Missing link in the Southern Ocean: sampling the marine benthic fauna of remote Bouvet Island

Bouvet (Bouvetøya) is a geologically young and very remote island just south of the Polar Front. Here we report samples taken during the RV ‘‘Polarstern’’ cruise ANTXXI/2 on 3 days in November 2003 and January 2004. This work was part of SCAR’s EASIZ programme and intended, by providing data on the marine fauna of this ‘‘white gap’’ in the Atlantic sector of the Southern Ocean, to contribute to identifying the role of Bouvet in the faunal exchange between the Suband high Antarctic. While this goal demands extensive molecular analysis of the material sampled (future work), a checklist of the samples and data at hand widens the faunal and environmental inventory substantially. We suggest some preliminary conclusions on the relationship of Bouvet Island’s fauna with that of other regions, such as Magellanic South America, the Antarctic Peninsula, and the high Antarctic Weddell Sea, which have been sampled previously. There seem to be different connections for individual higher taxa rather than a generally valid consistent picture

New records of shelled marine molluscs at Bouvet Island and preliminary assessment of their biogeographic affinities

Bouvet Island is one of the most isolated islands in the Southern Ocean and its marine benthic fauna has rarely been investigated and so is poorly known. This study adds 30 molluscan species to the previous faunal record of 16 species. During the expedition ANT XXI-2 of PFS Polarstern 25 species of shelled gastropods, 12 species of bivalves, 3 species of polyplacophorans and 1 species of solenogaster (Aplacophora) were collected at four sites around Bouvet Island in depths between 120 m and 550 m. High percentages of the species representing the shelled molluscan fauna of Bouvet Island are known from sub and high (continental) Antarctica

Is the Scotia Sea a centre of Antarctic marine diversification? Some evidence of cryptic speciation in the circum-Antarctic bivalve Lissarca notorcadensis (Arcoidea: Philobryidae)

The bivalve Lissarca notorcadensis is one of the most abundant species in Antarctic waters and has colonised the entire Antarctic shelf and Scotia Sea Islands. Its brooding reproduction, low dispersal capabilities and epizoic lifestyle predict limited gene flow between geographically isolated populations. Relationships between specimens from seven regions in the Southern Ocean and outgroups were assessed with nuclear 28S rDNA and mitochondrial cytochrome oxidase subunit I (COI) genes. The 28S dataset indicate that while Lissarca appears to be a monophyletic genus, there is polyphyly between the Limopsidae and Philobryidae. Thirteen CO1 haplotypes were found, mostly unique to the sample regions, and two distinct lineages were distinguished. Specimens from the Weddell and Ross Sea form one lineage while individuals from the banks and islands of the Scotia Sea form the other. Within each lineage, further vicariance was observed forming six regionally isolated groups. Our results provide initial evidence for reproductively isolated populations of L. notorcadensis. The islands of the Scotia Sea appear to act as centres of speciation in the Southern Ocean