forming row on infold of caudal process of

seven adult females is tabulated below:

Left valve Right valve

Specimen

number

1

2

4

6

7

8

21

Large

bristles

6

5

5

5

5

5

5

Small

bristles

3

2

3

2

3

3

3

Large

bristles

5

5

5

3

4

5

4

Small

bristles

3

3

3

3

2

3

2

Selvage: Similar to S. menziesi.

Muscle scars (Figures lib, c) : Central muscle scars

consisting of about 14 individual scars.

Pore canals: Normal pore canals scattered over

valve surface (Figure 1 Id). Radial pore canals numerous around anterior, ventral, and posterior margins.
24 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

Size: Dimensions of holotype: length 1.77 mm,

height 1.42 mm, height as percent of length 80.2. Average dimensions of 7 specimens: length 1.77 mm,

height 1.45 mm, height as percent of length 82.0. Dimensions of measured specimens are as follows:

Specimen

number

1

2

4

6

7

8

21

First antenna (Figures 11;*, k), mandible, maxilla:

Similar to S. bisetula.

Second antenna (Figures ll/-n): Exopodite similar to S. bisetula. Endopodite weakly 2-jointed: 1st

joint with 2 (rarely 1) bristles, 2nd joint with 1 long

bristle. The distribution of bristles on the endopodites

of six adult females is tabulated below:

Bristles on 1st joint

Len

[inclut

Pr

:

gth mm

ies caudal

ocess)

.77

.74

.71

.79

1.79

1.80

1.79

h'eight

mm

.42

.41

.45

.46

.48

.45

.49

Height as

percent of

length

80.2

81.0

84.8

81.6

82.7

80.6

83.2

Specimen number

1

2

4

6

7

8

Left limb

1

2

2

2

1

2

Right limb

1

2

2

2

2

2

Mandible, maxilla Figure 1 lo: Similar to S. bisetula.

Fifth limb (Figures Up, q): Endite with 1 bristle.

Exopodite: 1st joint with 3 bristles; 2nd joint with 6

(rarely 5) bristles; 3nd joint with 3 (rarely 4) bristles

on the inner lobe and 1 on outer lobe; 4th + 5th

joints with total of 6 (rarely 3, 4, 5) bristles. Epipodite

with 38-42 bristles. The distribution of bristles on six

adult females is tabulated below:

Exopodite

Endite 1st joint 2nd joint inner lobe

bagSpecimen

number

1

2

4

6

7

8

Sixth limb (Figures llr, s): Endites not sharply defined from each other or from end joint except by

spaces between them; 1st endite with 3 (rarely 4)

bristles; 2nd endite with 2 or 3 bristles; 3nd endite

with 3 or 4 bristles; 4th endite with 3 (rarely 2, 4)

3rd joint

3

3

3

3

3

3

3

3

3

2?

3

3

6

6

6

6

6

6

6

5

6

6

6

6

3

3

3

4

3

3

3

3

3

3

3

3

er lobe 4th + 5th joints

1 5

1 6

1 6

1 3?

1 6

1 6

1 6

1 6

1 6

1 5

1 6

1 4

Epipodite

frag41

frag.

38

39

38

frag.

42

frag.

frag.

frag.

frag.

bristles; end joint with 2-4 (rarely 5) anterior bristles,

1 or 3 (rarely 3) middle bristles, and 2 posterior

bristles; surface and margin in vicinity of posterior

bristles of end joint hirsute. The distribution of bristles

on six adult females is tabulated below:

End joint

Specimen

number

1

2

4

6

7

8

Endite I

3

3

3

3

3

3

3

4

4

3

3

3

Endite II

2

2

2

2

3

2

2

1

3

3

2

2

Endite III

4

3

4

3

4

4

4

2

4

4

3

4

Endite IV

4

3

3

3

2

3

3

3

3

3

3

4

Anterior

2

3

4

4

5

4

4

3

4

2

2

2

Middle

2

1

2

2

2

2

2

3

2

2

2

1

Posterior

2

2

2

2

1

2

2

2

2

2

2

2
NUMBER 8 25

Seventh limb (Figures lit, u) : Proximal group

with 4 (rarely 3) bristles; distal group with 6 bristles,

3 on each side; each bristle with 1-4 bells and marginal spines distally; terminus with opposing combs,

each with about 10 teeth. Number of bristles in proximal group on left and right limbs of six adult females

is tabulated below:

Number of bristles in

Specimen number proximal group

1 4

3

2 4

4

4 4

4

6 4

7 4

4

8 4

3

Furca: Each lamella with 7 or 8 claws; 3rd claw

smaller than 4th; only claw 1 continuous with lamella.

(A single specimen has 7 claws on 1 lamella and 9 on

the other; on the latter, the 5th as well as the 3rd claw

is smaller than the following claw.) The distribution

of claws on seven specimens is as follows:

Specimen number

1

2

4

6

7

8

21

Left lamella

7

8

8

8

8

8

7

Right lamella

8

7

8

7

8

8

7

Rod-shaped organ (Figures lly, w): Elongate,

1-jointed (rarely weakly 2-jointed), tip acuminate or

rounded. The number of joints and shape of tip of six

adult females are tabulated below:

Specimen number

1

2

4

6

7

8

Number of joints

1

1

1

1

faintly 2-jointed

2

Shape of tip

pointed

rounded

pointed

rounded

pointed

pointed

Eyes, brush-like organ, posterior, upper lip: Similar

to S. menziesi.

Genitalia (Figures 2l-n) : Not observed on whole

mount. In section, genital opening observed to be covered laterally by thin flap; opening in spermatophore

facing outward abutting against genital opening; tubular oviduct passing upward into body.

Discussion of reproduction: Only distal portion of

oviduct could be clearly observed in sections studied.

Sperm present in duct only in vicinity of genital opening suggesting that eggs are fertilized as they leave

oviduct. Eggs are present both in the ovaries and marsupium of some adult females having attached spermatophores. It seems probable that part of the genital

opening is sufficiently free from the spermatophore to

permit passage of eggs.

Eggs: Gravid females contain 2-4 eggs in the marsupium; some specimens also contain 3 or 4 eggs in

the ovaries. Generally, when 4 eggs were observed in

the brood chamber 2 were in the right valve and 2

in the left. The distribution of eggs in thirteen adult females is tabulated below:

Specimen number

1

2

4

6

7

8

21

29

66

67

68

69

71

In brood chamber

3

4

4

3

0

2

3

3

4

3

4

3

3

In ovaries

0

0

4

3

4

0

0

0

3

1

3

?

3

COMPARISONS.—The adult 9 of S. sandersi differs

from previously described species in having large, but

shallow, punctations. The endopodite of the 2nd antenna on the 9 differs from that of S. menziesi and

S. variabilis in having only 2 bristles on the 1st joint.

The 5th limb of S. sandersi differs from that of described species in having a total of 6 bristles on the

4th + 5th joints of at least 1 limb; all other species

have a maximum of 5 bristles. The carapace of S.

sandersi is much smaller than those of S. menziesi and

S. bisetosa, and slightly smaller than that of S. variabilis (see Figure 12).

DESCRIPTION OF ADULT MALE (Figures 2a-k, 13;

Plates la, 4e-f, 5).—Shape (Figure 13a; Plate la) :

More elongate than female and with prominent

rostum and caudal process; carapace highest posterior

to middle.
26

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 11.—Spinacopia sandersi, $ adult: a, carapace, right lateral view showing some eggs

and punctae, L=1.77 mm, Central muscle scars, lateral view: b, left valve; c, right valve.

