82 



R. BOTTGER-SCHNACK 



Swimming legs 1-4 (Fig. 30A-D) with armature as for genus and 

 surface ornamentation as in O. clevei. Spine length of exopodal and 

 endopodal segments not substantially different between the two 

 species, except for outer distal spine on P4 endopod, which is 

 slightly longer, measuring > 1/2 to 3/5 length of distal spine (Fig. 

 30D). 



P5 (Fig. 29G) as for O. clevei, except exopodal setae slightly 

 curved, and small seta arising from lateral surface of somite plumose. 



P6 (Fig. 29H) represented by operculum closing off each genital 

 aperture; armed with a spine and 2 small spinous processes. 



Egg-sacs as in O. clevei. 



Adult male. Unknown. 



Etymology. The Greek prefix para-, meaning beside, refers to 

 the great similarity of the species with O. clevei. 



Taxonomy 



O. paraclevei is closely related to O. clevei, from which it can be 

 distinguished by differences in the form of the genital double- 

 somite, which is more elongate, location of genital apertures, which 

 are more medial and somewhat more posterior than in O. clevei, and 

 by the resulting differences in form and location of sclerotization 

 between genital apertures. The combination of these characters 

 enables rapid separation of the two species during routine counts. 

 Further minor differences are found in ornamentation of the labrum, 

 in proportional spine lengths on P4 enp-3, and in P5 setae. 



Males of O. paraclevei were not encountered during the present 

 study, although ovigerous females and specimens carrying 

 spermatophores were observed in the samples. Those males co- 

 occurring with females of 0. clevei and O. paraclevei were all 

 assigned to the first species at closer examination, based on the 

 proportional length of endopodal spines on P4. However, as this is a 

 variable character in O. paraclevei, it might not be adequate to 

 separate males of these two species. Further investigation using 

 alternative methods, such as molecular analysis, may help to iden- 

 tify males of O. paraclevei, which cannot be distinguished 

 morphologically. 



Size variation 



O. paraclevei exhibited variable body morphology, most obviously 

 in the form and size of the dorso-posterior projection on P2-bearing 

 somite, which varied greatly in size and conspicuousness according 

 to the degree of telescoping of somites (cf. Figs. 29a-c). Variation 

 was also expressed in the form of sclerotization on the dorsal surface 

 of genital double-somite, in the ornamentation of the anal opening, 

 in length to width ratio of caudal ramus and in proportional lengths 

 of terminal spines on P4 endopod. 



Geographical distribution 



O. paraclevei was recorded from the central and southern Red Sea as 

 well as from the Gulf of Aden and the northern Arabian Sea. Its 

 potential distribution in the northern Red Sea still has to be con- 

 firmed, as the species was not separated from the closely related O. 

 clevei during the earlier quantitative counts. 



Vertical distribution 



No quantitative data on the vertical distribution of O. paraclevei are 

 available, because the species was not distinguished from O. clevei 

 by Bottger-Schnack (1990a, b, 1995). It generally co-occurred with 

 this species in the upper epipelagic zone, at 0-20 or 0-50 m depth, 

 and was absent in the meso- and bathypelagic zones. 



Acknowledgements. I am very grateful to Dr R. Huys (The Natural 

 History Museum, London) for his encouragement, fundamental help and 

 indefatigable advice in the study of oncaeid taxonomy and for arranging the 



loan of O. waldemari and O. media sensu Malt. His critical comments helped 

 to improve the manuscript. Sincere thanks are due to Prof. J. Lenz, Prof. D. 

 Schnack and Drs H. Weikert and K. Schulz for continuous support during the 

 study. I wish to thank H. Itoh (Kawasaki, Japan) for translating the Japanese 

 text of his recent taxonomic study on oncaeids into English. I appreciate 

 assistance from the following persons or institutions, who provided speci- 

 mens, samples or information pertinent to the study: Dr G. A. Heron (University 

 of Washington, Seattle); Prof. J.-s. Ho (California State University, Long 

 Beach); the late Prof. A.G. Humes (Boston University Marine Program. 

 Woods Hole); Dr F. Krsinic (Laboratory of Plankton Ecology, Dubrovnik): 

 Dr D. McKinnon ( Australian Institute of Marine Science. Townsville ); Dr S. 

 Nishida (Ocean Research Institute, Tokyo); Dr S. Ohtsuka (Hiroshima Uni- 

 versity); Dr H. Postel (Institut furOstseeforschung, Warnemunde);Dr D.K. 

