Demosponge fauna of Ormonde and Gettysburg Seamounts (Gorringe Bank, north-east Atlantic): diversity and zoogeographical affinities

Seamounts, although abundant features of the world's oceans, constitute one of the least studied marine ecosystems. In the present work we assessed the diversity and zoogeographical affinities of the demosponge assemblages of Gettysburg and Ormonde Seamounts (Gorringe Bank, north-east Atlantic)...

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Bibliographic Details
Published in:Journal of the Marine Biological Association of the United Kingdom
Main Authors: Xavier, Joana, van Soest, Rob
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2007
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Online Access:http://dx.doi.org/10.1017/s0025315407058584
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315407058584
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Summary:Seamounts, although abundant features of the world's oceans, constitute one of the least studied marine ecosystems. In the present work we assessed the diversity and zoogeographical affinities of the demosponge assemblages of Gettysburg and Ormonde Seamounts (Gorringe Bank, north-east Atlantic). Twenty-three demosponge species were identified adding to the thirteen previously reported for Gorringe shallow-water. Gorringe's demosponge assemblage was found to be mainly composed of species with a wide Atlanto–Mediterranean distribution (61%) and a group of species (28%) that are endemic to this Bank or have a restricted geographical distribution. This high level of endemism suggests the Gorringe Bank as a hotspot for demosponge fauna in the north-east Atlantic. Gorringe demosponge fauna was found to present an overall moderate similarity to the Mediterranean, Iberian coasts and Macaronesian archipelagos. We compare our findings with patterns reported for fish and molluscan faunas for this Bank and discuss some evolutionary aspects on the role of these ecosystems for the north-east Atlantic marine biota.