Punctae and hairs on left valve: d, posterodorsal area; e, ventral margin. Caudal process,

medial view: /, g, left valve; h, i, right valve. Left 1st antenna, medial view: ;, joints 3—5; k,

joints 6, 7 (not all bristles shown). Left 2nd antenna, medial view: /, protopodite, endopodite,

exopodite joints 1 and 2; m, sclerotized region in vicinity of endopodite; n, endopodite and

joints 1 and 2 of exopodite, medial view. Left maxilla, endites I—III: o, medial view. Limbs:

p, q, 5th (spines on bristles not shown); r, s, 6th. Terminal combs of 7th limbs: t, right, u,

left. Head region: v, w, rod-shaped organs. (Same scale in microns: b, c, e—j, I, n, p—s; d, m,

o, v, w; k, t, u. Figures a, g, h, j—m, o—u from specimen 1; c—e from specimen 6; b, f, i, n, w

from specimen 2; v from specimen 8.)
NUMBER 8 27

-

-

-

_

1

0

o

°k

i i i

• S biatuli

nhtf*

1 1 1

lirmumi +

1 1 1 1

2.4

2.3

2.2

2.1

1 2.0

X

3 1.8

la

1.6

1.5

1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

CARAPACE LENGTH (mm)

FIGURE 12.—Comparison of relationship between shell length

and height of gravid females of Spinacopa menziesi, S. bisetula, S. variabilis, and S. sandersi.

Ornamentation, selvage, pore canals: Similar to

female.

Infold: Infold below rostrum with single bristle

(Figure 13^); infold in front of caudal process with

4 or 5 spinous bristles near posterior margin and 2 or

3 smaller spinous bristles ventral to them (Figures

136, c); minute bristle present along inner margin

of infold anterior to caudal process.

Muscle scars: Central muscle scars consisting of

about 18 individual scars (Figure 13d).

Size: Length of allotype 1.70 mm, height 1.18 mm,

height as percent of length 69.4. Average dimensions

of 10 specimens: length 1.56 mm, height 1.08 mm,

height as percent of length 77.1. Dimensions of measured specimens are as follows:

Specimen

number

3

5

38

39

40

42

43

45

48

49

Length mm (includes

caudal process)

1.59

.60

.62

.54

.53

.52

.48

.54

.54

.46

Height

mm

1. 17

1.09

1.08

1.07

1.06

1.08

1.02

1.08

1. 12

1.05

Height

as percent

of length

73.6

68. 1

66.7

69.5

69.3

71. 1

68.9

70. 1

72.7

71.9

First antenna (Figure 13/; Plate 5b) : 2nd joint

with 1 dorsal bristle and clusters of surface spines; 3rd

joint not separated from 4th and with a ventral and

dorsal bristle; 4th joint with 2 ventral and 1 dorsal

bristle; 5th joint triangular and placed ventrally between 4th and 5th joints; sensory bristle with 3 filaments; filaments of basal part of sensory bristles numerous (not shown in Figure 13/) and about equal in

length to bristles; 6th joint with short medial bristle.

7th joint: a-bristle with marginal spines distally;

b-bristle with 2 filaments; c-bristle with 6 filaments.

8th joint: d- and e-bristles bare, slightly longer than

b-bristle; f-bristle with 4 filaments; g-bristle with 6

filaments.

Second antenna (Figures I3g, h; Plate 5c): 1st

joint with short recurved medial spine on distal margin; joints 2-8 with combs of short spines along distal

margins; bristles of joints 2-8 with sparse natatory

hairs; joint 9 with 1 long stout bristle with natatory

hairs and 1 shorter and more slender bristle. Endopodite 3-jointed: 1st joint with 2 short proximal spines

and clusters of surface hairs; 2nd joint with 3 medium

bristles near proximal end; 3rd joint recurved, with

2 short bristles near terminal end.

Mandible (Figures 13:-*:) : Basale with 3 dorsal

bristles with sparse marginal spines and 1 very long

and 7 short ventral bristles; exopodite reaching about

one-third length of 1st endopodite joint and with

spinous ventral bristle with base near middle (Figure

13;). Endopodite: 1st joint with clusters of surface

spines and 1 long and 2 short distoventral bristles;

2nd joint with clusters of surface spines, 2 dorsal bristles

near middle of margin, 1 medial bristle on distal margin, and 1 long stout distoventral bristle; 3rd joint

with short a-bristle, stout clawlike b-bristle with short

spines on surface, short clawlike c-bristle with teeth

along ventral margin, and long spinous d-bristle; dorsal margin of 1st endopodite joint indented in region

of exopodite (Figure 13t).

Maxilla (Figure 13/): Appendage reduced; exopodite with 3 bristles; coxale with spinous dorsal bristle.

Fifth limb (Figure 13m) : Reduced to about half

size of female. Epipodite with about 39 bristles; single

endite with short spinous bristles. Endopodite: 1st

joint with 3 spinous bristles; 2nd joint with 1 short bare

bristle and 5 longer spinous bristles; inner lobe of 3rd

joint with 3 spinous bristles; outer lobe of 3rd joint

with 1 long bristle; 4th + 5th joints with 5 spinous

bristles.
28

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 13.—Spinacopia sandersi, $ adult, allotype, carapace: a, lateral view, L—1.70 mm.

Caudal process, medial view: b, right valve; c, left valve. Central muscle scars, left valve: d,

medial view (scars obscure). Anterior left valve: e, medial view. Left 1st antenna: /, lateral

view (filaments of sensory bristle of 5th joint not shown). Endopodite of 2nd antenna: g, medial

view; h, tip of 3rd joint. Mandible: i, left limb, medial view; ;, expodite of right limb, lateral

view; k, detail of b-claw on 3rd joint of endopodite on right limb, medial view. Limbs: /,

maxilla; m, 5th; n, right 6th, lateral view. Seventh limb: o, tip of left limb; p, tip of right limb;

q, left limb. Posterior region: r, furca. (Same scale in microns: b-f, i, n, q, r; g, I, m; h, j ,

k.o.p.)
NUMBER 8 29

Sixth limb (Figure 13n): 1st, 2nd, and 4th endites

with 3 bristles; 3rd endite with 4 bristles; end joint

with 4 anterior bristles, 2 middle bristles and 1 or 2

posterior bristles; 4th endite not differentiated from

end joint except by narrow space; bristles of middle

and anterior group of end joint not distinctly separated

from each other.

Seventh joint (Figures \3o-q; Plate 5d): Well developed, 4 bristles in distal group, 3 or 4 in proximal

group, each with 2-4 bells and marginal spines distally; terminus with opposing combs each containing

3 teeth; joint is shorter and more slender than that of

adult female.

Furca (Figure 13r): Each lamella with 7 claws

(rarely 8); claw 1 continuous with lamella; claw 3

about half length of claw 4; claw 1 with medial hairs

near base; all claws with marginal spines; dorsal margin of right lamella with about 5 spines.

Rod-shaped organ: Elongate, 1-jointed.

Eyes: Lateral eyes absent, medial eye about same

size as on female.

Posterior: Posterior differs from female in not

having clusters of long hairs.

Genitalia (Figures 2a-*; Plates 4e, f, 5e-f): Two

pear-shaped testes present, one on each side above

penis, connected to seminal vesicle by tubular vas

deferens. Seminal vesicle bilobed consisting of core

(secretion) and sperm peripheral to core, sperm

mainly restricted to ventral part; core of secretion consisting of 2 discrete masses either completely separated

or fused at middle (vas deferens somewhat larger

when secretion fused). Ductus ejaculatorius curved,

apparently opening at side of penis. Complex clasping

organs hanging down on each side of penis; each

clasper consisting of 3 lobes, each with 3-5 bristles;

main lobe terminating in sclerotized hook and with

triangular tooth proximally; ridges and minute projections present on triangular tooth (Figures 1g, t).

Spermatophore (observed on adult female): Ovoid

having amber color in transmitted light; consisting of

sperm enclosed in sheath of secretion (Figures 2/-n).

Sperm: Numerous in testis (Figure 2;), seminal

vesicle (Figure 2k) and spermatophore (Figures 21,

m). When stained with Mallory's, head yellow, posterior blue; flagellum observed on some. When stained

with aceto-carmine, head pink, posterior unstained

(Plate 4e,f).

