Biogeographical structure and affinities of the marine demersal ichthyofauna of Australia

Aim To investigate the biogeographical structure and affinities of the Australian marine demersal ichthyofauna at the scale of provinces and bathomes for the purposes of regional marine planning. Location Australia. Methods Patterns of distribution in the Australian fish fauna, at both intra‐regional and global scales, were examined using a science‐based, management framework dividing Australia’s marine biodiversity into 16 province‐level biogeographical units. Occurrences of 3734 species in eight depth‐stratified bathomes (from the coast to the mid‐continental slope) within each province were analysed to determine the structure and local affinities of their assemblages and their association with faunas of nearby regions and oceans basins. Results Strong geographic and depth‐related structure was evident. Fish assemblages in each province, and in each bathome of each province, were distinct, with the shelf‐break bathome more similar to the adjacent continental shelf bathome than to the upper slope bathome. Data based only on endemic species performed well as a surrogate of the entire dataset, yielding comparable patterns of similarity between provinces and bathomes. Tropical and temperate elements were better discriminated than elements of the Pacific and Indian oceans, with the central western province more similar to the tropical provinces (including those in the east), and the eastern province closer to southern temperate provinces. The fauna shares the closest regional affinities with those of the adjacent south‐west Pacific, western Pacific Rim, and elements of wide‐ranging Indo‐Pacific components. Elements unique to the Pacific and Indian oceans are poorly represented. Main conclusions The complex nature of Australia’s marine ichthyofauna is confirmed. A hierarchy of provinces and bathomes, used to ensure that Australia’s developing marine reserve network is both representative and comprehensive, is equally robust when based on all known Australian fish species or on only those species endemic to this continent. Latitude and depth are more important than oceanic influences on the composition of this fauna at these scales.     

Bryozoans of the Weddell Sea continental shelf,slope and abyss: did marine life colonize the Antarctic shelf from deep water,outlying islands or in situ refugia following glaciations?

Aim At the height of glaciations such as the Last Glacial Maximum (LGM), benthic life on polar continental shelves was bulldozed off nearly all of the Antarctic shelf by grounded ice sheets. The origins of the current shelf benthos have become a subject of considerable debate. There are several possible sources for the current Antarctic shelf fauna, the first of which is the continental slope and deep sea of the Southern Ocean. The high levels of reported eurybathy for many Antarctic species are taken as evidence supporting this. A second possible source for colonists is the southern margins of other continents. Finally, shelves could have been recolonized from refugia on the continental shelves or slopes around Antarctica. The current study investigates whether the patchily rich and abundant biota that now occurs on the Antarctic continental shelf recolonized from refugia in situ or elsewhere. Location Weddell Sea, Antarctica. Methods We examined bryozoan samples of the BENDEX, ANDEEP III and SYSTCO expeditions, as well as the literature. Using similarity matrices (Sørensen coefficient), we assessed similarities of benthos sampled from around Antarctica. By assessing numbers of species shared between differing depths and adjacent shelf areas, we evaluated the origins of cheilostome bryozoan communities. Results Bryozoans decreased from 28, 6.5 and 0.3 colonies per trawl, and 0.16, 0.046 and 0.0026 colonies per cm² of hard surface from shelf to slope to abyssal depths. We found little and no support for recolonization of the Weddell Sea shelf by bryozoans from the adjacent slope and abyss, in the scenario of LGM faunal wipe‐out. The Weddell Sea shelf bryozoan fauna was considerably more similar to those on other Antarctic shelves than to that of the adjacent (Weddell Sea) continental slope. The known bryozoan fauna of the Weddell Sea shelf is not a subset of the Weddell Sea slope or abyssal faunas. Main conclusions We consider that the composition of the current Weddell Sea bryozoan fauna is most easily explained by in situ survival. Thus we consider that at least some of the Weddell Sea fauna persisted throughout the LGM, although not necessarily at the same locations throughout, to recolonize the large area currently occupied.     

