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The hydrothermal vents on the East Scotia Ridge are the first to be explored in the Antarctic and are dominated by large peltospiroid gastropods, stalked barnacles (Vulcanolepas sp.) and anomuran crabs (Kiwa sp.) but their food webs are unknown. Vent fluid and macroconsumer samples were collected at three vent sites (E2, E9N and E9S) at distances of tens of metres to hundreds of kilometres apart with contrasting vent fluid chemistries to describe trophic interactions and identify potential carbon fixation pathways using stable isotopes. δ13C of dissolved inorganic carbon from vent fluids ranged from −4.6‰ to 0.8‰ at E2 and from −4.4‰ to 1.5‰ at E9. The lowest macroconsumer δ13C was observed in peltospiroid gastropods (−30.0‰ to −31.1‰) and indicated carbon fixation via the Calvin-Benson-Bassham (CBB) cycle by endosymbiotic gamma-Proteobacteria. Highest δ13C occurred in Kiwa sp. (−19.0‰ to −10.5‰), similar to that of the epibionts sampled from their ventral setae. Kiwa sp. δ13C differed among sites, which were attributed to spatial differences in the epibiont community and the relative contribution of carbon fixed via the reductive tricarboxylic acid (rTCA) and CBB cycles assimilated by Kiwa sp. Site differences in carbon fixation pathways were traced into higher trophic levels e.g. a stichasterid asteroid that predates on Kiwa sp. Sponges and anemones at the periphery of E2 assimilated a proportion of epipelagic photosynthetic primary production but this was not observed at E9N. Differences in the δ13C and δ34S values of vent macroconsumers between E2 and E9 sites suggest the relative contributions of photosynthetic and chemoautotrophic carbon fixation (rTCA v CBB) entering the hydrothermal vent food webs vary between the sites.

Information regarding the molluscs in this dataset is based on the Rauschert dredge samples collected during the Latitudinal Gradient Program (LGP) on board the R/V “Italica” in the Ross Sea (Antarctica) in the austral summer 2004. A total of 18 epibenthic dredge deployments/samplings have been performed at four different locations at depths ranging from 84 to 515m by using a Rauschert dredge with a mesh size of 500µm. In total 8,359 specimens have been collected belonging to a total of 161 species. Considering this dataset in terms of occurrences, it corresponds to 505 discrete distributional records (incidence data). Of these, in order of abundance, 5,965 specimens were Gastropoda (accounting for 113 species), 1,323 were Bivalvia (accounting for 36 species), 949 were Aplacophora (accounting for 7 species), 74 specimens were Scaphopoda (3 species), 38 were Monoplacophora (1 species) and, finally, 10 specimens were Polyplacophora (1 species). This data set represents the first large-scale survey of benthic micro-molluscs for the area and provides important information about the distribution of several species, which have been seldom or never recorded before in the Ross Sea. All vouchers are permanently stored at the Italian National Antarctic Museum (MNA), Section of Genoa, enabling future comparison and crosschecking. This material is also currently under study, from a molecular point of view, by the barcoding project “BAMBi” (PNRA 2010/A1.10).

In 2008 the BIOPEARL II expedition on board of RRS James Clark Ross sailed to the eastern Amundsen Sea Embayment and Pine Island Bay, one of the least studied Antarctic continental shelf regions due to its remoteness and ice cover. A total of 37 Agassiz trawls were deployed at depth transects along the continental and trough slopes. A total of 5,469 specimens, belonging to 32 higher taxonomic groups and more than 270 species, were collected. Species richness per station varied from 1–55. The benthic assemblages were dominated by echinoderms and clearly different to those in the Ross, Scotia and Weddell seas. Here we present the macro- and megafaunal assemblage structure, its species richness and the presence of several undescribed species.