Gut content: Gut examined in three specimens and

found empty.

DESCRIPTION OF INSTAR I (sex undetermined)

(Figure 14).—Shell (Figure 14a): Oval with shallow

sinus and short caudal process and similar in lateral

outline to adult female, but not inflated in posterodorsal region; infold below sinus with single bristle as

in adult female; infold in front of caudal process with

single large spinous bristle near middle; in addition,

several small bare bristles present along inner margin

of infold in front of caudal process.

AVERAGE DIMENSIONS OF FIVE SPECIMENS.—Length

0.88 mm, height 0.64 mm, height as percent of length

72.4. Dimensions of measured specimens are as follows:

Specimen

number

16

24

26

27

30

Length mm (includes

caudal process)

0.89

0.86

0.89

0.91

0.84

Height

Tflffl

0.68

0.62

0.65

0.64

0.60

Height

as percent

of length

76.4

72. 1

73.0

70.3

71.4

First antenna: Similar to adult female but with no

bristles on 2nd and 4th joints.

Second antenna (Figure 14fe): Protopodite similar

to adult female; medial spine on 1st joint of exopodite

not recurved as on adult female; endopodite 1 or 2

jointed with single long terminal bristle.

Maxilla, mandible, 5th limb: Well developed, similar in general morphology to adult female.

Sixth limb (Figure 14c): Reduced, not divided into

endites, without bristles but with abundant marginal

and surface hairs.

Seventh limb: Absent.

Furca (Figure 14a"): Each lamella with 2 claws

similar to claws 1 and 2 of adult female followed by a

single prong with long marginal hairs; prong continuous with lamella; clusters of hairs present on

margin of lamellae posterior to prong and medially at

base of claw 1.

Rod-shaped organ (Figure 14*): Elongate without

joints or with 1-3 weak sutures.

Gut content: Specimen 26 contained in the gut 1

polycopid ostracod and 3 copepods.

DESCRIPTION OF INSTAR n (sex undetermined) (Figure 15; Plate 2c).—Shell (Figure 15a): Similar in

shape to instar I; infold differs from instar I in having

2 long spinous bristles forming row in front of caudal

process. Average dimensions of 3 specimens: length

1.02 mm, height 0.78 mm, height as percent of length

77.1. Dimensions of measured specimens are as follows:
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 14.—Spinacopia sandersi, instar I, specimen 16: a,

carapace, left lateral view, L=0.89 ; b, endopodite and joints

1 and 2 of exopodite of left 2nd antenna, medial view; c, 6th

limbs; d, furcal lamella; e, rod-shaped organ. (Same scale in

microns: b, d, e.)

Specimen

number

17

28

29

Length mm (includes

caudal process)

1.06

1.07

0.92

Height

mm

0.86

0.79

0.70

Height

as percent

of length

81.1

74.2

76. 1

First antenna: Similar to instar I except for having 1

dorsal bristle on 2nd and 4th joints.

Second antenna: Protopodite similar to instar I.

Exopodite similar to instar I except medial spine of 1st

joint recurved. Endopodite 2-jointed (Figure 156):

1st joint with 1 or 2 short proximal bristles; 2nd joint

with 1 long terminal bristle.

Mandible, maxilla, 5th limb, rod-shaped organ: All

well developed and similar in general morphology to

instar I and adult female.

Sixth limb (Figure 15c) : Similar to instar I except

for having single bristle on anteroventral section of

margin.

Seventh limb (Figure 15<f): Very short and without

bristles or terminal comb.

Furca (Figures \be, /) : Each lamella with 3 or 4

(usually 4) claws decreasing in length posteriorly; differs from adult female in having fewer claws and in 3rd

claw not being shorter than 4th. The distribution of

claws on each lamella of three specimens is as

follows:

Specimen number

17

28

29

Left lamella

4

4

4

Right lamella

3

4

4

Gut content (Plate 1c, d): Specimen 28 contains

within the gut a large complete copepod with its head

toward the posterior part of the gut, indicating that it

had been swallowed head first. The gut of specimen

29 contains a large podocopid ostracod; although the

ingested specimen is toward the rear of the gut, it is

still strongly calcified, and the shell fragmented when

flattened under a cover glass. This suggests that the

gut is not sufficiently acid to dissolve the calcium carbonate of the podocopid. The ingested ostracod contains its appendages in place, but they appear cleaned

of internal muscles and cells.

DISCUSSION OF SPECIMEN 29.—The dimensions of

the carapace of specimen 29 would suggest that the

specimen is a stage I instar. However, the number of

spinous bristles on the infold of the caudal process, the

number of bristles on the 2nd and 4th joints of the 1st

antenna, the recurved nature of the medial spine on

the 1st joint of the exopodite of the 2nd antenna, the

number of furcal claws, and especially the presence of

a single bristle on the 6th limb indicate that specimen

29 is a stage II instar, and it has been considered so

herein.

FIGURE 15.—Spinacopia sandersi, instar II, specimen 17: a,

carapace, right lateral view, L=1.06 mm; b, endopodite, 2nd

antenna; c, 6th limb; d, 7th limb. Furcal lamellae: e, right,

lateral view; /, left, medial view. (Same scale in microns:

b-f.)
NUMBER 8 31

DESCRIPTION OF FEMALE INSTAR in (Figure 16;

Plate 2a) .—Shell (Figure 16a): Differs from instar II

in having 2 or 3 (usually 3) large spinous bristles and

1 or 2 small spinous bristles forming row near middle

of infold in front of caudal process. Average dimensions of 2 specimens: length 1.22 mm, height 0.92

mm, height as percent of length 75.5. Dimensions of

measured specimens are as follows:

ximen

mber

19

34

Length mm (includes

caudal process)

1.18

1.26

Height

mm

0.91

0.93

Height

as percent

of length

77. 1

73.8

First antenna: Differs from instar II in having a

ventral bristle on the 4th joint.

Second antenna, maxilla, mandible, 5th limb, rodshaped organ (Figure 16<?) : Similar in general morphology to instar II.

Sixth limb (Figure 166, c): Well developed, similar in general morphology to adult instar, except having only 3 endites and fewer bristles, about 15.

Seventh limb (Figure I6d): Longer than on instar

II but otherwise similar.

Furca: Each lamella with 6 claws; 3rd claw shorter

than 4th, otherwise similar to instar II.

DESCRIPTION OF MALE INSTAR m (Figure 17; Plate

46, d).—Shell (Figure 17a): Similar to female instar III. Average dimensions of 5 specimens are length

1.25 mm, height 0.92 mm, height as percent of length

73.7. Dimensions of measured specimens are as follows:

xtmen

mber

10

18

25

32

33

Length mm (includes

caudal process)

1.21

1.28

1.21

1.28

1.29

Height

mm

0.92

0.93

0.88

0.94

0.95

Height

as percent

of length

76.0

72.7

72.7

73.4

73.6

First antenna (Plate 46), mandible, maxilla, 5th,

6th, 7th limbs (Figure 17d"), rod-shaped organ (Figure 17 c), furca: Similar to female instar III.

Second antenna: Protopodite and exopodite similar to female instar III. Endopodite 2-jointed or

weakly 3-jointed (Figure 176; Plate 4rf): 1st joint with

2 short proximal bristles; 2nd joint with 2 long proximal bristles; 3rd joint with 1 short terminal bristle

(this bristle is on tip of 2nd joint when 3rd joint is

absent).

DISCUSSION OF SPECIMEN 3i (Figure 18).—This

specimen could not easily be placed in any particular

stage. The shell dimensions are as follows: length 1.14

mm, height 1.04 mm, height as percent of length 91.2.

