Bijdragen lot de Dierkunde, 49 (2): 219-226 1979

Amsterdam Expeditions to the West Indian Islands, Report 5.

Notodiaptomus caperatus, a new calanoid copepod

from phreatic groundwater in Barbuda

(Crustacea: Diaptomidae)

by

Thomas E. Bowman

Department of Invertebrate Zoology, Smithsonian Institution, Washington, DC 20560, U.S.A.

Abstract Description. — Female: Length 1.6-1.7

mm. In dorsal view body widest at posterior from well in is Notodiaptomus caperatus n. sp., a Barbuda, cephalosome and pediger 1, gradually narrowing described and illustrated. It is the first diaptomid from the 4 and 5 5 Lesser Antilles and the first West Indian diaptomid having posteriorly. Pedigers separate. Pediger affinities with South American species. produced into small wings; left wing directed

slightly obliquely, armed with 2 conical spines;

right wing directed nearly laterad, armed with 2 INTRODUCTION conical spines.

Urosome 2-merous, most or all of 2nd segment Recently Dr. Jan H. Stock (Zoologisch Museum, telescoped into genital segment. Genital segment University of Amsterdam) sent to me for study a 1.5 as of anterior nearly X long as rest urosome; sample of calanoid copepods that he had collected part expanded laterally into lobe on either side; in phreatic groundwaters of Barbuda, the north- with right lobe steeper sides, bearing conical spine easternmost of the Leeward Islands of the Lesser at summit; left lobe with unarmed summit, but Antilles. The copepods proved to be the new with conical spine at posterior base. In lateral view diaptomid described below, the first from the genital segment produced into posteroventral Lesser Antilles.

pouchlike protuberance, anterior to which are

several vertical folds. Caudal ramus symmetrical,

TAXONOMIC PART half slightly more than as wide as long.

Antenna 1 reaching slightly beyond caudal rami;

Notodiaptomus Antenna caperatus n. sp. segments 11-21 each with 1 seta. 2 with 2-4. Figs. inner and outer lobes of endopod with 9 and 7

setae respectively. Maxilliped with lobes of 1st

Material examined. — Sta. 78/19, of University basipod well developed; 4th lobe with only 3 Amsterdam Expeditions to the West Indian Islands. Barbuda, and of setae row spinules on distal margin. Guava Farm, S.E. of Codrington (17°37'39"N6l°48'51"W), 1-4 with normal of (fig. 1), from round, almost covered well, water table at Legs armature spines and

of water 0.75 3 m, depth m, chlorinity 1400 mg/1, leg. 2 with cuticular setae. Leg triangular lobe on H. J. Stock, 9 April 1978: 30 $ £ (holotype in Zoologisch posterior surface of 2nd Museum Amsterdam endopod segment. (ZMA), coll. no. ZMA Co. 102.655a; 1st ZMA Co. 10 Leg 5, with 19 paratypes, 102.655b; paratypes in United basipod prominent posterior

States National DC coll. Museum, Washington (USNM) no. conical spine; 2nd basipod with short lateral seta. USNM 172318; 12 9 9 (10 ZMA Co. paratypes, 102.655c; First exopod segment 2 X as long as wide. Second 2 paratypes, USNM 172318); 45 copepodids of various without lateral claw stages (ZMA Co. 102.655d). exopod segment seta; mod-

armed middle erately stout, on parts of both mar- 4 in *) Report no. appeared Verslagen en technische gege- with gins close-set spinules. Third exopod segment vens, Instituut voor Taxonomische Zoologie (Zoologisch

Universiteit 20. slightly longer than medial seta to Museum), van Amsterdam, no. wide; fused 220 TH. E. BOWMAN - NOTODIAPTOMUS FROM BARBUDA

Fig. 1. Map of Barbuda (from Russell & McIntire, 1966) showing the location of station 78/19 (indicated by a star), where collected. Notodiaptomus caperatus n. sp. was BIJDRAGEN TOT DE DIERKUNDE, 49 (2) - 1979 221

2. and left Fig. Notodiaptomus caperatus n. sp.: a, ￿, dorsal; b, ￿ pediger 5 urosome, side; c, same, light side; d,