The ecology of Antarctic deep-sea fauna is poorly understood and few studies have gone beyond assessing biodiversity when comparing deep regions of the Southern Ocean. Protobranch bivalves are ubiquitous in the deep ocean and are widely distributed in the Southern Ocean. This paper examines the potential respon ses to environmental differences in the common protobranchs Yoldiella valettei, Yoldiella ecaudata, and Yoldiella sabrina from contrasting deep-sea environments of the Weddell Sea, Scotia Sea, Amundsen Sea, and South Atlantic. There are significant differences in morphology between deep-sea regions in all species and a significant difference in shell weight in Y. valettei between the Amundsen Sea and Weddell Seas. Growth rates of Y. valettei and Y. ecaudata in the Amundsen Sea are also higher than elsewhere and Y. valettei have heaviest shells in the Amundsen Sea, suggesting more favourable conditions for calcification and growth. The plasticity observed among deep-sea regions in the Southern Ocean is likely to be driven by different oceanographic influences affecting temperature and food fluxes to the benthos, and demonstrate the species’ ability to differentially adapt between cold-stenothermal environments. This study suggests that subtle changes in the environment may lead to a divergence in the ecology of invertebrate populations and showcases the protobranch bivalves as a future model group for the study of speciation and radiation processes through cold-stenothermal environments.

Large cetacean carcasses at the deep-sea floor, known as ‘whale falls’, provide a resource for generalist-scavenging species, chemosynthetic fauna related to those from hydrothermal vents and cold seeps, and remarkable bone-specialist species such as Osedax worms. Here we report the serendipitous discovery of a late-stage natural whale fall at a depth of 1444 m in the South Sandwich Arc. This discovery represents the first natural whale fall to be encountered in the Southern Ocean, where cetaceans are abundant. The skeleton was situated within a seafloor caldera, in close proximity (<250 m) to active hydrothermal vents. We used a DNA barcoding approach to identify the skeleton as that of an Antarctic minke whale (Balaenoptera bonaerensis). The carcass was in an advanced state of decomposition, and its exposed bones were occupied by a diverse assemblage of fauna including nine undescribed species. These bone fauna included an undescribed species of Lepetodrilus limpet that was also present at the nearby hydrothermal vents, suggesting the use of whale-fall habitats as stepping stones between chemosynthetic ecosystems. Using Remotely Operated Vehicle (ROV) videography, we have quantified the composition and abundance of fauna on the whale bones, and tested a hypothesis that varying concentrations of lipids in the bones of whales may influence the microdistribution of sulfophilic whale-fall fauna. Our data supported the hypothesis that more lipid-rich bones support a greater abundance of sulfophilic bacterial mats, which are also correlated with the abundance of grazing limpets (Pyropelta sp.). The abundance of Osedax sp. on bones however, showed a negative correlation with the bacterial-mat percentage cover, and hence greatest abundance on bones predicted to have lowest lipid content.

Information regarding the molluscs in this dataset is based on the epibenthic sledge (EBS) samples collected during the cruise BIOPEARL II / JR179 RRS James Clark Ross in the austral summer 2008. A total of 35 epibenthic sledge deployments have been performed at five locations in the Amundsen Sea at Pine Island Bay (PIB) and the Amundsen Sea Embayment (ASE) at depths ranging from 476 to 3501m. This presents a unique and important collection for the Antarctic benthic biodiversity assessment as the Amundsen Sea remains one of the least known regions in Antarctica. Indeed the work presented in this dataset is based on the first benthic samples collected with an EBS in the Amundsen Sea. However we assume that the data represented are an underestimation of the real fauna present in the Amundsen Sea. In total 9261 specimens belonging to 6 classes 55 families and 97 morphospecies were collected. The species richness per station varied between 6 and 43. Gastropoda were most species rich 50 species followed by Bivalvia (37), Aplacophora (5), Scaphopoda (3) and one from each of Polyplacophora and Monoplacophora.

The phylogenetic relationships of seven Antarctic barnacle species, one verrucomorph and six scalpelliforms from the Scotia, Weddell and Ross seas were investigated using DNA sequences from two nuclear genes (18 S and 28 S) and one mitochondrial gene (COI), with a combined total length of 3,151 base pairs. Analyses of these new sequences, together with those of previously published ibliform, lepadiform, scalpelliform, balanomorph and verrucomorph species, confirm that the Scalpelliformes are not monophyletic. Bayesian and maximum likelihood analyses consistently recovered a monophyletic group which comprised Ornatoscalpellum stroemii (Sars) and the Southern Ocean scalpellomorphs; Arcoscalpellum sp. from the Weddell Sea, Arcoscalpellum africanum from Elephant Island, A. bouveti from Bouvet Island, the circum-Antarctic Litoscalpellum discoveryi, Litoscalpellum sp. from Shag Rocks and Scalpellum sp. from the Falkland Trough. We also used multiple fossil constraints in a relaxed clock Bayesian framework to estimate divergence times for the 18 S+28 S phylogeny. Our results indicate a mid Cretaceous divergence for the Weddell Sea Arcoscalpellum sp, followed by a late Cretaceous divergence from the North Atlantic O. stroemii. Subsequent to this, the Antarctic scalpellomorphs began to radiate at the Cretaceous-Tertiary boundary. Monophyly within the scalpellid genera Arcoscalpellum, Litoscalpellum and Scalpellum was strongly rejected by all loci. Our results show incongruence between taxonomy and molecular systematics and highlight the need for more species to be sequenced as well as taxonomic revisions to resolve uncertainties in the phylogenetic relationships of the stalked barnacles.