The shell dimensions, the number of bristles on the infold of the caudal process (Figure 18a), the number

of bristles on the 4th joint of the 1st antenna and the

development of the 6th limb, which has 15 bristles, and

the length of the bare 7th limb (Figure 18c) indicate

that it belongs in stage III. The endopodite of the

2nd antenna is 2-jointed (Figure 186), the 1st joint

has the usual 2 short bristles, but the end joint has 1

long terminal bristle and 1 longer proximal bristle

FIGURE 16.—Spinacopia sandersi, 9 instar III, specimen 19,

carapace: a, left lateral view, L=1.18 mm. Lateral view,

limbs: b, 6th, left; c, 6th, right; d, 7th. Head region: e,

rod-shaped organ. (Same scale in microns: b-e.)

331-394 O-69—3

FIGURE 17.—Spinacopia sandersi, $ instar III, specimen 10:

a, carapace, right lateral view, L=1.21 mm; b, endopodite

of left 2nd antenna, medial view; c, rod-shaped organ; d, 7th

limb. (Same scale in microns: b-d.)
32 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 18.—Spinacopia sandersi, $ instar III, specimen 31:

a, caudal process right valve, medial view; b, endopodite 2nd

antenna; c, 7th limb; d, right furcal lamella, medial view.

(Same scale in microns: a, d; b,c.)

oriented anteriorly. This type endopodite is not present on either male or female instars. The endopodite

would fit nicely as a developmental stage between male

instars II and III. The 5 claws on the furca (Figure

I8d) also fit between the number on the furcae of instar II (3 or 4 claws) and instar IV (6 claws). The dimensions of instars II and III, however, are such that

it seems unlikely that another instar could fit between

them. I have considered specimen 31 to be an aberrant male instar III on Figure 21 but have not included it in the description of male instar III above.

DESCRIPTION OF FEMALE INSTAR rv (Figure 19;

Plates 2b, \c) .—Shell (Figures 19a, b): Shape of carapace similar to adult female but not globose in posterodorsal region. Infold below shallow sinus with single

bristle; infold in front of caudal process with 4 (rarely

3) large and 2 or 3 small spinous bristles forming row

FIGURE 19.—Spinacopia sandersi, $ instar IV: a, carapace, left lateral view, L=1.54 mm;

b, muscle scars right valve, medial view; c, endopodite of 2nd antenna; d, right mandible, basale

and exopodite, lateral view; e, left mandible, basale and exopodite, lateral view; /, rod-shaped

organ; g, section of esophagus; h, Polycope from gut. (Same scale in microns: b, g, h; c-f.

Figures a-c from specimen 13; d-h from specimen 15.)
NUMBER 8 33

near middle of infold and about 10 bare slender bristles

along inner margin. Average dimensions of twelve

specimens: length 1.54 mm, height 1.23 mm, height

as percent of length 80.3. Dimensions of measured

specimens are as follows:

Height

Specimen

number

13

15

22

51

53

55

58

59

60

62

64

65

Length mm (includes

caudal process)

1.54

1.54

1.54

1.56

1.53

1.53

1.51

1.50

1.49

1.51

1.58

1.59

Height

mm

1.21

1.21

1.24

1.27

1.25

1.26

1.24

1. 18

1. 17

1.28

1.22

1.26

as perc

of leng

78.6

78.6

80.5

81.4

81.7

82.4

82. 1

78.7

78.5

84.8

77.2

79.2

First antenna: Similar to instar III except for having

2 ventral bristles on the 4th joint.

Second antenna (Figure 19c), mandible (Figures

\9d, e; Plate Ac), maxilla, rod-shaped organ (Figure

19/): Similar in general morphology to instar III

female and adult female.

Fifth limb: Similar to adult female. Distribution

of bristles on 1 appendage is as follows: endite with

single bristle. Exopodite: 1st joint with 3 bristles; 2nd

joint with 6 bristles; inner lobe of 3rd joint with 3

bristles; outer lobe of 3rd joint with 1 bristle; 4th +

5th joints with 5 bristles; surface of exopodite hirsute;

epipodial appendage with about 39 bristles.

Sixth limb: Similar to adult female. Distribution

of bristles on 1 appendage is as follows: endite I

with 3 bristles; 2nd endite with 3 bristles; 3rd endite

with 4 bristles; 4th endite with 3 bristles; end joint with

2 or 3 anterior bristles, 2 middle bristles and 2 hirsute

posterior bristles; all endites fairly well defined; surface and margin of end joint hirsute.

Seventh limb: Proximal group with 4 bristles; distal

group with 4 or 5 (usually 4) bristles; bristles tapering

distally, each with 2-5 bells; terminus with opposing

closely spaced combs with few teeth.

Furca: Each lamella with 7 claws; claw 1 continuous with lamella; claw 3 shorter than claw 4; clusters of hairs medially at base of claw 1 and following

claw 7.

Gut: Specimen 15 with complete specimen of the

ostracod Polycope sp. present in rear portion of gut

(Plate 2b). Measured length of polycopid shell 0.21

mm; height 0.20 mm (Figure 19Jt). (Apparently the

esophagus [Figure 19g] of this specimen is capable of

stretching to a diameter of about 0.2 mm.)

DESCRIPTION OF MALE INSTAR rv (Figure 20).—

Shell (Figure 20a): Similar to female instar IV. Average dimensions of 13 specimens: length 1.51 mm,

height 1.18 mm, height as percent of length 78.0. Dimensions of measured specimens are as follows:

Specimen

number

9

11

12

14

20

23

35

52

54

56

57

61

63

Length mm (includes

caudal process)

1.43

1.54

1.55

1.51

1.56

1.53

.42

.55

.51

.57

.49

.50

.53

Height

mm

19

18

21

24

20

18

.09

.22

.15

.20

. 12

.19

. 18

Height

as percent

of length

83.2

76.6

78.1

82.1

76.9

77.1

76.8

78.7

76.2

76.4

75.2

79.3

77. 1

First antenna, maxilla, mandible, 7th limb, furca,

frontal organ, posterior: Similar to female instar IV.

Second antenna: Protopodite and exopodite similar to adult female; endopodite 3-jointed (Figure

20b): 1st joint with 2 small proximal bristles and clusters of surface hairs; 2nd joint elongate with 3 proximal

bristles; 3rd joint elongate with 2 terminal bristles.

Fifth limb: Similar to female instar IV. Distribution of bristles on fifth limb of 1 specimen is as follows: endite with single bristle. Exopodite: 1st joint

with 3 bristles; 2nd joint with 4 or 5 bristles; outer

lobe of 3rd joint with 4 or 5 bristles; inner lobe of 3rd

joint with 1 bristle; 4th + 5th joint with 5 bristles;

surface of exopodite hirsute.

Sixth limb: Similar to female instar IV. Distribution of bristles of 1 appendage is as follows: endite I

with 3 bristles; 2nd endite with 2 bristles; 3rd endite

with 3 bristles; 4th endite with 4 bristles; end joint

with 3 anterior bristles, 2 middle bristles, 2 hirsute

posterior bristles; surface and margin of end joint

hirsute.

Copulatory organ: 2 or 3 poorly developed lobes

with few bristles (Figure 20c).

Gut content: Specimen 9 contained remains of a

copepod.
34

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FIGURE 20.—Spinacopia sandersi, S instar IV: a, carapace,

left lateral view, L=1.43 mm; b, endopodite of right 1st antenna, medial view; c, copulatory apparatus, lateral view

from right. (Same scale in microns: b, c. Figures a and b

from specimen 9; c from specimen 11.)

SUMMARY OF DEVELOPMENT.—Shell: The overall

shape of the instars are quite similar to the female adult

except for not having the inflated posterodorsal region

which serves as a brood pouch for eggs. As indicated

in Table 4 below, the average adult female is also

higher relative to length than juveniles of both sexes.

The number of both large and small spinous bristles

on the list of the infold in front of the caudal process

increases fairly regularly in each succeeding developmental stage (Table 5; Figure 21A). The average

growth factor of the shell excluding the growth factor

between male instar V and the adult male is 1.216.