5 and of same, dorsal; e, ￿, lateral;f, ￿ pediger urosome, dorsal; g, ￿ right wing of pediger 5, lateral; h, ￿ left wing pediger 5, lateral; i, ￿ antenna 1, segments 11-19. 222 TH. E. BOWMAN - NOTODIAPTOMUS FROM BARBUDA

than of lateral — From Latin segment at base, more 2 X length Etymology. the caperatus

seta. Endopod reaching beyond middle of 1st meaning wrinkled, referring to the folds on the

2nd exopod segment, 2-merous; segment longer female genital segment. with than 1st, distal margin oblique, armed row

of fine setae. Relationships. — The Barbudan diap-

tomid is provisionally assigned to the South Amer-

in Male: Length 1.4-1.5 mm. Prosome shape as ican genus Notodiaptomus Kiefer, 1936, which

of 5 the female. Right posterior corner pediger corresponds to nordestinus group of Wright

left rounded; corner slightly angular; both corners (1935). The limits of South American diaptomid

armed with terminal knob have been established and spinule-tipped having genera not firmly,

setule dorsal it. Genital future studies alter the to segment asymmetrical, revisionary may generic

with higher bulge on left side bearing postero- assignment of the Barbudan species.

dorsal Posterior of curved to As with other N. be seta. part urosome diaptomids, caperatus may

right. identified by a combination of distinguishing

Right antenna 1 with spines on segments 8, 10, characters rather than by one or two characters.

11, 12, 13, 15, and 16. Spines on segments 10 The shape and armature of pediger 5 and the

the in both and 11 subparallel to axis of antenna, those of genital segment, armature of antenna 1

and 16 that of and the of in both segment 12 especially quite small, sexes, structure leg 5 sexes,

with incised taken will N. segment 13 suberect, large, slightly together, distinguish caperatus from

tip. Segment 23 with strong recurved spinous other diaptomids. Perhaps the most striking char-

than half of acteristics the wrinkled in the process more length segment. are genital segment

with and and inner Right leg 5, 1st basipod moderately devel- female, the shape denticulate mar-

in oped sensillum-bearing process. Second basipod gin of the distal process of the left leg 5 exopod

medial with the male. about 1.5 X longer than 1st; margin

cuticular thickening at midlength; distomedial part of posterior surface with crescentic patch of fine

hairs. Second exopod segment about 1.5 X longer HABITAT

with than 1st and 1.6 X longer than wide,

H. rounded knob at base medially; lateral spine sub- Barbuda is "hollow as Swiss cheese" (J. Stock,

in has terminal, more than half length of segment; litt.) and substantial underground water,

claw third than but terminal nearly a longer exopod, no surface streams. Rainfall averages nearly

arched with with recorded maximum gently recurved tip. Endopod 2- 100 cm/year, a of nearly

of 1st 670 cm in 1913 and a minimum of about 55 cm merous, not quite reaching midlength

armed is within 6 exopod segment; apical margin oblique, in 1930. The water table high, m of the

with row of setules. surface on practically all lowland parts of the

Left leg 5 slightly more slender than right, island. Two of the major wells provide more than reaching about midlength of 1st exopod segment 300,000 and 94,000 1/day (data from Martin- of right leg. First basipod about 1/4 longer than Kaye, 1956). The water is rather saline; Martin- 2nd. Exopod with widely separated proximal and Kaye (1956) gives measurements for salinity

and distal pads. Proximal pad slightly smaller than between 352 2865 ppm (= mg/1) for the

medial wells. bodies of distal, bilobed. Distal process subconical, major Larger underground water

and denticulate in distal surface exist in number of but of margin nearly straight a caves, none

lateral with contained part, margin bend near midlength. those sampled calanoids.

medial Some Proximal process straight, slender, pointed, diaptomids prefer small, temporary bodies

with minute margin a few spinules. of water, e.g. Hemidiaptomus amblyodon (Maren-

