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Group Title: Planktonic ostracods of the Sargasso Sea off Bermuda (FLMNH Bulletin v.26, no.2)
Title: The Planktonic ostracods of the Sargasso Sea off Bermuda
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
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Permanent Link: http://ufdc.ufl.edu/UF00095811/00001
 Material Information
Title: The Planktonic ostracods of the Sargasso Sea off Bermuda species composition and vertical and seasonal distribution between the surface and 2000 m
Physical Description: p. 37-124 : ill. ; 23 cm.
Language: English
Creator: Deevey, Georgiana Baxter, 1914-
Brooks, Albert, 1929-
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1980
Copyright Date: 1980
 Subjects
Subject: Ostracoda -- Vertical distribution -- Sargasso Sea   ( lcsh )
Ostracoda -- Seasonal distribution -- Sargasso Sea   ( lcsh )
Ostracoda -- Vertical distribution -- Bermuda Islands   ( lcsh )
Ostracoda -- Seasonal distribution -- Bermuda Islands   ( lcsh )
Crustacea -- Vertical distribution   ( lcsh )
Crustacea -- Seasonal distribution   ( lcsh )
Crustacea -- Sargasso Sea   ( lcsh )
Crustacea -- Bermuda Islands   ( lcsh )
Genre: bibliography   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Spatial Coverage: Bermuda
 Notes
Bibliography: Bibliography: p. 122-124.
General Note: Bulletin of the Florida State Museum, Volume 26, Number 2
Statement of Responsibility: Georgiana B. Deevey and Albert L. Brooks.
 Record Information
Bibliographic ID: UF00095811
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 08591501
lccn - 81623586

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Full Text











of the
FLORIDA STATE MUSEUM
Biological Sciences

Volume 26 1980 Number 2






THE PLANKTONIC OSTRACODS OF THE SARGASSO SEA OFF
BERMUDA: SPECIES COMPOSITION AND VERTICAL AND
SEASONAL DISTRIBUTION BETWEEN THE SURFACE
AND 2000 M


GEORGIANA B. DEEVEY
AND
ALBERT L. BROOKS


UNIVERSITY OF FLORIDA


GAINESVILLE








Numbers of the BULLETIN OF THE FLORIDA STATE MUSEUM, BIOLOGICAL SCIENCES,
are published at irregular intervals. Volumes contain about 300 pages and are not necessarily
completed in any one calendar year.












OLIVER L. AUSTIN, JR., Editor
RHODA J. RYBAK-BRYANT, Managing Editor

Consultants for this issue:

MARTIN V. ANGEL

Louis S. KORNICKER














Communications concerning purchase or exchange of the publications and all manuscripts
should be addressed to: Managing Editor, Bulletin; Florida State Museum; University of
Florida; Gainesville, Florida 32611.
Copyright 1980 by the Florida State Museum of the University of Florida

This public document was promulgated at an annual cost of $2,550.00
or $2.55 per copy. It makes available to libraries, scholars, and all in-
terested persons the results of researches in the natural sciences, em-
phasizing the circum-Caribbean region.


Publication date: December 22, 1980


Price: 2.50







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


THE PLANKTONIC OSTRACODS OF THE SARGASSO
SEA OFF BERMUDA: SPECIES COMPOSITION AND
VERTICAL AND SEASONAL DISTRIBUTION BETWEEN
THE SURFACE AND 2000 M


GEORGIANA B. DEEVEY AND
ALBERT L. BROOKS1


SYNOPSIS: A year-round qualitative and quantitative study of the planktonic ostracods was
made over four depth zones (0-500, 500-1000, 1000-1500, and 1500-2000 m) at station S,
3210'N, 64030'W, in the Sargasso Sea off Bermuda. Samples were collected monthly from
July 1968 to September 1970 with No. 8 nets (aperture 0.202 mm), and from January to
September 1970 with comparable No. 2 nets (aperture 0.363 mm). Total numbers varied con-
siderably during the period of study and decreased greatly in going from the upper waters to
the 500-1000 m depth zone, where ca. one-seventh as many ostracods were found. The No. 8
net caught three to four times as many ostracods as the No. 2 net. The mean total crop ob-
tained for the 2,000 m column was 7,000/m2 for the No. 8 net samples, and 1,920/m2 of sea
surface for the No. 2 net hauls. The three lower depth zones together contained a quarter to a
fifth as many ostracods as the upper 500 m.
Of 65 species recorded, one was a cypridinid and the others halocyprids. Of these there
were 3 species of Halocyprinae, 11 species of Archiconchoecinae, 1 species of Eucon-
choecinae, and 49 species of Conchoecinae, including 1 new species. The total numbers of
species recorded for the four depth zones by the two nets were 35 species from 0 to 500 m, 52
from 500 to 1000 m, 42 from 1000 to 1500 m, and 33 from 1500 to 2000 m. The year-round
variations in numbers of the more abundant species over the four depth zones are given,
together with brief descriptions and figures of most of the species not hitherto described from
these waters.



TABLE OF CONTENTS


INTRODUCTION ................. ...................................... 38
ACKNOWLEDGMENTS ................................................. 40
METHODS .............................................................. 40
THE OSTRACODS ..................................................... 40
SPECIES COMPOSITION ................................................... 43
THE SPECIES OF OSTRACODS .................. .......................... 53
Family Cypridinidae ................................................. 53


IDr. Deevey is an Adjunct Curator in Biological Oceanography at the Florida State Museum, University of Florida,
Gainesville 32611. Dr. Brooks is at the Naval Underwater Systems Center New London, Connecticut 06320.

DEEVEY, G.B., and A.L. BROOKS. 1980. The Planktonic Ostracods of the Sargasso Sea off
Bermuda: Species Composition and Vertical and Seasonal Distribution Between the Surface
and 2000 m. Bull. Florida State Mus., Biol. Sci. 26(2):37-124.


1980







38 BULLETIN FLORIDA STATE MUSEUM Vol. 26, No. 2

Family Halocyprididae ................................................. 55
Subfam ily Halocyprinae ............................................. 55
Subfam ily Euconchoecinae ........................................... 59
Subfamily Archiconchoecinae ......................................... 59
Subfamily Conchoecinae ................................... ...... 66
Mamillata Group .................................... ......... 66
Conchoecia nanomamillata, new species ............................ 67
Spinifera Group M uller ........................................ 74
Elegans Group M uller ........................................... 82
Procera Group Muller ............ ............................ 84
Acuminata Group M uller ...................................... 85
Rotundata Group M uller ....................................... 85
Curta G roup M uller ............................................. 91
Bispinosa Group M uller ................................... ..... 96
Edentata Group Gooday ......................................... 99
Gaussae Group Skogsberg ............................ .......... 101
M agna Group Muller .............................. ............ 105
Loricata Group M fuller. ................... ....................... 112
Serrulata Group Skogsberg ...................... ....... ..112
M ollis G roup M uller ............................................. 113
Im bricata Group M uller ......................................... 116
Daphnoides Group Muller .................................... .. 121
LITERATURE CITED ...................................................... 122

INTRODUCTION

Most recent investigations on planktonic ostracods have been con-
cerned with the taxonomy of the species or with their vertical or
geographic distributions (e.g., Angel 1969a; Poulsen 1973; Angel and
Fasham 1975; Fasham and Angel 1975; Deevey 1978a, 1978b). Most
planktonic ostracods are oceanic and thus virtually no year-round quan-
titative investigations of particular species have been made at a single sta-
tion and over a wide depth range, although some seasonal data have been
reported. In his year-round study of the zooplankton at Station M at 660N
in the Norwegian Sea, Ostvedt (1955) tabulated the total numbers over
several depth levels down to 2000 m of the three species that occur in those
waters and found that from March to September the bulk of the ostracod
population was between 600 and 1000 m; fewest were in the surface
waters, and next highest numbers were caught between 1000 and 2000 m.
Kielhorn (1952) indicated the seasonal occurrence of several species, of
which Conchoecia obtusata was the most numerous, at Station B in the
Labrador Sea, and Fish (1954) tabulated the relative percentages of
ostracods over two years at Station E in the Sargasso Sea at 350N, but
both these studies sampled only the upper 150 m. Also, some data on
seasonal variations in total numbers of ostracods in the Sargasso Sea have
already been reported (Deevey 1968, 1971; Deevey and Brooks 1971).
As part of a year-round qualitative and quantitative study of the







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


zooplankton of the Sargasso Sea off Bermuda, special emphasis has been
centered on the ostracods. The general results obtained during the first
year of sampling and the data for the copepods have been reported
(Deevey and Brooks 1971, 1977); and also several species of bathypelagic
copepods have been described (Deevey 1972, 1973a, 1973b, 1974a), as
well as new species of Archiconchoecia (Deevey 1978a). This report
presents the quantitative data obtained for the planktonic ostracods dur-
ing two years of monthly sampling, over four depth zones between the
surface and 2000 m at Station S, and also includes brief descriptions and
figures of the species not previously described from these waters.
The planktonic ostracods of this region of the North Atlantic should
now be better known than those of any other waters as, aside from our in-
vestigations, Angel (1979) studied them on a DISCOVERY cruise, and in
10 days' intensive sampling at Ocean Acre, centered at 320N, 640W,
caught a total of 60 species between the surface and 3500 m. He obtained
data for day and night vertical distributions of the species over 16 depth
zones between the surface and 2000 m and compared the relative abun-
dances and the vertical ranges of the species here with their occurrences at
30N, 23W in the eastern Atlantic. He also made many measurements on
the more numerous species, discussed differences in size ranges with
depth, considered the effects of a number of variables on clutch size, and
gave the zoogeographical groupings based on factor analyses of many of
the species in the eastern and western North Atlantic.
Station S, 15 miles southeast of Bermuda at 32010'N, 6430'W, in
3200 m of water, has been occupied almost continuously as a
hydrographic station since 1957. The hydrographic data for the period
studied, July 1968 to September 1970, is contained in a report from the
Bermuda Biological Station (Morris et al. 1973). The temperature data
over a number of depth levels between 1 and 2500 m-depths are il-
lustrated in Figure 1. Seasonal temperature changes between ca 180 and
28C occurred primarily within the upper 200 m, although variations of
considerable magnitude were noted to depths of 800 to 1000 m in
February and from July to September 1970, and these incursions of cold
water masses had a marked effect on the numbers and species of
zooplankton. These cold water masses of lower salinity may be cold core
rings from the Gulf Stream, bringing less saline slope water into this area,
rather than due, as has been suggested (Angel pers. comm.), to mesoscale
eddies or Meddies (McDowell and Rossby 1978) which contain higher
salinity Mediterranean water mixed with eastern Atlantic water and are
thought to be generated south of the Azores and to move west across the
Atlantic into the region of the Sargasso Sea. The cold water masses were
most noticeable throughout the permanent thermocline, which extends
from ca 400 to 1000 m-depths, where the temperature decreases to 6-70C.


1980







BULLETIN FLORIDA STATE MUSEUM


North Atlantic Central Water extends to depths of ca 800 m, and overlies
North Atlantic Intermediate Water which extends down to the level of the
4C isotherm at ca 1700 m; this marks the boundary with North Atlantic
Deep Water.

ACKNOWLEDGMENTS
This work was partially supported by Grants GB-15575 and GA-31736 from the National
Science Foundation, and by NAVSEA, Code 06H1-4, Subproject and Task Numbers
SF52552601 and 19325 respectively, supporting NUSC Project Number A62602. This is con-
tribution number 856 from the Bermuda Biological Station.

METHODS
Our methods have been described in detail (Deevey and Brooks 1971, 1977). From July
1968 to September 1970 zooplankton samples were collected monthly in daytime over four
depth zones (0-500, 500-1000, 1000-1500, and 1500-2000 m), from the Bermuda Biological
Station's research ship, PANULIRUS II. No. 8 nets (aperture 0.202 mm) were used
throughout the period, an open net for the upper 500 m and a Bd (1962) multiple plankton
sampler, 4 X /4 m, equipped with three nets (with separate TSK flow-meters) that were
pressure-activated to sample successively the three lower depth zones. We also collected
samples with comparable No. 2 (aperture 0.363 mm) mesh nets from January to September
1970. These samples are now stored at Florida State Museum.
In our study of the total zooplankton, quantitative counts were made on aliquots of the
samples collected from the three upper depth zones. In the samples collected during the first
year all organisms were counted from the 1500-2000 m-hauls; during the second year only
half of the deepest samples were counted, as the samples were halved to obtain biomass deter-
minations. Ostracods were counted from a greater proportion of the samples, usually from 5
to 10% of the 0-500 m hauls, from a quarter to all of the 500-1000 m samples, and one half to
all of the samples collected between 1000 and 2000 m. Unless some of the species performed
annual vertical migrations, such as have been noted for some species of copepods (Deevey and
Brooks 1977), seasonal variations should be reflected only in the samples from the upper 500
m, where the annual temperature range was ca 160-280C (see Fig. 1). The 500-1000 m hauls
sampled the waters of the permanent thermocline, where temperature decreased with depth
from 160 to 70C. The 1000-1500 m tows were taken in North Atlantic Intermediate Water,
where the temperature dropped from ca 70 to 40C. The temperature remained around 40C in
the deepest depth zone sampled.


THE OSTRACODS

TOTAL NUMBERS AND PERCENTAGES

For the 2000 m water column ostracods were second in abundance
after copepods in both the No. 2 and the No. 8 net samples. In the earlier
study (Deevey 1968, 1971) pelagic tunicates were slightly more abundant
than ostracods in the upper 500 m, but this was not the case in 1968-1970.
It is of interest to note that fstvedt's (1955) data for his 0-2000 m study in
the Norwegian Sea also indicated that ostracods were second in numbers
after copepods; his data were not quantitative, but he tabulated the total


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


1500 M

2500 M
J J'A'S'O'N'DI'J FM'A'M' J 'J A'S'O'N' DJ F'M'A'M'J J AS
1968 1969 1970
FIGURE 1. The variations in temperature at eight depths between 1 and 2500 m at Station S,
from July 1968 to September 1970. The unlabelled depth is 2000 m.

numbers caught per depth zone during the year and ostracods were sec-
ond in numbers, after copepods, followed by pteropods, chaetognaths
and coelenterates.
The No. 8 net caught three to four times as many ostracods as the No.
2 net (see Table 1). The mean total crop obtained for the 2000 m column
is 7,000/m2 for the No. 8 net samples and 1,920/m2 for the No. 2 net
samples. The decrease in total numbers is greatest in going from the upper
waters to the 500-1000 m depth zone, where approximately a seventh as
many ostracods were found. The three lower depth zones together con-
tained a quarter to a fifth as many ostracods as the upper 500 m.
Figure 2 shows the seasonal variations in total numbers over the four
depth zones from July 1968 to September 1970 in the No. 8 net samples.
Within the upper 500 m highest numbers were found in January, March







BULLETIN FLORIDA STATE MUSEUM


TABLE 1. Mean numbers of ostracods/1000 m3 with their standard deviations, percent
of total zooplankton, and number of species/depth zone, for 1968-1970 for
the no. 8 net samples, 1970 for the no. 2 net samples.

Net Depth (m) No./1000 m3 % of Total Zoopl. No. Species
8 0-500 12,340 + 3,607 6.5 33
8 500-1000 1,716 620 8.4 49
8 1000-1500 367 162 5.0 42
8 1500-2000 173 216 3.0 28
8 0-2000 3,502 930 5.7 64
8 500-2000 778 309 5.5
2 0-500 3,983 2,384 9.2 30
2 500-1000 492 242 8.6 39
2 1000-1500 101 47 5.7 29
2 1500-2000 43 20 3.4 16
2 0-2000 961 296 6.7 55
2 500-2000 205 100 5.9


or April, June or July, and September or October. In general the variation
in numbers was similar to that of the copepods (Deevey and Brooks 1977,
Fig. 2), although in 1970 highest numbers of copepods were present in
June, whereas ostracods were most numerous in September. Between 500
and 1000 m and 1000 and 1500 m the variations in numbers also followed
the cycles in numbers of copepods, but relatively fewer ostracods were
taken in the deeper waters in 1970. Between 500 and 1000 m highest
numbers were found from July to September 1968 and in March and July
1969; numbers remained low in 1970. Between 1000 and 1500 m
ostracods were most numerous in July to September 1968, March and
May to June 1969, and in June 1970. Over 1500-2000 m depths numbers
were consistently low except for a maximum in March 1969. It would ap-
pear that the smaller numbers of ostracods found between 500 and 1000
m in 1970 were related to the intrusions of cold water masses during this
period (see Fig. 1). In the upper waters total numbers were higher at this
time. The No. 2 net samples yielded a maximum of 10/m3 in March 1970
in the upper 500 m, but otherwise only low numbers were caught
throughout the water column by the coarser net.
The mean total numbers recorded for the No. 8 net samples for the
2000 m water column and for 500-2000 m depths are compared in Figure
3. The 0-2000 m data reflect the seasonal variations in numbers in the up-
per 500 m, where numbers were much higher. Below 500 m, as in the case
of the copepods, numbers were minimal in October 1968, April 1969, and
in 1970 at times of maxima in the upper waters. Throughout the water
column numbers were minimal in July and December 1968, June and
November 1969, and April-May 1970. Highest numbers in the deeper


Vol. 26, No. 2







1980


DEEVEY & BROOKS: PLANKTONIC OSTRACODS


waters were found in July to September 1968, and in March and May to
July 1969. Total numbers between 500 and 2000 m mirrored the varia-
tions in numbers over 500-1000 m depths, with a higher maximum in
March 1969 when maxima were noted over each of the three lower depth
zones.

11 iIi i I FI Ii i I I I I
20- -500 m






I F I I I
3- \ | 500-1000 m






z 0.5 -
00









10 / 1000-1500m
/.- 0














09 1500-2000 m


0.6-
0 \/i .0 / /.








0.3 0*



J'A'S'O'N'DIJ'F'M'AM' J 'J AISO'N'DI J FMA'M J J A'S
1968 1969 1970
FIGURE 2. The variations in total numbers/m3 of ostracods over the four depth zones, caught
by the No. 8 nets from July 1968 to September 1970.


SPECIES COMPOSITION

Over 40 species of planktonic ostracods have already been described
from Station S (Deevey 1968). That study was based primarily on samples







BULLETIN FLORIDA STATE MUSEUM


IJ'A' S'O N'DJ'F'M'A'M'J' J'A'S'O'N'DJ 'F 'M'A'M' J S
1968 1969 1970
FIGURE 3. Seasonal variations in the standing crop of total ostracods from the No. 8 net
samples, in numbers/m3, from July 1968 to September 1970, for the 2000 m water column
and for 500-2000 m depths.

collected year-round in the upper 500 m in 1961-1962, although a few
deeper samples were also available. Few quantitative seasonal data on the
occurrence of individual species were included in that investigation.
Sampling monthly down to 2000 m from 1968 to 1970 yielded records of
some 65 species, of which 64 are halocyprid ostracods, and one,
Macrocypridina castanea, belongs to the family Cypridinidae. The
species are listed, with their periods of occurrence and depth distribu-
tions, in Table 2. The 64 halocyprids included 3 species of the subfamily
Halocyprinae, 11 species of Archiconchoecinae, 1 species of Eucon-
choecinae and 49 species of Conchoecinae, including one new species. All
but one species were taken during the 2-year period in the No. 8 net hauls.


Vol. 26, No. 2






TABLE 2. The species of ostracods with their depth distributions and periods of occurrence, from 1968-1970.

