78 



differences were observed between these morphs, which need to be 

 clarified. 



Developmental stage cv 9 of o. waldemari 

 The developmental stages (NI-NVI, CI-CVI 9 and 3) of O. 

 waldemari were described by Malt (1982b, as O. media f. minor), 

 based on individuals reared in the laboratory and collected at sea. 

 According to her report, the female CV exhibits a 4-segmented 

 urosome ( 1 segment between genital double-somite and anal somite), 

 which is very unusual among copepods exhibiting the full comple- 

 ment of urosomites in the adult. Typically, the number of somites 

 between female CV and CVI does not change in female copepods 

 possessing a genital double-somite because the addition of one 

 abdominal somite from CV to CVI is compensated for by the fusion 

 of the genital somite and the first abdominal somite in the female 

 (e.g. Itoh & Nishida, 1995). Remarkably, the only other taxonomic 

 report of copepodid stages of oncaeids by Bjornberg (1972) also 

 describes the female CV of an unidentified Oncaea sp. with a 4- 

 segmented urosome. So both Malt and Bjornberg must in fact have 

 been dealing with a CIV. In the present study, late female copepodid 

 stages of O. waldemari and related species, such as O. venusta, O. 

 mediterranean and O. scottodicarloi, were found with a 5-seg- 

 mented urosome, which exhibited no genital apertures (cf. Fig. 28C, 

 E). According to the general rule mentioned above, these stages 

 should be regarded as the typical female CV. A more detailed re- 

 examination of developmental stages of O. waldemari and other 

 oncaeid species is in progress. 



Geographical distribution 



O. waldemari was confined to the Gulf of Aden / Strait of Bab al 

 Mandab area and the southernmost, shallow parts of the Red Sea. It 

 was not found in the deep oceanic area of the southern Red Sea or 

 further north in the central/northern regions (Bottger-Schnack, 1 995, 

 as Oncaea sp. AD). Thus, it cannot be regarded as a typical Red Sea 

 species. In the Arabian Sea, it was present in somewhat greater 

 numbers near Oman than in the central Arabian Sea (Bottger- 

 Schnack, 1996, as Oncaea sp. B). The species is also present in the 

 Eastern Mediterranean, but was not separated from the closely 

 related O. scottodicarloi during earlier quantitative counts in that 

 area (Bottger-Schnack, 1997, as O. media f. minor). 



Vertical distribution 



Both sexes of O. waldemari occurred in the lower epipelagic zone, 

 with maximum concentrations between 20-60 m in the Gulf of Aden 

 and the Strait of Bab al Mandab. In the southern, shallow region of 

 the Red Sea (total water depth 190 m), the populations showed a 

 strong tendency to submerge: they were generally found between 

 20-175 m, with maximum concentrations between 125-175 m 

 (females) or 100-150 m (males). 



Oncaea paraclevei sp. nov. 



Type LOCALITY. Southern Red Sea, oceanic area, 15° 34.8'N, 41° 

 54.9E, at 0-50 m; total water depth 970 m. 



Material examined. 



(1) Southern Red Sea, 15° 34.8'N, 41° 54.9'E: Stn. 703; RW Meteor 



leg 5/5: collected 03 August 1987 with MSN 0.05 mm net (Haul 



39/5); depth 0-50 m; total water depth 970 m. 



(a) holotype 9 dissected on 11 slides (urosome partly damaged 

 after documentation (ZMH K-39578a-j); paratypes: 6 99in 

 alcohol, some ovigerous (ZMH K-39579). 



(b) additional paratypes: 1 9 dissected on 10 slides (BMNH 

 1998.2820), 5 99 in alcohol (BMNH 1998.2821-2825). 



(c) additional paratypes: 1 6 dissected on 10 slides, 1 9 dis- 





R. BOTTGER-SCHNACK 



sected on 1 1 slides, 6 99(1 ovigerous, 2 with spermatophores, 

 1 with small dorsal projection, 1 without dorsal projection) 

 in alcohol (RBS). 