Endopod reaching base of distal pad, becoming zeller) (see Dussart, 1967: 108, who terms such

narrower I not slightly distally; apex slightly oblique, species "telmatoplanktonic"). However, am

armed with of slender other row setules. aware of any diaptomid known only from - BIJDRAGEN TOT DE DIERKUNDE, 49 (2) 1979 223

10-16; b, d, Fig. 3. Notodiaptomus caperatus n. sp.: a, ￿ right antenna 1, segments same, segment 23; c, ￿ antenna 2; ￿ mandibularpalp; e, ￿ maxilliped, 1st basipod; f, ￿ leg 1; g, ￿ leg 2. 224 TH. E. BOWMAN - NOTODIAPTOMUS FROM BARBUDA

4. of lateral; Fig. Notodiaptomus caperatus n. sp.: a, ￿ leg 4; b, ￿ leg 5, posterior; b', endopod same, anterior; c, ￿ leg 5,

2nd and d, ￿ leg 5, posterior; e, ￿ left leg 5, anterior; f, ￿ right leg 5, basipod, 1st exopod, endopod, anterior. BIJDRAGEN TOT DE DIERKUNDE, 49 (2) - 1979 225

phreatic groundwater. C. B. Wilson (1936) re- Until now, no diaptomids have been reported from

Herrick and the Lesser and the of ported Diaptomus albuquerquensis Antilles, presence a diap-

tomid is that D. novamexicanus Herrick from underground on Barbuda remarkable, considering

waters of Yucatan, but in open-air cenotes. Only the Amsterdam Expeditions sampled 580 stations

one described diaptomid, the blind unpigmented on 29 islands for stygobionts and obtained cala-

from Cueva noids 16 In Diaptomus cokeri Osorio-Tafall, 1942, only at 1 of the stations on Barbuda.

Chica and Cueva de los Sabinos, San Luis Potosi contrast to the other West Indian diaptomids, N.

but has affinities with South rather State, Mexico, appears to be a true troglobite, caperatus American

least live than at some epigean diaptomids are able to North American species.

in I have How N. Barbuda underground waters. identified Diap- caperatus arrived at can only

tomus dorsalis Marsh, an epigean species of the be conjectured. Some diaptomids can produce

southern and southwestern United resistant that withstand desiccation could States, Haiti, eggs and

and from in Cueva distances Cuba, phreatic groundwater be transported considerable on water-

Grande Las insects. subterranean de Caguanes, Cayo Caguanes, Villas fowl or even Invasion of

Province, Cuba, where it was collected by L. Boto- waters would necessarily be preceded by establish-

the in saneanu during Cubano-Romanian Biospeleo- ment surface waters, which could have been

in Barbuda before karst fea- logical Expeditions. present the present

In phreatic waters diaptomids obviously cannot tures developed.

feed the usual food for most to N. on phytoplankton, Attempts explain the presence of caperatus

Diaptomidae, but phytoplankton is not essential by vicariance will have to take into consideration

to all members of this family. For example, Eu- the youth of Barbuda, which is composed of

diaptomus gracilis (Sars) can survive for long Pleistocene limestones and calcarenites plus Recent

periods by feeding on bacterial and organic detritus accretions (Martin-Kaye, 1959). At times when

N. have Pleistocene seas were lowered because of accumula- (Nauwerck, 1962). caperatus may a

similar diet, and in addition might possibly obtain tion of continental ice, the Barbuda Bank, which

some food by predation. Anderson (1970) has underlies Barbuda and Antigua, emerged but the

shown that arcticus did find in Diaptomus Marsh, D. neva- Expedition not any diaptomids Antigua

densis Light, and D. shoshone Forbes, while not groundwaters (15 stations sampled).

catch and A vicariance obligate predators, can fairly large active model might suggest that at some

and eat them six other time in the ancestral prey efficiently. However, past an diaptomid was wide-

diaptomid species studied by Anderson were spread in the Lesser Antilles and northern South

entirely herbivorous. America, but now survives in the Lesser Antilles

only as a relict population. A cautionary note,

however: N. caperatus is not widespread, being

ZOOGEOGRAPHY collected at only 1 of 16 stations in Barbuda, and

its failure to turn in collections the up from other

The three species of Diaptomidae thus far known islands could reflect its rarity rather than its

from the West Indies absence from them. have been found only on the Greater Antilles: Diaptomus proximus Kiefer,

