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Melbourne, Australia

O'Hara T.D.,Museum Victoria | Rowden A.A.,NIWA - National Institute of Water and Atmospheric Research | Bax N.J.,CSIRO
Current Biology | Year: 2011

The large-scale spatial distribution of seafloor fauna is still poorly understood. In particular, the bathyal zone has been identified as the key depth stratum requiring further macroecological research [1], particularly in the Southern Hemisphere [2]. Here we analyze a large biological data set derived from 295 research expeditions, across an equator-to-pole sector of the Indian, Pacific, and Southern oceans, to show that the bathyal ophiuroid fauna is distributed in three broad latitudinal bands and not primarily differentiated by oceanic basins as previously assumed. Adjacent faunas form transitional ecoclines rather than biogeographical breaks. This pattern is similar to that in shallow water despite the order-of-magnitude reduction in the variability of environmental parameters at bathyal depths. A reliable biogeography is fundamental to establishing a representative network of marine reserves across the world's oceans [1, 3]. © 2011 Elsevier Ltd.

O'Hara T.D.,Museum Victoria | Tittensor D.P.,Dalhousie University
Marine Ecology | Year: 2010

Benthic communities on seamounts are frequently characterised as being species rich, yet there is considerable variation in observed species richness. Although large-scale patterns of species richness have been described from many marine and terrestrial habitats, their environmental drivers often remain poorly understood. We compared species richness of ophiuroids (brittle-stars) on 60 seamounts throughout the South West Pacific Ocean, and used an information-theoretic approach and generalized linear models to determine the relative importance of predictor variables. Due to high correlation among many environmental variables, we used a reduced set of predictors in an a priori model framework. Temperature was the only environmental predictor of any importance in these models over the bathymetric range of the study. Post-hoc analyses of other potential environmental predictor variables showed that depth, calcite saturation state, temperature range, modelled current velocity and latitude all had some predictive value, but were also highly correlated with temperature or other environmental variables included in the a priori model. Longitude, large-area species richness, habitat suitability for stony corals, and modelled POC flux did not have high predictive value. We hypothesise that temperature affects richness by constraining species distributions; in particular fewer species can tolerate the conditions on relatively warm shallow seamount summits. © 2010 Blackwell Verlag GmbH.

Poore G.C.B.,Museum Victoria | Bruce N.L.,James Cook University | Bruce N.L.,University of Johannesburg
PLoS ONE | Year: 2012

The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater taxa) comprise 3154 described marine species in 379 genera in 37 families according to the WoRMS catalogue. The history of taxonomic discovery over the last two centuries is reviewed. Although a well defined order with the Peracarida, their relationship to other orders is not yet resolved but systematics of the major subordinal taxa is relatively well understood. Isopods range in size from less than 1 mm to Bathynomus giganteus at 365 mm long. They inhabit all marine habitats down to 7280 m depth but with few doubtful exceptions species have restricted biogeographic and bathymetric ranges. Four feeding categories are recognised as much on the basis of anecdotal evidence as hard data: detritus feeders and browsers, carnivores, parasites, and filter feeders. Notable among these are the Cymothooidea that range from predators and scavengers to external blood-sucking micropredators and parasites. Isopods brood 10-1600 eggs depending on individual species. Strong sexual dimorphism is characteristic of several families, notably in Gnathiidae where sessile males live with a harem of females while juvenile praniza stages are ectoparasites of fish. Protandry is known in Cymothoidae and protogyny in Anthuroidea. Some Paranthuridae are neotenous. About half of all coastal, shelf and upper bathyal species have been recorded in the MEOW temperate realms, 40% in tropical regions and the remainder in polar seas. The greatest concentration of temperate species is in Australasia; more have been recorded from temperate North Pacific than the North Atlantic. Of tropical regions, the Central Indo-Pacific is home to more species any other region. Isopods are decidedly asymmetrical latitudinally with 1.35 times as many species in temperate Southern Hemisphere than the temperate North Atlantic and northern Pacific, and almost four times as many Antarctic as Arctic species. More species are known from the bathyal and abyssal Antarctic than Arctic GOODS provinces, and more from the larger Pacific than Atlantic oceans. Two areas with many species known are the New Zealand-Kermadec and the Northern North Pacific provinces. Deep hard substrates such as found on seamounts and the slopes are underrepresented in samples. This, the documented numbers of undescribed species in recent collections and probable cryptic species suggest a large as yet undocumented fauna, potentially an order of magnitude greater than presently known. © 2012 Poore, Bruce.

Kempson I.M.,Academia Sinica, Taiwan | Kempson I.M.,University of South Australia | Henry D.A.,Museum Victoria
Angewandte Chemie - International Edition | Year: 2010

Fresh physical evidence about the demise of the racehorse Phar Lap (see photograph) has been gathered from the study of mane hair samples by synchrotron radiation analysis with high resolution Xray fluorescence (XRF) and X-ray absorption near edge structure (XANES) analyses. The results are indicative of arsenic ingestion and metabolism, and show that the racing champion died from arsenic poisoning. [Figure Presented] © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Stohr S.,Swedish Museum of Natural History | O'Hara T.D.,Museum Victoria | Thuy B.,University of Gottingen
PLoS ONE | Year: 2012

This review presents a comprehensive overview of the current status regarding the global diversity of the echinoderm class Ophiuroidea, focussing on taxonomy and distribution patterns, with brief introduction to their anatomy, biology, phylogeny, and palaeontological history. A glossary of terms is provided. Species names and taxonomic decisions have been extracted from the literature and compiled in The World Ophiuroidea Database, part of the World Register of Marine Species (WoRMS). Ophiuroidea, with 2064 known species, are the largest class of Echinodermata. A table presents 16 families with numbers of genera and species. The largest are Amphiuridae (467), Ophiuridae (344 species) and Ophiacanthidae (319 species). A biogeographic analysis for all world oceans and all accepted species was performed, based on published distribution records. Approximately similar numbers of species were recorded from the shelf (n = 1313) and bathyal depth strata (1297). The Indo-Pacific region had the highest species richness overall (825 species) and at all depths. Adjacent regions were also relatively species rich, including the North Pacific (398), South Pacific (355) and Indian (316) due to the presence of many Indo-Pacific species that partially extended into these regions. A secondary region of enhanced species richness was found in the West Atlantic (335). Regions of relatively low species richness include the Arctic (73 species), East Atlantic (118), South America (124) and Antarctic (126). © 2012 Stöhr et al.

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