The Antarctic marine environment is extreme in its low temperatures and short periods of primary productivity. Invertebrates must therefore adapt to maximise reproductive output where low temperature and limited food slow larval development. Brooding is a common reproductive trait in Antarctic marine bivalves; larval development occurs within the mantle cavity, and larvae are released as fully developed young. Lissarca miliaris is a small, short-lived, shallow-water brooding bivalve of circum-Antarctic distribution and found most abundant in the sub-Antarctic Magellan Region and islands of the Scotia Arc. Here, an unusual hermaphrodite reproductive trait is described for L. miliaris from King George Island (62°14′S, 58°38′W) and Signy Island (60°42′S, 45°36′W), Antarctica, using histological and dissection techniques. Specimens demonstrate simultaneous and sequential hermaphrodite traits; male and female gonads develop simultaneously, but the production of oocytes is reduced while testes are ripe. Functional females are more abundant in specimens above 3 mm shell length, although male reproductive tissue persists and functional males are found in all size classes. The number of previtellogenic oocytes produced by far exceeds the number of oocytes extruded and brooded, which may indicate an ancestral link to a planktotrophic past. Hermaphroditism in L. miliaris maximises reproductive efficiency in a short-lived species, in which the female’s capacity to brood its young is limited, and demonstrates a specialised adaptation to a cold stenothermal and food-limited environment prevailing in the Southern Ocean.

Iheyaspira bathycodon sp. nov. is described from the Von Damm Vent Field on the world's deepest spreading centre, the Mid-Cayman Spreading Centre (MCSC), Caribbean, at 2300 m depth. The new species is defined and illustrated from 11 specimens, with brief notes on habitat and known distribution. Molecular phylogenetic data from partial COI mDNA, 16S rDNA and nuclear 18S rDNA regions are used to analyse the species’ phylogenetic position and its morphology is compared with previously described skeneid and vent taxa. The new species is distinguished from the most closely allied vent species, Iheyaspira lequios Okutani, Sasaki & Tsuchida, 2000 by morphological differences in radula diagnosis and appendage structure of the head-foot. Iheyaspira bathycodon sp. nov. is the tenth turbinid to be described from a hydrothermal-vent environment and the second species to be named from recently discovered hydrothermal vents on the MCSC. Determining the faunal composition of assemblages at the vent fields of the MCSC will help to elucidate the vent biogeography of the region.

Ophiuroids are a conspicuous and often dominant component of the Antarctic continental shelf benthos. Here we report on the ophiuroids collected from the Burdwood Bank, off the Patagonian Shelf, through the shallow water areas of the Scotia Arc, down the west Antarctic Peninsula and as far south as Pine Island Bay in the eastern Amundsen Sea. This preliminary and primarily pattern based study identifies some regional differences in assemblages and highlights the role of the Antarctic Circumpolar Current as a barrier, as well as a facilitator, to dispersal. In order to effectively compare between studies we highlight the need for accurate, expert taxonomic identification of specimens.

Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent biogeography, but the spatial dynamics of their distinct fauna have yet to be elucidated. This study determines patterns of faunal zonation, species associations, and relationships between faunal microdistribution and hydrothermal activity in a vent field at a depth of 2,400 m on the ESR. Remotely operated vehicle (ROV) dives obtained high-definition imagery of three chimney structures with varying levels of hydrothermal activity, and a mosaic image of >250 m2 of seafloor co-registered with temperature measurements. Analysis of faunal microdistribution within the mosaiced seafloor reveals a consistent pattern of faunal zonation with increasing distance from vent sources and peak temperatures. Assemblages closest to vent sources are visibly dominated by a new species of anomuran crab, Kiwa n. sp. (abundance >700 individuals m−2), followed by a peltospiroid gastropod (>1,500 individuals m−2), eolepadid barnacle (>1,500 individuals m−2), and carnivorous actinostolid anemone (>30 individuals m−2). Peripheral fauna are not dominated by a single taxon, but include predatory and scavenger taxa such as stichasterid seastars, pycnogonids and octopus. Variation in faunal microdistribution on chimneys with differing levels of activity suggests a possible successional sequence for vent fauna in this new biogeographic province. An increase in δ34S values of primary consumers with distance from vent sources, and variation in their δ13C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent environment over a greater extent than previous studies, these results p

Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previou

The Antarctic Peninsula has experienced a rapid increase in atmospheric temperature over the last 50 years. Whether or not marine organisms thriving in this cold stenothermal environment are able to cope with warming is of concern. Here, we present changes to the growth and shell characteristics of the ecologically important, small and short lived brooding bivalve Lissarca miliaris from Signy Island, Antarctica. Using material collected from the 1970's to the present day, we show an increase in growth rate and adult shell deterioration accompanied by a decrease in offspring size, associated with an increase in annual average temperatures. Critical changes to the bivalve's ecology seen today evidence the problem of a shift in baseline since the onset of warming recorded in Antarctica. These small bivalves are demonstrating ecophysiological responses to subtle warming that, provided warming continues, could soon surpass a physiological tipping point, adding to warming associated threats such as increased predatory pressure and ocean acidification.

Nuculid bivalves of the Cape Melville Formation (Early Miocene, King George Island) are reviewed. Ten bivalve taxa are listed from the formation in the families Nuculidae (two species), Sareptidae, Malletiidae, Limopsidae (two species), Limidae, Pectinidae, Hiatellidae, and Periplomatidae. The Nuculidae consist of two species of Leionucula Quenstedt, 1930. One of these, L. melvilleana n. sp., is described and the other consists of the two species named previously by Anelli et al. (2006), which are demonstrated to be synonymous and are assigned to the species Leionucula frigida (Anelli, Rocha-Campos, Santos, Perinotto & Quaglio 2006). This assemblage, dominated by protobranchs (89% of specimens), is a typical fauna of offshore soft substrates, with a few specimens transported from hard substrates nearby. The diversity of Nuculidae has decreased in the Antarctic region through the Cenozoic.

High throughput sequencing technologies are revolutionizing genetic research. With this ‘‘rise of the machines’’, genomic sequences can be obtained even for unknown genomes within a short time and for reasonable costs. This has enabled evolutionary biologists studying genetically unexplored species to identify molecular markers or genomic regions of interest (e.g. micro- and minisatellites, mitochondrial and nuclear genes) by sequencing only a fraction of the genome. However, when using such datasets from non-model species, it is possible that DNA from non-target contaminant species such as bacteria, viruses, fungi, or other eukaryotic organisms may complicate the interpretation of the results. In this study we analysed 14 genomic pyrosequencing libraries of aquatic non-model taxa from four major evolutionary lineages. We quantified the amount of suitable micro- and minisatellites, mitochondrial genomes, known nuclear genes and transposable elements and searched for contamination from various sources using bioinformatic approaches. Our results show that in all sequence libraries with estimated coverage of about 0.02–25%, many appropriate micro- and minisatellites, mitochondrial gene sequences and nuclear genes from different KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways could be identified and characterized. These can serve as markers for phylogenetic and population genetic analyses. A central finding of our study is that several genomic libraries suffered from different biases owing to non-target DNA or mobile elements. In particular, viruses, bacteria or eukaryote endosymbionts contributed significantly (up to 10%) to some of the libraries analysed. If not identified as such, genetic markers developed from high-throughput sequencing data for non-model organisms may bias evolutionary studies or fail completely in experimental tests. In conclusion, our study demonstrates the enormous potential of low-coverage genome survey sequences and suggests bioinforma

Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ,43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.