Evolutionary dynamics at high latitudes: speciation and extinction in polar marine faunas

Ecologists have long been fascinated by the flora and fauna of extreme environments. Physiological studies have revealed the extent to which lifestyle is constrained by low temperature but there is as yet no consensus on why the diversity of polar assemblages is so much lower than many tropical assemblages. The evolution of marine faunas at high latitudes has been influenced strongly by oceanic cooling during the Cenozoic and the associated onset of continental glaciations. Glaciation eradicated many shallow-water habitats, especially in the Southern Hemisphere, and the cooling has led to widespread extinction in some groups. While environmental conditions at glacial maxima would have been very different from those existing today, fossil evidence indicates that some lineages extend back well into the Cenozoic. Oscillations of the ice-sheet on Milankovitch frequencies will have periodically eradicated and exposed continental shelf habitat, and a full understanding of evolutionary dynamics at high latitude requires better knowledge of the links between the faunas of the shelf, slope and deep-sea. Molecular techniques to produce phylogenies, coupled with further palaeontological work to root these phylogenies in time, will be essential to further progress.     

Quantifying Fish Assemblages in Large,Offshore Marine Protected Areas: An Australian Case Study

As the number of marine protected areas (MPAs) increases globally, so does the need to assess if MPAs are meeting their management goals. Integral to this assessment is usually a long-term biological monitoring program, which can be difficult to develop for large and remote areas that have little available fine-scale habitat and biological data. This is the situation for many MPAs within the newly declared Australian Commonwealth Marine Reserve (CMR) network which covers approximately 3.1 million km² of continental shelf, slope, and abyssal habitat, much of which is remote and difficult to access. A detailed inventory of the species, types of assemblages present and their spatial distribution within individual MPAs is required prior to developing monitoring programs to measure the impact of management strategies. Here we use a spatially-balanced survey design and non-extractive baited video observations to quantitatively document the fish assemblages within the continental shelf area (a multiple use zone, IUCN VI) of the Flinders Marine Reserve, within the Southeast marine region. We identified distinct demersal fish assemblages, quantified assemblage relationships with environmental gradients (primarily depth and habitat type), and described their spatial distribution across a variety of reef and sediment habitats. Baited videos recorded a range of species from multiple trophic levels, including species of commercial and recreational interest. The majority of species, whilst found commonly along the southern or south-eastern coasts of Australia, are endemic to Australia, highlighting the global significance of this region. Species richness was greater on habitats containing some reef and declined with increasing depth. The trophic breath of species in assemblages was also greater in shallow waters. We discuss the utility of our approach for establishing inventories when little prior knowledge is available and how such an approach may inform future monitoring efforts within the CMR network.     

AN EARLY CENOZOIC NEOSELACHIAN SHARK FAUNA FROM THE SOUTHWEST PACIFIC

Abstract: An early Cenozoic shark fauna, comprising at least 16 taxa, is described from Paleocene sedimentary rocks on the South Island of New Zealand. Although representing a remote Southern Hemisphere location, the fauna includes forms closely comparable to contemporary species from the Northern Hemisphere, in addition to the new species Chlamydoselachus keyesi and Centroselachus goordi. Comparison with closely related extant species suggests the fauna may be interpreted as a deep water one, typical of the outer continental shelf and upper slope. However, after palaeogeography, sedimentology and mineralogy of the enclosing rock, and the nature of similar faunas from elsewhere are taken into consideration, the fauna is interpreted to have occupied a mid‐shelf environment.     

Seamounts: centres of endemism or species richness for ophiuroids?