 Steinberg (Bermuda Biological Station); Dr C.T. Walter (National Museum 

 of Natural History, Smithsonian Institution). The financial support for a visit 

 to The Natural History Museum. London, under the EC-funded TMR Pro- 

 gramme Bioresource LSF is gratefully acknowledged. This study was 

 supported by Deutsche Forschungsgemeinschaft grant Le 232/1 8 to J. Lenz. 



REFERENCES 



Almeida Prado-Por, M.S. 1983. The diversity and dynamics of Calanoida (Copepoda) 

 in the northern Gulf of Elat ( Aqaba). Red Sea. Oceanologica Acta, 6: 139-145. 



Beckmann, W. 1996. Der Einflufi der grojiraumigen Wasseraustauschvorgdnge auf 

 den Zooplanktonbe stand des Rolen Meeres und sein trophisches Gefiige Disserta- 

 tion Fachbereich Biologic Universitat Hamburg, 167pp. 



Bersano, J.G.F and Boxshall, G.A. 1994. Planktonic copepods of the genus Oncaea 

 Philippi (Poecilostomatoida: Oncaeidae) from the waters off southern Brazil. 

 Nauplius, Rio Grande. 2: 29— t 1 . 



Bjbmberg, T.K.S. 1972. Developmental stages of some tropical and subtropical 

 planktonic marine copepods. Studies on the Fauna of Curasao and other Caribbean 

 Islands. 40: 1-185. 



Bbttger, R. 1982. Studies on the small invertebrate plankton of the Sargasso Sea. 

 Helgoldnder Meeresuntersuchungen. 35: 369-383. 



1987. The vertical distribution of micro- and small mesozooplankton in the 



central Red Sea. Biological Oceanography, 4: 383-^102. 



Bottger-Schnack, R. 1988. Observations on the taxonomic composition and vertical 

 distribution of cyclopoid copepods in the central Red Sea. Hydrobiologia. 167/168: 

 311-318. 



1990a. Community structure and vertical distribution of cyclopoid copepods in 



the Red Sea. I. Central Red Sea. autumn 1980. Marine Biology. 106: 473-^85. 



1990b. Community structure and vertical distribution of cyclopoid copepods in 



the Red Sea. II. Aspects of seasonal and regional differences. Marine Biology. 106: 



487-501. 

 1994. The microcopepod fauna in the Eastern Mediterranean and Arabian Seas: 



a comparison with the Red Sea fauna. Hydrobiologia. 292/293: 271-282. 

 1995. Summer distribution of micro- and small mesozooplankton in the Red Sea 



and Gulf of Aden, with special reference to non-calanoid copepods. Marine Ecology 



Progress Series, 118: 81-102. 



1996. Vertical structure of small metazoan plankton, especially non-calanoid 



copepods. I. Deep Arabian Sea. Journal of Plankton Research. 18: 1073-1101. 



1997. Vertical structure of small metazoan plankton.especially non-calanoid 



copepods. II. Deep Eastern Mediterranean (Levantine Sea). Oceanologica Acta. 20: 

 399-419. 



1999. Taxonomy of Oncaeidae (Copepoda, Poecilostomatoida) from the Red 



Sea.I. 11 species of Triconia gen. nov. and a redemption of T. similis (Sars) from 

 Norwegian waters. Mitteilungen aus dem Hainburgischen Zoologischen Museum 

 und Institut, 96: 37-128. 



Bottger-Schnack, R. and Boxshall, G.A. 1990. Two new Oncaea species (Copepoda: 

 Poecilostomatoida) from the Red Sea. Journal of Plankton Research, 12: 861-871. 



Bottger-Schnack, R. and Huys, R. 1997a. Archioncaea arabica gen. et sp. nov., a 

 remarkable oncaeid from the northern Arabian Sea. Cahiers de Biologie marine, 38: 

 79-89. 



& 1997b. Morphological observations on Oncaea mediterranea (Claus. 



1863) (Copepoda, Poecilostomatoida) with a comparison of Red Sea and eastern 

 Mediterranean populations. Bulletin of the Natural History Museum London (Zoo- 

 logy), 63: 137-147. 



& 1998. Species groups within the genus Oncaea (Copepoda. 



Poecilostomatoida). Journal of Marine Systems, 15: 369-371. 



& in press. Taxonomy of Oncaeidae (Copepoda. Poecilostomatoida) from 



the Red Sea. III. Morphology andphylogenetic position of Oncaea subtilis Giesbrecht. 

 1892. Developments in Hydrobiology (= Hydrobiologia). 