DNA barcoding revealed four well-supported clades among amphipod specimens that keyed out to Epimeria georgiana Schellenberg, 1931, three clades with specimens from the southern Scotia Arc and one clade with specimens from the Weddell Sea. Detailed morphological investigations of sequenced specimens were conducted, through light and scanning electron microscopy. High magnification (500–2,000 fold) revealed features such as comb-scales on the first antenna and trich bearing pits on the fourth coxal plate to be similar for all specimens in the four clades. Consistent microstructure character differences in the Weddell Sea specimens combined with high genetic distances (COI divergence>20%) allowed the description of Epimeria angelikae, a species new to science. Specimens of E. georgiana in the other three COI clades from the Scotia Arc were morphologically indistinguishable. Representative specimens of clade A are also illustrated in detail. Our results on the high genetic divergences in epimeriid amphipods support the theory of the southern Scotia Arc being a centre of Antarctic diversification.

The crustacean genus Rhachotropis has a worldwide distribution and amongst the largest bathymetric range known from any amphipod genus. DNA barcoding of new material from around New Zealand and the Ross Sea indicated depth-related biogeographic patterns. New Zealand Rhachotropis do not form a monophyletic clade. Species from bathyal depths on the Chatham Rise, east of New Zealand, show lower sequence divergence to bathyal species from California and the Arctic than to abyssal New Zealand species. Species sampled in the Kermadec Trench, north of New Zealand below 5000 m, seem to be more closely related to Ross Sea abyssal species than to the New Zealand shelf species. The worldwide geographic and bathymetric distribution for all Rhachotropis species is presented here. Depth may have a greater influence on phylogeny than geographic distance. Molecular and morphological investigations of Rhachotropis specimens from the Chatham Rise, New Zealand revealed a species new to science which is described in detail, including scanning electron microscopy. This increases the number of described species of Rhachotropis to 60 worldwide.

The Dumont d’Urville Sea (East Antarctic region) has been less investigated for DNA barcoding and molecular taxonomy than other parts of the Southern Ocean, such as the Ross Sea and the Antarctic Peninsula. The Collaborative East Antarctic MARine Census (CEAMARC) took place in this area during the austral summer of 2007–2008. The Australian vessel RSV Aurora Australis collected very diverse samples of demersal and benthic organisms. The specimens were sorted centrally, and then distributed to taxonomic experts for molecular and morphological taxonomy and identification, especially barcoding. The COI sequences generated from CEAMARC material provide a sizeable proportion of the Census of Antarctic Marine Life barcodes although the studies are still ongoing, and represent the only source of sequences for a number of species. Barcoding appears to be a valuable method for identification within most groups, despite low divergences and haplotype sharing in a few species, and it is also useful as a preliminary taxonomic exploration method. Several new species are being described. CEAMARC samples have already provided new material for phylogeographic and phylogenetic studies in cephalopods, pycnogonids, teleost fish, crinoids and sea urchins, helping these studies to provide a better insight in the patterns of evolution in the Southern Ocean.

The marine ecosystem on the eastern shelf of the Antarctic Peninsula was surveyed 5 and 12 years after the climate-induced collapse of the Larsen A and B ice shelves. An impoverished benthic fauna was discovered, that included deep-sea species presumed to be remnants from ice-covered conditions. The current structure of various ecosystem components appears to result from extremely different response rates to the change from an oligotrophic sub-ice-shelf ecosystem to a productive shelf ecosystem. Meiobenthic communities remained impoverished only inside the embayments. On local scales, macro- and mega-epibenthic diversity was generally low, with pioneer species and typical Antarctic megabenthic shelf species interspersed. Antarctic Minke whales and seals utilised the Larsen A/B area to feed on presumably newly established krill and pelagic fish biomass. Ecosystem impacts also extended well beyond the zone of ice-shelf collapse, with areas of high benthic disturbance resulting from scour by icebergs discharged from the Larsen embayments.

Coordinated, circum-Antarctic sampling expeditions during International Polar Year 2008/09 have given access to comprehensive collections suitable for DNA barcoding. Collaborations between the Census of Antarctic Marine Life (CAML), the Marine Barcode of Life project and the Canadian Centre for DNA Barcoding have enabled the Antarctic scientific community to initiate large-scale DNA barcoding projects to record the genetic diversity of Antarctic marine fauna, coordinated by the CAML Barcoding Campaign. A total of 20,355 marine specimens from more than 2,000 morphospecies covering 18 phyla are in the processing pipeline, and to date, 11,530 sequences have been processed with the remainder due by the end of 2010. Here, we present results on the current geographic and taxonomic coverage of DNA barcode data in the Southern Ocean and identify the remaining gaps. We show how DNA barcoding in the Antarctic is answering important questions regarding marine genetic diversity and challenging current assumptions of species distribution at the poles.