Aim To test the hypotheses that seamounts exhibit high rates of endemism and/or species richness compared to surrounding areas of the continental slope and oceanic ridges. Location The south‐west Pacific Ocean from 19–57° S to 143–171° E. Methods Presence/absence museum data were compiled for seamount and non‐seamount areas at depths between 100 and 1500 m for the Ophiuroidea (brittle‐stars), an abundant and speciose group of benthic invertebrates. Large‐scale biogeographical gradients were examined through multivariate analyses at two spatial scales, at the scale of seamounts (< 1° of latitude/longitude) and regions (5–9°). The robustness of these patterns to spatially inconsistent sampling effort was tested using Monte Carlo‐style simulations. Levels of local endemism and species richness over numbers of samples were compared for seamount and non‐seamount areas using linear regressions. Non‐seamount populations were randomly generated from areas and depth ranges that reflected the typical sampling profile of seamounts. Results Seamount ophiuroid assemblages did not exhibit elevated levels of species richness or narrow‐range endemism compared with non‐seamount areas. Seamounts can exhibit high overall species richness for low numbers of samples, particularly on seamounts supporting a dense coral matrix, but this does not increase with additional sampling at the rates found in non‐seamount areas. There were relatively few identifiable seamount specialists. In general, seamount faunas reflected those found at similar depths in surrounding areas, including the continental slope. Seamount and non‐seamount faunas within the study area exhibited congruent latitudinal and bathymetric species turnover. Main conclusions Seamount faunas were variable for ophiuroid faunal composition, species richness and narrow‐range endemism, reflecting their environmental diversity and complex history. The continental slope was also variable, with some areas being particularly species rich. Broad geomorphological habitat categories such as ‘seamounts’ or ‘continental slope’ may be at the wrong scale to be useful for conservation planning.     

Long-term history of chemoautotrophic clam-dominated faunas of petroleum seeps in the Northwestern Gulf of Mexico

Summary Chemoautotrophic clam-dominated assemblages are commonly associated with petroleum seepage on the continental slope of the Gulf of Mexico. We examine the persistence and resilence of these communities by evaluating downcore trends in abundance, biomass, and trophodynamics in communities from four separate petroleum seep sites on the Louisiana continental slope. Some petroleum seep sites retained optimal habitat for some species continuously over geologically-relevant periods of time. More commonly, however, habitat optimality varied substantially over time scales of hundreds of years. Thus, one important characteristic of these sites was the degree of persistence of the chemoautotrophic biota. A fauna typically was persistent over a time span of a few hundred years, but was typically not persistent over a longer time span. The mechanisms producing local extinction remain unclear, however temporal variations in juvenile survivorship seem to be substantially larger than temporal variations in larval settlement, to the extent that the heavily taphonomically-biased record of juvenile individuals permits such a conclusion. When local extinctions occurred in the chemoautotrophic biota, the biota was replaced by a normal slope biota or a mixture of a normal slope biota and the juveniles of chemoautotrophic species that failed to survive to adulthood. Thus, the only faunal transitions were between specific chemoautotrophic faunas and the non-chemoautotrophic fauna. Not one distinctive faunal transition between two chemoautotrophic faunas was observed. Accordingly, each discrete chemoautotrophic fauna was resilient over long time scales; time scales of geological importance.     

Distribution patterns and biogeographic analysis of Austral Polychaeta (Annelida)

Aim We investigate the biogeography of Austral Polychaeta (Annelida) using members of the families Eunicidae, Lumbrineridae, Oenonidae, Onuphidae, Serpulidae and Spionidae and Parsimony Analysis of Endemicity (PAE). We determine whether observed polychaete distribution patterns correspond to traditional shallow-water marine areas of endemism, estimate patterns of endemism and relationships between areas of endemism, and infer the biological processes that have caused these patterns. Location The study is concerned with extant polychaete taxa occupying shallow-water areas derived from the breakup of the Gondwana landmass (i.e. Austral areas). Methods Similarity was assessed using a significance test with Jaccard's indices. Areas not significantly different at 0.99 were combined prior to the PAE. Widespread species and genera (155 taxa) were scored for presence/absence for each area of endemism. PAE was used to derive hypotheses of area relationships. Hierarchical patterns in the PAE trees were identified by testing for congruence with patterns derived from cladistic biogeographic studies of other Gondwanan taxa and with geological evidence. Results The polychaete faunas of four area-pairs were not significantly different and the areas amalgamated: South-west Africa and South Africa, New Zealand South Island and Chatham Islands, Macquarie Island and Antipodean Islands, and West Antarctica and South Georgia. Areas with the highest levels of species endemism were southern Australia (67.0%), South-east South America (53.2%) and South Africa (40.4%). About 60% of species and 7.5% of genera occupied a single area of endemism. The remainder were informative in the PAE. Under a no long-distance dispersal assumption a single minimal-length PAE tree resulted (l=367; ci=0.42); under dispersal allowed, three minimal-length trees resulted (l=278; ci=0.56). In relation to the sister grouping of the New Zealand areas and Australia we find congruence between our minimal-length trees and those derived from a biogeographic study of land plants, and with area relationships predicted by the Expanding Earth Model. Main conclusions The polychaete distribution patterns in this study differ slightly from the classical areas of endemism, most notably in being broader, thereby bringing into question the value of using single provincial system for marine biogeographic studies. The Greater New Zealand region is found to be ‘monophyletic’ with respect to polychaetes, that is comprising a genuine biogeographical entity, and most closely related to the polychaete fauna of southern Australia. This finding is consistent with studies of land plants and with the Expanding Earth model, but disagrees with conventional geology and biogeographic hypothesis involving a ‘polyphyletic’ New Zealand. Both vicariance and concerted range expansion (=biotic dispersion) appear to have played important roles in shaping present-day distribution patterns of Austral polychaetes. Shallow-water ridge systems between the Australian and Greater New Zealand continental landmasses during the Tertiary are thought to have facilitated biotic dispersion.     