Species Depth Dist., m Occurrence


Macrocypridina castanea (Brady) 1897
Halocypria globosa Claus 1874
Halocypris inflata (Dana) 1849
Fellia bicornis (Muller) 1906
Euconchoecia chierchiae Muller 1890
Archiconchoecia bifurcata Deevey 1978
A. bimucronata Deevey 1978
A. bispicula Deevey 1978
A. cucullata (Brady) 1902
A. cuneata Muller 1908
A. falcata Deevey 1978
A. gastrodes Deevey 1978
A. longiseta Deevey 1978
A. pilosa Deevey 1978
A. striata Muller 1894
A. ventricosa Muller 1906
Conchoecia acuminata (Claus) 1890
C. aequiseta Muller 1906
C. aequiseta hirsuta Muller 1906
C. ametra Muller 1906
C. arcuata Deevey 1978
C. atlantica (Lubbock) 1856
C. bispinosa Claus 1890
C. borealis Sars 1865
C. brachyaskos Muller 1906
C. concentrica Miller 1906
C. convexa Deevey 1977
C. curta Lubbock 1860


0-1500
0-2000
0-2000
500-1000
0-500
500-1500
1000-1500
500-1000
500-2000
500-1000
1000-2000
1000-1500
500-2000
1500-2000
0-1000
500-1000
0-500 (-1500)
500-1500
500-1500
500-2000
1000-2000
0-1000
0-1000
500-1500
500-2000
0-500
1000-1500
0-1000 (-2000)


Occasional, during year
February to June
Year-round
July 1969
Rare, during year
July-November 1968, April 1969
October 1968, September 1970
June, July 1970
Year-round
Year-round 1968-69, then rarer
February, June 1969
February 1970
July to December, February
June 1969
Year-round
April, August 1969, February 1970
Occasional, July to February
Occasional, year-round
December to May, occasional
Year-round
Year-round
July to October, January
July to September, January to April
June to December
Year-round
June to September, January
July 1969
Year-round












TABLE 2 continued


C. daphnoides (Claus) 1890
C. dichotoma Muller 1906
C. dorsotuberculata Muller 1906
C. echinulata (Claus) 1890
C. elegans Sars 1865 (small)
C. elegans Sars 1865 (large)
C. gaussae Muller 1908
C. glandulosa Muller 1906

C. haddoni Brady & Norman 1896
C. imbricata (Brady) 1880
C. inermis (Claus) 1890
C. kampta Muller 1906
C. lophura Mullerl906
C. loricata (Claus) 1894
C. macrocheira Muller 1906
C. macromma Muller 1906
C. magna Claus 1874
C. mamillata Muller 1906
C. microprocera Angel 1971
C. nanomamillata, n. sp.
C. nasotuberculata Muller 1906
C. oblonga (Claus) 1890
C. parthenoda Muller 1906
C. plinthina Muller 1906
C. porrecta Claus 1890
C. procera Muller 1894
C. pseudoparthenoda Angel 1972


0-2000
1000-2000
500-2000
0-1000 (-2000)
0-1500
500-1500
1000-2000
500-2000

500-2000
0-1000 (-2000)
500-1000
500-2000
500-1500 (-2000)
500-1000 (-1500)
500-1500
1000-2000
0-1000 (-2000)
1500-2000
0-500
1000-1500
0-1000
0-1000 (-1500)
0-1000
1000-1500
0-500
0-1000
0-500


Year-round
Essentially year-round
Essentially year-round
Year-round
Year-round
Between July and March
June to October, March
September-November, February
to June
April, June-August
Year-round
Essentially year-round
Essentially year-round
Essentially year-round
Essentially year-round
Between September and May
October-December, April, July
Year-round
Year-round
Year-round
Year-round
June 1969 & 1970
Year-round
Year-round
February 1970
Between July and January
Year-round
Between June and September






C. pusilla Muller 1906
C. reticulata Muller 1906
C. rhynchena Muller 1906
C. rotundata Muller 1890
C. secernenda Vavra 1906
C. skogsbergi lies 1953
C. spinifera (Claus) 1890
C. spinirostris Claus 1874
C. stigmatica Muller 1906
C. subarcuata Claus 1890

C. subedentata Gooday 1976


500-1500 (-2000)
1000-2000
500-1000
0-1000
0-1000 (-2000)
500-2000
0-1000 (-2000)
0-1000
500-1000 (-2000)
0-1000


500-1000


Essentially year-round
Occasional, year-round
May 1969
Year-round
Year-round
Year-round
Year-round
Year-round
Occasional, year-round
Between June and November,
February
Between March and November







BULLETIN FLORIDA STATE MUSEUM


A single juvenile Conchoecia plinthina was the only species caught
by the No. 2 net and not by the No. 8. In 1970 the No. 2 net caught 55
species; during this period the No. 8 net also caught 55 species, though not
necessarily the same species on the same occasions. A total of only 56
species was recorded in 1970. Angel (1979) identified 58 species in the up-
per 2000 m at Ocean Acre in March 1973. Together, his species list and
ours yield a total of 73 species from these waters.
As in the case of the copepods, the greatest number of species was
found between 500 and 1000 m depths, and the next highest number be-
tween 1000 and 1500 m. The No. 8 net hauls caught a total of 33 species
within the upper 500 m, 49 species between 500 and 1000 m, 42 species
from 1000-1500 m depths, and 28 species from between 1500 and 2000 m
(see Table 1). The No. 2 net tows, in the same sequence, caught 30, 39,
29, and 16 species. The total number of species recorded for the four
depth zones by the two nets were 35 species from 0 to 500 m, 52 species
from 500 to 1000 m, 42 from 1000 to 1500 m, and 33 from 1500 to 2000 m.
Although the total numbers of ostracods decreased sharply below 500 m,
the number of species nearly doubled.
Seasonal variations in total numbers of species are illustrated in Figure
4. In general, within the upper 500 m higher numbers of species were pre-
sent in winter and summer to fall; lowest numbers were found from April
to June. In the deeper waters, from 500 to 2000 m, the reverse was true,
especially in 1969, when low numbers were found in winter and highest
numbers from March to June. Fewer species were found throughout the
water column in November 1969 than at any other time during the
2-year period. This was also the month when minimal numbers of
ostracods were taken. Below 500 m, numbers of species increased in 1970
to a maximum in July. Fewer species were noted in August and September
1970, when maximal numbers of species were present in the upper waters.
The present investigation increased the species list for Station S by
some 24 species, most of which occurred below 500 m depths and most of
which were recorded by Angel (1979) from Ocean Acre. Two of the
species now known to occur in the surface waters, C. microprocera (Angel
1971) and C. pseudoparthenoda (Angel 1972), had not been described at
the time of the previous study. A number of other species now known
from Station S have also been recently described. Of seven species of Ar-
chiconchoecia, six are new (Deevey 1978a). Three other species of Con-
choecia, C. arcuata (Deevey 1978b), C. convexa (Deevey 1977), and C.
subedentata (Gooday 1976), are also newly described, but of these C. ar-
cuata was previously wrongly identified as C. kyrtophora Muller. Other
species we have now found at Station S include Fellia bicornis, C. ae-
quiseta hirsuta, C. dorsotuberculata, C. echinulata, C. gaussae, C. had-
doni, C. inermis, C. nasotuberculata, C. plinthina, C. stigmatica, and C.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


*\ 0 500 m

-\" \ / .-
a--


S500- 2000 m


0 2000 m


J'A'S'O'N'DIJ'F'M'A'M'J'JA' S 'O'NDI J'F M'A M J'J A'S
1968 1969 1970
FIGURE 4. The seasonal cycles in total numbers of ostracod species caught by the No. 8 nets
from July 1968 to September 1970, solid line, and the No. 2 nets between January and
September 1970, dotted line, for the upper 500 m, 500-2000 m depths, and the 2000 m water
column.

macromma, and also a new species closely related to C. mamillata.
Larger forms of C. elegans have also been found between 500 and 1500 m
depths. A notable change in the species composition between the early
and late 1960s was the appearance of C. echinulata, which was not noted
in the earlier study, but which by 1968 began to appear in larger numbers
than the very closely related C. curta, becoming second or third in abun-
dance of all the species. Angel (1979) recorded species that we did not find
from between the surface and 2000 m. These include Gigantocypris
muelleri, Conchoecia dasyophthalma, C. hyalophyllum, C. kyrtophora,
and C. major.
Because our sampling program lasted for a little more than 2 years, it


'r.



i\ v







BULLETIN FLORIDA STATE MUSEUM


is possible to determine whether continued sampling at the same oceanic
station yielded greater numbers of different species over a long sampling
period. In day and night tows in July 1968, 35 species or 54% were
recorded; by the first four months 50 or 77 % had been noted, and this in-
creased to 80% during the first 6 months; 58 species or 90% were re-
corded during the first year. After 24 months of sampling the 65 species
had been recorded. These percentages of numbers of species noted for
months of sampling are similar to those obtained for species of copepods
during the same period (Deevey and Brooks 1977). More than half the
total number of species was caught on the first sampling date, but con-
tinued sampling continued to yield more different species. These results
apply to our sampling methods and equipment, of course. As we have
noted, in a week's time by concentrated day and night sampling in these
waters with a combination of two much larger nets over 16 depth zones
between the surface and 2000 m, Angel (1979) caught 58 species, in-
cluding five we did not find in 2 years of sampling. Later sampling be-
tween 2000 and 3500 m yielded two more species: possibly C. sym-
metrica, hitherto known only from the Southern Hemisphere, and Gigan-
tocypris dracontovalis. The nets used on the DISCOVERY cruise are the
RMT 1 and RMT 8, described by Baker, Clarke, and Harris (1973).
Of the total number of species we noted, 35 or 54% were caught
within the upper 500 m, even if only rarely or in a night tow, and 30 or
46% were found only below 500 m. Within the upper 1000 m 55 species
occurred, and 57 species were found between the surface and 1500 m.
Thirteen, or 20%, of the total number of species were found only above
1000 m, and 10 or 15% occurred only between 1000 and 2000 m. Fifteen
species were noted, at one time or another, over the four depth zones be-
tween the surface and 2000 m, but only one species, Archiconchoecia
pilosa, has thus far been recorded only from 1500 to 2000 m depths.
The overall size ranges of the species of halocyprid ostracods, ca 0.5-5
mm, is similar throughout the 2000 m water column because tiny species
0.5-0.8 mm long occur at all depths, as does the largest halocyprid
species, C. daphnoides. The cypridinid Macrocypridina castanea is
6.0-6.4 mm long and was taken between the surface and 1500 m, with
mature individuals present between 500 and 1500 m; the total length
range was therefore greater over those depths. In the surface waters and
between 1500 and 2000 m, C. daphnoides females were the largest
specimens encountered (4.7-5.4 mm long). Most of the species of ostracods
are between 1 and 3 mm long, but, as in the copepods, the dominant
species in the upper waters are small, ranging from 0.8 to 2.0 mm in
length. The two largest species, which constituted 1% or more of the No.
2 or No. 8 net samples, C. secernenda and C. imbricata, are less than 3
mm long. Angel (1979) considered extensively the question of changes in


Vol. 26, No. 2






DEEVEY & BROOKS: PLANKTONIC OSTRACODS


size ranges of ostracods with depth at Ocean Acre, illustrated by a series of
30 histograms showing the sizes of ostracods over 25 to 100 m depth inter-
vals down to 1000 m and over three depth zones down to 2000 m by day
and by night. Diurnal migration made the day and night histograms dif-
fer somewhat within the upper 800 m; below 800 m the length spectra
were the same by day and by night. He concluded that in general by day
smaller animals inhabited the near surface layers and the size range
gradually lengthened with larger and larger animals down to 700 m;
below 700 m there were fewer larger animals. He noted changes in the
size spectra at 300 m, with an increase in ostracods greater than 1.5 mm in
length at 500 m, with fewer animals less than 1.0 mm long and an in-
crease in those more than 2.0 mm in length, and at 700 m and deeper
where smaller animals again predominated. Thus, although larger
copepods were predominant between 1000 and 1500 m at Station S
(Deevey and Brooks 1977), this does not appear to be true of the
ostracods. The commoner bathypelagic species living below 1000 m
depths are not necessarily larger than epipelagic species, as suggested by
Mauchline (1972) for bathypelagic organisms, especially Crustacea.
Most of the species of ostracods that constituted 1% or more of the No.
2 or No. 8 net samples over the four depth zones are listed in Tables 3 and
4, which given the mean numbers/1000 m3 and the mean percent of total
ostracods obtained for the various species. The standard deviations given
for the numbers in Table 3, in some instances larger than the means, in-
dicate the wide variations in numbers taken during the period studied.
The total numbers given for the species include identifiable juveniles.
Unidentified juveniles constituted 39-72% of the ostracods caught by the
No. 8 net, but no more than 16% of the No. 2 net samples. Conchoecia
spinirostris was by far the dominant species within the upper 500 m,
followed by C. echinulata, C. magna, C. procera, C. parthenoda, C.
oblonga, C. rotundata, and C. spinifera. C. rotundata, C. spinifera, C.
secernenda, C. imbricata, and C. daphnoides made up a higher percen-
tage of the ostracods from the 500-1000 m depth zone than from the upper
waters, although mean total numbers were lower except in the cases of
the No. 8 net catches of C. imbricata and C. daphnoides. All these species
occurred in varying numbers year-round. The one species that was
definitely seasonal, but nonetheless constituted an appreciable percentage
of the total numbers averaged over the period, was Halocypria globosa,
which appeared only between February and April in the upper 500 m. It
was also found throughout the water column with appreciable numbers
between 1000 and 2000 m. Other species of numerical importance in the
upper waters were Halocypris inflata and Archiconchoecia striata, small
species not adequately sampled by the No. 2 net. H. inflata was present
year-round throughout the water column and increased in percentage of






BULLETIN FLORIDA STATE MUSEUM


total numbers in the deeper waters, although the mean numbers/m3
decreased with depth.
Between 500 and 1000 m depths, aside from the species already men-
tioned, C. skogsbergi, C. brachyaskos, C. ametra, C. loricata, and Ar-
chiconchoecia cucullata were relatively abundant. Although some 52
species were noted from this depth zone, most occurred only occasionally
or in small numbers. Below 1000 m and to 1500 m-depths the commonest
species were Halocypria globosa, H. inflata, A. cucullata, C. daphnoides,
C. skogsbergi, C. ametra, C. dorsotuberculata, C. mamillata spp., C. ar-
cuata, and C. dichotoma. Most of these species constituted an equal or
greater proportion of the total numbers present between 1500 and 2000
m.
Thus, although some 65 species of ostracods were noted from the 2000
m water column, only two dozen species occurred consistently or in suffi-
cient numbers to make up an appreciable percentage of the total number
of ostracods recorded from Station S.
The mean numbers noted in Table 3 for the various ostracod species
indicate, over these broad depth zones, several patterns of depth distribu-
tion (see Fig. 5.)
1) Epipelagic species, such as C. microprocera (Fig. 5B) and C.
spinirostris inhabit the upper 500 m.
2) Most of the important species living in the upper waters followed
the general pattern of distribution with depth and were found in con-
siderably lesser numbers between 500 and 1000 m. Such species include
C. procera, C. magna, C. parthenoda, C. oblonga, C. rotundata, C.
spinifera, and C. secernenda (Fig. 5B). Of these, the last three constituted
higher percentages of the total numbers over 500-1000 m depths than they
did in the upper waters. H. inflata is notable in that it was found in
decreasing numbers throughout the 2000 m water column (Fig. 5B).
3) Other species, such as C. imbricata (Fig. 5A) and C. daphnoides,
occurred throughout the two upper depth zones, but were more
numerous between 500 and 1000 m than they were in the upper waters.
4) Some species were absent, or rarely noted, in the upper 500 m, but
were most numerous between 500 and 1000 m. Of these, C. loricata was
found only between 500 and 1000 m, and C. ametra (Fig. 5A) was
prevalent only between 500 and 1500 m, whereas C. skogsbergi (Fig. 5A)
occurred in decreasing numbers between 500 and 2000 m.
5) The C. mamillata species complex (Fig. 5A) and C. brachyaskos
were found between 500 and 2000 m, but were present in higher numbers
between 1000 and 1500 m.
6) C. arcuata and C. dichotoma were noted only between 1000 and
2000 m, in equal numbers in the No. 8 net samples.


Vol. 26, No. 2






DEEVEY & BROOKS: PLANKTONIC OSTRACODS


Mean No./1000m3
0 100


FIGURE 5. The patterns of depth distribution of ostracod species, plotted as mean
numbers/1000 m3 at the midpoints of the four depth zones. A: C. imbricata, C. skogsbergi,
C. ametra, C. mamillata spp. B: H. inflata, C. microprocera, C. secernenda.


THE SPECIES OF OSTRACODS
SUBORDER CYPRIDINIFORMES SKOGSBERG
FAMILY CYPRIDINIDAE DANA
Macrocypridina castanea (Brady) s. str.
Juvenile specimens of this species were caught within the upper 1500
m every month of the year except August and November. Mature females,
ranging in length from 6.0 to 6.4 mm, were taken in May and July be-
tween 500 and 1500 m-depths. In the Canary Island region Angel (1969a)
found M. castanea most numerous between 220 and 300 m, but in the
Sargasso Sea (Angel 1979) this species was taken from an overall range of
100-1250 m. In our samples it was more commonly noted between 500
and 1000 m.
DISTIBUTION 600N-35S in the Atlantic. The Indo-Pacific form has
been put in a different species, M. poulseni (Martens 1979).










TABLE 3. Mean numbers/1000 m3 with the standard deviations of the more important ostracod species for the four depth zones in the no. 2 and no. 8 net
samples.


No. 8 Net Samples No. 2 Net Samples

500- 1000- 1500- 500- 1000- 1500-
0-500 1000 1500 2000 0-500 1000 1500 2000

Halocunria globosa 138 370 13 12 550 1383 4 9 2 5


Halocypris inflata
Total Archiconchoecia
A. striata
A. cucullata
Conchoecia sp. juv.
C. spinirostris
C. echinulata
C. procera spp. total
C. magna
C. parthenoda
C. oblonga
C. rotundata
C. spinifera
C. secernenda
C. microprocera
C. imbricata
C. daphnoides
C. skogsbergi
C. brachyaskos
C. ametra
C. loricata
C. dorsotuberculata
C. mamillata spp. total
C. arcuata
C. dichotoma


8 18
85

74
127 199


93 61



10 18
1216+ 859
491 241
272 74
387 190
237 77
202 102
88 49
184 136
105 85

58 51
14 20


34
24 15

84
18 21
35 26
911
16 20
28 22
146 82
37 46


89
16 13


262 233
146 116
139 138

4955 1252
2258 1254
880 621
1208 618
594 311
412 426
346 167
391 288
331 293
188 184
180 156
51 53
17 32


18 13
47 27
98
27 21
847 335

29 38
37 45
46 21
13 18
27 28
99 73
190 89
6565

9255
22 30
57 52
11 16
3733
16 15
23
47


12 15
27 12

2512
213 127














37 27
16 13
75

22
17 12
86
24


48 26
106 23
5437 2012
76 1618
54 57
13 15
12
23
118
35







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


SUBORDER HALOCYPRIFORMES SKOGSBERG
FAMILY HALOCYPRIDIDAE DANA
SUBFAMILY HALOCYPRINAE POULSEN
Halocypria globosa Claus
As noted during the previous study (Deevey 1968), this species was
definitely a winter-spring form at Station S (see Fig. 6). It occurred from
February to May 1969 and from February to June 1970, with highest
numbers in the surface waters in March. Females and juveniles were


4I I T I I

. ,- k ,,-


J A S'OWD J F M'A'M'JJ 'A'S'ON'DIJ F'MA'M'JJ A'S'
1968 1969 1970
FIGURE 6. Seasonal variations in numbers/m3 within the upper 500 m of A. striata taken in the
No. 8 net samples and of H. globosa caught in the No. 2 net samples, solid line, and the No. 8
net samples, dashed line, from July 1968 to September 1970.


