Remarks on the genus Mesotanais Dollfus, 1897 (Crustacea, Tanaidacea). Redescription of the type-species and description of M. elongatus sp. nov

Abstract

Examination of deep-sea tanaidaceans collected dunng cruises of the R.R.S. ' Discovery', and the R.V. 'Cryos' (BALGIM Expedition) from the Northeast Atlantic provided material of the 'outstanding leptocheliid genus Mesotanais. The type-species M. dubius Dollfus, 1897, is redescrlbed and differences to the original are discused. An additional speceis represented in the material, M.elongarus sp. nov., is described in detail. Finally a key as well as a table demonstrating the most important characters for the so far known species is presented, including those two species, M. longisetosus Sieg & Heard and M. vadicola Sieg & Heard, only recently described from the Gulf of Mexico.