A new kinorhynch genus, Mixtophyes (Kinorhyncha: Homalorhagida), from the Guinea Basin deep-sea, with new data on the family Neocentrophyidae

A new homalorhagid genus and species, Mixtophyes abyssalis gen. et sp. nov., is described from the deep-sea of the Guinea Basin in the Atlantic Ocean. The new genus and species was collected during the R/V Meteor Diva2 M63/2 Cruise, and it is characterized by a trunk with segment 1 consisting of a tergal and a single sternal plate, without any subdivisions or differentiations, segment 2-10 of one tergal and two sternal plates and segment 11 of a tergal and a sternal plate. Lateral terminal spines are present in both sexes. As part of the study of the new taxon, the type material of Neocentrophyes intermedius and N. satyai was re-examined, and new information is provided for both species. Based on the information from Mixtophyes abyssalis gen. et sp. nov. and re-examination of the two Neocentrophyes species, emended diagnoses for Neocentrophyes and Neocentrophyidae are proposed, and an updated identification key to homalorhagid genera and species of Neocentrophyidae is provided. Mixtophyes abyssalis gen. et sp. nov. is tentatively assigned to Neocentrophyidae, but evaluation of our current hypotheses about homalorhagid evolution and phylogeny also indicated that the family most probably is paraphyletic and that revision of homalorhagid classification is required when new results from phylogenetic analyses become available.