1980







BULLETIN FLORIDA STATE MUSEUM


caught in the upper waters; males were found only between 500 and 2000
m depths. Males have been rarely recorded, but were reported by Muller
(1906) and Poulsen (1969a) who had abundant material from the "Dana"
collections. Poulsen found that females vary in length with latitude,
largest specimens occurring at high latitudes, and the smallest in
equatorial waters, the overall range being 2.10-2.93 mm. At Station S,
females were 2.0-2.5 mm long, males 2.3 mm in length. Males differ in
shape from the females, as shown in Figure 7, which also includes figures
of the 1st antenna, furca and penis, and parts of the 2nd antennae.
Species of this subfamily are separated from the Conchoecinae by the lack
of a tubercle or processus mammillaris on the basal segment of the en-
dopodite of the 2nd antenna (Fig. 7f); also although the distal segments of
the 1st antenna bear five setae or filaments, one of them longer than the
other four, these are not sexually dimophic but similar in both sexes (Fig.
7d).
It is not clear from the published data whether H. globosa occurs
seasonally in other localities, but it most definitely was found only be-
tween February and June at Station S. The fact that it was taken in the
southeast Indian Ocean only in late spring and not on two cruises there
during the winter months may indicate that it occurs seasonally also in
those waters (Deevey 1981.)
DISTRBUTION --64N-450S in the Atlantic, ca 380N-52S in the
Pacific, and ca 0-42oS in the Indian Ocean.

Halocypris inflata (Dana)
Martens (1979) recently noted that this species, previously called H.
brevirostris (Dana) by Skogsberg (1920), Deevey (1968 and later publica-
tions), Poulsen (1969a,b), Angel (1979 and earlier publications), and
others, by a ruling of the International Commission for Zoological
Nomenclature must now by called H. inflata (Dana). This species oc-
curred year-round throughout the 2000 m water column, although in
small numbers in the deeper waters (see Figs. 5B and 8). In the upper 500
m it was most numerous in November 1968 and February 1969 and 1970.
Throughout the water column numbers were minimal in September 1968,
the fall of 1969, and the spring of 1970 (see Fig. 8). In general the
numbers were maximal in winter and low the rest of the year. The mean
number obtained for the total water column was 75/1000 m3, or 150/m2 of
sea surface. The majority of the specimens noted were juveniles.
This is the only species in this genus. Poulsen (1969a) observed no mor-
phological differences between specimens from the Atlantic, Pacific, and
Indian Oceans. There is considerable variation in size, and Poulsen
reported an overall size range of 1.1-2.1 mm for females and of 0.9-1.9
mm for males. Angel (1979) suggested that possibly the large and small


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


FIGURE 7. Halocypria globosa male. a, b, and e, Lateral, ventral, and posterior views of shell;
c, Left clasping organ; d, First antenna; f, Endopodite of right second antenna, filaments and
setae cut off; g, Furca; h, Penis. Scale on a, b, and e; at left center for c; on lower right
margin for d, f, g, h. Scales in mm.

forms may represent two species. At Station S only small specimens were
found, females 1.1-1.3 mm and males 0.95-1.15 mm in length. Angel gave
length ranges of 1.0-1.4 mm for females and of 1.0-1.2 for males from the
Ocean Acre samples.
DISTRIBUTION--Ca 470N-490S in the Atlantic, ca 40N-54S in the
Pacific, and ca 10'N-45S in the Indian Ocean.







BULLETIN FLORIDA STATE MUSEUM


Fellia bicornis (Muller)
A single female, 2.04 mm long by 1.66 mm high, was taken in a night
tow in July 1969 from 500 to 1000 m-depths. This is the first record of this
species from the Sargasso Sea. F. bicornis has been rarely recorded
(Poulsen 1969a, Deevey 1970, 1978c, Chavtur 1977) since it was almost
simultaneously described by Vavra and by Muller in 1906, from between
100N and 100S in the Atlantic and Indian Oceans. This species was briefly
described and figured from the waters off Barbados (Deevey 1970, Fig.
2).
DISTRIBUTION F. bicornis has been found mainly in tropical waters.
Poulsen recorded two specimens from 46028'N, 80W in the eastern North
Atlantic, but other Atlantic records are from 200N-8S. It has also been
found in equatorial Indian Ocean waters, in Indonesian Seas, and ca
40 + N (Chavtur 1977) to 42S in the Pacific.



I I I I II i .11 I Ii I I I I I I
H. inflata
0-500 m
800-



400

o0
SI I I I I I
0 0-
500- 1000 m
o 40-



0 , I, I I I I I.I
1000- 1500 m

20
\. ______ ____
J'A'S'O'ND J F'M'MA J'ASS'ON'D J'FMAMJ AS
1968 1969 1970

FIGURE 8. Seasonal variations in numbers/1000 m3 of H. inflata, taken in the No. 8 net
samples, from 0-500 m, 500-1000 m, and 1000-1500 m, from July 1968 to September 1970.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


SUBFAMILY EUCONCHOECINAE POULSEN
Euconchoecia chierchiae Muller
Although this species was previously observed as occurring seasonally
between September and April (Deevey 1968), between 1968 and 1970 it
occurred occasionally during the year, more frequently during the first
year than during the second. This is a small neritic epipelagic species
described from off the coast of Brazil (Muller 1890) and presumably is
more abundant in Bermuda's inshore waters. It has been recorded from
outside Delaware Bay and from Block Island Sound off southern New
England (Deevey 1952, 1960), but according to Poulsen (1969a) is most
abundant in tropical and subtropical regions. Females are 1.1-1.3 mm
long, males 1.0-1.2 mm.
DISTRIBUTION 420N-ca 37S off South Africa in the Atlantic, 0-30S
in the Indian Ocean, ca 250N-30S in the western Pacific Ocean.


SUBFAMILY ARCHICONCHOECINAE POULSEN
A recent report on the species of Archiconchoecia found at Station S in
1968-1970 described six new species from these waters (Deevey 1978a). In
all, 16 species have now been described, and the report on the species at
Station S included a key to 14 of them, 10 of which occurred in the
Sargasso Sea. Descriptions of the other two species, from south of the Ant-
arctic Convergence in the South Pacific, are now in press (Deevey 1981).
At present, 11 species are known from Station S, and a species described
from the Caribbean Sea has since been found in these waters. Two species
occurred year-round in appreciable numbers (see Tables 3 and 4), A.
striata in the upper waters, and A. cucullata between 500 and 2000
m-depths. Table 4 shows that the species of Archiconchoecia, primarily
because of A. cucullata, increased in importance with depth, and con-
stituted 7% of the total numbers of ostracods between 1000 and 1500 m.

Archiconchoecia striata Muller
A. striata was most numerous in the upper waters in October-
November 1968 and in January 1969 and 1970, with small numbers pre-
sent in spring and summer (see Fig. 6). The picture changed in February
1970 coincident with the influx of the cold water mass, when none were
taken, but numbers were relatively high from June to September, and
highest in September after the second cold water mass had moved in (see
Fig. 1). A. striata also occurred consistently in much smaller numbers,
between 1 and 28/1000 m3, between 500 and 1000 m, especially from July
1968 to November 1969. The mean number obtained for the upper 500 m
was 139/1000 m3.









TABLE 4. Percent of total ostracods of the more important species in the no. 2 and no. 8 net samples over the four depth zones.


No. 8 Net Samples No. 2 Net Samples
500- 1000- 1500- 500- 1000- 1500-
0-500 1000 1500 2000 0-500 1000 1500 2000

Halocypria globosa 1.1 0.3 0.6 13.8 4.0 4.7
Halocypris inflata 2.1 1.1 3.3 4.6 2.6 -
Total Archiconchoecia 1.2 2.8 7.4 4.6 0.8 7.9 14.0
A. striata 1.1 0.5 -
A. cucullata 1.6 6.8 4.0 0.6 7.9 7.0
Conchoecia sp. juv. 39.5 49.4 58.2 72.3 0.3 4.9 15.8 9.3
C. spinirostris 18.2 30.5 -
C. echinulata 7.2 1.7 12.3 1.6 -
C. procera spp. total 9.7 2.2 6.8 3.7 -
C. magna 4.5 2.7 9.7 7.1 -
C. parthenoda 3.2 0.8 5.9 1.8 -
C. oblonga 2.8 1.6 5.1 3.3 -
C. rotundata 3.2 5.7 2.2 5.7 -
C. spinifera 2.6 11.0 4.6 29.7 -
C. secernenda 1.5 3.7 2.6 7.5 -
C. microprocera 1.4 -
C. imbricata 0.4 5.4 1.5 9.8 -
C. daphnoides 0.1 1.3 0.4 1.4 2.0 2.3
C. skogsbergi 3.9 10.1 1.2 11.0 19.8 4.7
C. brachyaskos 0.7 4.4 0.6 1.4 15.8 2.3
C. ametra 2.2 1.9 1.0 5.0 -
C. loricata 0.8 2.6 -
C. dorsotuberculata 0.1 0.5 0.6 1.0 7.0
C. mamillata spp. total 0.2 4.6 5.2 2.0 9.3
C. arcuata 1.9 4.0 10.9 4.7
C. dichotoma 0.5 1.2 3.0 9.3







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


This is the smallest ostracod that occurs at Station S, males and
females being 0.5-0.6 mm long, and it was therefore not caught by the
coarser No. 2 mesh nets.
DISTRIBUTION- 36N-420S in the Atlantic, 330N-33S in the Pacific,
7N-33S in the Indian Ocean, and the Mediterranean Sea. It has not
been taken south of the Subtropical Convergence in the Southern
Hemisphere.
A. cucullata (Brady)
The variations in mean numbers of this distinctive species over the
three lower depth zones between 500 and 2000 m are shown in Figure 9.
Between 500 and 1000 m, A. cucullata was most numerous in August and
December 1968, February-March and July to October 1969, and
S I I I I i I I I I I I



40 *







O c1000- 1500 m
0 45-







0 1500- 2000m C
245 \ 0Aj









1968 1969 1972000
10, /.-.\0.. ^ ^ ^.^. .

SAj'A'S O'N'DlJ'F 'M'A'M'J j'A'S O'N'D J FM A M J JJ'A'S
1968 1969 1970
FIGURE 9. Seasonal variations in numbers/1000 m3 of A. cucullata, taken in the No. 8 net
samples, from A: 500-1000 m, B: 1000-1500 m, and C: 1500-2000 m, between July 1968
and September 1970.







BULLETIN FLORIDA STATE MUSEUM


February, May, and September 1970. Between 1000 and 1500 m, highest
numbers were noted in July 1968 when minimal numbers were present
over the other two depth zones; in general A. cucullata was more abun-
dant in 1968 and 1969 and only small numbers were taken after
November 1969. Between 1500 and 2000 m small numbers were present
year-round. This species constituted 7-8% of the total numbers of
ostracods caught below 1000 m-depths (see Table 4). The mean number
obtained from the No. 8 net samples for the 1500 m column was 21/1000
m3, or 31.5/m2 of sea surface.
A. cucullata differs from all other known species of Archiconchoecia
in the shape and sculpturing of the shell, and in features of the 1st and 2nd
antennae from all other known species of this genus, and should possibly
be placed in a separate genus. It is also the largest known species. Females
ranged from 1.75 to 2.45 mm in length, males from 1.6 to 2.55 mm.
Poulsen (1969a) noted a similar wide size range. Angel (1979) gave length
ranges of 1.58-1.80 mm for females and of 1.62-1.82 mm for males; he
noted larger specimens were caught from below 1500 m at Ocean Acre
and suggested that these forms may prove to be taxonomically distinct.
The majority of the specimens caught at Station S were juveniles, and
males were rarely noted. As this species was taken only below 500 m and
the overall temperature range was ca 4-160C.
DISTRIBUTION 600N-50030'S in the Atlantic, 450N-57S in the
Pacific, 0-52S in the Indian Ocean, and in Indonesian Seas.
A. cuneata Muller
This rarely recorded species was previously noted and described from
these waters (Deevey 1968, Fig. 6). The female was described by Muller
(1908) from a female and a juvenile specimen caught at 190S in the Atlan-
tic, but the male was only recently described (Deevey 1978a: 112, Figs.
3-4). Angel and Fasham (1975) have noted its presence at 180 and 400N in
the eastern North Atlantic, and Angel (1979) found it at a number of the
stations on his transect at 320N across the Atlantic as well as at Ocean
Acre, where it was caught between 200 and 800 m. At Station S A.
cuneata was the third most abundant species of this genus and was found
consistently between 500 and 1000 m in numbers varying between 4 and
26/1000 m3, especially during 1968-1969. During the second year studied
it was less commonly noted. This is a small species, males being 0.7-0.8
mm long and females 0.8-0.9 mm in length.
DISTRIBUTION -400N-190S in the Atlantic Ocean.

A. bifurcata Deevey
This species was described from this station on the basis of a female
1.65 mm long, an immature female 1.4 mm long, and an immature male
1.25 mm long (Deevey 1978a: 131, Figs. 15, 16). Four other juvenile


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


specimens have also been noted. One specimen was caught between
500-1000 m depths, but all others were from between 1000 and 1500 m.
The juvenile specimens were present from July to November 1968, and
the single female was taken in April 1969. The female 6th limb and the tip
of the frontal organ are shown in Figures 10 i and j. This species is known
only from this locality.

A. bispicula Deevey
This species was described from a single female 1.02 mm long col-
lected in the western Caribbean Sea (Deevey 1978a: 123, Fig. 10), but it
has since been noted at Station S. A female 0.96 mm long was taken in
July and an immature female 0.8 mm long in June 1970, both from
500-1000 m depths. The tip of the frontal organ and the 6th limb are il-
lustrated in Figure 10 g and h.
DISTmBUTION 320N in the western North Atlantic and 17 18'N in the
western Caribbean Sea.

A. longiseta Deevey
This species was described from two females, 1.30 and 1.27 mm long,
caught between 1500 and 2000 m in February and July 1970; it differs
from all other known species in that one of the six filaments or setae on the
distal segments of the 1st antenna is much longer than the other five
(Deevey 1978a: 119, Figs. 7-9). Females and juveniles have since been
found between 1500 and 2000 m from October to December 1968, July
and October 1969, and in August and September as well as February and
July 1970. In October 1968 it was also present between 500 and 1500 m
depths. It has therefore been caught between July and February, primar-
ily from depths where the temperature was ca 40C.
DISTRIBUTION- 320N in the Sargasso Sea.

A. pilosa Deevey
This species is known from a single male, 1.35 mm long, collected be-
tween 1500 and 2000 m in June 1969 (Deevey 1978a: 115, Figs. 5-6); it is
most closely related to A. cuneata.

A. ventricosa Muller
Muller briefly described this species in 1906; the male has since been
redescribed from a specimen collected in the eastern Caribbean Sea
(Deevey 1978c, Figs. 4-5). At Station S two females, 0.90 and 0.94 mm
long, and a male, 0.8 mm long, were taken in April and August 1969 and
February 1970 between 500 and 1000 m. This species has a characteristic
shape, with a strongly swollen anterior margin (see Fig. 10a), which led
Muller to give it the specific name from the Latin for "pot-bellied." Seven
other species are now known to have a similar shape, and five of these


1980







BULLETIN FLORIDA STATE MUSEUM


O 0.5


FIGURE 10. a, Lateral view of shell of female A. ventricosa; b, Lateral and dorsal view of
frontal organ of female A. ventricosa; c, Sixth limb of male A. ventricosa; d, Sixth limb of
female A. gastrodes; e and f, Sixth limb and dorsal and lateral view of frontal organ of male
A. bimucronata; g and h, Sixth limb and dorsal and lateral view of tip of frontal organ of
female A. bispicula; i and j, Sixth limb and tip of frontal organ of female A. bifurcata; k and
1, frontal organ of female and sixth limb of immature male A. falcata. Scale on a for a, at bot-
tom left for b to 1. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


have been found at Station S. These species differ from each other in size,
number of claws on the furca, and particularly in the shape of the frontal
organ, in characters of the endopodite of the 2nd antenna, and in the
relative lengths of the three setae on the distal segment of the 5th and 6th
limbs. The ventricosa-shaped species known from Station S include A.
bifurcata, A. bispicula, A. gastrodes, A. falcata, and A. bimucronata.
Figure 10 illustrates the female A. ventricosa shell and the frontal organs
and 6th limbs of these species. In A. ventricosa the tip of the frontal organ
has a single, long, needle-like prolongation (Fig. 10b). In the known
males of this type, the shell height decreases markedly posteriorly,
whereas the shell height in females is similar at the anterior and posterior
ends.
DISTRIBUTION -A. ventricosa has been listed as occurring up to 600N
in the eastern North Atlantic (Angel and Fasham 1975), but without any
documentation. Muller (1906: 45, pl. 7, figs. 1-6) described this species
from the equatorial Atlantic and Indian Oceans. Otherwise it is known
from 11045'N in the Caribbean Sea and 32010'N in the Sargasso Sea.
Other records (e.g. Poulsen 1969a and Chavtur 1977) have not been
documented.


A. falcata Deevey
This species is also known only from Station S and was described from
a 1.3 mm female collected in June 1969 from 1000-1500 m depths and a
1.1 mm immature male caught in February 1969 from between 1500 and
2000 m (Deevey 1978a: 125, Figs. 11-12). This species has a rounded fron-
tal organ (Fig. 10k). The 6th limbs were missing from the female, but the
immature male had distinctive 6th limbs with only two long setae on the
distal segment (Fig. 10 1) although the 5th limbs were of the usual type.
A. gastrodes Deevey
This is the largest ventricosa-shaped species found at Station S and was
described from a female, 1.85 mm long, collected in February 1969 from
between 1000 and 1500 m (Deevey 1978a: 134, Figs. 17-18). The frontal
organ was lost from this specimen, but the 6th limb is illustrated in Figure
10d. A. gastrodes is known only from Station S.
A. bimucronata Deevey
This species was described from a 0.9 mm male taken at Station S from
between 1000 and 1500 m in September 1970 (Deevey 1978a: 128, Figs.
13-14). An immature female, 0.9 mm long, was found in October 1968
within the same depth range. These are the only specimens to date. The
frontal organ of A. bimucronata has two slim needle-like prolongations at
its tip, and the ventral seta on the distal segment of the 6th limb is excep-
tionally short (see Figs. 10e, f).