Limopsis is one of the most speciose and widespread bivalve genera in the Southern Ocean at the present day. However, the fossil record of the genus is poorly known from the southern high latitudes. Here, we review the fossil record in this region to help understand the evolutionary origins of the genus. Limopsis infericola sp. nov. and additional specimens of a previously described species are added to the fossil record of Antarctica. The globally distributed limopsid clade had its earliest occurrences in the Early Cretaceous of Europe and New Zealand, then radiated during the Late Cretaceous (Maastrichtian, 70.6-65.5 Ma). Fossil evidence shows that the genus underwent a second, Cenozoic, radiation related to the isolation of Antarctica and the onset of cooling in the southern hemisphere. The genus has persisted in Antarctica for the last 50 myr, adapting to extreme changes in the environmental conditions, including surviving the last glacial maximum in marine refugia.

Three hundred and fifty specimens of the endemic Southern Ocean octopus genus Pareledone, were sequenced for the barcoding gene COI. Geographic coverage comprised the South Shetland Islands, the Ross Sea, Adélie Land, George V Land, the Weddell Sea, under the site of the former Larsen B ice shelf, Prydz Bay, the South Orkney Islands and the Amundsen Sea. The greatest number of specimens was captured at the three first-mentioned localities. At least 11 species were represented in the samples and the analyses revealed cryptic species. Six species were found to have extended distributions. Circumpolarity is supported for at least one species. Evidence is presented for a barrier to gene flow to the west of the Antarctic Peninsula, with haplotypes of P. aequipapillae becoming progressively more diverse in a clockwise direction from the South Shetland Islands to the Amundsen Sea. This pattern is akin to that seen in ring species, although we suggest that comparatively warm bottom water acts as a physical barrier preventing completion of the ring.

The benthic fauna was investigated during the expedition ANT-XXIV/2 (2007/08) in relation to oceanographic features, biogeochemical properties and sediment characteristics, as well as the benthic, pelagic and air-breathing fauna. The results document that Maud Rise (MR) differs distinctly from surrounding deep-sea basins investigated during previous Southern Ocean expeditions (ANDEEP 2002, 2005). Considering all taxa, the overall similarity between MR and adjacent stations was low (∼20% Bray-Curtis-Similarity), and analyses of single taxa show obvious differences in species composition, abundances and densities. The composition and diversity of bivalves of MR are characterised by extremely high abundances of three species, especially the small sized Vesicomya spp. Exceptionally high gastropod abundance at MR is due to the single species Onoba subantarctica wilkesiana, a small brooder that may prey upon abundant benthic foraminiferas. The abundance and diversity of isopods also show that one family, Haplomunnidae, occurs with a surprisingly high number of individuals at MR while this family was not found at any of the 40 bathyal and abyssal ANDEEP stations. Similarly, polychaetes, especially the tube-dwelling, suspension-feeder fraction, are represented by species not found at the comparison stations. Sponges comprise almost exclusively small specimens in relatively high numbers, especially a few species of Polymastiidae. Water-column sampling from the surface to the seafloor, including observations of top predators, indicate the existence of a prospering pelagic food web. Local concentrations of top predators and zooplankton are associated with a rich ice-edge bloom located over the northern slope of MR. There the sea ice melts, which is probably accelerated by the advection of warm water at intermediate depth. Over the southern slope, high concentrations of Antarctic krill (Euphausia superba) occur under dense sea ice and attract Antarctic Minke Whales (Balaenopter

Three hundred and fifty specimens of the endemic Southern Ocean octopus genus Pareledone, were sequenced for the barcoding gene COI. Geographic coverage comprised the South Shetland Islands, the Ross Sea, Adélie Land, George V Land, the Weddell Sea, under the site of the former Larsen B ice shelf, Prydz Bay, the South Orkney Islands and the Amundsen Sea. The greatest number of specimens was captured at the three first-mentioned localities. At least 11 species were represented in the samples and the analyses revealed cryptic species. Six species were found to have extended distributions. Circumpolarity is supported for at least one species. Evidence is presented for a barrier to gene flow to the west of the Antarctic Peninsula, with haplotypes of P. aequipapillae becoming progressively more diverse in a clockwise direction from the South Shetland Islands to the Amundsen Sea. This pattern is akin to that seen in ring species, although we suggest that comparatively warm bottom water acts as a physical barrier preventing completion of the ring.