Demersal fish assemblages and spatial diversity patterns in the Arctic-Atlantic transition zone in the Barents Sea

Direct and indirect effects of global warming are expected to be pronounced and fast in the Arctic, impacting terrestrial, freshwater and marine ecosystems. The Barents Sea is a high latitude shelf Sea and a boundary area between arctic and boreal faunas. These faunas are likely to respond differently to changes in climate. In addition, the Barents Sea is highly impacted by fisheries and other human activities. This strong human presence places great demands on scientific investigation and advisory capacity. In order to identify basic community structures against which future climate related or other human induced changes could be evaluated, we analyzed species composition and diversity of demersal fish in the Barents Sea. We found six main assemblages that were separated along depth and temperature gradients. There are indications that climate driven changes have already taken place, since boreal species were found in large parts of the Barents Sea shelf, including also the northern Arctic area. When modelling diversity as a function of depth and temperature, we found that two of the assemblages in the eastern Barents Sea showed lower diversity than expected from their depth and temperature. This is probably caused by low habitat complexity and the distance to the pool of boreal species in the western Barents Sea. In contrast coastal assemblages in south western Barents Sea and along Novaya Zemlya archipelago in the Eastern Barents Sea can be described as diversity "hotspots"; the South-western area had high density of species, abundance and biomass, and here some species have their northern distribution limit, whereas the Novaya Zemlya area has unique fauna of Arctic, coastal demersal fish. (see Information S1 for abstract in Russian).     

Comparison of seastar (Asteroidea) fauna across island groups of the Scotia Arc

The Antarctic shelf fauna is isolated from other continental shelf faunas both physically by distance, and oceanographically by the Antarctic circumpolar current (ACC). To elucidate the relative importance of these two isolating mechanisms, we used the seastar fauna of the south-Atlantic sub-Antarctic islands to address the hypothesis that the ACC is dominant in controlling the distribution pattern of Antarctic fauna. We expected that seastar faunas from islands on the high latitude side of the ACC would show more similarities to each other than to faunas from islands on the low latitude side. The alternative isolation by distance model predicted that the island furthest from others would have the most unique fauna. For shelf-depth (<500 m) Asteroidea of the Scotia Arc region, assemblages were more similar between islands on each side of the ACC barrier than islands that were closer together, and this pattern was caused by differences in abundance of a few ubiquitous species.     

Control mechanisms of Carboniferous brachiopod zones in eastern Australia

Analysis of the Carboniferous brachiopod zones of eastern Australia shows that they were affected by two major controlling factors - eustatic changes of sea level, and a deterioration (cooling) of climate. Eustatic lowering of sea level caused the removal of the sea from narrow shelf areas and a loss of habitat, and was responsible for the first (late early to middle Visean) of two major episodes of faunal extinction. Subsequent transgression restored a modified warm-water cosmopolitan fauna to the shelf regions. Smaller changes in sea levels were probably responsible for the abrupt disappearance of many species or genera at zonal boundaries and their replacement by a new set of species and genera in succeeding zones. The second major episode of extinction was caused by the lowering of temperature in the latest Visean to early Namurian because of the rapid southerly movement of Australia. The warm water cosmopolitan fauna was eliminated and replaced by the low-diversity Gondwana fauna. Both mechanisms produced particular faunal signatures. The diversity of faunas on either side of the hiatus produced by eustatic lowering of sea level is constant in areas with uniform climatic conditions, and in warm to temperate regions there are low levels of endemism. Faunas associated with a sudden lowering of temperature suffer a significant drop in diversity but are characterized by a high level of endemism.     

