A new genus of Pseudomesochrinae Willen , 1996 ( Copepoda , Harpacticoida , Pseudotachidiidae ) from the Guinea Basin *

A new species of the new genus Keraia gen. nov. from the Guinea Basin is described in the present paper. The new taxon belongs to the Pseudomesochrinae Willen, 1996, which until now has contained only the genus Pseudomesochra T. Scott, 1902. Both genera are prevalent in the deep sea. Whereas Pseudomesochra reaches quite high individual and species numbers in the investigated samples of the DIVA 1, DIVA 2 and ANDEEP deep-sea expeditions, Keraia is found only occasionally and as single specimens. Keraia is characterised among others by a modified antenna exopodite and the shape of P1. Pseudomesochra on the other hand can still be identified as a monophylum by specialised setation on the P1 endopodite and the lack of the inner setae of the first segment of swimming leg exopodites. Other species of Keraia gen. nov. are K. longiseta (Vasconcelos, George & Santos 2008) and the type species K. tamara (Smirnov, 1946). The available records implicate a widespread occurrence of Keraia gen. nov. from the northern to the southern Atlantic, and even reaching both northern and southern polar regions. Up to now all individuals that have been found occur exclusively at deep-sea sites and in very low abundances.