Many members of the benthic fauna of the Antarctic continental shelf share close phylogenetic relationships to the deep-sea fauna adjacent to Antarctica and in other ocean basins. It has been suggested that connections between the Southern Ocean and the deep sea have been facilitated by the presence of a deep Antarctic continental shelf coupled with submerging Antarctic bottom water and emerging circumpolar deep water. These conditions may have allowed 'polar submergence', whereby shallow Southern Ocean fauna have colonised the deep sea and 'polar emergence', whereby deep-sea fauna colonised the shallow Southern Ocean. A recent molecular study showed that a lineage of deep-sea and Southern Ocean octopuses with a uniserial sucker arrangement on their arms appear to have arisen via polar submergence. A distantly related clade of octopuses with a biserial sucker arrangement on their arms (historically placed in the genus Benthoctopus) is also present in the deepsea basins of the world and the Southern Ocean. To date their evolutionary history has not been examined. The present study investigated the origins of this group using 3133 base pairs (bp) of nucleotide data from five mitochondrial genes (12S rRNA, 16S rRNA, cytochrome c oxidase subunit I. cytochrome c oxidase subunit III, cytochrome b) and the nuclear gene rhodopsin from at least 18 species (and 7 outgroup taxa). Bayesian relaxed clock analyses showed that Benthoctopus species with a high-latitude distribution in the Southern Hemisphere represent a paraphyletic group comprised of three independent clades. The results suggest that the Benthoctopus clade originated in relatively shallow Northern Hemisphere waters. Benthoctopus species distributed in the Southern Ocean are representative of polar emergence and occur at shallower depths than non-polar Benthoctopus species.

The shelled pteropod (sea butterfly) Limacina helicina is currently recognised as a species complex comprising two sub-species and at least five "forma". However, at the species level it is considered to be bipolar, occurring in both the Arctic and Antarctic oceans. Due to its aragonite shell and polar distribution L. helicina is particularly vulnerable to ocean acidification. As a key indicator of the acidification process, and a major component of polar ecosystems, L. helicina has become a focus for acidification research. New observations that taxonomic groups may respond quite differently to acidification prompted us to reassess the taxonomic status of this important species. We found a 33.56% (+/-0.09) difference in cytochrome c oxidase subunit I (COI) gene sequences between L. helicina collected from the Arctic and Antarctic oceans. This degree of separation is sufficient for ordinal level taxonomic separation in other organisms and provides strong evidence for the Arctic and Antarctic populations of L. helicina differing at least at the species level. Recent research has highlighted substantial physiological differences between the poles for another supposedly bipolar pteropod species, Clione limacina. Given the large genetic divergence between Arctic and Antarctic L. helicina populations shown here, similarly large physiological differences may exist between the poles for the L. helicina species group. Therefore, in addition to indicating that L. helicina is in fact not bipolar, our study demonstrates the need for acidification research to take into account the possibility that the L. helicina species group may not respond in the same way to ocean acidification in Arctic and Antarctic ecosystems.

To investigate whether the biogeographical regions proposed by J. W. Hedgpeth and widely adopted by other authors hold true, are an oversimplification or with further data might show a unified Antarctic province. Southern Hemisphere. The distributions of 1318 species of bivalves, 4656 species of gastropods, 1465 species of cheilostome and 167 species of cyclostome bryozoans were analysed for 29 regions in the Southern Hemisphere, including South American, South African, Tasmanian, New Zealand, sub-Antarctic and Antarctic regions. We present data on species richness, rates of endemism, patterns of radiation, faunal similarities and multivariate biogeographical analyses. The most striking pattern to emerge from our data set of species counts per region was a strong east-west hemispheric asymmetry, with high species numbers in New Zealand, Tasmania and South Africa and low numbers in South America. In contrast, no difference was found in richness between the east and west parts of the Southern Ocean. We compared findings in our model taxa with published data on ascidians, cephalopods and pycnogonids. Further evidence of strong faunal links between the Antarctic and South America is reported in this study, although we found little evidence for a biogeographical relationship between the Antarctic or South America and New Zealand/Tasmania. Strong evidence exists for a long-term influence of the Antarctic Circumpolar Current upon the distribution of Southern Ocean benthos. This is demonstrated by the reduced prevalence of South American species in the Antarctic and sub-Antarctic with increasing distance from South America in the direction of the current. Three of our four study taxa (bivalves, cheilostomes and cyclostomes) show the Southern Ocean as a 'single functional unit' with no evidence for a biogeographical split between east and west. Unlike the biogeographical schemes previously proposed, we show that biogeographical regions in the Southern Ocean differ depending