BULLETIN FLORIDA STATE MUSEUM


SUBFAMILY CONCHOECINAE MULLER
This subfamily contains all the species of the genus Conchoecia, which
Poulsen (1973) divided into 17 genera. Martens (1979) pointed out that
nine of these genera are nomina nuda, as no type species were designated
for them. He listed eight genera as valid, and proposed five more, two of
which were among those he had named as nomina nuda. In this report the
proposed genera are listed in parentheses as subgenera, and Muller's
(1906) system of grouping species into more or less natural groups is
followed. The species that Muller grouped together in the Spinifera
Group do not all form a natural assemblage, and it is now necessary to
place one of these species, C. mamillata, in a group of its own.
Mamillata Group
C. mamillata Muller
This species differs from others that Muller put in the Spinifera group,
and indeed from all described species of Conchoecia, except C.
cophopyga and C. dentata of the Dentata Group, in the rather primitive
structure of the male 6th limb; the distal segment bears two rather long
setae and a short seta, instead of three very long plumose setae as in other
male Conchoecinae. This fact was noted by Rudyakov (1962), who had a
single damaged male specimen of C. mamillata that he could not fully
describe. Muller (1906: 60, pl. 16, figs. 1-9, pl. 35, fig. 8) described only
the shell and the 1st and 2nd antennae. Poulsen (1973) had only females
and juveniles in the Dana material, and although this species was listed
and figured from the Sargasso Sea (Deevey 1968, Fig. 12d-f), at that time
only juvenile specimens had been caught. The male has therefore never
been fully described.
This species also differs from most other Conchoecia in the location of
the left asymmetrical gland, which opens on a process on the posterior
margin of the shell. The location of the asymmetric glands is in fact
reminiscent of some species of Archiconchoecia, particularly A. cucullata,
in that the left gland opens on the posterior margin near the posterodorsal
corner and the right gland a short distance down the posterior margin.
Only in members of the Daphnoides Group and in C. dasyophthalma does
the left gland open on the posterior margin. The armature of the principal
seta of the 1st antenna of both sexes is different from that of most
members of the Spinifera Group. The male has a large brush of in-
numerable long fine hairs on the principal seta, whereas other males have
"teeth" or spines, though the C. inermis and C. dasyophthalma males also
have long hairs. The female does not have a row of long hairs on the
anterior side of this seta at the proximal end, but has short hairs on both
the anterior and posterior sides. Also the distal end of the male principal
seta is widened.


Vol. 26, No. 2






DEEVEY & BROOKS: PLANKTONIC OSTRACODS


Muller gave the lengths of females as 1.4-1.9 mm. Most of his male
specimens were 1.6-1.75 mm long, but he had two males 1.35-1.45 mm
long that had a differently shaped frontal organ. At Station S, males were
1.4-1.8 mm long, and females 1.4-1.88 mm long. Examination of the
males showed that two species were present. Males 1.4-1.48 mm long had
the frontal organ of Muller's small form, and were different from males
1.5-1.8 mm long. The small specimens, males 1.4-1.48 mm long and
females 1.4-1.5 mm long, were caught only between 1000 and 1500 m.
The larger males, 1.6-1.8 mm long and females 1.7-1.88 mm long, were
taken from 1500 to 2000 m depths. Juvenile specimens were caught be-
tween 500 and 2000 m. As documented records (Rudyakov 1962; Poulsen
1973; Deevey 1978b) apply to the large form, which Muller also found
more frequently, the larger form is here considered to be C. mamillata
Muller. The small form must be described as a new species.
Conchoecia nanomamillata, new species
Figures lla-d, i-n: Figures 12b-g; Figures 13a, c, d
Conchoecia mamillata G. W. Muller 1906 (part): 34, pl. 16, figs. 1-9, pl.
35, fig. 8.
HOLOTYPE--Male, 1.48 mm long, 1 slide, to be deposited in the
National Museum of Natural History, Smithsonian Institution.
TYPE LOCALITY- Station S, 32010'N, 64030'W, in the Sargasso Sea off
Bermuda. Collected in a tow from 1000-1500 m on 19 February 1970.
DESCRIPTION OF MALE
SHELL- In both male and female (Figs. llk, 1) the shell is distinctively
sculptured and shaped as figured by Muller (1906, pl. 16, figs. 1-2) for C.
mamillata. The height is approximately 40% the length, with rounded
anteroventral and posteroventral corners. The left asymmetric gland
opens on a rounded process at the posterodorsal corner, the right gland on
a similar process on the posterior margin. At the posterodorsal corner of
the right shell is a sharp point and a medial gland opens at its base as well
as at the base of the left asymmetric gland.
FRONTAL ORGAN AND 1ST ANTENNA (Figs. lla-d) -The capitulum of
the frontal organ has some hairs or spinules proximally and ventrally and
a large bulbous distal section (Fig. lid), which readily distinguishes this
species from the male C. mamillata. In C. mamillata the capitulum is
long and slim with hairs on the proximal half (Fig. lle). The armature of
the 1st antenna is similar to that of the male C. mamillata, but there are
several differences. In C. nanomamillata the principal seta has the large
brush of long fine hairs as in C. mamillata, but it is also slightly longer
than the distal secondary seta (Fig. la), whereas in C. mamillata the
distal secondary seta is longer (Fig. llf). In both species the proximal
secondary seta has a row of spines near the distal end that are virtually in-


1980







BULLETIN FLORIDA STATE MUSEUM


FIGURE 11. C. nanomamillata, n. sp., a-d: a, Male 1st antenna; b, Armature of male 1st
antenna; c, Distal segments of the male 1st antenna; d, Capitulum of male frontal organ. C.
mamillata Muller, e-h: e, Capitulum of male frontal organ; f, Male 1st antenna; g, Male right
clasping organ; h, Endopodite of male left 2nd antenna, setae and filaments cut off. C.
nanomamillata, n. sp., i-n: i, Endopodite of male left 2nd antenna, setae and filaments cut
off; j, Male right clasper; k and 1, ventral and lateral views of female shell; m, Toothrow of
basale of mandible and toothrows and masticatory pad of coxa; n, coxal and precoxal endites
of male. Scale on 1 for k and 1; at bottom left for b-e, g-j, m and n; at upper right for a and f.
Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


visible when folded flat against the seta; C. nanomamillata has a distinc-
tive bump or rounded protrusion on this seta near the proximal end that is
not found in C. mamillata, as well as a similar protrusion near the ventral
distal end of the 2nd segment of the 1st antenna (see Figs. 11a and c and
compare with Fig. llf). The proximal filament is very long in both
species.
SECOND ANTENNA (Figs. ii, j)-The lengths of the 2 setae and 3
filaments of the distal segment of the endopodite are as figured by Muller
(1906, P1. 16, fig. 6); the 3 filaments are short and about half as long as
the 2 setae, which are of about the same length and widened distally (Fig.
13i). The distal bristle on the basal segment of the endopodite is long,
with several long hairs proximally and tiny spinules distally, as in C.
mamillata (Fig. 1lh). The right clasping organ (Fig. llj) is slimmer and
lacks the pronounced protrusion near its base that is found on the C.
mamillata right clasper (Fig. llg).
MANDIBLE (Figs. llm, 12g) -The toothrow of the basale has 6 serrate
teeth and 2 larger teeth, as in other species. The coxale has several strong
toothrows, the outermost of 10 large teeth, and a masticatory pad with
bristles. No differences were noted between the two species in the
character of the toothrows or the station of the endopodite of the mandi-
ble.
MAXILLA (Figs. 1 In, 12f) The endopodite of the maxilla has 10 setae,
only 1 of which is plumose in males and females of both species. There are
6 bare anterior setae, 1 short lateral seta, and 3 posterior setae. The distal
segment bears the 2 claw-setae and 3 short slimmer setae. The C.
mamillata maxilla is similar.
FIFTH LIMB (Fig. 12b)- The protopodite and endopodite have a total
of 11 setae, including the 2 claws, of which 5 are plumose. The 1st seg-
ment of the exopodite has 9 setae, of which 2 are plumose, plus the long
dorsal seta. The C. mamillata male 5th limb has 10 setae plus the long
dorsal seta (Fig. 12a). The relative lengths of the 3 setae on the distal seg-
ment appear similar in both species.
SIXTH LIMB (Fig. 12c)- The station of the male 6th limb definitely
separates C. mamillata and C. nanomamillata from other species of Con-
choecia. The basal exopodite segment has 6 plumose setae and a short dor-
sal seta. These plumose setae are exceptionally long and not vestigial or
lacking as in many species of Conchoecia. This is a primitive character, as
is the short ventral seta on the distal segment, which is not known for any
other male Conchoecia except C. cophopyga and C. dentata. The ventral
seta is only ca 20 % the length of the other 2 setae (Fig. 12c). The 6th limb
is also not so large and strong as in most Conchoecia males and appears
relatively weak.
SEVENTH LIMB-This is a stronger appendage than is usual in Con-


1980







BULLETIN FLORIDA STATE MUSEUM


S0.1 b


FIGURE 12. a, Exopodite of the 5th limb of male C. mamillata. C. nanomamillata, n. sp.,
b-g: b, Male 5th limb; c, Male 6th limb; d, Female 6th limb; e, Distal segment of female 5th
limb; f, Endopodite of male maxilla; g, Endopodite and basale of male mandible. Scale at top
in mm for a-g.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


choecia species, although it is similar in structure with 2 setae, one more
than twice as long as the other. The C. nanomamillata 7th limb is similar
to that of C. mamillata (Fig. 13f).
PENIS (Fig. 13d) -This is distinctive and is distinguishable from that
of the C. mamillata male (Fig. 13g) in that the chitinized processes at the
distal end are larger and more ornate.
FURCA -This is similar in both sexes of the 2 species (Fig. 13e). The
claws decrease evenly in size, and there is no unpaired single bristle.
DESCRIPTION OF FEMALE
The shell (Figs. llk, 1) is similar in shape and sculpturing to that of
the male and of C. mamillata. The frontal organ extends well beyond the
distal end of the 1st antenna (Fig. 13a). The capitulum of the frontal
organ is similar in shape to that of the C. mamillata female (Fig. 13b), but
differs in that it appears to be jointed to the stem; also, about half way
down the dorsal margin of the capitulum is an indentation not noted on
the C. mamillata female capitulum (compare Figs. 13a and 13b). No dif-
ferences were observed in the female 1st or 2nd antennae of the two
species. The principal seta of the 1st antenna has coarse hairs on the
anterior and posterior sides for about two-thirds of its length. The distal
bristle on the basal segment of the endopodite of the 2nd antenna is
notable in that, as in the male, there are long hairs proximally and tiny
spinules distally (Fig. 13c). In other species the female does not have long
hairs on this bristle when the male does. The 5 filaments of the distal seg-
ment of the endopodite are subequal in length.
The mandible, maxillae, and 5th and 7th limbs appear similar in both
sexes of both species. The 3 setae on the distal segment of the female 5th
limb are the same relative lengths as in the male (Fig. 12e). The female
6th limb (Fig. 12d) differs from the male's only in the relative lengths of
the 3 setae on the distal segment. In females of both species the basal seg-
ment of the exopodite has 6 plumose setae and a short dorsal seta as in the
male.
REMARKS At Station S C. mamillata and C. nanomamillata can be
distinguished on the basis of size and possibly depth of capture. C.
mamillata males were 1.62-1.8 mm long, and females 1.7-1.88 mm long,
whereas C. nanomamillata males were 1.4-1.48 mm long and females
1.45-1.5 mm in length. However a 1.5 mm male from the Caribbean Sea
proved to have the frontal organ, 1st antenna, and penis of C. mamillata,
despite its small size. These characters differentiate the males, but aside
from slight differences in the frontal organ, which may vary in in-
dividuals, females seem to differ only in size. Although C. mamillata
adults were caught only between 1500 and 2000 m, where the
temperature remains at ca 40C year-round, and C. nanomamillata only
from 1000 to 1500 m depths, juveniles of either or both species were found


1980








BULLETIN FLORIDA STATE MUSEUM


FIGURE 13. a, Frontal organ and 1st antenna of female C. nanomamillata, n. sp.. b, Fron-
tal organ of female C. mamillata. c, Endopodite of 2nd antenna of female C. nanomamillata,
n. sp.; d, Penis of male C. nanomamillata, n. sp.. C. mamillata e-j: e, Female furca; f, Male
7th limb; g, Penis; h, Two views of coxal toothrows and masticatory pad of mandible; i, Male
right 2nd antenna; j, Male 6th limb. Scale on i for i; at upper left for e; at bottom for a-d, f-h,
and j. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


between 500 and 2000 m. In other localities adults of both species might
be found over similar depth ranges.
The two species together constituted an appreciable percentage of the
total numbers of ostracods taken between 1000 and 2000 m (see Table 4).
They were not differentiated at the time the counts were made. In any
event this would have been impossible, as most of the specimens taken
were juveniles. The total numbers taken from between 1000 and 2000 m
are shown in Figure 14C. The two species were more numerous in 1969
between 1000 and 1500 m, when maximal numbers were noted in
February, April-May, and July. Fewer were caught in 1968 and 1970.


1.0- A C. spinifera 0-500 m--
500- 1000 m----



0.5 -




0 O I A \ "

B C. oblong
-S
- 0.5 1.

0 .. . .
oI "


C C. mamillata spp. 1000-1500m-
0.04 15002000m---




J A S 0'N'Dl' F'M AM'J J AS O 'DIJ F MA MJJ A S
1968 1969 1970
FIGURE 14. Seasonal variations in total numbers/m3 of A: C. spinifera from 0-500 m, solid
line, and 500-1000 m, dotted line; B: C. oblonga from 0-500 m; and C: C. mamillata and C.
nanomamillata from 1000-1500 m, solid line, and 1500-2000 m, dotted line, from July 1968
to September 1970, taken in the No. 8 net samples.


1980







BULLETIN FLORIDA STATE MUSEUM


Together these species constituted around 5% of the total numbers of
ostracods caught from between 1000 and 2000 m in the No. 8 net samples.
DISTRIBUTION C. mamillata has been documented from 32N-56S
in the Atlantic and from 49029'N-49"S in the Pacific Ocean. It has been
recorded but not documented from 80N-640S in the Indian Ocean. Muller
(1906) did not cite the locations where his smaller form was found, so at
present C. nanomamillata is known only from 32N in the Sargasso Sea
and presumably from 300N, 230W in the eastern North Atlantic, where
Angel (1979) found both large and small forms of C. mamillata. In the
Sargasso Sea Angel found most adults between 1000 and 1250 m, and gave
length ranges of 1.24-1.48 for females and 1.20-1.42 for males, so his
specimens must have been C. nanomamillata.

Spinifera GROUP MULLER
Poulsen (1973) placed the species of this group in the genus Paracon-
choecia, which Martens (1979) declared a nomen nudum until a type
species is named. Excluding C. mamillata, seven species of this group
have been noted at Station S, of which C. dorsotuberculata, C. inermis,
and C. aequiseta hirsuta were not previously recorded (Deevey 1968),
although Angel (1979) took them in these waters.
C. spinifera (Claus)
This was a common species year-round within the upper 1000 m.
Although decreasing in numbers with depth, it constituted a higher pro-
portion of the total numbers between 500 and 1000 m, and had the same
pattern of depth distribution as C. secernenda (Fig. 5B). In 1968 and 1969
low numbers were present in winter, spring, and fall, but in 1970 C.
spinifera was more abundant in the upper waters, with maxima in
March, June, and September (Fig. 14A). Between 500 and 1000 m
numbers were higher from March or April to September. The mean crop
obtained for 0-1000 m depths from the No. 8 net samples was 261/m2. C.
spinifera constituted 11% of the total numbers of ostracods taken in the
500-1000 m hauls with the No. 8 net and about 30% of the total numbers
caught by the No. 2 nets over this depth zone (see Table 4).
C. spinifera is one of the larger species commonly caught in the upper
waters, length of females is 1.9-2.0 mm and males 1.60-1.75 mm. Poulsen
(1973) noted that the smallest individuals were found between 20N and
200S, and larger specimens at higher latitudes. This species undergoes
some diurnal vertical migrations, but tends to remain below the seasonal
thermocline (Angel 1968). In the Canary Island region it was most
numerous around 500 m by day, but moved up to below 100 m at night
(Angel 1969a). Angel and Fasham (1975) include C. spinifera with others
they consider shallow mesopelagic species whose center of abundance is


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


between 300 and 400 m at 300N in the eastern North Atlantic, but
deepens to 400-800 m at 400N, and then becomes shallower farther north
at 530 and 60N. In the Sargasso Sea Angel (1979) reported large catches
between 300 and 800 m.
DISTRIBUTION 600N-42S in the Atlantic, to 47'30'S in the Indian
Ocean, ca 40'N-56S in the Pacific and Indonesian Seas. Poulsen (1973)
noted that in the "Dana" collections it was common in Indonesian Seas,
but rarely taken in the Indian Ocean and not at all in the Pacific.

C. oblonga (Claus)
This is also a common year-round species at Station S, much more
abundant in the upper waters than between 500 and 1000 m (see Tables 3
and 4). C. oblonga is medium-sized, females being 1.5-1.7 mm long,
males 1.35-1.50 mm long. Angel (1979) reported females up to 1.84 mm
long, with a mean length of 1.72 for females and 1.47 for males collected
in these waters. Muller (1906) distinguished two forms on the basis of the
location of the right asymmetric gland; form A had the gland at the
posteroventral corner of the right shell, and in form B the gland was
moved forward a bit on the ventral margin. Both forms occur at Station S
but were not differentiated in the counts. Angel (1969a) distinguished the
two forms in studying their depth distribution in the Canary Island
region; both forms had their center of abundance within the upper 300 m.
He noted (1968) that form A moved freely across the thermocline discon-
tinuity, whereas form B found the thermocline a partial barrier. In the
eastern North Atlantic both forms had a depth range above 500 m at
18N, but occurred a little below 500 m at 300N; at 400N only form A was
found above 400 m. Form A has been found more abundant east of 30W
in the North Atlantic, and form B more numerous west of 30'W (Angel
1979).
The variations in numbers/m3 of C. oblonga in the upper 500 m are
shown in Figure 14B. Times of maximal numbers reflect times of maximal
numbers of juveniles. Probably at least four generations were produced
during the year. In 1969 higher numbers of females and males were pre-
sent in January, April, June, and October-November, but we lack data
for September when higher numbers were present in 1970. C. oblonga is
one of the species that was taken in highest numbers in September 1970
after the influx of the second cold water mass. Other such species include
C. parthenoda, C. spinirostris, C. procera, C. magna, and C. rotundata.
DISTRIBUTION--480N-420S in the Atlantic, ca 400N-40S in the
Pacific, to 380S in the Indian Ocean, and in the Mediterranean Sea. It has
not been taken south of the Subtropical Convergence in the Southern
Hemisphere.







BULLETIN FLORIDA STATE MUSEUM


C. aequiseta Muller and C. aequiseta hirsuta Muller
As few samples were collected at depths greater than 500 m, C.
aequiseta was previously recorded from Station S only on the basis of an
immature male and a younger juvenile (Deevey 1968, Figs. 12a-c). Con-
tinued sampling of the deeper waters showed that one or both of these
forms occurred fairly commonly between 500 and 1500 m. Females and
juveniles of the two forms are indistinguishable; Muller separated the
males into two species solely on the basis of long hairs on the distal bristle
of the basal segment of the endopodite of the 2nd antenna of C. hirsuta
(Fig. 15f); in the C. aequiseta male this bristle is bare (Fig. 16g, i). The
armature of the male 1st antenna is similar in both forms. The principal
seta has 45-50 closely packed pairs of teeth (Figs. 15d, 16c). The proximal
secondary seta has a double comb of fine hairs or spinules, and distally
spinules nearly to the tip. The distal secondary seta has a few spinules.
The shape of the clasping organs is also similar in both forms (Figs. 15e, f,
16g, i), but the hirsuta male has only one protuberance on the inner side
near the base of the right clasper (Fig. 15f), whereas the aequiseta male
has two (Fig. 16i). Females, 3.05-3.2 mm long, and juveniles were found
from August 1968 to August 1969 between 500 and 1500 m. Only a single
C. aequiseta male, 2.5 mm long, was taken in September 1968 in a haul
from 1000 to 1500 m. C. aequiseta hirsuta males, 2.55-2.6 mm long, oc-
curred between 500 and 1500 m from December 1968 to May 1969;
another male was noted in April 1970 in a 1000-1500 m tow. The hirsuta
form therefore appeared to be more common, although Muller (1906)
recorded it only from 35' to 370S in the Atlantic and from 260 to 290S in
the Indian Ocean, whereas he recorded aequiseta males from 240N to
310S in the Atlantic and to 29S in the Indian Ocean. Angel (1979) con-
sidered C. aequiseta, including the hirsuta form, a deep mesopelagic
species restricted to central gyre waters in the North Atlantic.
DISTRIBUTION The two forms have been recorded from 40N-44S in
the Atlantic, 11-56S in the Pacific, 0-25S in the Indian Ocean and
from Indonesian Seas.