This estimated factor was obtained by averaging both

the length and height factors between male and female instars (see Tables 6 and 7). The growth factors between the preadult and adult male is quite low,

1.03 for the length growth factor and 0.92 for the

height factor.

TABLE 4.—Height as percent of length

Sex not

determined

Female Male

Instar

Instar II

Instar III

Instar IV

Adult

72.4 (N = 5)

77.1 (N = 3)

75.5 (N = 2)

80.3 (N=12)

82.0 (N=7)

73.7 (N = 5)

78.0 (N=13)

77.1 (N=10)

20

15

10

_ 5

3 0

§15

10

5

15

10

5

5 25

Z 20

15

10

5

INSTAR HI

4

B

 8

z 2 INSTAR I

3 M ^ O- CO O to C

A

? J

J

1 1 1 1 1

p1

1

11 1 1 1 1 1

B

1

1

1

1

1

1

1

1

C

• •

1

I

J

j

1 • 1 1 1 1 1 1 1 .

23456 7 0 12 3

NUMBER OF BRISTLES

2345678 9 10

NUMM R OF CLAWS

FIGURE 21.—Development: A, number of long spinous

bristles on infold of caudal process of each valve; B, number

of bristles on 4th joint of 1st antenna; c, number of furcal

claws on each lamella. (Figures on left indicate number

of valves or appendages examined.)

Specimen 29 is especially interesting in that the dimensions of the shell would lead one to believe that

the specimen is at the instar I stage of development.

The appendages of the specimen, however, have

reached the same stage of development as those at the

instar II stage. The mechanism causing the specimen

to develop in this manner is not clear, nor is it known

whether it is a rare or common phenomenon. One

must conclude that either the shell is dwarfed, or

the appendages have skipped one stage. I have assumed the former to be true in the present paper.

First antenna: The general morphology of the 1st

antenna is quite similar for all instars and the adult

female. The adult male develops the characteristic
NUMBER 8 35

TABL E 5.—Summary of development

Character

Shell, infold of caudal process:

Large spinous bristles

Small spinous bristles

First antenna: bristles on 2d joint

Dorsal bristles on 4th joint

Ventral bristles on 4th joint

Sixth limb: bristles

7th limb: proximal bristles

Distal bristles

Terminal teeth per comb

Furca, claws per lamella

Sex undetermined

I

1

0

0

0

0

0

limb absent

« <<

« ii

2 + prong

II

2

0

1

1

0

1

0

0

0

3-4

/ / /

2-3

1-2

1

1

1

15

0

0

0

6

IV

3-4

2-3

1

1

2

20

4

4

3

7

Females

Adult

5 (rarely 4 or 6)

3 (rarely 2)

1

1

2

20

4

6

10

7-8

III

2-3

1-2

1

1

1

15

0

0

0

6

Males

IV

3-4

2-3

1

1

2

20

4

4

3

7

Adult

4-5

2-3

1

1

2

20

4

4

3

7-8

TABLE 6.—Average shell dimensions and calculated growth

factors for females

Growth

stage

adult

IV

III

II»

!•

Average

length

(mm)

1.77

1.54

1.22

1.02

0.88

Growth

/actor

1. 15

1.26

1.20

1.16

Average

height

(mm)

1.45

1.23

0.92

0.78

0.64

Growth

factor

1. 18

1.34

1.18

1.22

Number of

specimens

7

12

3

3

5

Sex not determined.

TABLE 7.—Average shell dimensions and calculated growth

factors for males

Growth

stage

Adult

IV

III

II"

I »

Average

length

(mm)

1.56

1.51

1.25

1.02

0.88

Growth

factor

1.03

1.21

1.23

1. 16

Average

height

(mm)

1.08

1. 18

0.92

0.78

0.64

Growth

factor

0.92

1.28

1. 18

1.22

Number

of

specimens

10

13

5

3

5

' Sex not determined.

small 5th joint with its brush-like bristle and the long

6th joint. Instar I is without a dorsal bristle on the

2nd and 4th joints; a single dorsal bristle is present

on each joint on all following stages. The number of

ventral bristles on the 4th joint increases fairly gradually: lnstars I and II have no bristles; instar III has

1; instar IV and adults of both sexes have 2. The distribution of bristles on the 2nd and 4th joints is

tabulated in Table 5. The number of bristles on the

4th joint is shown in Figure 21B.

Second antenna: The form of the protopodite remains about the same in all stages of development. The

medial spines on the 1st joint of the exopodite is

straight on instar I and recurved in all following

stages. The sclerotized proximal tip of the exopodite,

where it attaches to the protopodite, seems less developed in instar I than in following stages, but this was

not studied in detail herein. The endopodites of instars

I and II are fairly similar to that on female instars

III, IV, and the adult but differ as follows: instar I

is without bristles on the 1st joint and on some specimens the 2nd joint cannot be distinguished; instars

II-IV, and the adult have well denned 2nd joints

and 1 or 2 bristles on the 1st joint; 1st joints with only

1 bristle are rare among adult females, but are fairly

common in juveniles. The 1st joint of male instars III,

IV, and the adult are similar, each usually having 2

bristles, but the 2nd and 3rd joints become more complex in each succeeding growth stage. The 2nd joint

of male instar III, which bears 1 proximal bristle, is

short and on some specimens fused with the 3rd joint.

The 2nd joint of instar IV and the adult male is elon-
36 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

gate and bears 3 proximal bristles. The 3rd joint of

instar III bears 1 short terminal bristle (this bristle

is on the 2nd joint if the 3rd joint should be undeveloped) . On instar IV the 3rd joint is much longer than

on instar III and it bears 2 bristles on the terminal end.

In the adult male the 3rd joint is recurved and, in

addition to the 2 terminal bristles, the tip bears several

ridges.

Specimen 31 is unusual in that the short 2nd joint of

the 2-jointed endopodite bears 2 long bristles. I have

considered this specimen herein to be an abnormal

male at the instar II stage of development; however,

it could also be an abnormal female or a male intermediate between what is considered herein instars I

and II.

Kornicker and Wise (1962, p. 69) suggested that

the 2-jointed endopodite of the 2nd antenna of the

female of Sarsiella texana may have developed by a

reduction in the number of joints. Although such a

reduction may occur in some species, e.g., Vhxlomed.es

dentata Poulsen (1962), it is possible with present

knowledge to conclude from the data presented by

Kornicker and Wise that the development of the endopodite of the 2nd antenna of S. texana is similar to

that described herein for Spinacopia sandersi, and previously for Sarsiella zostericola by Jones (1958) and

Kornicker (1967).

Mandible, maxilla, 5th limb: These appendages

are well developed in instar I and are similar in both

males and females. Little change except for size and

possibly numbers of bristles takes place during later

development. The male mandible differs considerably

from the female, but in a manner typical for the family,

and so will not be described here; both males and

females have well-developed exopodites. The maxilla

and 5th limbs of the adult male are reduced, but otherwise are fairly similar to those of the female.

Sixth limb: No sexual dimorphism. The 6th limb on

instar I is a hirsute plate without bristles. On instar

II the 6th limb bears 1 anteroventral bristle; on some

specimens the margin is indented, suggesting division

into more than 2 joints. Instar III has the 6th limb

well developed, with 3 endites and a broad end joint;

the limb bears a total of about 15 bristles; the 6th

limb is fully developed in instar IV with 4 endites and

the end joint, and bears a total of 17-22 bristles

(Table 5).

Seventh limb: A 7th limb was not observed on instar

I. On instar II the 7th limbs are short and without

bristles or end combs. The 7th limbs on instar III are

longer but still without bristles or end combs. On

instar IV the 7th limbs are longer and have 3 or 4

proximal and 4 distal bristles (rarely 5 distal bristles

on female) and also 2 opposing terminal combs containing 3 teeth. The adult female has 4 (rarely 3)

proximal bristles, 6 terminal bristles, and opposing

terminal combs, each with about 10 teeth. The adult

male has the same number of proximal bristles as the

female, but only 4 distal bristles and 3 teeth in the

terminal combs; it is also somewhat shorter and more

slender than the female appendage (Table 5).

