Abstract

Pogonophryne stewarti, new species, is described from collections made at 1700 m on the continental slope of the Indian Ocean Sector of the Southern Ocean, off Wilkes Land, Antarctica. The new species is assigned to the unspotted P. albipinna species group and is related to P. immaculata. It is distinguished from all other species of the P. albipinna species group by the following combination of characters: a long (about 15–20% SL) mental barbel without a terminal expansion, a shallow head and slender trunk with only slight taper to caudal peduncle, 8–13 middle lateral-line pores, and divergence in the mitochondrial ND2 gene. We discuss the composition and validity of the P. albipinna group, which, up to this point, has been based on three holotype specimens. We provide meristic and morphometric data for seven recently collected adult specimens of P. immaculata. Bayesian analyses of mitochondrial gene sequences for 11 of the now 19 recognized species of Pogonophryne, sampled from all five of the proposed species groups, resulted in reciprocal monophyly of the monotypic species groups. The P. albipinna and P. mentella species groups were each monophyletic and resolved as sister lineages. We provide a revised key for the four species of Pogonophryne classified in the P. albipinna group.