Abstract:A new thambematid species, Thambema thunderstruckae sp. n., is described from King George Island, South Shetland Islands, Antarctic. Specimens of the new species were collected during two Polish Antarctic Expeditions in 1985 and 2007. It is the first re− cord of this family from the Southern Hemisphere. The new species most closely resembles Thambema golanachum Harrison, 1987 and T. fiatum Harrison, 1987 but can be distin− guished from both species by the shape of male pleopod 1, the number of claws on pereopods 2-7 and the setation of pereopod 1 and 2 carpus, respectively. A key to all known genera and species in the family Thambematidae is also provided.

Fifteen species of isopods, representing 10 families, were recorded on holdfasts of the brown alga Himantothallus grandifolius. Material was collected in the 15-75 m depth range during the austral summer of 1979/80. The isopod community was dominated by Caecognathia antarctica (mean density 12.4 ± 13.1 ind./100 ml) followed by Cymodocella tubicauda (mean density 0.7 ± 2.1 ind./100 ml). Mean total density of isopods reached the value of 16.1 ± 14.0 ind./100 ml. The comparison with the other studies showed that hold− fasts are inhabited by a distinctive isopod community that differs from the isopod fauna as− sociated with soft bottom of Admiralty Bay.

Isopods belong to the most speciose groups of the Antarctic benthic fauna, although the knowledge on their diversity and small-scale distribution patterns is still limited. Here we analyze the diversity of the isopod fauna in the Admiralty Bay, a glacial fjord on the King George Island. The basin is located in the region of the Antarctic Peninsula, the fastest warming area of the Southern Ocean. The study provides important baseline data for future research, particularly with respect to temporal fluctuations in benthic fauna, associated with global changes observed in that part of the world. Forty species of isopods representing 19 families were recorded on the soft bottom of the Admiralty Bay. The analyses were based on 99 quantitative samples collected, within the 20-502-m depth range, with a 0.1 m 2 van Veen grab. The materials for the analyses were obtained in the austral summer seasons of 1984/1985 and 1985/1986. The data revealed a high number of isopod species occurring at a low abundance, the mean abundance amounting to 4.8 ± 8.6 ind./0.1 m 2 . Most of the species occurred at low abundances, 25% of the species being represented by singletons. Caecognathia polaris, the most abundant species, showed the mean abundance of merely 1.2 ± 4.2 ind./0.1 m 2 . Species richness, diversity and abundance of the isopod fauna were much higher in the central basin of the Admiralty Bay than in the Ezcurra Inlet, an area affected by a strong disturbance of glacial origin.

Th is paper presents a description of the new species Metatanais bipunctatus sp. n. found on coral reefs at two sites in Australia: Lizard Island (Queensland) and Ningaloo Reef (north-western Australia). Th e new species is the second member of the genus and it is morphologically almost identical to type species M. cylindricus Shiino, 1952, recorded from algae on the surface of ascidians or sponges in shallow waters off Seto (north-western coast of Japan). Th e new species was compared with the holotype of M. cylindricus and it can be distinguished from it by relatively short fi rst article in antennule, compact propodus of pereopod 6 (about three times as long as wide) and robust ventral spiniform seta on propodus of last three pairs of pereopods. Th e defi nition of the genus has been amended and appendages (where possible) of M. cylindricus has been fi gured.

Abstract:Two new species of desmosomatid isopods, Eugerdella margaretae sp. n. and Eugerdella celata sp. n. are described from Admiralty Bay, King George Island, South Shetlands. Information is added to the original description of Eugerdella falklandica (Nordenstam, 1933) based on re−examination of the holotype. Both new species are similar to E. falklandica, for example by the body shape, the shape of pleotelson and presence of rows of four horn−like spines on the head. They are distinguished from E. falklandica by the number of setae on pereopod articles. Eugerdella celata sp. n. is distinguished by the pres− ence of ventral spines on pereonites 1-4.