(2) Central Red Sea, 21° 25.53'N, 38° 01.91'E: Stn. 130; R/V 

 Valdivia leg 29: collected 28 October 1980 with MSN 0.1 mm 

 net (Haul 117/5); depth 0-20 m; total water depth ca 1960 m. 



(a) 1 paratype 9 in alcohol (BMNH 1998.2826). 



(b) 2 paratype 99 in alcohol (ZMH K-39580). 



(c) 1 paratype 9 dissected on 10 slides (RBS). 



(3) Northern Arabian Sea, near Oman, 20° 44.3'N, 59° 40.5'E: Stn. 

 347; RW Meteor leg 5/3a: collected 05 April 1987 with MSN 

 0.05 mm net (Haul 8/1 ); depth 0-50 m; total water depth ca 2500 

 m:2 99 in alcohol (RBS). 



Description. Note illustrations are based on the holotype, except 

 for habitus, maxilliped and labrum. 



Adult female (Figs. 29-31). 



Body length (measured in lateral aspect; from anterior margin of 

 rostral area to posterior margin of caudal rami, calculated as sum of 

 individual somites): 770 um [traditional method: 650-660 urn, 

 based on 2 specimens]. 



Exoskeleton well chitinized. Prosome 2. 1 times length of urosome, 

 excluding caudal rami, 1 .8 times urosome length including caudal 

 rami. P2-bearing somite with dorso-posterior projection in lateral 

 aspect (Fig. 29B), variable in conspicuousness according to degree 

 of telescoping of somites (Fig. 29a-c). Integumental pores on 

 prosome as indicated in Fig. 29A, B. Pleural areas of P4-bearing 

 somite elongate and with rounded posterolateral corners. 



Proportional lengths (%) of urosomites 9.4 : 58.5 : 9.9 : 10.4 : 

 11.8. Proportional lengths (%) of urosomites and caudal rami 7.9 : 

 49.2 : 8.3 : 8.7 : 9.9 : 15.9. 



Genital double-somite oval-elongate, 1 .6 times as long as maxi- 

 mum width (measured in dorsal aspect) and 1.9 times as long as 

 postgenital somites combined (Fig. 29C); largest width measured at 

 anterior third, lateral margins of genital double-somite rounded 

 anteriorly, tapering posteriorly. Paired genital apertures located near 

 dorsolateral margin at about 1/3 distance from anterior margin of 

 genital double-somite; armature represented by 1 spine and 2 minute 

 spinous processes (Fig. 29H). Double-curved sclerotization between 

 genital apertures, varying in form as in Fig. 28d, e; pore pattern on 

 dorsal surface as in Fig. 29C. 



Anal somite 1 .3 times wider than long; about 3/4 length of caudal 

 rami (Fig. 29C). Anterior margin of anal opening (vestigial anal 

 opening) with transverse row of minute denticles, which are variable 

 in number, ranging between 4 (holotype) and 10. Other surface 

 ornamentation as in O. venusta. 



Caudal ramus (Fig. 29F) about 2.3 times as long as wide, variation 

 within (Fig. 29F) and between specimens ranging between 2.1-2.4 

 : 1 (4 specimens). Surface ornamentation and length ratios of caudal 

 setae as in O. clevei, except for longer outer terminal seta (IV), 

 reaching 4/5 the length of inner terminal seta (V). 



Antennule (Fig. 29E) with relative lengths (%) of segments 

 measured along posterior non-setiferous margin 6.0 : 24.5 : 42.9 . 

 10.9 : 4.3 : 11.4. Armature formula as for genus. 



Antenna (Fig. 30A) as in O. clevei, except for seta III on second 

 endopod segment unipinnate. 



Labrum (Fig. 30B,C) as in O. clevei, except for anterior surface 

 lacking row of denticles on proximal part of each lobe. 



Mandible (Fig. 30D) similar to O. clevei, except for number of 

 dentiform processes along distal margin of blade C varying between 

 3 or 4 (Fig. 30D, d). 



Maxillule (Fig. 30E), maxilla (Fig. 30F), and maxilliped (Fig. 

 30G) as in O. clevei. 