~ " ------1936 D. dorsalis Marsh, fide M. S. Wilson, (= ACKNOWLEDGEMENTS 1959) from Haiti and Cuba; D. asymmetricus I most am grateful to Dr. Jan H. Stock for sending me the Marsh, 1907, and D. purpureus Marsh, 1907, diaptomids and collection data and to Dr. Louis S. Kornicker

from Cuba. These three species have been assigned for a helpful review of the manuscript.

The fieldwork in the various West Indian Islands has been to North' American subgenera (M. S. Wilson, supported by various subventions (to J. H. Stock): three 1959). The two latter species are known only grants of the Netherlands Foundation for the Advancement from of Cuba, but D. dorsalis occurs in Louisiana Tropical Research (WOTRO), The Hague (WR 87-79,

and of 87-114, 87-144), two grants the Treub Maatschappij, and Florida (M. S. Wilson, 1959), Oklahoma Utrecht (1976 and 1978), and a grant of the Beijerinck- (Robertson, 1970), and Arizona (Cole, 1961). Popping Fonds, Amsterdam (1977).

15 226 TH. E. BOWMAN - NOTODIAPTOMUS FROM BARBUDA

REFERENCES NAUWERCK, A., 1962. Nicht-algische Ernahrung bei Eudiap-

tomus gracilis (Sars). Arch. Hydrobiol., Suppl., 25 (4): ANDERSON, R. S., 1970. Predator-prey relationships and 393-400. from predation rates for crustacean zooplankters some OSORJO-TAFAM., B. F., 1942. Diaptomus (Microdiaptomus) lakes in western Canada. Can. J. Zool., 48 (6): 1229- de cokeri, nueva de Diaptomido las 1240. subgenero y especie

cuevas de la region de Valles (San Luis Potosi, Mexico). COLE, G. A., 1961. Some calanoid copepods from Arizona Ciencia Mex., 3 (7): 206-210. with of notes on congeneric occurrences Diaptomus spe- ROBERTSON, A., 1970. Distribution of calanoid copepods cies. Limnol. Oceanogr., 6 (4): 432-442. (Calanoida, Copepoda) in Oklahoma. Proc. Okla. Acad. DUS&AUT, B., 1967. Les Copepodes des eaux continentales Sci., 50: 98-103. d'Europe occidentale, I. Calano'ides et Harpacticoi'des: RUSSELL, R. J. & W. G. MCINTIRE, 1966. Barbuda reconnais- 1-500 (N. Boubee & Cie, Paris). sance. Louisiana State Univ. coastal Stud. Inst., Tech. KIEFER, F., 1936. tJber die Systematik der siidamerikanischen Rep., 11 (J): i-viii, 1-53. Diaptomiden (Crustacea Copepoda). Zool. Anz., 116 WILSON, C. B., 1936. Copepods from the cenotes and caves (7/8): 194-200. of the Yucatan Peninsula, with notes on cladocerans. MARSH, C. D., 1907. A revision of the North American Pubis. Carnegie Instn., 457: 77-88. species of Diaptomus. Trans. Wis. Acad. Sci. Arts Lett., WILSON, M. S., 1959. Calanoida. In: W. T. EDMONDSON 15 (2): 381-516, pis. XV-XXVIII. Ward and fresh-water 738-794 water of ed., Whipple's biology: MARTIN-KAYE, P. H. A., 1956. The resources (John Wiley & Sons, New York). Antigua and Barbuda, B.W.I.: 1-109 (B. G. Lithographic WRIGHT, S., 1935. Three new species of Diaptomus from Co., La Penitence, British Guyana). northeast Brazil. Anais Acad. bras. Cienc., 7 (3): 213- , 1959. Reports on the geology of the Leeward and 233, pis. I-IV. British Islands: Leeward Virgin 1-117, maps (Governor

Islands, St. Lucia).

Received: 16 July 1979