C. reticulata Muller
The generic name Macroconchoecia Granata and Caporiacco 1949
has been proposed for this species.
A few individuals of C. reticulata were taken throughout the year be-
tween 1000 and 2000 m. Most of the specimens were juveniles, but a few
males and females were caught. The females were 3.55-3.75 mm long and
the males 3.1-3.4 mm. Previously a single female was recorded, and its
shell and 1st antenna figured (Deevey 1968, Fig. 13). Angel (1979) sug-
gested that more than one species may be involved, because he noted both
smaller specimens with spines on the shell and larger deeper-living in-


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


FIGURE 15. C. aequiseta hirsuta male. a, b, and c, Lateral, ventral and posterior views of
shell; d, Frontal organ and 1st antenna; e, Left clasper; f, Endopodite of right 2nd antenna,
setae and filaments cut off. Scale below a for a-c; beside d for d; at bottom for e and f. Scales
in mm.

dividuals without spines. The males collected at Station S agree with
Muller's (1906: 64, pl. 12, figs. 10-17) description and figures of the male
shell and 1st and 2nd antennae, except that they have rounded pro-
tuberances inside at the proximal ends of the clasping organs (see Figs.
17e, f). The armature of the 1st antenna, (Fig. 17b) is as he described. The







BULLETIN FLORIDA STATE MUSEUM


principal seta has a relatively short and very thick double row of countless
slim lamellae that do not appear to be spines. The two secondary setae are
of about the same length (Fig. 17i), the distal one with only a few tiny
spinules, whereas the proximal seta has a long thin callous and rows of
spinules more distally. The sculpturing of the shell is distinctive as


FIGURE 16. C. aequiseta male. a, Lateral view of shell; b, postero-dorsal corner of shell; c,
Setae and filaments of 1st antenna; d, Distal end of toothrow of principal seta of 1st antenna;
e, Armature of proximal secondary seta; f, Frontal organ and 1st antenna of female; g, En-
dopodite of male left 2nd antenna, setae and filaments cut off; h, Endopodite of female 2nd
antenna, setae and filaments cut off; i, Part of endopodite of male right 2nd antenna. Scale at
upper right for a; beside f for c and f; at bottom right for d, e, g-i. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


described. Especially over the dorsal part of the shell on the shoulder
vaults and toward the posterior end the rectangles of the sculpturing are
armed with strong spines (Fig. 17k). The relative lengths of the setae and
filaments of the endopodite of the 2nd antenna (Fig. 17c) are as figured by


FIGURE 17. C. reticulata male. a, Lateral view of shell; b, Armature of 1st antenna; c, En-
dopodite of left 2nd antenna; d, Endopodite of left 2nd antenna, setae and filaments cut off;
e, Left clasper; f, Right clasper; g, Fifth limb; h, Capitulum of frontal organ; i, 1st antenna;
j, Penis; k, detail of sculpture and spines on shouldervault; 1, Furca; m, 6th limb. Scale on a
for a; on left margin for c, g, i, 1, m; at bottom for d, h, j, k; at top for b, e, f. Scales in mm.







BULLETIN FLORIDA STATE MUSEUM


Muller. Although Muller did not mention the protuberances on the inner
proximal sides of the clasping organs (Figs. 17e, f), Poulsen (1973, Fig. 12)
described them. The 6th limb has 6 relatively long plumose setae on the
basal segment, and the ventral seta of the distal segment is slightly shorter
than the other two and not plumose (Fig. 17m). Judging from Muller's
and Poulsen's descriptions, C. reticulata is most closely related to C.
caudata, and both species should probably be removed from the Spinifera
Group.
DISTRIBUTION--400N-6S in the Atlantic, 4N-30S in the Indian
Ocean and the tropical Pacific Ocean. According to Poulsen, this species
is widely distributed over the tropical parts of the three oceans from
280N-330S.

C. dorsotuberculata Muller
This species, taken throughout the year in numbers of 1-12/1000 m3
between 500 and 2000 m (see Tables 3 and 4), has been rarely recorded.
Muller (1906) described it from specimens caught at 40014'N and 2443'N
in the Atlantic and from 26S and 2043'S in the Indian Ocean. Poulsen
(1969b, 1973) recorded one specimen from the Gulf of Guinea, one male
from 2940'S in the western Pacific, and one shell from 1S in the Indian
Ocean. Angel and Fasham (1975) list it as occurring from 180 to 530N in
the eastern Atlantic as a deep mesopelagic to bathypelagic species. Most of
the specimens caught at Station S were juveniles. Males 2.4-2.5 mm long
and females 2.6-2.7 mm long were found between 1000 and 2000 m;
juveniles occurred between 500 and 2000 m. Muller's females were 2.6
and his males 2.4 mm long. Angel (1979) gave a length range of 2.48-2.72
mm for females from Ocean Acre in the Sargasso Sea. The specimens
caught at Station S agree well with Muller's brief description of the shell
and 1st and 2nd antennae, except that he neither described nor figured
the long hairs on the distal bristle of the basal segment of the endopodite
of the 2nd antenna (see Fig. 18f), which Poulsen (1973, Fig. 8) described.
The principal seta of the male 1st antenna has at least 60 long closely
packed teeth, impossible to count. The principal seta is widened distal to
the toothrow and the 2 filaments are exceptionally long (Fig. 18b). This
species is readily identified by the location of the left asymmetric gland,
which is moved forward on the dorsal shell margin to ca two-thirds of the
total length from the anterior end (Figs. 18a, j), and also by the rounded
posterior margin and the backward curving 5th claw on the furca. Medial
glands were especially noticeable on the posterior margins near the
posterodorsal corner (Fig. 18j) of the male shell.
DISTRIBUTION -530N-0050'S in the Atlantic, ca 3-26S in the Indian
Ocean, and 300S in the Pacific.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


FIGURE 18. C. dorsotuberculata. a, Lateral view of female shell; b, Male 1st antenna; c, Ven-
tral view of female shell; d, Female frontal organ and 1st antenna; e, Endopodite of female
2nd antenna, setae and filaments cut off; f, Endopodite of male right 2nd antenna, setae and
filaments cut off; g, Male left clasper; h, Penis; i, Capitulum of male frontal organ; j, Lateral
view of male shell. Scale on a for a, c, and j; in center for b, d, and h; at bottom for e-g, i.
Scales in mm.
C. inermis (Claus)
This species was taken infrequently in July, August and November
1968, from April to June and in August 1969, and in January, February,
June, July, and September 1970, only from between 500 and 1000 m.







BULLETIN FLORIDA STATE MUSEUM


Angel (1979) found it only between 600 and 800 m at Ocean Acre and at
comparable depths off the Canary Islands (1969a). A total of 4 females, 6
males, and several juveniles were noted. The females were 2.05-2.25 mm
long and the males 1.85-2.05 mm long. This species is easily recognized by
its shell shape (Figs. 19a, g) with the straight posterior margin forming
right angles with the dorsal and ventral margins. The right asymmetric
gland opens at the posteroventral corner, the left gland just back from the
posterodorsal corner as illustrated by Muller (1906, pl. 10, fig. 4), and not
on the posterior margin as figured by Claus (1891, pl. 11, fig. 1). The
capitulum of the male frontal organ is similar to the female's (Fig. 19c).
The principal seta of the female 1st antenna has some long hairs on the
anterior surface proximally, and short spinules on the posterior surface
distally (Fig. 19c). The principal seta of the male 1st antenna has a brush
of long thin hairs, rather as in C. mamillata (Fig. 19h).
DISTRBUTION-530N-160S in the Atlantic, 11-28S in the Pacific, to
26S in the Indian Ocean, and in Indonesian Seas.

Elegans Group Muller
C. elegans Sars
Poulsen (1973) placed this species in the genus Paraconchoecia, now
declared a nomen nudum. Martens (1979) designated it the type species of
his proposed genus Discoconchoecia.
This common cosmopolitan ostracod that has a wide length range of
1.0-2.2 mm and occurs from the Arctic to the Antarctic baffles in-
vestigators who have not discovered that more than one species is in-
volved. Small individuals, 1.15-1.25 mm long, occurred year-round
within the upper 1000 m in numbers up to 68/1000 m3, especially during
the first year studied. None were noted during the fall of 1969, and fewer
were recorded in 1970. Larger specimens were not previously noted
(Deevey 1968), but from July 1968 to March 1969 males and females vary-
ing from 1.4-1.9 mm in length were caught, most from between 1000 and
1500 m, but a few from 500-1000 m depths. Larger forms were also taken
in October 1969 and July 1970. In the eastern Atlantic Angel and Fasham
(1975) were able to differentiate a 1.2 mm southern form that occurred
from 10'30' to 180N from a 1.6 mm form found from 300 to 600N and a
1.8 mm form recorded from 400 to 600N. At 4413'N in the Bay of Biscay
Angel (1977) found a wide size range that he suggested might have
resulted from hybridization of the small and larger forms. Because the
smaller and larger forms were not usually found over the same depth
ranges at Station S, it seems likely that the larger forms have been
transported at depth from more northern waters, as appears to be the case
with other organisms, such as Calanus finmarchicus.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


DISTIBUTION--800N-560S in the Atlantic, 700N-68S in the Pacific,
to 600S in the Indian Ocean, and in Indonesian Seas.


FIGURE 19. C. inermis. a, b, and f, Lateral, ventral and posterior views of female shell; c,
Female frontal organ and 1st antenna; d, Endopodite of male left 2nd antenna, setae and
filaments cut off; e, Endopodite of female 2nd antenna, setae and filaments cut off; g, Lateral
view of male shell; h, Male 1st antenna; i, Male right clasper. Scale on a for a, b, f, g; at bot-
tom right for c and h; on left margin for d-e and i. Scales in mm.


1980






BULLETIN FLORIDA STATE MUSEUM


Procera Group Muller
C. procera Muller and C. microprocera Angel
C. procera was one of the commonest species, probably second in
numbers after C. spinirostris, in the upper 500 m. The total numbers,
counting juveniles, may include some juveniles of C. microprocera.
Figure 20A shows the seasonal variations in total numbers of the procera
species and Figure 20B the variations in total numbers of the females and
males of the two species. It would appear, in general, that C. procera was
more abundant when C. microprocera was not. Maxima of C.
microprocera were noted in January, March, and October 1969 and in
January, March, and September 1970, whereas adults of C. procera were
more numerous in February, April, and July 1969 and in February-
March, June, and September 1970. There were four maxima of juveniles
in 1969 and also four between February and September 1970. The C. pro-
cera complex was most numerous in the fall of 1968 and 1969 and in
September 1970, and tended to show a spring minimum. These are small
species. C. procera adults are 1.0-1.2 mm long, C. microprocera 0.8-0.95
mm long. Angel (1979) reported length ranges of 0.94-1.24 for C. procera
and of 0.76-1.04 for C. microprocera. Based on over 800 measurements he
gave mean lengths of 0.949 mm for female and 0.824 mm for male C.
microprocera and of 1.173 mm for female and 1.003 mm for male C. pro-
cera in the Sargasso Sea.
DISTRBUTION -For C. procera: 530N-40S in the Atlantic, 33-40S
in the Pacific, and 34o38'-43o34'S in the Indian Ocean. Chavtur (1977)
recorded it from the subartic front in the North Pacific. As Angel (1971)
divided C. procera into three species, most records are questionable. C.
microprocera is known from 400N-250S in the Atlantic.


C. brachyaskos Muller
This is a common species at Station S, occurring year-round between
500 and 2000 m depths, predominantly between 1000 and 1500 m (see
Tables 3 and 4). Between 500 and 1000 m it was most numerous in March
and May-June 1969 and in January-February and June to August 1970
(see Fig. 21B). Between 1000 and 1500 m it was relatively abundant in
August 1968, January to March, May-June, and October-November 1969,
and in May-June 1970. Females were 1.35-1.5 mm long, males 1.3-1.4
mm long. Larger specimens are found at higher latitudes. In the Pacific
between 40-68S females were 1.56-1.66 mm long and males 1.45-1.6
mm in length (Deevey 1978b).
DISTRIBUTION -600N-56030'S in the Atlantic, ca 400N-77028'S in the
Pacific, and to 65S in the Indian Ocean.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


Total C. procera & microprocera
No. 8 net
No. 2 net


IZ I .,....- -... .
0

0 T 1
0.6- C. microprocera ----- B
C. procera \

\ /
0.42 \- ..
0.2

J'A'S 'N'DIJ FMAMJ J 'S N J FMAMJ J AS
1968 1969 1970
FIGURE 20. Seasonal variations in total numbers/m3, 0-500 m, of A: C. procera and C.
microprocera caught by the No. 8 net, solid line, between July 1968 and September 1970, and
No. 2 net, dashed line, from January to September 1970; and B: C. procera, solid line, and C.
microprocera, dashed line, females and males taken in the No. 8 net samples from December
1968 to September 1970.

Acuminata Group Muller
C. (Conchoecetta) acuminata (Claus)
A few specimens of this species were taken in the upper 500 m,
especially between July 1968 and February 1969. C. acuminata has been
described and figured from these waters (Deevey 1968, fig. 19). The other
member of this group, C. giesbrechti, has never been recorded from the
western North Atlantic. Females were 3.0-3.6 mm long, males 2.0-2.6
mm in length.
DISTRIBUTION -430N-370S in the Atlantic, the tropical Indian and
Pacific Oceans, and Indonesian Seas.

Rotundata Group Muller
Seven species of this group, which Poulsen placed in the genus


1980







BULLETIN FLORIDA STATE MUSEUM


Vol. 26, No. 2


o '
0 "

0.' on -e 0 ... -- "
0 0



B II I
40- C. brachyaskos


201 "1 ** -



S'AS ND F'MA'MJ J 'ASO'N'D J F'M'AMJ J AS
1968 1969 1970
FIGURE 21. Seasonal variations in total numbers/1000 m3 of A: C. skogsbergi and B: C.
brachyaskos between 500 and 1000 m, solid line, and 1000 to 1500 m, dashed line, taken in
the No. 8 net samples from July 1968 to September 1970.
Metaconchoecia, now a nomen nudum until a type species is designated,
have been taken at Station S. Five of these were previously recorded, one
of which, C. arcuata, was wrongly identified as C. kyrtophora Muller,
but has since been described as a new species (Deevey 1978b). The two
species we have not previously noted are C. nasotuberculata and C.
macromma, although Angel (1979) recorded the latter from his Ocean
Acre samples.

C. rotundata Muller
The species identified and figured as C. rotundata (Deevey 1968: 51)
has been designated as C. rotundata form 15 by Angel (1979) and Angel







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


and Fasham (1975), who found it only at 300N in the eastern Atlantic be-
tween 100 and 500 m. In the Sargasso Sea Angel found it between 100 and
600 m. This species occurred year-round within the upper 1000 m, in con-
siderably greater numbers in the upper waters, although it constituted a
higher percentage of the total numbers between 500 and 1000 m (see
Table 4). When taken below 1000 m it was assumed to be a contaminant.
The No. 8 net samples yielded mean numbers of 98/1000 m3 for 500-1000
m depths (see Table 3). Total numbers varied considerably during the
year, with four to five maxima in the upper waters (Fig. 22A). C. rotun-
data was taken in higher numbers from November 1969 to September
1970, with minima in January, May, and August 1970, than during the
first half of the period studied. This is one of the species that was most

A0
A O-500 m
C. rotundata
1 500-1OOOm .--








"' ",-. '" .,----,- O---O. ,,o
0-0
*, /
B r

0 C.secernenda \ /


0 ,k-'o-- ., ......-o....- ..
J 'AF 'A'M'AM' J'J 'A' S'O'N'DIJ'F'M'A'M J 'J'A'S
JASO'N'DJ FMAMJJASONDJFMAM
1968 1969 1970
FIGURE 22. Seasonal variations in total numbers/m3 of A: C. rotundata, and B: C. secernenda
caught within the upper 500 m, solid line, and between 500 and 1000 m, dashed line, in the
No. 8 net samples from July 1968 to September 1970.


1980







BULLETIN FLORIDA STATE MUSEUM


abundant in the surface waters in September 1970. C. rotundata is a small
species. Females are 0.8-1.0 mm long, males 0.75-1.0 mm in length.
DISTRBUTION--400N-350S in the Atlantic, tropical Pacific to 490S,
and at 34038'S in the Indian Ocean (Deevey 1981.)
C. skogsbergi Iles
The species so designated has been described and figured (Deevey
1968: 54) from Station S. Angel (1979) indicated this species is probably
the same as Angel and Fasham's (1975) C. rotundata form 6, which they
found at 300N, 30W as a deep mesopelagic species between 800 and 1500
m. In the Sargasso Sea Angel reported that it was common from 900 to
1500 m. At Station S it occurred year-round, primarily between 500 and
1500 m, but was occasionally taken between 1500 and 2000 m. Although
it decreased in numbers with depth below 500-1000 m (see Fig. 5 and
Table 3), it was more numerous than any other species between 1000 and
1500 m (see Table 4), where it constituted 10% of the total numbers
caught by the No. 8 net. Highest numbers were taken in early 1970 be-
tween 500 and 1000 m, coincident with the influx of a cold water mass,
although fewer were noted between 1000 and 1500 m at that time. Total
numbers varied considerably from month to month (see Fig. 21A).
In the Sargasso Sea C. skogsbergi is small, 1.0-1.2 mm in length.
Specimens up to 1.8 mm long have been recorded from Antarctic waters
(Deevey 1978b). In the South Atlantic a gradual increase in size was noted
in passing to higher latitudes (Deevey 1974b); small specimens were found
down to 35s and south of the Subtropical Convergence, and down to
55S individuals were up to 1.75 mm long.
DISTmBUTION- 660N-65S in the Atlantic, 630N-76S in the Pacific,
and 34-64o21'S in the Indian Ocean.
C. arcuata Deevey
This bathypelagic species was previously erroneously listed as C. kyr-
tophora Muller (Deevey 1968: 55, fig. 23), but has since been described
from the South Pacific (Deevey 1978b, figs. 12-13). Also this is Angel and
Fasham's (1975) C. rotundata form 7. At Station S it occurred continu-
ously from July 1968 to August 1969 and from February to September
1970 between 1000 and 2000 m, and constituted an appreciable percen-
tage of the total numbers over these depths (Tables 3 and 4). Mean
numbers of 7/1000 m3 were obtained for the No. 8 net samples. In in-
dividual hauls total numbers varied from 2 to 27/1000 m3. Angel (1979)
also found it abundant in the Sargasso Sea even to depths of 2500-3500 m.
This is also a small species, males and females being ca 1.0 mm long in this
locality.
DISTRIBUTION- 600N-450S in the Atlantic, and 5672S in the Pacific
Ocean.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


C. pusilla Muller
This is another small species, females being 0.9-1.0 mm and males
0.85-0.95 mm long, that was caught consistently, especially during the
first year studied, between 500 and 1000 m. Occasional specimens were
taken from 1000 to 2000 m depths. It was previously recorded from two
specimens caught in a haul from 500 to 1800 m (Deevey 1968: 57, fig. 25).
It was not noted between August 1969 and April 1970, but was present
during the rest of the period studied in numbers varying from 1 to 16/1000
m3. Angel (1979) also found C. pusilla in the Sargasso Sea between 700
and 1560 m and noted that it is not a very common species there.
DISTRIBUTION --600N-64S in the Atlantic, 28-45S in the Pacific,
and the equatorial Indian Ocean.