Biodiversity and biogeography of southern temperate and polar bryozoans

Aim To describe the distribution of biodiversity and endemism of bryozoans in southern temperate and polar waters. We hypothesized that we would find: (1) no strong latitudinal richness gradient; (2) striking contrasts in richness and endemism between clades and between regions; and (3) that faunal similarity of regions would cluster geographically around each southern continent. Location South Atlantic, Indian and Pacific Oceans and the Southern Ocean. Methods We constructed a data base from known literature, regional data bases and recent finds. We regionalized each southern continent, calculated levels of richness and endemism for each region and continent, and used primer 5 to perform multivariate statistical analysis. Results A third (1681) of global bryozoan species described occur south of 30° S, of which c. 87% were cheilostomes. In richness we found no latitudinal cline and change across longitude was stronger. New Zealand was richest and had the most (60%) endemic species, followed by Antarctica at 57%. There were striking contrasts in regional richness and endemism between clades but the highest levels of between‐region similarity were around Antarctica. The timing of past continent connectivity was reflected. Main conclusions Bryozoans show strong hemispherical asymmetry in richness and, like molluscs and corals, decrease away from Australasia rather than with latitude. Species endemism is much lower in Antarctic bryozoans than previously thought, and as this taxon is not particularly dispersive and is now amongst the best studied regionally, maybe Antarctic endemism in general is lower and Antarctica less cut‐off to species dispersal than previously thought. However, Antarctic generic endemism is double the level previously calculated and regional faunal similarities are much higher than around other continents – both reflecting long‐term isolation. Bryozoans, in contrast to the paradigm of Antarctic fauna, may be fairly robust to predicted climate change. Paradoxically, they may also be one of the best taxa to monitor to sensitively detect marine benthic responses.     

Cold‐water coral habitats on seamounts: do they have a specialist fauna?

Aim The large biogenic structures formed by colonial cold‐water scleractinian corals provide valuable habitat for marine invertebrates on seamounts and the continental slope of all world oceans. These patchily distributed long‐lived structures are easily damaged by several human activities, particularly bottom trawling for fish, and are potentially vulnerable to ocean acidification caused by climate change. Consequently, an important conservation question is whether these structures support a specialized invertebrate fauna restricted to these habitats. Here we investigate the relationship between structures formed by the coral Solenosmilia variabilis and its associated ophiuroid (brittlestar) fauna, one of the dominant components of deep‐sea ecosystems. Location Seafloor habitat around Southern Australia, New Zealand, and the Macquarie Ridge from 35 to 53° S and 117° E–176° W, 500–1500 m depth. Methods Data were derived from samples collected by numerous scientific expeditions to the study region. Because these samples were collected using a variety of gear and effort, a two‐step approach was used. First, the largest consistently collected data set (73 ophiuroid species from 59 samples) was assembled for multivariate analysis. ANOSIM was used to test for differences in ophiuroid community composition between Solenosmilia and non‐Solenosmilia habitat on seamounts and the continental slope, and SIMPER was used to identify species that characterized Solenosmilia habitat. Second, these results were validated against all known data to ensure that these characteristic species had not been found in non‐Solenosmilia habitat elsewhere. Results The ophiuroid assemblages from Solenosmilia habitat were distinct from those found on other habitats on the continental slope and offshore seamounts across the study region. Although a suite of ophiuroid species characterized Solenosmilia habitat, most have also been collected from dead coral or other rubble, suggesting a physical rather than biological association between the coral matrix and its associated invertebrate fauna. Main conclusions Despite the lack of an exclusive ophiuroid–coral relationship, cold‐water scleractinian coral remains the principal habitat for a number of ophiuroid species across southern Australia and New Zealand. The slow growth rate of the coral and the low dispersal potential of some associated species suggest that recovery of damaged cold‐water coral assemblages will be a long‐term process.     