Furca: Instar I with 2 claws similar to claws 1 and 2

of adult followed by a single prong continuous with

lamellae and with long marginal hairs (Table 5).

Instar II with 4 claws (rarely 3) decreasing in length

posteriorly. Instar III with 6 claws, 3rd claw shorter

than 4th; 1 specimen (no. 31) has 5 claws decreasing in

length posteriorly. Instar IV with 7 claws, claw 3

shorter than claw 4. Adult with 7 or 8 claws, claw 3

shorter than claw 4. Variability in the number of claws

is shown in Figure 21c.

Rod-shaped organ: The organ is elongate and similar in all instars and adults but varies in the number

of sutures that vaguely divide the appendage into

joints. More of these were observed in early instars

than on adults, where they are often absent. In some

organs the sides are parallel, in others there are several

constrictions or indentations. The tips are rounded

or pointed.

POSTADULT MOLTING.—New appendages and valves

were observed within the old in 2 instars, but none

were present inside 12 adults examined for evidence

of molting.

Kornicker (in Bowman and Kornicker, 1967, p. 16)

mentions the occurrence in collections from the southern New England coast of 3 males of Parasterope pollex equal in size or larger than adult males, but having

some juvenile characters. In that paper, I postulated

that the large forms were caused by a delay of sexual

maturity and did not result from postadult molting.

Since then I have read the interesting paper by Word

and Hobbs (1958) in which the form I and form II

dimorphs of the male crayfish are discussed. Form I

(first form males) are fully developed males. These,

upon molting, become form II males (second form

males), which have some juvenile characters. Upon

molting the form II males revert to form I. It seems

possible to attribute the juvenile characters of the
NUMBER 8 37

large males of Parasterope pollex to a similar phenomenon, but data are too fragmentary at this time to

draw conclusions. In the present study all adult males

of Spinacopia sandersi are fully developed.

Comparative Variation

The present study consisted mostly of counting

bristles on the appendages and infolds of valves of

adult females. These data are discussed below and summarized in histograms in Figures 22-26. Because only

one specimen each of S. menziesi and S. bisetula are

available, it is not possible to study their variability;

however, they are included for comparative purposes.

Knowledge of the variability limits of the two abundant species S. variabilis and S. sandersi permitted

greater confidence in establishing as new species

S. menziesi and S. bisetula, which are each represented

in the collections by only one specimen. A similar technique was used by Poulsen (1962, p. 117) for differentiating species of Gigantocypris.

CARAPACE.—The carapace of S. sandersi is strongly

punctate, whereas the carapaces of S. variabilis,

S. menziesi, and S. bisetula are not. All specimens examined have a small bristle on the infold below the rostrum. All specimens with the exception of one specimen of S. sandersi have 5 large spinous bristles in a row

on the infold anterior to the caudal process; the excepted specimen has 6 bristles on one valve and 5 on

the other. As shown in Figure 22A, the number of

small spinous bristles on the infold anterior to the caudal process varies. In general, S. variabilis has a greater

number of these bristles than the other species.

Carapace height-to-length and carapace length relationships are presented in histograms in Figures 22

B and c, respectively. Both measurements seem useful

in distinguishing species.

FIRST ANTENNA.—No variation was observed in the

number of bristles on the 2nd or 3rd joints, bu,t the

bristles varied somewhat in length and spinosity. The

distribution of ventral bristles on the 4th joint is shown

in a histogram in Figure 23A. Seventeen specimens of

S. variabilis were studied; of these, thirteen have 2

ventral bristles on the 4th joint of both limbs, two have

3 bristles on both limbs, and two have 2 bristles on one

limb and 3 on the other. Six specimens of S. sandersi

have 2 ventral bristles on the 4th joint of both limbs.

The only specimen of S. bisetula available also has 2

bristles on each limb. The specimen of S. menziesi differs from the other species in having 3 bristles on each

1 2 3 4 5 6 7 8

NUMBER OF BRISTLES

80 84 8S 92 96

PERCENT

2.3 2.5 2.7

FIGURE 22.—Comparison of adult female carapaces: A, number of short spinous bristles on infold of caudal process; B,

height of complete carapace as percent of length; c, length

of complete carapace including caudal process.

limb. The constancy of the number of ventral bristles

on the 4th joint of the two more numerous species

suggests that the number of bristles on the 4th joint

may be useful in distinguishing S. menziesi from the

other three species.

The 6th joint has a small medial spine on most specimens but it is lacking in some. However, no detailed

study was made of the distribution of this bristle. The

bristles on the 7th and 8th joints may vary somewhat

in the number of filaments on some of the bristles,

but this was not studied. The length of the a-bristle was

observed to vary within specimens of the same species.

SECOND ANTENNA.—The distribution of bristles on

the exopodite is quite constant on all four species. It

was observed that the lengths of the smaller bristle on

the 9th joint and the medial spine on the 1st joint vary,

but they were not measured. The distribution of

bristles on the 1st and 2nd joints of the endopodite is

shown in histogram in Figures 23B and c, respectively. All 14 specimens of S. variabilis examined have

at least 3 bristles on the 1st joint of the endopodite of

either the left or right limbs, 12 have 3 bristles on

both left and right limbs; only one specimen has 2

bristles on one of its limbs, and only one specimen has 4
38 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

bristles on one limb. The 1st joint of both limbs of the

unique specimen of S. menziesi has 3 bristles. On the

other hand, the 1st joint of the endopodite of S. bisetula (one specimen) has only 2 bristles, and S. sandersi has 2 bristles on each limb of four specimens, 1

bristle on each limb of one specimen, and on another

specimen, 1 bristle on the left limb and 2 on the right.

The absence of 1st joints with 3 bristles on S. sandersi

(six specimens) and the presence of 3 bristles on at

least one limb of S. variabilis (14 specimens) suggests

that 2 versus 3 bristles may be a useful criterion for

distinguishing the species in the collection.

The 2nd joints of the endopodites of all specimens

of S. menziesi (1), S. bisetula (1), S. sandersi (6), and

most specimens of S. variabilis (11 of 14) have only 1

bristle. Two specimens of S. variabilis have 1 bristle on

one limb and 2 on the other; one specimen has 2

bristles on each limb.

MANDIBLE.—The number of bristles on the mandible is constant on all specimens examined with one

exception. The basale of one limb of the unique specimen of S. menziesi has an additional bristle on the lateral surface near the ventral margin, making 4 bristles

compared to 3 on the other limb. All specimens on the

other three species in the collection have 3 bristles in

this region.

The bristle on the exopodite of S. menziesi reaches

about one-third the distance up the 1st endopodite

joint. The exopodite bristle on specimens of other species reaches only about one-quarter the distance or

less.

Two small bristles on the 3rd endopodite joint vary

in length in specimens of the same genus, but this was

not studied in detail.

MAXILLA.—The number of bristles on the exopodite

and endopodite of the maxilla is constant on the specimens examined. The number of bristles on the endites

probably vary, but the difficulty in accurately counting these discouraged me from a detailed study.

FIFTH LIMB.—The number of bristles on the endite

and exopodite joints of each 5th limb is shown in the

histogram in Figure 24. The single endite on all species

except S. bisetula has 1 bristle. The unique specimen of

S. bisetula has 1 bristle on the endite of one limb and 2

on the other limb.