C. glandulosa Muller
This bathypelagic and rarely noted species was previously recorded
from Station S on the basis of a single juvenile 0.82 mm long (Deevey
1968, Fig. 24). Continued sampling yielded only a few more specimens
from between 500 and 2000 m in October and November 1968, February,
March, June, and October 1969, and February and September 1970.
Angel (1979) has not caught this species in the eastern North Atlantic, but
recorded a number of females, males, and juveniles from between 1500
and 3500 m in the Sargasso Sea. This is the largest member of the Rotun-
data Group, and is readily identified by its size and the location of the
asymmetric glands. The female shell and 1st antennae are illustrated in
Figures 23a-f. Although no males were taken at Station S, features of the
1st and 2nd antennae of a 1.7 mm male, caught at 2000 m in the Carib-
bean Sea are shown in Figures 23g-k. The armature of the male 1st an-
tenna consists of a row of 15-16 pairs of teeth on the principal seta and a
few spinules on the proximal secondary seta (Fig. 23j). The 2nd segment
of the female 1st antenna is covered with short hairs and bears dorsally
and distally a small spine in the spot where many other female Con-
choecia have a seta (Fig. 23b). Only two females, 1.8 and 1.85 mm long,
were caught at Station S in hauls from 1500 to 2000 m in June 1969 and
February 1970. The other specimens were juveniles. Muller (1906)
described this species from a few specimens taken in the Indian Ocean; his
female was 1.9 mm and his male 1.85 mm long.
DISTRIBUTION -320N-64S in the Atlantic, 46031'N in the Pacific,
26-29S in the Indian Ocean usually at depths of ca 2000 m or greater.

C. nasotuberculata Muller
A single female 0.9 mm long and a juvenile were the only represen-
tatives of this species recorded. The female was caught in June 1970 in the
upper 500 m and the juvenile in June 1969 from between 500 and 1000 m.








BULLETIN FLORIDA STATE MUSEUM


FIGURE 23. C. glandulosa, a-k: a, e, and f, Lateral, ventral and posterior views of female
shell; b, Female frontal organ and 1st antenna; c, Endopodite of female 2nd antenna, setae
and filaments cut off; d, Endopodite of female 2nd antenna; g, Endopodite of male right 2nd
antenna, setae and filaments cut off; h, Male frontal organ; i, Male 1st antenna; j, Armature
of male 1st antenna; k, Male left clasper. C. plinthina: 1, Shell of 3.8 mm juvenile, opened
out; m, Endopodite of 2nd antenna of juvenile, setae and filaments cut off. Scale on a for a, e,
and f; on 1 for 1; at top for c, g, j, k, m; at upper right for i, at bottom for b, d, h. Scales in
mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


This species is distinguished by the fact that the left asymmetric gland is
moved forward onto the rostrum.
DIsTRIBTIoN Angel and Fasham (1975) recorded this species from
110 to 180N in the eastern Atlantic, and it has also been reported and
described from Barbados (Deevey 1970, figs. 5-6), but it has not previ-
ously been found as far north as Station S in the Atlantic. At present it is
known from 320N to 42030'S in the Atlantic, 400N to 54S in the Pacific,
and 20 to 46S in the Indian Ocean.

C. macromma Muller
Although juveniles possibly of this species were noted continuously in
1968 and 1969 between 500 and 2000 m, only 3 females and a male were
caught, all from between 1000 and 1500 m. The females were 1.24-1.28
mm long and were caught in October and November 1968 and April
1969. The male was 1.2 mm long and was taken in July 1969. In C.
macromma the left asymmetric gland is moved back on the dorsal
margin, and the right asymmetric gland is a quarter to a third of the
distance down the posterior margin from the posterodorsal corner (Fig.
24a). The capitulum of the male and female frontal organs are of distinc-
tive shape, compared with other members of this group (Figs. 24c, f). The
male had 11 pairs of teeth on the principal seta of the 1st antenna (Fig.
24j), whereas Muller (1906, p. 79) described 15. These specimens were a
little larger than Muller's; he gave the length of females as 1.0-1.07 mm
and of males as 0.9-1.0 mm.
This species has been rarely reported. Poulsen (1973) noted a single
female, 1.2 mm long, from the South Pacific. Larger specimens recorded
from the South Atlantic (Deevey 1974b) have since been described as a
new species (Deevey 1981). One female from 44S was the same size as the
specimens from Station S. Angel and Fasham (1975) listed C. macromma
as occurring between 110 and 30N in the eastern Atlantic, and Iles
(1953) recorded it from the Benguela Current. Angel (1979) has taken
deep-living specimens from 2000 to 2500 m depths in the Sargasso Sea,
but is not sure they are conspecific with Muller's species.
DISTRIBUTION -The recorded range is 320N-44S in the Atlantic,
22-64S in the Pacific, and 13N-2S in the Indian Ocean.

Curta Group Muller
Three members of this group, placed by Poulsen (1973) in the genus
Microconchoecia, now amended to Mikroconchoecia (Martens 1979), oc-
curred at Station S. C. echinulata and C. stigmatica were not previously
recorded (Deevey 1968), but Angel (1979) caught C. stigmatica in these
waters.


1980







BULLETIN FLORIDA STATE MUSEUM


I-- 0 0.1
0 0.1
FIGURE 24. C. macromma. a, Lateral view of male shell; b, Endopodite of female 2nd an-
tenna; c, Female frontal organ and 1st antenna; d, Male right clasper; e, Endopodite of male
left 2nd antenna, setae and filaments cut off; f, Capitulum of male frontal organ; g, En-
dopodite of female maxilla; h, Toothrows and masticatory pad of female coxa of mandible; i,
Female 6th limb; j, Armature of male 1st antenna; k, Female 5th limb; 1, Penis, m, Furca.
Scale on a for a, at bottom left for b-1; at bottom center for m. Scales in mm.

C. curta Lubbock and C. echinulata (Claus)
C. curta was one of the three most abundant species in the upper 500
m at the time of the previous study (Deevey 1968), and C. echinulata was


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


not noted. By 1968-1970 C. echinulata had appeared and, judging from
the numbers of males, was more numerous than C. curta. It is virtually
impossible to differentiate the females and juveniles of these two species,
but the males are fairly easily separated by the shape of the penis, which is
exceptionally large in C. echinulata (see Figs. 26n, o). Angel (1979; pers.
comm.) does not differentiate these two species, but lumps them together
as C. curta. Therefore, data reported by Angel (1968, 1969a, 1979),
Angel and Fasham (1975), and Moguilevsky and Angel (1975) on the
quantities, depth levels, and distribution of C. curta include any C.
echinulata that might have been present.
When the quantitative counts were made on the samples, the juveniles
and females associated with the male C. echinulata were assumed to
belong to the same species, and the total numbers and percentages listed
in Tables 3 and 4 are based on this assumption. Both species were most
abundant in the upper waters, and together were second or third in total
numbers, although C. curta males were virtually absent in spring and
summer 1970. Both species also occurred regularly between 500 and 1000
m, and were occasionally noted down to 2000 m depths. Possibly they
were contaminants in the samples collected below 1000 m. The seasonal
variations in the numbers of C. echinulata and C. curta males in the up-
per 500 m are shown in Figure 25A. It is evident that few C. curta males
were noted, and highest numbers were found in July 1969 and January
1970. C. echinulata males were most numerous in January, March, July,
and October-November 1969 and in March, July, and September 1970.
The total numbers of the two species including females and juveniles (Fig.
25B) show maxima usually at the same times as the C. echinulata males,
except that highest total numbers of over 3/m3 were noted in January
1970, when males of both species were not abundant.
C. echinulata and C. curta are small species with strikingly
reticulated sculptured shells, males and females being 0.75-0.9 mm long.
C. curta was previously described and figured (Deevey 1968: 60, fig. 26).
C. echinulata is similar in shape (Fig. 26 a, c) but the right asymmetric
gland opens at about half the shell height on the posterior margin,
whereas in C. curta it is a little below half the shell height (Fig. 26j). The
principal and secondary setae of the male 1st antenna (Fig. 26g) are of
equal length, and the principal seta has 5-6 small bumps as its armature,
compared with 8-15 tiny knobs on the C. curta male principal seta. Three
of the 4 filaments of the female 1st antenna are bilobed, as in C. curta
(Fig. 26e). The most obvious difference between males of the two species
is in the shape of the penis (compare Figs. 26 m and n), which in C.
echinulata is as large or larger than the furca (Fig. 260).
DISTRIBUTION C. curta has been recorded from 480N to 370S in the
Atlantic, ca 400N to 400S in the Pacific, to 380S in the Indian Ocean, and


1980







BULLETIN FLORIDA STATE MUSEUM


S0. C. curta Of -- --

O *






0 T' ' r-'I'i\
3 B
S Total C. echinulata & C. curta I
6 No. 8 net
Z No. 2 net








Z1

Otj'A-T S O'A J D' SIOIN' O J'F'M'A'M'J 'J 'A' S
J ASONDJFMAMJ JASONDJ FMAMJ I A
1968 1969 1970
FIGURE 25. Seasonal variations in total numbers/m3, 0-500 m, of A: C. curta and C.
echinulata males, and B: Total C. echinulata and C. curta taken in the No. 8 net, solid line,
from July 1968 to September 1970 and in the No. 2 net, dashed line, from January to
September 1970.
from the Mediterranean Sea. C. echinulata is known from 34N to 37S
in the Atlantic and from 250 to 290S in the Indian Ocean. Neither species
occurs south of the Subtropical Convergence in the Southern Hemisphere.
C. stigmatica Muller
This species is very closely related in shape and structure to C. curta
and C. echinulata, but is slightly larger. As in C. echinulata, the right
asymmetric gland opens on the posterior margin at a little above half the
shell height (Fig. 27 a,b), and this distinguishes this species from C.
acuticosta, which is similar in size but has the right gland opening at
below half the shell height on the posterior margin. Specimens of C.
stigmatica were noted from August 1968 to July 1969, and in February,
June, July, and September 1970, most from 500 to 1000 m depths, but a


Vol. 26, No. 2








DEEVEY & BROOKS: PLANKTONIC OSTRACODS


FIGURE 26. C. echinulata a-i: a and b, Lateral and ventral views of male shell; c and d,
Lateral and ventral views of female shell; e, Female frontal organ and 1st antenna; f, En-
dopodite of female 2nd antenna; g, Male frontal organ and 1st antenna; h, Endopodite of
male right 2nd antenna, setae and filaments cut off; i, Endopodite of male left 2nd antenna,
setae and filaments cut off; C. curta male j-m:j, Lateral view of male shell; k, Endopodite of
right 2nd antenna, setae and filaments cut off; 1, Left clasper; m, Penis. C. echinulata male:
n, Penis; o, Penis and furca. Scale on c for a-d and j; at lower left on n for e-i; k-n; at bottom
center for o. Scales in mm.


1980







BULLETIN FLORIDA STATE MUSEUM


few from between 1000 and 2000 m. Most of the specimens were
juveniles, but two males and two females were taken, the females from
1000 to 1500 m hauls in December 1968 and June 1969, and the males
from between 500 and 1000 m in June and July 1970. The females were
1.0 and 1.05 mm long, the males 1.1 and 1.25 mm in length.
The female and male shells and 1st and 2nd antennae are illustrated in
Figure 27. All four filaments of the female 1st antenna are bilobed (Fig.
27c), as is the proximal filament on the male 1st antenna (Fig. 27d). The
armature of the male principal seta consists of 7-8 small knobs. Juveniles
of this species can be distinguished by the overdeveloped strongly arched
shoulder vaults (Fig. 27j).
DISTRIBUTION -Angel and Fasham (1975) list C. stigmatica as occur-
ring from 300 to 600N in the eastern Atlantic, but all other records are
from tropical and subtropical waters. It has been recorded from ca 35S
in the Pacific north of New Zealand (Barney 1921), from 7N in the Sulu
Sea (Poulsen 1973), from 7N to 290S in the Indian Ocean and to 31S in
the Atlantic. This is a common species in the Caribbean Sea (Deevey
1978c; unpublished data).

Bispinosa Group Muller
Four species of this group, which Poulsen (1973) placed in the genus
Orthoconchoecia, were taken at Station S. Martens (1979) noted that this
is a nomen nudum as no type species had been designated, but he then
gave it as a new genus name with 0. striola (Muller) as the type species.
Except for C. haddoni, three of these four species were also reported by
Angel (1979). Of these, C. secernenda occurred commonly within the up-
per 1000 m, the others were noted only occasionally.

C. secernenda Vavra
This species was found year-round within the upper 500 m but con-
stituted a higher percentage of the ostracods caught between 500 and
1000 m (see Tables 3 and 4). In the No. 8 net samples it decreased in mean
total numbers with depth, from 188/1000 m3 within the upper 500 m to
64/1000 m3 over 500-1000 m depths (Fig. 5). Total numbers of C.
secernenda varied considerably during the year (see Fig. 22B). Within the
upper 500 m maxima were noted in July and December 1968, March-
April and July 1969, and February-March and July to September 1970.
Over 500-1000 m depths highest numbers were found in August. At least
3-4 generations must have been produced each year.
This is the largest species that occurs regularly in numbers in these
waters, has been described and figured (Deevey 1968: 65, figs. 29-31),
and has been compared with C. bispinosa, a closely related species.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


0 0.5 j

FIGURE 27. C. stigmatica. a and b, Lateral views of female and male shells; c, Female frontal
organ and 1st antenna; d, Male frontal organ and 1st antenna; e, Endopodite of male right
2nd antenna, setae and filaments cut off; f, Endopodite of male left 2nd antenna, setae and
filaments cut off; g, Endopodite of male right 2nd antenna; h, Endopodite of female 2nd
antenna; i and j, Ventral and posterior views of male shell; k, Capitulum of male frontal
organ; 1, Penis. Scale on b for a and b; at bottom left for i and j; on right margin for d and g;
below d for c, e, f, h, k, 1. Scales in mm.







BULLETIN FLORIDA STATE MUSEUM


Females were 2.2-2.85 mm long, males 2.0-2.5 mm in length. Angel
(1970) also described this species from the Canary Island region in the
eastern North Atlantic, and gave the length range of females as ca 2.4-2.7
mm and of males as 2.2-2.4 mm.
DISTmBUTION-400N-380S in the Atlantic, and 340-36S in the
Pacific, and 38-51S in the Indian Ocean (Deevey 1981). Poulsen (1973)
synonymized this species with C. bispinosa and therefore his distribution
records cannot be included.
C. bispinosa Claus
From 1968-1970 this species was noted less frequently than during the
previous study (Deevey 1968). Only 5 males and 4 females were taken
within the upper 1000 m in August and September 1968, April and July
1969, and January-February and July to September 1970. The females
were 1.75-1.95 mm long, the males 1.75 mm long. Angel's (1979)
specimens from these waters were larger, the females having a length
range of 1.92-2.16 mm, the males of 1.64-1.88 mm. His specimens from
the Canary Island region (1970) were also slightly larger, the length range
of females being 1.8-2.1 mm and of males 1.65-1.9 mm. This species is
larger in the South Atlantic, South Pacific, and southeast Indian Ocean
(Deevey 1981).
DISTIBUTION-430N-42S in the Atlantic, 40-510S in the Pacific,
and 38-51S in the Indian Ocean. Other records are for C. secernenda
and C. bispinosa combined. Chavtur (1977) recorded C. bispinosa from
ca 400N in the Pacific, but he did not state whether he considers these two
species synonymous.
C. atlantica (Lubbock)
This species was noted infrequently from July to October 1968, in
January and July 1969, and from July to September 1970. Most of the
specimens were juveniles caught within the upper 500 m. Three females,
3.35-3.5 mm long, and one male 3.6 mm long were collected in the
500-1000 m hauls. According to Angel (1979) C. atlantica is a low latitude
near surface species with its northern limit close to 300N in the eastern
Atlantic. Poulsen (1973) found it frequent and abundant in tropical and
subtropical zones of all oceans, and it is a common epipelagic species in
the Caribbean Sea (unpublished data). Station S at 320N is apparently
near the northern limit of its range.
DISTRIBUTION-400N-37S in the Atlantic, ca 400N-42S in the
Pacific, ca 100N-38S in the Indian Ocean, and in Indonesian Seas.

C. haddoni Brady and Norman
This is one of the few species recorded during our two-year study that
was not caught by Angel (1979) in his intensive day and night sampling


Vol. 26, No. 2






DEEVEY & BROOKS: PLANKTONIC OSTRACODS


with the RMT 1 and RMT 8 nets. It was not taken until July 1969, when 3
females were caught between 500 and 1500 m. In 1970, 3 females and 4
males were collected in April, June, and July, mostly from 500 to 1500 m
depths, although 1 male was caught in a 0-500 m night tow and 1 female
in a haul from 1500 to 2000 m. A juvenile specimen was also taken in
August 1970, so several of these specimens appeared with the influx of the
second cold water mass. The females were 2.65-3.05 mm long and the
males 2.2-2.4 mm, and these are therefore larger forms than Muller's
(1906) and Angel's (1970) forms from the Canary Island region, where
Angel found the length range of females to be 2.15-2.53 mm and of males
1.75-2.0 mm. Although some of these specimens appeared at the time of
the cold water incursions, because of their size they must have been car-
ried into this region from more northern Atlantic waters, and possibly not
as the result of mesoscale eddies that originated south of the Azores. Brady
and Norman's specimens from off the coast of Ireland at 530N were also
larger forms, and larger forms occur in the South Atlantic, South Pacific,
and Indian Ocean (Skogsberg 1920; Muller 1906; Deevey 1974b, 1978b,
1981).
Descriptions of C. haddoni have been given by Muller, Skogsberg
(1920), Angel (1970), and Poulsen (1973). Figure 28 illustrates the shape
of the shell and features of the appendages of the specimens from Station
S. The principal seta of the male 1st antenna had 43-46 pairs of tiny teeth
(Fig. 28g). Angel reported 37-42 pairs of teeth for the smaller form, but
no other differences have been noted. As in other members of the
Bispinosa Group, the female has an extra long spine on the distal segment
of the endopodite of the 2nd antenna (Figs. 28d, j), and one of the two
bristles at the base of the clasping organs on the endopodites of the male
2nd antenna is exceptionally long (Fig. 28i). Muller (1906, pl. 18, fig. 6)
showed a short proximal filament on the male 1st antenna. The males
from Station S had a longer proximal filament (Fig. 28h), as illustrated by
Angel (1970, fig. 6C) and Skogsberg (1920, fig. 127-3).
DISTmBUTION -630N-51030'S in the Atlantic, ca 40N-54S in the
Pacific, 340-540S in the Indian Ocean, and Indonesian Seas. Poulsen
(1973) noted it from only one station in the Indian Ocean at ca 80S, and
pointed out that it is rarely found in tropical regions and is commoner at
higher latitudes.
Edentata Group Gooday
This group contains only two species, C. edentata and C. subeden-
tata, as Gooday (1976) removed C. edentata from the Gaussae Group and
described C. subedentata. Poulsen (1973) placed members of the Gaussae
and Edentata Groups in the genus Gaussicia, now a nomen nudum. Only
C. subedentata was taken at Station S.