Habitat specialization in tropical continental shelf demersal fish assemblages

The implications of shallow water impacts such as fishing and climate change on fish assemblages are generally considered in isolation from the distribution and abundance of these fish assemblages in adjacent deeper waters. We investigate the abundance and length of demersal fish assemblages across a section of tropical continental shelf at Ningaloo Reef, Western Australia, to identify fish and fish habitat relationships across steep gradients in depth and in different benthic habitat types. The assemblage composition of demersal fish were assessed from baited remote underwater stereo-video samples (n = 304) collected from 16 depth and habitat combinations. Samples were collected across a depth range poorly represented in the literature from the fringing reef lagoon (1-10 m depth), down the fore reef slope to the reef base (10-30 m depth) then across the adjacent continental shelf (30-110 m depth). Multivariate analyses showed that there were distinctive fish assemblages and different sized fish were associated with each habitat/depth category. Species richness, MaxN and diversity declined with depth, while average length and trophic level increased. The assemblage structure, diversity, size and trophic structure of demersal fishes changes from shallow inshore habitats to deeper water habitats. More habitat specialists (unique species per habitat/depth category) were associated with the reef slope and reef base than other habitats, but offshore sponge-dominated habitats and inshore coral-dominated reef also supported unique species. This suggests that marine protected areas in shallow coral-dominated reef habitats may not adequately protect those species whose depth distribution extends beyond shallow habitats, or other significant elements of demersal fish biodiversity. The ontogenetic habitat partitioning which is characteristic of many species, suggests that to maintain entire species life histories it is necessary to protect corridors of connected habitats through which fish can migrate.     

Mammals of the northern Philippines: tolerance for habitat disturbance and resistance to invasive species in an endemic insular fauna

Aim Island faunas, particularly those with high levels of endemism, usually are considered especially susceptible to disruption from habitat disturbance and invasive alien species. We tested this general hypothesis by examining the distribution of small mammals along gradients of anthropogenic habitat disturbance in northern Luzon Island, an area with a very high level of mammalian endemism. Location Central Cordillera, northern Luzon Island, Philippines. Methods  Using standard trapping techniques, we documented the occurrence and abundance of 16 endemic and two non‐native species along four disturbance gradients where habitat ranged from mature forest to deforested cropland. Using regression analysis and AIC_c for model selection, we assessed the influence of four predictor variables (geographic range, elevational range, body size and diet breadth) on the disturbance tolerance of species. Results Non‐native species dominated areas with the most severe disturbance and were rare or absent in mature forest. Native species richness declined with increasing disturbance level, but responses of individual species varied. Elevational range (a measure of habitat breadth) was the best predictor of response of native species to habitat disturbance. Geographic range, body size and diet breadth were weakly correlated. Main conclusions The endemic small mammal fauna of northern Luzon includes species adapted to varying levels of natural disturbance and appears to be resistant to disruption by resident alien species. In these respects, it resembles a diverse continental fauna rather than a depauperate insular fauna. We conclude that the long and complex history of Luzon as an ancient member of the Philippine island arc system has involved highly dynamic ecological conditions resulting in a biota adapted to changing conditions. We predict that similar responses will be seen in other taxonomic groups and in other ancient island arc systems.     

Late Late Cambrian Trilobites From Near Birch Inlet, South-Western Tasmania

The first late Late Cambrian basinal-facies trilobites to be described from Tasmania are from a succession exposed 8.5 km west of Birch Inlet, south-western Tasmania. Twenty-one taxa are described; the six agnostoid species include a new species of Leiagnostus, L inletensis. The polymeroids include five new species: Hedinaspis uniformis, Proceratopyge longa, Niobella birchensisSkljarella expansa and Ivshinaspis reticulata.SkljarellaIvshinaspis are described for the first time from Australia. The specimens are preserved in siltstone belonging to a basinal facies; the fauna has more in common with those of the South-East China Faunal Province than with the shallow-water carbonate-facies faunas from northern Australia. The fauna is of late Late Cambrian age (Payntonian–earliest Datsonian) on the north Australian biostratigraphic scale. The Birch Inlet fauna is correlated with those of the Siyangshan Formation of Zhejiang, the Guoziguonen Formation of Xinjiang and the Shengjiawan Formation of Hunan. There are similarities with late Late Cambrian faunas from Nevada, Kazakhstan and New Zealand. K ey words : Trilobita, Late Cambrian, Tasmania, basinal facies, biostratigraphy, palaeobiogeography.     