The 1st joint of the exopodite has 3 bristles on all

except two specimens of S. variabilis which have 4

bristles on one of the 2 limbs and 3 on the other. One

limb of a specimen of S. sandersi has only 2 bristles,

3 -

2 -

1 -

~ S. bisetula

2

1

0

14

12

10

8

*Z? 6

E 4

— S. sandersi

§ 28

LU

Sf 26

24

22

20

18

16

14

12

10

8

6

4

2

S. menziesi

— S. variabilis

B

1 2 3 4 0 1 2 3 4 0 1 2 3

NUMBER OF BRISTLES

FIGURE 23.—Comparison of 1st and 2nd antennae of adult

females: A, 1st antenna, number of ventral bristles on 4th

joint. Second antenna, endopodite: B, number of bristles on

1st joint; c, number of bristles on 2nd joint.

but it is possible that a 3rd bristle was broken off during the dissection.

The 2nd joint of the exopodite has 6 bristles on all

except two specimens of S. variabilis and one specimen of S sandersi, which have 5 bristles on one limb

and 6 on the other.
NUMBER 8 39

The inner lobe of the 3rd joint of both limbs of S.

bisetula has 4 bristles. All other specimens examined

have only 3 bristles with the exception of one specimen of S. variabilis, which has 4 bristles on one limb

and 5 on the other. The presence of 4 bristles on S.

bisetula suggests that this may be a specific character.

The outer lobe of the third joint has 1 bristle on all

specimens examined with the exception of a single

specimen of S. variabilis, which has 3 bristles on each

limb.

The end joints (4th + ) have a varying number of

bristles. The unique specimen of S. menziesi has 4

bristles on both limbs. The specimen of S. bisetula has

4 bristles on one limb and 5 on the other. Seven specimens of S. variabilis have 4 bristles on both limbs; one

specimen has 5 bristles on both limbs, and two specimens have 4 bristles on one limb and 5 on the other.

The number of bristles on the end joints on specimens

of S. sandersi differs from the other species. All specimens of this species have at least 6 bristles on one of

the limbs; two specimens have 6 bristles on both limbs;

two have 5 bristles on one limb and 6 on the other; one

has 4 bristles on one limb and 6 on the other; one has

3 bristles on one limb; it is possible, however, that 4

bristles were on this limb prior to the dissection. The

presence of 6 bristles on the end joints of S. sandersi

clearly may be considered a specific character useful

in distinguishing that species from others in the

collection.

The number of bristles on the epipodial appendage

of each 5 th limb is not shown in Figure 24, but they

may have significance as a specific character. The

epipodial appendages of the single specimen of S.

menziesi have 46-48 bristles; the single specimen of S.

bisetula has 41 bristles; four specimens of S. variabilis

examined have 40-42 bristles; four specimens of S.

sandersi have 38-42 bristles. The large number of

bristles on the specimen of S. menziesi stands out as

being different from specimens belonging to the other

three species.

SIXTH LIMB.—The 4 endites are separated from

each other by indentations on S. menziesi, S. bisetula,

and S. variabilis, but on S. sandersi the outer margin

of the joint is fairly evenly rounded, and the endites

are distinguishable mainly by clumping of bristles. The

number of bristles on the endites and end joint of each

6th limb is shown in Figure 25.

First endite: First endite has 3 bristles on most

species with the following exceptions: two specimens

a 6-

4 _ A

•* S. rrmimi

1

2 - S.tasetu/i

4 -

2 S umiira

20 -1

1

B

1

|

1

1

C

1

1

J

1

D

1

1

1

T

E

1

1

1

L

F

1

NUMBER OF BRISTLES 1.

FIGURE 24.—Comparison of number of bristles on 5th limbs

of adult females: A, endite. Joints of exopodite: B, 1st; c, 2nd;

D, inner lobe of 3rd; E, outer lobe of third; F, 4th plus.

of S. sandersi and S. variabilis have 4 bristles on one

of the limbs; two specimens of S. variabilis have 2

bristles on one of their limbs; the unique specimen of

S. menziesi has only 1 bristle on each 1st endite, but

it is possible that additional bristles were fragmented

during dissection.

Second endite: All specimens have 2 bristles on the

2nd endite with the following exceptions: The

unique specimen of S. menziesi, two specimens of S.

variabilis, and one specimen of S. sandersi have 3

bristles on one limb; one specimen of S. sandersi has 3

bristles on each limb, and one specimen has only 1

bristle on one limb.

Third endite: The unique specimen of S. menziesi

and six specimens of S. variabilis have 4 bristles on both

limbs of the 3rd endite. Only two specimens of the latter species have 3 bristles on one of the limbs and 4

on the other. This suggests that the presence of 4

bristles on both limbs is a fairly stable character for

S. variabilis. On the other hand, of the six specimens

of S. sandersi examined, only two have 4 bristles on

both limbs; three have 3 bristles on one of the limbs,

and one has only 2 bristles on one of the limbs. This

suggests the presence of 4 bristles on both limbs is less

characteristic of S. sandersi than it is of S. variabilis.

However, more material would have to be examined to
40 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

determine whether the differences are statistically significant. The unique specimen of S. bisetula has 3

bristles on one limb and 4 on the other.

Fourth endite: Of the ten specimens of S. variabilis

examined, eight have 3 bristles on the 4th endites of

both limbs, one has 3 bristles on one limb and 4 on

the other, and one has 4 bristles on one limb and 5 on

the other. Clearly the presence of 3 bristles on both

limbs of the 4th endite is a fairly stable characteristic

of S. variabilis. All six specimens of S. sandersi have 3

bristles on the 4th endite of at least one of the limbs,

only three have 3 bristles on each limb. Two of the remaining three specimens have 4 bristles on the opposing limb, and one specimen has only 2 bristles on one

limb. The unique specimen of S. menziesi has 3 bristles

on each limb. The single available specimen of S.

bisetula differs from the other species in having 4

bristles on the 4th endite of each limb.

End joint: On all specimens examined the bristles

on the end joint may be subdivided into an anterior

group, a middle group, and a posterior group, each

separated by a space. The posterior bristles differ from

the others in being stouter and having long, thin marginal hairs.

All ten specimens of S. variabilis examined have at

least 4 anterior bristles on one of the limbs; five specimens have 4 bristles on both limbs; three specimens

have 3 bristles, and two specimens 5 bristles on the

other limb. The single specimen of S. menziesi has 4

bristles on both limbs. The single specimen of S. bisetula has 3 bristles on one limb and 4 on the other. The

number of anterior bristles is more variable on specimens of S. sandersi than on the other three species.

None of the six specimens examined has the same number of anterior bristles. The combinations of bristles

on each limb of the six specimens are as follows: 2-2;

2-3; 3-4; 4-4; 4-5; 2-4.

All six specimens of S. sandersi have 2 bristles in the

middle group on at least one of the limbs; three specimens have 2 bristles on both limbs, two have only

1 bristle, and one has 3 bristles on one limb. On the

other hand, four of the ten specimens of S. variabilis

examined have only 1 middle bristle on each limb;

three'have 2 bristles on each limb, and two have 2

bristles on one limb and 1 on the other; one specimen

has 2 on one limb, but the number on the opposing

limb could not be determined. Both limbs of the unique

specimen of S. menziesi have 2 bristles; the speci1• | 12

i io

|

2

 4

£ 2

10 -

A

£/moms'

- Ubisttul,

- £ orates

S.rmbilis

10 1 2 3 4 5

B

•

ffl

0 1 2 3 4

C

•

]1 2 3 4 5

D

•

•

1

2 3 4 5 6

E

•

ffl

1 2 3 4 5 6

F

•

L0 1 2 3 4

G

•

•

1

A0 1 2 3 4 NUMBER OF BRISTLES

FIGURE 25.—Comparison of number of bristles of 6th limb of adult females: A, endite I; B,

endite II; c, endite III; D, endite IV; E, anterior bristles end joint; F, middle bristles end joint;

c, posterior bristles end joint.
NUMBER 8 41

men of S. bisetula has 1 bristle on one limb and 2 on

the other.

The single specimens of S. menziesi and S. bisetula

each have 2 posterior bristles on end joint of each limb.

Of the six specimens of S. sandersi examined, five have

2 posterior bristles on each limb; one specimen has 2

posterior bristles on one limb and only 1 on the other.