1980







BULLETIN FLORIDA STATE MUSEUM


FIGURE 28. C. haddoni. a, Lateral view of male shell; b, Capitulum of female frontal organ;
c, Female 1st antenna; d, Endopodite of female 2nd antenna, setae and filaments cut off; e,
Male left clasper; f, Male right clasper; g, Armature of setae of male 1st antenna; h, Male
frontal organ and 1st antenna; i, Endopodite of male right 2nd antenna; j, Endopodite of
female 2nd antenna; k, Penis; 1, Lateral view of female shell; m, Posterior view of male shell.
Scale on a for a and m; on 1 for 1; at top right for b, c, d, k; at left center for e-g; on lower right
margin for h-j. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


C. subedentata Gooday
A total of 9 females and 16 males of this species were recorded in
November-December 1968, March-April and from July to October 1969,
and from April to September 1970, primarily from 500-1000 m depths,
although 2 specimens were taken from between 1000 and 2000 m. The
length range of females was 1.05-1.3 mm, and of males 1.1-1.2 mm. C.
subedentata, as well as C. edentata, differ from other species of Con-
choecia in several ways, and most notably in that the 5 setae and
filaments of the distal segments of the female 1st antenna are of about the
same length (see Fig. 29e), the principal seta not being longer than the
other 4. Also, the female 6th limb, in other species considerably smaller
than the male's 6th limb, is as long or longer than the male's and the setae
are reduced as in the male (see Figs. 29q, r). The large ventral gland on
both shells (Fig. 29a) also occurs in members of the Gaussae Group. The
station of the endopodite of the mandible is reduced compared with
other species; the basal segment has no setae on the inner side and the 2nd
segment only 1 seta (Fig. 290). Also, the tips of some of the setae of the ex-
opodite of the 2nd antenna are widened (Fig. 29 1), but this is the case in
some other species. The principal seta of the male 1st antenna had 17-21
pairs of teeth and the proximal secondary seta a small callous and some
spinules (Figs. 29b, d); the distal and proximal filaments are exceptionally
long, and the proximal filament has a caecum at the proximal end (Fig.
29c). The female 1st antenna has a very short spine or seta dorsally and
distally on the 2nd segment in the location where some other species have
a dorsal seta (Fig. 29e).
DISTRIBUTION -600-10030'N in the Atlantic. Except for the specimens
from Station S the records are from the eastern North Atlantic.

Gaussae Group Skogsberg
This group is closely related to the Edentata Group and includes only
C. gaussae and C. incisa. Both these species have large glands on the ven-
tral margins of the shell as in C. edentata and C. subedentata. C. incisa
has not yet been recorded with certainty from Station S.

C. gaussae Muller
Six specimens were caught in September-October 1968, March and
August 1969, and June 1970 from between 1000 and 2000 m. Of these,
three were males 3.0-3.15 mm long (Fig. 30), one was an immature
female 2.6 mm long (Fig. 31), and the other two were juveniles, the
largest 2.0 mm long. In C. gaussae the 4 filaments of the female 1st an-
tenna are about half as long as the principal seta (Fig. 31b), the 6th limb
is about as long as the male's (Fig. 31h) and the setae, particularly of the
basal segment, are plumose and not reduced. These setae are also plumose


1980







BULLETIN FLORIDA STATE MUSEUM


FIGURE 29. C. subedentata. a, Lateral view of male shell; b, Male 1st antenna; c, Proximal
section of proximal filament of 1st antenna; d, Armature of the setae of the male 1st antenna;
e, Female frontal organ and 1st antenna; f, Endopodite of female 2nd antenna; g, En-
dopodite of male left 2nd antenna, setae and filaments cut off; h, Male right clasper; i,
Capitulum of male frontal organ; j, Penis; k, Male furca; 1, A seta from the exopodite of the
female 2nd antenna; m, Endopodite of the male maxilla; n, Coxal and precoxal endites of
female maxilla; o, Endopodite of female mandible; p, Lateral view of toothrows and
masticatory pad of coxa of female mandible; q, Male 6th limb; r, Female 6th limb. Scale on a
for a; at right center for c-e, g-k, m-p; at bottom right for b, f, 1, q, r. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


FIGURE 30. C. gaussae male. a, lateral view of male shell; b, 1st antenna; c, Capitulum of
frontal organ; d, Armature of 1st antenna; e, Endopodite of right 2nd antenna; f, Endopodite
of left 2nd antenna, setae and filaments cut off; g, Right clasper; h and i, Ventral and
posterior views of male shell; j, Penis; k, Furca. Scale on a for a, h, i; on left margin for b, e,
k; at right center for d; beside g for c, f, g, j. Scales in mm.


1980







BULLETIN FLORIDA STATE MUSEUM


FIGURE 31. C. gaussae. a, Lateral view of shell of 2.6 mm juvenile female; b, Frontal organ
and 1st antenna of juvenile female; c, Capitulum of frontal organ of mature female. d, En-
dopodite of immature female 2nd antenna; e, Endopodite and basale of male mandible; f, 5th
limb of male; g, 6th limb of male; h, Female 6th limb; i, Endopodite of the male maxilla.
Scale on a for a; on left margin for e-h; at upper right for b-d, i. Scales in mm.


and not reduced in the male's 6th limb (Fig. 31g). C. gaussae also differs
from members of the Edentata Group in having 4 setae instead of 1 on the
inner side of the 1st segment of the endopodite of the mandible. The prin-


Vol. 26, No. 2






DEEVEY & BROOKS: PLANKTONIC OSTRACODS


cipal seta of the male 1st antenna has over 40 pairs of tiny teeth, very dif-
ficult to count (Fig. 30d), and as in the Edentata Group there is a callous
on the proximal secondary seta. The relative lengths of the setae and
filaments of the endopodite of the female 2nd antenna are similar to those
of C. subedentata, and the longer seta is widened at the tip (Fig. 31d).
The exopodite setae of the 2nd antenna are also slightly widened at the
tip. The capitulum of the female frontal organ shown in Figure 31b is that
of the juvenile specimen caught at Station S; that of the mature female
has many more spines, as shown in Figure 31c from a mature female
caught in the South Atlantic.
DISTRIBUTION -600N-51030'S in the Atlantic. Poulsen (1973) recorded
3 specimens from ca 34S off New Zealand in the Pacific and 4S from off
New Guinea. Rudyakov (1962) described a subspecies, C. gaussae curilen-
sis, from the Kuril Kamchatka region of the North Pacific. Muller (1908)
described this species from a male caught at 350S in the Atlantic.
Magna Group Muller
Eight members of this group occurred at Station S. One of these, C.
pseudoparthenoda, was described by Angel in 1972 and not previously
recorded from these waters. Poulsen (1973) placed some of the members
of this group in the genus Conchoecia and others in the genus Spinoecia.
The latter name is now a nomen nudum.

C. (Conchoecia) magna Claus
This is a common species that occurred year-round in the upper 1000
m, in highest numbers in the upper 500 m, where mean numbers of
570/1000 m3 were obtained for the No. 8 net samples. It was fourth in
abundance in the No. 8 net samples and third in the No. 2 net tows (see
Table 3 and 4). Except in September 1970, it was more abundant than C.
parthenoda, a closely related species whose cycle of abundance was
similar to that of C. magna. C. magna was most numerous in July and
December 1968, March-April, July, and October 1969, and March-April,
July, and September 1970 (Fig. 32B). The majority of the specimens
counted were juveniles; adults were most numerous from March to July
1969 and in April 1970 (see Fig. 32B).
As previously noted (Deevey 1968), females were 1.7-1.9 mm long and
males 1.6-1.75 mm in length. Angel (1979) gave length ranges of
1.70-1.96 mm for females and 1.56-1.80 mm for males from his Ocean
Acre samples. He also (1969b) described this species from the Canary
Island region and there females ranged in length from 1.75 to 2.05 mm,
and males from 1.65 to 1.88 mm. A comparable length range has been
recorded from the South Atlantic (Deevey 1974b), but larger specimens
have been noted from the South Pacific, where females were 1.95-2.3 mm
long and males 1.9-2.1 mm long (Deevey 1978b, 1981).


1980







BULLETIN FLORIDA STATE MUSEUM


Vol. 26, No. 2


Z o '-" o


\ o .-- --. . *V____ **- ** '**



-C. magna


0 o



-..
0 I


*- ............. ... ... .* V.... .
SAS ON D J F MAM J 'JA S O'N'D J'F M A M J J A S
1968 1969 1970
FIGURE 32. Seasonal variations in total numbers/m3, 0-500 m, of A: C. parthenoda, and B: C.
magna taken in the No. 8 net samples from July 1968 to September 1970. Total numbers in-
cluding juveniles, solid line; females and males, dashed line.

DISTRIBUTION-530N-550S in the Atlantic, ca 550N-54S in the
Pacific, to 500S in the Indian Ocean, and in Indonesian Seas and the
Mediterranean Sea.

C. (Conchoecia) subarcuata Claus
Although during the previous study (Deevey 1968: 86, figs. 42-43) oc-
casional specimens of this species were noted during every month of the






DEEVEY & BROOKS: PLANKTONIC OSTRACODS


year within the upper 500 m, C. subarcuata was infrequently noted in
1968-1970, in August-September 1968, February, July, and November
1969, and in February and June to September 1970. The length range for
females was 1.85-2.2 mm and for males 1.75-1.95 mm. Angel's (1979)
specimens from Ocean Acre were slightly larger, the females varying in
length from 1.96 to 2.36 mm and the males from 1.88 to 1.96 mm.
DISTRIBUTION 600N-560S in the Atlantic, 420N-44S in the Pacific,
to 350S in the Indian Ocean, and in Indonesian Seas.
C. (Conchoecia) lophura Muller
C. lophura occurred in small numbers throughout the year between
500 and 2000 m. Numbers of 2-29/1000 m3 were recorded for the
500-1000 m depth zone and of 2-9/1000 m3 for the 1000-1500 m hauls
with the No. 8 nets. Several specimens were noted from the upper 500 m
in 1970; only a few were caught from between 1500 and 2000 m. Most of
the specimens taken were juveniles. Females were 2.4-2.6 mm long, males
2.3-2.4 mm. Angel (1979) gave length ranges of 2.28-2.68 mm for females
and 2.16-2.52 mm for males from his Ocean Acre series in these waters.
This species is relatively large and easily recognized by the group of gland
cells at the posteroventral corner of the left shell (see Fig. 33a). Only a few
females were taken during the previous study so the male was not de-
scribed. Figure 33 illustrates the shape of the male shell and features of
the appendages. The principal seta of the male 1st antenna has ca. 60
pairs of tiny teeth, very difficult to count, and proximally on the anterior
surface a row of spinules (Figs. 33b, f). The distal bristle of the basal seg-
ment of the endopodite of the 2nd antenna (Fig. 33c) has large spines
distally as well as many long fine hairs near its base. In the northeast
Atlantic Angel and Fasham (1975) considered C. lophura a widespread
shallow mesopelagic species. In the Sargasso Sea Angel (1979) found it at
slightly greater depths. Females were taken between 400 and 1250 m,
males from 500 to 800 m, and juveniles ranged from 500 to 1500 m.
DISTRIBUTION-600N-48S in the Atlantic, ca 400N-51030'S in the
Pacific, 50N-460S in the Indian Ocean, and 240N-6S in Indonesian Seas.

C. (Conchoecia) macrocheira Muller
Only a few juvenile specimens of this species were noted, usually be-
tween 500 and 1000 m, in September and December 1968, March 1969,
and February to May 1970. Two juveniles were recorded during the
previous study. Angel and Fasham (1975) found C. macrocheira more
numerous between 30 and 11N in the eastern Atlantic, and it occurs
commonly in the Caribbean Sea (Deevey 1978c; unpublished data).
DISTRIBUTION -460N-350S in the Atlantic, to 330S in the Pacific, to
38S in the Indian Ocean, and in Indonesian Seas. It has not been taken
south of the Subtropical Convergence in the Southern Hemisphere.


1980








BULLETIN FLORIDA STATE MUSEUM


FIGURE 33. C. lophura male. a, Lateral view of left shell; b, Frontal organ and 1st antenna; c,
Endopodite of left 2nd antenna, setae and filaments cut off, d, Capitulum of frontal organ; e,
Endopodite of right 2nd antenna; f, Armature of setae of 1st antenna; g, Endopodite of max-
illa; h, Right clasper; i, Penis. Scale on a for a; at upper left for b and e; at lower left for d, g,
i; on right margin for c, f, and h. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


Poulsen (1973) found C. macrocheira most abundant in the tropics and
less common in the Pacific than in the other seas.

C. (Conchoecia) parthenoda Muller
This species occurred year-round in the upper 500 m in somewhat
smaller numbers than C. magna, except in September 1970 when over
2/m3 were recorded (see Fig. 32A). In general it was more abundant at the
same times as C. magna, although it did not have a maximum in July 1969
when highest numbers of C. magna were noted. For the upper 500 m
mean total numbers of 404/1000 m3 were obtained for the No. 8 net
samples and of 236/1000 m3 for the No. 2 net tows. In the upper waters it
was as abundant as C. rotundata (see Tables 3 and 4).
Muller described the female in 1906 and placed the species in the Ob-
tusata Group. The male was not described until recently (Deevey 1968:
73, figs 34-35; Angel 1969b: 59, figs. 8-9), and Angel placed the species in
the Magna Group. Poulsen (1969b: 153, fig. 10) also described the male
C. parthenoda, but judging by the location of the left asymmetric gland
and the size, his specimens were C. pseudoparthenoda. At Station S
females were 1.5-1.65 mm long and males were 1.35-1.5 mm long. Angel
(1979) gave length ranges of 1.5-1.8 mm for females and of 1.4-1.6 mm
for males. In the northeast Atlantic Angel and Fasham (1975) and Angel
(1979) considered C. parthenoda principally an epipelagic species
associated with North Atlantic Central Water.
DISTRIBUTION-530N-30S in the Atlantic, ca 400N-370S in the
Pacific, to 43S in the Indian Ocean, and in Indonesian Seas. This is a
common epipelagic species in tropical and subtropical waters and has not
been noted south of the Subtropical Convergence in the Southern
Hemisphere.

C. (Conchoecia) pseudoparthenoda Angel
This species, closely related to C. parthenoda, was taken in the upper
500 m on only three occasions, in August 1969 and July and September
1970. C. pseudoparthenoda is a little larger than C. parthenoda and is
easily differentiated from that species by the fact that the left asymmetric
gland is moved anteriorly on the dorsal margin to ca a quarter of the total
length from the posterodorsal corner. A male was 1.6 mm long and two
females were 1.8 and 1.85 mm long. Angel (1972) described this species
from specimens caught at 10016'N, 1947'W in the eastern Atlantic. His
males had a length range of 1.56-1.72 mm and the females of 1.72-1.90
mm. An unusually large C. parthenoda male, 1.6 mm long, described and
figured from the waters off Barbados (Deevey 1970, fig. 7) is now known
to be C. pseudoparthenoda.







BULLETIN FLORIDA STATE MUSEUM


DISTRIBUTION-320N-30S in the Atlantic, 37S in the Pacific. This
epipelagic species appears to be restricted to tropical and subtropical
waters.

C. (Porroecia) spinirostris Claus
This species is by far the most abundant ostracod at Station S, and
constituted 18% of the total numbers taken in the No. 8 net samples and
30% of the No. 2 net tows collected in the upper 500 m. Mean numbers of
2228/1000 m3 for the period studied were obtained for the No. 8 net hauls
and of 1216/1000 m3 for the No. 2 net samples (see Tables 3 and 4). C.
spinirostris was most numerous in August to October 1968, January,
April-May, and August to October 1969, and in January, March, and
June to September 1970 (see Fig. 34B). A number of generations must
have been produced during a year. Highest numbers of over 5/m3 were
caught in September 1970. Most of the specimens counted were juveniles,
and these were responsible for the maxima shown by the solid line in
Figure 34B. Total numbers of males and females are indicated by the
dashed line. Adults were most numerous in August and October 1968,
April and August 1969, and in January to March, July, and September
1970.
Angel (1979) noted that C. spinirostris is one of the most abundant
epipelagic species in tropical and temperate waters, more numerous in the
Sargasso Sea than at comparable latitudes in the eastern North Atlantic,
where Angel and Fasham (1975) found it associated with South Atlantic
Central Water. It was the dominant species caught at dusk and night in
the neuston samples collected on cruises between ca 300N and 400S in the
Atlantic, male C. spinirostris constituting 88% of the halocyprids sam-
pled (Moguilevsky and Angel 1975).
This is a small species. Females were 0.95-1.22 mm long and males
0.9-1.12 mm long. Angel (1979) listed length ranges of 1.02-1.24 mm for
females and 0.94-1.08 mm for males from the Ocean Acre series, and
reported a comparable length range for this species from the Canary
Island region (1969c). Larger specimens have been recorded from the In-
dian Ocean, where females had a length range of 1.25-1.4 mm and males
of 1.15-1.3 mm (Deevey 1981).
DISTRIBUTION-450N-42S in the Atlantic, ca 40N-370S in the
Pacific, to 39S in the Indian Ocean, and in Indonesian Seas and the
Mediterranean Sea. It has not been taken south of the Subtropical Con-
vergence in the Southern Hemisphere.

C. (Porroecia) porrecta Claus
This species is closely related to C. spinirostris but is larger, females
being 1.5-1.6 mm long and males 1.25-1.35 mm long. Muller (1906)


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


S. ,, ,,,\ /
0-
Z B Total Numbers
C. spinirostris Females & Males ------
0-500 m
42




2- /.. V _i




J jAi S'O N'D[J'F'M'A'M'JAJ JA'S'ON D J F M A M J'J'A'S
1968 1969 1970
FIGURE 34. Seasonal variations in total numbers/m3 caught by the No. 8 net between July
1968 and September 1970 of A: C. daphnoides in the upper 500 m, dashed line, and between
500 and 1000 m, solid line, and B: C. spinirostris in the upper 500 m. Total numbers of C.
spinirostris including juveniles, solid line, females and males, dashed line.

synonymized this species with C. spinirostris, but Skogsberg (1920) be-
lieved they were different species, although he lacked sufficient material
to prove it. C. porrecta is now definitely considered a separate species
(Angel 1969c, figs. 1-3; Deevey 1968: 83, figs. 40-41). Between 1968 and
1970 only 5 females and 3 males were noted from 0 to 500 m hauls made
in October 1968, January, July, and November 1969 and July 1970, so
this species was less common during this period than at the time of the
previous study. Station S must be near C. porrecta's northern limit in the
Atlantic. Angel and Fasham (1975) found it quite abundant in the near-
surface waters south of 30N in the eastern Atlantic.


