JPR Advance Access published online on July 2, 2009
Journal of Plankton Research, doi:10.1093/plankt/fbp051
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Taxonomy of Oncaeidae (Copepoda, Cyclopoida s.l.) from the Red Sea. IX. Epicalymma bulbosa sp. nov., first record of the genus in the Red Sea
,*Leibniz-Institute for Marine Sciences (IFM-GEOMAR), FB2 (Biological Oceanography), DÜsternbrooker Weg 20, D-24105 Kiel, Germany
* CORRESPONDING AUTHOR: dschnack{at}ifm-geomar.de
Received on April 3, 2009; accepted on June 3, 2009
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Abstract |
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The oncaeid genus Epicalymma comprises small copepod species usually living at meso- and bathypelagic depth layers in oceanic areas. The genus had previously been assumed to be absent from the Red Sea, due to the unusually high deep-sea temperatures and salinities in this area. In the present account a new species, Epicalymma bulbosa, is described from the Red Sea, which appears to be the only representative of the genus in the region. The new species is the smallest Epicalymma species so far recorded, with a total body length of 
0.32 and 0.29 mm in the female and male, respectively. Apart from its small size, it differs from all known Epicalymma species by an extremely long exopodal seta on P5 in both sexes, and by a free exopod segment of P5 and a very long and basally swollen spinule on the syncoxa of the maxilliped in the female. In contrast to other Epicalymma species, which are distributed between 500 and >2500 m depth, the new species occurred much shallower (100–750 m) in the Red Sea, which may be interpretated as an avoidance mechanism of the unfavourable environmental conditions in the deep Red Sea. The taxonomic status of the new species within the genus Epicalymma is discussed and the few available ecological data on Epicalymma species in the world ocean are summarized.
Present Address: Moorsehdener Weg 8, D-24211 Rastorf-Rosenfeld, Germany.