The variability of numbers of posterior bristles on S.

variabilis may differ from the other species. Three of

ten specimens examined have 3 posterior bristles on

each limb; one specimen has 3 bristles on one limb and

2 on the other; five specimens have 2 bristles on each

limb; one specimen has 2 bristles on one limb, but the

number of bristles on the opposing limb could not be

determined.

SEVENTH LIMB.—The number of comb teeth, the

angle at which the teeth project, and the distance between combs seem to vary, but were not studied herein.

The 7th limbs of all the specimens examined have 6

bristles in the distal group, 3 on each side. The number

of bells located distally on each bristle vary somewhat

but were counted on only a few specimens. The number of bristles in the proximal group seemed to vary

significantly, and their distributions are shown in the

histogram in Figure 26A.

All specimens of S. sandersi have 4 bristles in the

proximal group of at least one of the limbs; three

specimens have 4 bristles on each limb; two specimens

have 3 bristles on one of the limbs; on one specimen

the tip of the 7th limb is missing. The unique specimen

of S. bisetula has 4 bristles in the proximal group on

each limb. The unique specimen of S. menziesi is quite

different, having 8 bristles in the proximal group of

one limb and 10 in the other. S. variabilis falls between

S. menziesi and the other two species in having 5 or 6

bristles in the proximal group of the 7th limb of most

specimens; only one of seven specimens examined has

4 bristles on each limb, the rest have at least 5 bristles

on one of the limbs; one specimen has 5 on one limb

and 7 on the other; two specimens have 6 bristles on

each limb.

CAUDAL FURCA.—The number of claws on the left

and right lamellae are shown in the histogram in Figures 26B and c, respectively. Six specimens of S. sandersi have 8 claws on at least one of the lamellae; three

have 8 claws on both lamellae, three have 7 on one

and 8 on the other, and one has 7 claws on 1 lamella

A

_ S. msmiesi

- S. bisetula

m i £ sandersi

- S. variabilis

B

J

c

m

j

3 4 5 6 78 9 10 11

NUMBER OF BRISTLES

7 8 9 10 678 9

NUMBER OF CLAWS

10

FIGURE 26.—Comparison of 7th limb and furca of adult females: A, bristles in proximal group of 7th limb; B, number

of claws on left lamella; c, number of claws on right lamella.

and 9 on the other. Seven of the eight specimens of S.

variabilis have 8 claws on at least one of the lamellae;

four of these have 8 claws on both lamellae, and three

have 7 on one and 8 on the other. The eighth specimen

of S. variabilis has 7 claws on one lamellae and 9 on

the other. The single specimen of S. menziesi and S.

bisetula have 8 claws on each lamella.

All specimens examined have only claw 1 continuous with the lamellae; the remaining claws are separated from the lamellae by a suture. On all specimens

claw 3 is smaller and weaker than claw 4. The lamella

having 9 claws on the single specimens of S. variabilis

and S. sandersi mentioned above differed in having

both the 3rd and 5th claws small and weak. It is possibly significant that the specimen of S. variabilis with

9 claws and an unusual 5th claw is from station V18-13 (135 m depth), whereas the remaining specimens with the normal furca are from station V-15-131

(1475 m depth), but additional material is needed to

investigate this possibility.
42

References

Darby, D. G.

1965. Ecology and Taxonomy of Ostracoda in the Vicinity

of Sapelo Island, Georgia. In Four Reports of

Ostracod Investigation, University of Michigan,

2: iii-vi+1—76, figures 1-89.

Elofson, O.

1941. Zur Kenntnis der Marinen Ostracoden Schwedens

mit Besondered Beriicksichtigung des Skageraks.

Uppsala Universitet, Zoologiska Bidrag frdn Uppsala, 19:215-534, 52 figures, 42 maps.

Jones, Meredith L.

1958. Sarsiella tricostata, a New Ostracod from San Francisco Bay (Myodocopa: Cypridinidae). Journal of

the Washington Academy of Sciences, 48(2):48-52,

figures 1, 2.

Kesling, Robert V.

1951. The Morphology of Ostracod Molt Stages. Illinois

Biological Monographs, XXI (1-3): 1-324.

Kornicker, L. S.s and C. D. Wise

1962. Sarsiella (Ostracoda) in Texas Bays and Lagoons.

Crustaceana, 4(1): 57-74, figures 1-10.

Kornicker, Louis S.

1967. A Study of Three Species of Sarsiella (Ostracoda:

Myodocopa). Proceedings of the United States

National Museum, 122(3594): 1-46, 3 plates, 19

figures.

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

Mullcr, G. W.

1894. Die Ostracoden des Golfes von Neapel und der

Angrenzenden Meeres-Abschnitte. In Fauna und

Flora des Golfes von Neapel, 21 :viii+404, 40 plates.

Poulsen, E. M.

1962. Ostracoda-Myodocopa, 1: Cypridiniformes-Cypridinidae. Dana Report No. 57, 414 pages, 181

figures. Copenhagen: Carlsberg Foundation.

1965. Ostracoda-Myodocopa, 2: Cypridiniformes-Rutidermatidae, Sarsiellidae and Asteropidae. Dana Report No. 65, 484 pages, 156 figures. Copenhagen:

Carlsberg Foundation.

Ramsch, von Alfred

1906. Die Weiblichen Geschlechtsorgane von Cypridina

mediterranea. Zoologischer Anzeiger, XXIX: 133-

136, 1 figure.

Skogsberg, T.

1920. Studies on marine ostracods, 1: Cypridinids, halocyprids, and polycopids. Zoologiska Bidrag frin

Uppsala, supplement, 1:1-784, 153 figures.

Tessier, Georges

1960. Relative Growth. In Waterman, The Physiology of

Crustacea, 1:537-560. New York and London:

Academic Press.

Word, B. H., Jr., and H. H. Hobbs, Jr.

1958. Observations on the Testis of the Crayfish Cambarus

montanus acuminatus Faxon. Transactions of the

American Microscopical Society, LXXVII(4) :435-

450, 3 plates.
PLATES

331-394 O-69—4

NUMBER 8 45

a

0.5 mm

d

PLATE I.—Spinacopia sandersi: a, $ adult, USNM 122692; b, $ adult, USNM 122561.

Spinacopia menziesi: c, 9 USNM 122086. Spinacopia variabilis: d, $ adult, USNM 122691.
SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

PLATE 2.—Food: a, copepod in stomach of Spinacopia sandersi, $ instar III, specimen 34; b,

polycopid ostracod in stomach of S. sandersi, 9 instar IV; c, podocopid ostracod in stomach of

S. sandersi, instar II, specimen 29; d, detail of podocopid ostracod from specimen 29; e, gut

content of S. variabilis from station V-15-131.
NUMBER 8 47

PLATE 3.—Spinacopia menziesi, holotype: a, carapace, L=2.75 mm; b, 2nd antenna; c, furca.

Spinacopia bisetula, holotype: d, carapace, L=1.92 mm. Spinacopia variabUis, holotype: e, f,

2nd antenna.
48

SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

PLATE 4.—Spinacopia sandersi: a, carapace, 9 adult, holotype L=1.77 mm; b, 1st antenna,

$ instar III, specimen 10; c, mandible, 9 instar IV, specimen 15; d, 2nd antenna, $ instar III,

specimen 10; e, smear showing sperm from testes, S adult, specimen 3 (stained); /, smear

showing sperm from seminal vesicle, $ adult, specimen 36 (stained). (Figures e and / made

with phase illumination.)
NUMBER 8 49

PLATE 5.—Spinacopia sandersi, $ adult, specimen 3: a, carapace, L=1.59 mm; b, 1st antenna;

c, 2nd antenna; d, 7th limb; e, copulatory organ. Specimen 37: /, copulatory organ.
50 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

o.i mm

PLATE 6.—Spinacopia buetula, carapace of holotype.

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