1980







BULLETIN FLORIDA STATE MUSEUM


DISTMRBUTION-410N-37030'S in the Atlantic, ca 40N-300S in the
Pacific, to 39S in the Indian Ocean, and in Indonesian Seas. Gooday and
Angel (1977) described a subspecies, C. porrecta adriatica, from the north
Adriatic Sea, which Martens (1979) named the type species of the genus
Porroecia.
In the southeast Pacific, Martens (1977) noted that the distribution of C.
porrecta corresponded with Subtropical Surface Water.

Loricata Group Muller
This group contains two species, C. loricata and C. ctenophora, only
the former of which occurred at Station S. Although Poulsen (1973)
recorded the latter species from 460 to 120N in the eastern Atlantic, and
Angel and Fasham (1975) listed it as occurring from 18 to 530N, also in
the eastern Atlantic, C. ctenophora has not as yet been taken in the
Sargasso Sea. Angel (1979) noted that this species was most abundant at
his most easterly station on his 320N transect across the Atlantic, but it
rapidly decreased in numbers west of 210W and he also did not find it in
the Sargasso Sea.

C. loricata (Claus)
C. loricata occurred year-round in small numbers between 500 and
1000 m, although it was not noted in December 1968, or February or
November 1969. On several occasions it was also taken within the upper
500 m and from 1000 to 1500 m depths. It was more abundant between
May and September, with numbers up to 48/1000 m3, but no seasonal cy-
cle was discernible. Males and females were taken during the previous
study and were briefly described and figured (Deevey 1968: 92, figs.
46-47). Females were 1.8-1.85 mm long and males 1.7-1.8 mm long.
Angel (1979) gave length ranges of 1.78-2.06 mm for females and
1.68-1.92 mm for males from Ocean Acre in the Sargasso Sea. Angel and
Fasham (1975) considered this a widespread mesopelagic species. In his
transect across the Atlantic at 320N Angel (1979) found C. loricata twice
as abundant in the eastern Atlantic as in the Sargasso Sea.
DISTIBUTION-600N-37S in the Atlantic, ca 110N-52S in the
Pacific, to 500S in the Indian Ocean, and the Mediterranean Sea and In-
donesian Seas.

Serrulata Group Skogsberg

C. concentrica is included in this group with C. serrulata, mainly
because the shape of the shell and location of the glands are somewhat
similar, but these two species are not very closely related and differ in the
type of armature on the male 1st antenna and in other ways. As Poulsen


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


(1973) pointed out, the basale of the mandible is short in both these
species; also the 1st segment of the endopodite of the mandible is longer
than usual in both. C. serrulata is known only from the Southern
Hemisphere.

C. (Pseudoconchoecia) concentrica Muller
Only a male and a few juvenile specimens of this species were noted in
0-500 m hauls in September 1968, July and August 1969, and in January
and June 1970. C. concentrica was taken more frequently and described
during the previous study (Deevey 1968: 95, figs. 48-50), when the length
range of females was 1.55-1.8 mm and of males 1.55-1.6 mm. This is an
epipelagic warm water species, recorded by Angel and Fasham (1975)
only from 180N in the eastern Atlantic. In the Gulf of Mexico and Carib-
bean Sea it is a common species (Deevey 1970, unpublished data) and
even occurs in the waters over the Cariaco Trench where few ostracod
species can survive (Deevey 1978c).
DISTRIBUTION -460N (Poulsen, 1973) to 30N in the Atlantic, to 29S
in the Pacific, the equatorial Indian Ocean and Indonesian Seas.


Mollis Group Muller
Four members of this group, which Poulsen (1973) separated into
three genera, Mollicia, Paramollicia, and Boroecia, were found at Station
S. These three names have been declared nomina nuda (Martens 1979).
C. kampta Muller
Females, males, and juveniles of C. kampta were caught occasionally
between 500 and 2000 m depths in July, September to December 1968,
March and October 1969, and April, June, July, and September 1970.
Females were 2.95-3.3 mm long and males 2.55-2.82 mm long. Angel
(1979) also found this a relatively uncommon species in the Sargasso Sea,
and believed from his data that it is associated with Mediterranean Water
in the eastern North Atlantic. The species was previously described and
figured (Deevey 1968: 99, figs. 51-53).
DISTRIBTION -530N-20N in the Atlantic, and the Mediterranean Sea.

C. rhynchena Muller
C. rhynchena is represented by a single male, 2.3 mm long, taken in
May 1969 in a 500-1000 m haul. During the previous study also a single
male, 2.3 mm long, was caught in a 1250-2000 m sample collected in
February 1960 (Deevey 1968: 101, fig. 56). This species is apparently
much more abundant in the eastern North Atlantic, where Angel and
Fasham (1975) found it a mesopelagic species most abundant between 30
and 40'N, and recorded it from 110 to 600N. Angel (1979) noted in his


1980







BULLETIN FLORIDA STATE MUSEUM


transect of the Atlantic at 320N that C. rhynchena decreased greatly in
numbers west of 44W and was very uncommon in the Sargasso Sea.
DISTRIBUTION-600N-380S in the Atlantic, to 460S in the southwest
Pacific, equatorial Indian Ocean, and Indonesian Seas.

C. dichotoma Muller
This species occurred more or less regularly, usually as single in-
dividuals, between 1000 and 2000 m depths throughout the period
studied. A number of juveniles, 10 females, and 11 males were noted. The
females had a length range of 2.4-2.7 mm, the males of 2.0-2.2 mm. A
female and several juveniles were taken during the previous study
(Deevey 1968: 104, fig. 55), but the male was not described or figured.
The shape of the shell and features of the appendages are shown in Figure
35. The principal seta of the male 1st antenna has 28-33 pairs of squat
proximally pointing teeth (Fig. 35d), and the proximal secondary seta has
a long slim callous opposite the distal end of the toothrow, and distal to
this many spinules. The distal secondary seta is shorter, and extends just
past the end of the toothrow; it has many tiny spinules distally (Figs. 35c,
d). As noted by Muller (1906) in the original description and by Poulsen
(1973) the proximal filament has a double caecum (Figs. 35c, e) and is ex-
ceptionally long. Neither Muller nor Poulsen noted the long hairs on the
distal bristle of the basal segment of the endopodite of the 2nd antenna
(Figs. 35g, h). The capitulum of the frontal organ is exceptionally long
and slim, with strong spines proximally (Fig. 35f). Muller's description
was based on several specimens from the equatorial Atlantic and Indian
Oceans. He gave the length of females as 2.25-2.35 mm and of males as
1.85 mm, so his specimens were smaller than those since reported.
DISTBUTION 600N-350S in the Atlantic, and the equatorial Indian
Ocean at 90N. Angel (1979) considers C. dichotoma a medium to high
latitude deep mesopelagic to bathypelagic species.

C. borealis Sars
Only a few specimens of C. borealis, most of them juveniles, were
caught at Station S in 500-1500 m hauls, from July to December 1968,
June, October, and November 1969, and June, August, and September
1970. As this is an arctic species, the occurrence of C. borealis in the
Sargasso Sea in summer and fall indicates the influx of more northern
waters into this region. Three females were 2.6-2.7 mm long, and 3 males
were 2.1-2.15 mm in length; 5 of these were caught from 1000 to 1500 m
depths. C. borealis is closely related to C. antipoda, the Antarctic form
that Skogsberg (1920) did not consider a separate species. C. antipoda is
larger, the length range of females being 3.0-3.25 mm and for males
2.8-3.05 mm (Deevey 1974b, Muller 1906, Skogsberg, 1920). According


Vol. 26, No. 2








DEEVEY & BROOKS: PLANKTONIC OSTRACODS


FIGURE 35. C. dichotoma male. a and b, Lateral and posterior views of shell; c, Frontal organ
and 1st antenna; d, Armature of setae of 1st antenna; e, Proximal part of proximal filament of
1st antenna; f, Capitulum of frontal organ; g, Endopodite of left 2nd antenna; h, Endopodite
of left 2nd antenna, setae and filaments cut off; i, Right clasper; j, Toothrow of basale and
toothrows and masticatory pad of coxa of mandible; k, Ventral view of shell, 1, Penis; m,
Furca. Scale on a for a, b, k; at upper left for I and m; at lower left for c and g; at bottom for
d-f, h-j. Scales in mm.


1980







BULLETIN FLORIDA STATE MUSEUM


to Skogsberg, male C. borealis from the Skager Rak, Lofoten, and the
Arctic Ocean are 2.1-2.3 mm long and females 2.4-2.9 mm in length.
Although smaller, C. borealis males have more pairs of teeth on the prin-
cipal seta of the 1st antenna, 49-55 pairs (Fig. 36b), whereas C. antipoda
males have 40-45 pairs. Female C. antipoda have an extra spine on the
distal segment of the endopodite of the 2nd antenna that has not been
noted on C. borealis females. Since only juvenile specimens of C. borealis
were caught and figured (Deevey 1968, fig. 54) during the previous study,
features of the male and female shell and appendages are illustrated in
Figures 36 and 37. This species is easily recognized by the shape of the
shell, the sculpturing, the location of the shell glands and the sharp-edged
shoulder vaults, particularly in the female shell (Figs. 36a, j, 37a, b).
DISTIBUTION -ca 800N-300N in the Atlantic, and the North Pacific.
Angel (1979) characterized C. borealis as a northern high latitude species
with a circumpolar distribution. Angel and Fasham (1975) recorded it
from 30 to 600N in the eastern Atlantic.

Imbricata Group Muller
Three species belonging to this group, which Poulsen placed in the
genus Conchoecissa, occurred at Station S. Two of these, C. imbricata
and C. ametra, were present year-round. Angel (1979) recorded several
specimens of C. plinthina and also possibly of C. symmetrica, a species
otherwise known only from the Southern Hemisphere, in his Ocean Acre
series of samples.
C. imbricata (Brady)
This common species occurred in relatively small numbers year-round
within the upper 1000 m. It was taken in higher numbers in the No. 8 net
samples from 500 to 1000 m depths, and also constituted a greater propor-
tion of the total numbers of ostracods over this depth level (see Tables 3
and 4 and Fig. 5). It was also taken year-round during the previous study,
and figured and briefly described at that time (Deevey 1968: 108, figs.
57-58). The seasonal variations in numbers over 0-500 m and 500-1000 m
depths are shown in Figure 38B. Within the upper 500 m it was most
abundant in summer, and between 500 and 1000 m it was most numerous
July to September 1968, February and July 1969, and from June to
September 1970. Throughout the water column it was most abundant in
summer, but this might represent in part a seasonal migration to deeper
waters. This species also undergoes diurnal migrations, the adults moving
up from 600-800 m to 100-500 m (Angel 1979) at night.
This is an easily recognized and relatively large species, females being
2.7-3.0 mm long and males 2.25-2.45 mm in length. Angel (1979) listed
length ranges of 2.6-3.2 mm for females and of 2.28-2.64 mm for males


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


k


FIGURE 36. C. borealis male. a, i, and j, Lateral, ventral and posterior views of shell; b, 1st
antenna; c, Capitulum of frontal organ; d, Endopodite of left 2nd antenna, setae and
filaments cut off; e, Right clasper; f, Toothrows and masticatory pad of coxa of mandible; g,
Toothrow of basale of mandible; h, Endopodite of maxilla: k, Penis; 1, Furca. Scale on a for
a, i, j; at top for b, h, k, 1; on lower right margin for c-g. Scales in mm.

from the Ocean Acre series. He characterized C. imbricata as a
widespread shallow mesopelagic species.
DISTRIBUTION-Ca 650N-550S in the Atlantic, ca 40oN-500S in the








BULLETIN FLORIDA STATE MUSEUM


Pacific, ca 8N-480S in the Indian Ocean, and Indonesian Seas. This is a
common species in tropical and subtropical waters.


FIGURE 37. C. borealis female, a and b, Lateral and posterior views of shell; c, Frontal organ
and 1st antenna; d, Endopodite and basale of mandible; e, Endopodite of 2nd antenna, setae
and filaments cut off; f, 5th limb; g, 6th limb. Scale on a for a and b; on left margin for d; at
lower right for c, e-g. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


C. ametra Muller
This species was taken year-round in small numbers between 500 and
1500 m, although a few specimens were noted from the upper 500 m and
from 1500 to 2000 m depths. It was more numerous between 500 and 1000
m, but constituted a higher percentage of the total numbers caught in the
1000-1500 m hauls (see Tables 3 and 4). Between 500 and 1000 m it was
most numerous from July to September 1968, in January, March, and
May 1969, and in January-February, May, and August 1970 (see Fig.
38A). Small numbers occurred year-round between 1000 and 1500 m.
Most of the specimens counted were juveniles.
Although the female C. daphnoides is 5 mm or more in total length,
C. ametra is the largest species that occurs regularly in the deeper waters
at Station S. Females had a length range of 4.0-4.65 mm and males of
3.55-4.2 mm, including rostral and posterodorsal spines. Angel (1979)


0.11 1 A
C1- ametra
500-1000 m
SO 1000-1500 m -----





\ \ -

0 B
Z C. imbricata O- 500 m
500- 1000 m -.
0.2




0.1 "- I\




Si AS N J 'M'A' J'A'S OND J 'FMAMJ J i'A S
1968 1969 1970
FIGURE 38. Seasonal variations in total numbers/m3 taken by the No. 8 nets between July 1968
and September 1970, of A: C. ametra between 500 and 1000 m, solid line, and 1000 and 1500
m, dashed line, and B: C. imbricata 0-500 m. solid line, and between 500 and 1000 m. dashed
line.


1980







BULLETIN FLORIDA STATE MUSEUM


gave length ranges of 3.33-4.42 mm for females and of 3.17-4.17 mm for
males from the Ocean Acre series of samples. As no males were caught
during the previous study, features of the male shell and appendages are
shown in Figure 39. The principal seta of the male 1st antenna has ca 34


FIGURE 39. C. ametra male. a, g, and h, Lateral, ventral and posterior views of shell; b, En-
dopodite of right 2nd antenna; c, 1st antenna; d, Right clasper, e, Left clasper; f, Armature of
setae of 1st antenna; i, Capitulum of frontal organ; j, Furca. Scale on a for a, g, h; at upper
right for b, c, j; beside f for d-f; above i for i. Scales in mm.


Vol. 26, No. 2







DEEVEY & BROOKS: PLANKTONIC OSTRACODS


pairs of leaf-like teeth (Fig. 39f); the proximal secondary seta has a long
row of spinules near its tip, and the distal seta has some very fine spinules
that are difficult to see. The male right clasping organ is strongly curved
with one projection near the base on the inner side (Fig. 39d), but the left
clasper is much smaller and straight (Fig. 39e). The claws on the furca are
relatively short and strong (Fig. 39j). In the mature shell the right rostrum
and the right posterodorsal spine are shorter than on the left shell (Figs.
39a, g), and this differentiates this species from C. symmetrica; the
juveniles of these two species are less easily distinguished. The principal
seta of the female 1st antenna has tiny spinules part of the way down the
anterior surface, as well as spinules down the posterior surface distal to
the 4 filaments.
DISTRIBUTION 64N-440S in the Atlantic, 20'N-49S in the Pacific,
ca 80N-50S in the Indian Ocean, and in Indonesian Seas.

C. plinthina Muller
A single juvenile specimen, 3.8 mm long, with 7 claws on the furca,
was taken in February 1970 in a haul from 1000-1500 m (see Figs. 23 m,
1). The longer bristle on the basal segment of the endopodite of the 2nd
antenna had a number of long hairs (Fig. 23m). In his description of this
species Muller (1906: 116, pl. 27, figs. 1-6, 9, 10, 20) said these bristles
were bare, but Poulsen (1973, fig. 98c) described and figured long hairs as
occurring on the male 2nd antenna. Muller gave the length range of
females as 5.5-5.9 mm and of males as 4.8-5.2 mm. Poulsen reported that
the largest individuals were found in the Pacific between 70N and 4S and
790 and 120W. Next largest specimens were found in the western South
Pacific, the Indian Ocean, and Indonesian Seas, whereas smallest in-
dividuals were taken in the Atlantic Ocean. Angel and Fasham (1975)
recorded this species from 11 to 400N in the eastern Atlantic, and Angel
(1979) found none on the transect across the Atlantic at 320N; several
specimens were taken in the day and night Ocean Acre samples between
1000 and 2000 m. Angel concluded that this is an infrequent bathypelagic
species restricted to tropical and subtropical waters.
DISTRBUTION Ca 480N-42030'S in the Atlantic. Poulsen reported
that C. plinthina occurs in the Atlantic, Pacific, and Indian Oceans,
almost exclusively in the tropical zones, 25N-350S. Chavtur (1977) listed
it as occurring in the Bering Sea.

Daphnoides Group Muller
C. (Conchoecilla) daphnoides (Claus)
C. daphnoides was present year-round over 500-1000 m depths, but
was not taken as consistently in the upper waters (see Fig. 34A). It occur-







BULLETIN FLORIDA STATE MUSEUM


red in the upper 500 m mainly in fall to spring and over 500-1000 m
depths in spring and fall, with a summer minimum. There were indica-
tions of a seasonal vertical migration, with the bulk of the population
within the upper 1000 m from fall to spring and over 500-1500 m depths
from spring to fall. C. daphnoides was never abundant, but constituted a
small percentage of the total numbers of ostracods (see Tables 3 and 4). In
general, it was least numerous in summer and most abundant from
January to March or April. Most of the specimens counted were juveniles,
but males and females were present from February to September and
most numerous in March, April and May. With respect to length, C.
daphnoides females are the largest halocyprid ostracods found commonly
in these waters. The females had a length range of 4.7-5.4 mm; the males
are considerably shorter, 2.85-3.2 mm long. Angel (1979) gave a length
range of 4.17-5.25 for females and of 2.64-3.12 mm for males from the
Ocean Acre samples. He lists C. daphnoides as a widespread shallow
mesopelagic species. The female was illustrated in the previous study
(Deevey 1968, fig. 60), and the male from the waters off Barbados
(Deevey 1970, fig. 9).
DISTRIBUTION--630N-42S in the Atlantic, 40N-5130'S in the
Pacific, ca 100N-430S in the Indian Ocean and in Indonesian Seas.

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Baker, A. de C., M. R. Clarke and M. J. Harris. 1973. The N. I. O. Combination Net


Vol. 26, No. 2








DEEVEY & BROOKS: PLANKTONIC OSTRACODS


(RMT 1+8) and further developments of rectangular midwater trawls. J. Mar. Biol.
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Sargasso Sea. Proc. Biol. Soc. Wash. 86:247-260.
1973b. Bathypontia (Copepoda: Calanoida): Six species, one new, from the
Sargasso Sea. Proc. Biol. Soc. Wash. 86:357-372.
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six new, from the Sargasso Sea. Bull. Mar. Sci. 24:439-472.
1974b. Pelagic ostracods collected on HUDSON 70 between the equator and
55S in the Atlantic. Proc. Biol. Soc. Wash. 87:351-380.
1977. Conchoecia convexa, new species of halocyprid ostracod from the
Caribbean Sea and Gulf of Mexico. Proc. Biol. Soc. Wash. 90:358-366.
1978a. On new and little known species of Archiconchoecia (Myodocopa,
Halocyprididae) from the Sargasso and Caribbean Seas, with descriptions of seven new
species. Bull. Florida State Mus., Biol. Sci. 23(2):105-138.
.1978b. A taxonomic and distributional study of the planktonic ostracods
collected on three cruises of the Eltanin in the South Pacific and the Antarctic Region
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1980







BULLETIN FLORIDA STATE MUSEUM


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Vol. 26, No. 2
















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