Oahutanais makalii, a new genus and species of colletteid tanaidacean (Crustacea, Peracarida) from shelf-waters off Hawaii, with a taxonomic key

A new colletteid tanaidacean, Oahutanais makalii gen. et sp. n., is described from Hawaiian coastal waters at depths ranging from 19 to 102 m. The new taxon is tentatively designated as a new genus, although it displays many features in common with the genus Leptognathiella. The new species is distinguished from the morphologically similar tanaidomorphans by having (1) a small body, less than 1.0 mm (reproductively active specimens), (2) a maxillule with two bifid spiniform setae; (3) a maxilliped palp article-2 with geniculate, finely pectinate spiniform seta on sub-distal inner margin, (4) a cheliped attachment ventrally via sclerite not connected to the carapace, and (5) the pereopods 1 to 6 with ischial seta shorter than the merus. A key to the five extant genera of Colletteidae in the North Pacific Ocean is presented herein.