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.

We provide our perspective on the species-level taxonomy of notothenioid fishes, the dominant component of the fish fauna of Antarctica. There are 140 species in 45 genera, an increase of 15% since the previous summary in 2000. Biogeographically, 30 species are non-Antarctic, 33 are sub-Antarctic and 77 are Antarctic. The checklist is documented with footnotes that provide the rationale for our decisions. Supplementary Material provides additional details for our decisions on two species of Pogonophryne.

International audienceA primary objective of the ICEFISH 2004 cruise was to collect and study notothenioid fishes from remote localities in the Atlantic sector of the Southern Ocean. Nearly 1 month was devoted to bottom trawling for fishes on the shelf and upper slope (to 1,000 m) areas around Shag Rocks, South Georgia, South Sandwich Islands and Bouvetøya. The focus was on the latter two locations, because their faunas are more poorly known. Eight species were collected at Shag Rocks with Patagonotothen guntheri most abundant; 17 at South Georgia with Lepidonotothen nudifrons, L. larseni and Gobionotothen gibberifrons most abundant; 13 at the South Sandwich Islands with L. larseni, L. nudifrons and G. gibberifrons most abundant; and 11 at Bouvetøya with L. larseni, Macrourus holotrachys and L. squamifrons most abundant. Ten new locality records were established: Shag Rocks (1), South Georgia (1), South Sandwich Islands (5), South Sandwich Trench at 5,350 m (1) and Bouvetøya (2). Total known demersal fish diversity on the shelf and upper slope at Shag Rocks/South Georgia, South Sandwich Islands and Bouvetøya is 42, 31 and 17 species, respectively. To examine population structure in the four most abundant notothenioids at Bouvetøya (L. larseni, L. squamifrons, Notothenia coriiceps and Chaenocephalus aceratus), we examined the ND2 portion of mitochondrial DNA. Chaenocephalus aceratus, N. coriiceps and L. larseni exhibited no significant genetic differentiation in comparison with samples from localities in the Scotia Sea and the Antarctic Peninsula. However, L. squamifrons showed significant genetic differentiation between the South Shetlands and Bouvetøya populations (F ST = 0.189, P = 0.015). Thus, these data combined with previous studies of two other notothenioids suggest that five of the six notothenioid species at Bouvetøya are not genetically differentiated from other localities in the Atlantic sector of the Southern Ocean. The location of Bouvetøya within the Antarctic Circumpolar Current and the long (1–2 years) pelagic stages of the notothenioids at Bouvetøya may be at least partly responsible for this genetic homogeneit

Notothenioid fish of the artedidraconid genus Artedidraco are a little studied, component of the bottom fauna on the Antarctic continental shelf. Trawling in the south-western Ross Sea, especially in shallow areas with sponge beds, yielded a collection of 65 specimens of Artedidraco. These included all four species occurring in the Ross Sea as well as a new species. The new species Artedidraco glareobarbatus is described and illustrated. This species is most similar to A. orianae, but is distinguished by barbel morphology, by higher counts for dorsal rays and vertebrae, by lower counts for upper lateral-line scales and by colour pattern and visceral anatomy. A distinctive spotted colour morph of A. shackletoni is also documented and compared with the typical barred morph. Depth distribution and meristic variation among species of Artedidraco are summarized, and a taxonomic key to the six species is provided.