The Census of Antarctic Marine Life (CAML) aims to collate DNA barcode data for Antarctic marine species. DNA barcoding is a technique that uses a short gene sequence from a standardised region of the genome as a diagnostic 'biomarker' for species. This study aimed to quantify genetic data currently available in GenBank in order to establish whether a representative cross-section of Antarctic marine taxa and bio-geographic areas has been sequenced and to propose priorities for barcoding, with a particular emphasis on marine invertebrate species. It was found that, amongst marine invertebrate fauna, sequence information covers a limited range of taxa and areas-mainly Crustacea, Annelida and Mollusca from the Weddell Sea and the Antarctic Peninsula. Only 15% of genes sequenced in Antarctic marine invertebrates were the standard barcode gene cytochrome c oxidase subunit 1 (CO1), the majority were other nuclear and mitochondrial genes. There is an urgent need for more in-depth genetic barcoding and species identification studies in Antarctic science, from a range of taxa and areas, given the rate of climate-driven habitat changes that might lead to extinctions in the region. CAML hopes to redress the balance, by collecting and sequencing over the circum-Antarctic area, using material from voyages that occurred during 2008 and 2009, within the framework of the International Polar Year (IPY).

We ask how biodiverse is a polar archipelago; how this faunal richness is spread across marine, intertidal, freshwater, terrestrial and parasitic realms; and how fast species are accumulated with increased sampling effort.

The aim of this study is to compare the depth distributions of four major Southern Ocean macrobenthic epi- and infaunal taxa, the Bivalvia, Gastropoda, Isopoda, and Polychaeta, from subtidal to abyssal depth. All literature data up to summer 2008, as well as the unpublished data from the most recent ANDEEP I-III (Antarctic benthic deep-sea biodiversity: colonisation history and recent community patterns) expeditions to the Southern Ocean deep sea are included in the analysis. Benthic invertebrates in the Southern Ocean are known for their wide bathymetric ranges. We analysed the distributions of four of the most abundant and species-rich taxa from intertidal to abyssal (5200 m) depths in depth zones of 100 m. The depth distributions of three macrofaunal classes (Bivalvia, Gastropoda, Polychaeta) and one order (Isopoda) showed distinct differences. In the case of bivalves, gastropods and polychaetes, the number of species per depth zone decreased from the shelf to the slope at around 1000 m depth and then showed stable low numbers. The isopods showed the opposite trend; they were less species rich in the upper 1000 m but increased in species numbers from the slope to bathyal and abyssal depths. Depth ranges of families of the studied taxa (Bivalvia: 31 families, Gastropoda: 60, Isopoda: 32, and Polychaeta: 46 families) were compiled and illustrated. At present vast areas of the deep sea in the Southern Ocean remain unexplored and species accumulation curves showed that only a fraction of the species have been discovered to date. We anticipate that further investigations will greatly increase the number of species known in the Southern Ocean deep sea. (C) 2009 Published by Elsevier Ltd.

The amphipod genus Epimeria is species rich in the Southern Ocean and at present eight of its 19 species are reported with circum-Antarctic distributions. For the first time, specimens of epimeriid species from the Antarctic Peninsula, the Weddell Sea and the Ross Sea were analysed using partial COI genes sequences and morphological characters. In total 37 specimens of 14 species of Epimeria and two species of Epimeriella were analysed and the resulting molecular topology checked by critically reviewing taxonomic characters. The genus Epimeriella, genetically grouping within Epimeria is synonymised with the genus Epimeria. Sequences distances between populations of the nominal species Epimeria robusta from the Weddell and Ross Sea led to detailed morphological investigations, resulting in the description of Epimeria robustoides sp. n. from the Weddell Sea. Epimeria robusta Barnard, 1930 from the Ross Sea is redescribed. Sequences of a damaged Epimeria specimen of a species new to science from the lower continental shelf of the eastern Weddell Sea were included. Based on the current study, the hypothesis of circum-Antarctic species' distributions in brooding amphipods proved to be unlikely.