Abstract
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.References
Ax, P. (1984) Das phylogenetische System. Gustav Fischer Verlag, Stuttgart, 349 pp.
Huys, R. & Boxshall, G.A. (1991) Copepod Evolution. The Ray Society, London, 468 pp.
Lang, K. (1936) Copepoda Harpacticoida. In: Bock, S. (Ed.), Further results of the Swedish Antarctic Expedition, 1901–1903, 3, 1–68.
Lang, K. (1948) Monographie der Harpacticiden I + II. Håkan Ohlssons Boktryckeri, Lund, 1682 pp.
Lang, K. (1965) Copepoda Harpacticoidea from the Californian Pacific coast. Kungliga Svenska Vetenskapsakademiens Handlingar, 10, 1–566.
Rose, A., Seifried, S., Willen, E., George, K.H., Veit-Köhler, G., Bröhldick, K., Drewes, J., Moura, G., Martínez Arbizu, P. & H. K. Schminke (2005) A comparison of core-scale species-level diversity of Harpacticoida (Copepoda) at two abyssal stations in the Angola Basin. Organisms, Diversity & Evolution, 5, 1–238
Scott, T. (1902) Notes on gathering of Crustacea collected by the fishery steamer “Garland” and the steam trawlers “Star of Peace” and “Star of Hope”, of Aberdeen, during the year 1901. 20th Annual Report of the Fishery Board for Scotland, Edinburgh, 20, 447–485.
Smirnov, S.S. (1946) New species of Copepoda Harpacticoida from the Arctic Ocean. Trud. Dreif.Exped. — Glavsevmov. Ledokol. Par. “Sedov”, 3, 231–263.
Vasconcelos, D.M., George, K.H. & P. J. Parreira dos Santos (2008) First record of the genus Pseudomesochra T. Scott, 1902 (Harpacticoida: Pseudotachidiidae) in the Northeastern Brazil with description of a deep sea species. Zootaxa, 1866, 337–348.
Willen, E. (1996) Pseudomesochra T. Scott, 1902 as a member of the Paranannopidae Por, 1986 (Copepoda, Harpacticoida) with a description of three new species. Senckenbergiana maritima, 28, 81–109.
Willen, E. (2004) Harpacticoida (Crustacea, Copepoda) from a hydrothermal active submarine volcano in the New Ireland Fore-Arc system (Papua New Guinea) with the description of a new genus and species of Pseudotachidiidae. Meiofauna Marina, 13, 113–135.
Willen, E. (2008) Pseudotachidiidae (Copepoda: Harpacticoida) from the Angola Basin and the Antarctic deep sea with the description of a new species of Paradanielssenia Soyer, 1970. Organisms, Diversity and Evolution, 8, 249–250 and doi: 10.1016/j.ode.2007.06.004