Skate assemblage on the eastern Patagonian Shelf and Slope: structure, diversity and abundance

The eastern Patagonian Shelf and continental slope of the south-west Atlantic Ocean support a high biodiversity and abundance of skates. In this study, meso-scale differences in the assemblages, spatial and seasonal distributions of skates are revealed among six habitat zones of the eastern Patagonian Shelf characterized by distinctive oceanographic conditions. Most skates belonged to temperate fauna, and their abundance was much greater in habitats occupied by temperate waters (north-western outer shelf) or mixed waters (northern slope) than in habitats occupied by sub-Antarctic waters (SASW) (south-eastern outer shelf and southern slope). Sub-Antarctic skates were not abundant on the shelf even in habitats occupied by SASW, occurring mainly in deep areas of the lower continental slope. The majority of temperate skates migrated seasonally, shifting northward in winter and spreading southward with warming waters in summer. Most temperate species had two peaks in female maturity (mainly spring and autumn) and spawned in the same habitats where they fed. It is hypothesized that the high biodiversity and abundance of skates on the Patagonian Shelf and Slope are due to the practical absence of their natural competitors, flatfishes, which occupy similar eco-niches elsewhere.     

Diurnal butterflies (Lepidoptera, Rhopalocera) of the Solovetskie Islands (Northwestern Russia, the White Sea)

The species composition and diversity of Lepidoptera Rhopalocera were studied on the Solovetskie Islands during five years (2001–2005). Twenty-nine species of five families were recorded. The most abundant species are Leptidea sinapis, Boloria aquilonaris, Heodes virgaureae, Plebejus argus, Arcia eumedon, and Cyaniris semiargus. The fauna of these islands is poorer than local faunas of the continental northern taiga, forest-tundra, and southern tundra of Europe. The species diversity of insular assemblages of diurnal lepidopterans is lower in comparison with analogous continental assemblages. They are characterized by the mixed species composition, when species with different ecological preference occur within the same habitat.     

On the origin of Antarctic marine benthic community structure

Environmental conditions fostering marine communities around Antarctica differ fundamentally from those in the rest of the world's oceans, particularly in terms of pronounced climatic fluctuations and extreme cold. Here, we argue that the rarity of pelagic larval stages in Antarctic marine benthic invertebrate species is a consequence of evolutionary temperature adaptation and that this has greatly contributed to the current structure of the Antarctic benthic community. In arguing this position, we challenge the likelihood of previously suggested survival strategies of benthic communities on the Antarctic continental shelf and slope during Cenozoic glacial periods. By integrating evidence from marine geology and geophysics, we suggest that the Antarctic continental shelf and slope were both unfavourable environments for benthic communities during glacial periods and that community survival was only possible in the deep sea or in shelters on the continental shelf as a result of the diachronism in maximum ice extent.     

Foraminiferida from Neogene sediments,Vestfold Hills,Antarctica

Sediment samples from several locations in the southern part of the Vestfold Hills have been examined for their foraminiferid content. Those from Early Pliocene sediments of Marine Plain immediately east of Burton Lake contain little foraminiferid evidence of marine deposition. Those from mid-late Holocene sections in and near the lakes contain good open marine faunas of species now known to be living on the continental shelf west of Cape Darnley.Foraminiferid faunas characterized by calcareous forms are most common, the most prevalent dominated by Globocassidulina crassa.The faunas examined contrast markedly with those in the present Prydz Bay which is characterized by agglutinated forms.The results, in relation to planktonic faunas, conflict with an earlier record of a diverse fauna.