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 presence of ventral spines on pereonites 1–4

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 record 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 distinguished 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 associated with soft bottom of Admiralty Bay.

Admiralty Bay (King George Island) is an Antarctic Specially Managed Area and one the most thoroughly studied small-scale marine basins in the Southern Ocean. Our study provides new data on the isopod fauna in this glacially affected fjord. Twelve species of isopods were recorded in this basin for the first time. Six of them were found for the first time in the region of the South Shetland Islands. The highest number of species new for Admiralty Bay were found in the families Munnopsidae (4 species) and Munnidae (3 species).