A new ostracod species of the genus Xestoleberis from Nansen Island, Wilhelmina Bay, Southern Ocean, Antarctica.

Comparing to the ostracod studies on the other islands in the world, studies on the ostracod fauna of the islands in Antarctica are scarce. During the sixth Turkish Antarctica Expedition (TAE 6) to the islands (Dismal, Horseshoe, Nansen, Livingstone) in Western Antarctica, sediment and water samples were collected from 32 different water bodies (lakes, ponds, creeks, springs, littoral zones of sea). Among several new reports of different taxonomic groups which are under investigation, a new marine ostracod species (Xestoleberis nansenensis n. sp.) was encountered from Nansen Island. This is the first report of an ostracod from this island below 60° S in Antarctica. The new species has several different features both in the carapace and soft body parts. Absence of ostracods from other islands sampled may be related to several a/biotic factors, such as water chemistry (e.g., relatively low calcium levels), extreme aquatic conditions (e.g., low-temperature values), improper habitat conditions (e.g., too little or absence of sediment in the water bodies), and isolation of the island(s) from the mainland. Although our new species is a marine form, comparative literature review indicated that there is no non-marine living ostracod species reported from the islands visited during the expedition. Possible reasons are discussed. [ABSTRACT FROM AUTHOR]