Growing Collection of Bottom-dwellers fr

Taxonomists from Russia have visited National Oceanography Centre, Southampton (UK) to process material collected by the James Cook ECOMAR expedition (JC037) in 2009.

By Anna Dilman and Andrey Gebruk (P.P. Shirshov Institute of Oceanology)





In February-March 2010 four taxonomic experts from Moscow, Russia visited the National Oceanography Centre, Southampton, UK to process material collected by the James Cook ECOMAR expedition (JC037) in 2009. The taxonomic experts, each specialists on particular animal groups, were Anna Dilman (Asteroidea), Konstantin Tabachnik (Porifera, Hexactinellida), Alexey Raiskyi (Pycnogonida) and Alexander Martynov

(Ophiuroidea). The former three work at the P.P. Shirshov Institute of Oceanology and A. Martynov at the Zoological Museum, Moscow State University. The visit of Russian scientists was hosted by Dr. Alan Hughes, prepared with a kind help of Pam Talbot and coordinated by Andrey Gebruk, Russian member of MAR-ECO Steering Group). Anna Dilman has examined material on sea stars from the JC037 ECOMAR expedition. Collection of Asteroidea sampled by this expedition is very abundant: 1708 specimens representing 21 species. Most numerous specimens are from the families Porcellanasteridae (genera Caulaster, Hyphalaster, Porcellanaster and Styracaster), Pterasteridae
(Hymenaster) and Pedicellasteridae (Hydrasterias sexradiata only). The number of specimens of Hymenaster appeared unexpectedly high: 450, representing 26% of the total specimen number in the collection. Most of the Hymenaster specimens in the material belong to the species H. membranaceus. These sea stars are very soft and slimy and usually very easily damaged in trawl catches because of their heavy weight and very thin supradorsal membrane.

The giant specimen of Hymenaster regalis with R=160 mm is a remarkable representative in this collection. This is the biggest specimen ever recorded for this species. Also in the collection five species of Hymenaster were found. In total 15 species of this genus occur in the Atlantic. Most are known only from descriptions made in the 19th century. Taxonomy of this genus is currently in a very poor state. One of the reasons for this is the extremely fragile skeletal elements and teguments of these sea stars.

Overall the JC037 ECOMAR collection added lots of valuable information for the taxonomy of deep-sea asteroids. Work on this material continues.

Financial support for this work was provided by MAR-ECO (allocation from grant from the Norwegian Foreign Office).