A new species of Aspidiophorus (Gastrotricha, Chaetonotida) from the Russian Far East with a key to marine species of the genus

Abstract

The Russian gastrotrich fauna is virtually unknown, particularly the marine fauna. In the ocean, investigations have been restricted to the White Sea, from where only three fully described species have been reported so far. In this study we describe a new species of Aspidiophorus found in a sandy sample collected from off of Vladivostok (Peter the Great Bay, Sea of Japan). Aspidiophorus oculatus n. sp. is the first marine chaetonotid gastrotrich described from Russia and the first representative of the order Chaetonotida reported from the Sea of Japan. Specimens of the new species are characterized by a body up to 147.5 µm in total length; enveloped by 57 alternating columns of 65–70 keeled, elongate scales. Pharyngeo-intestinal junction at U27; the head bears cephalion, hypostomion, pleuria and a pair of eye-spots; the furca is 20 µm long including the 12-µm long adhesive tube; the ventral interciliary field is naked, with the exception of a pair of elliptical, keeled scales occurring near the anus. Morphological differences between the new species and the other 13 marine con-generic taxa are discussed. A key to the known marine species of the world based on easily identifiable traits, visible in both living and formalin-fixed specimens is provided.

Keywords:

• Gastrotricha
• meiofauna
• taxonomy
• Russia
• taxonomic key
• Sea of Japan

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

The authors gratefully acknowledge the support of the US CRDF and the Russian Ministry of Education and Science (grant REC-03), and a grant from the President of the Russian Federation to A. Maiorova (MK-1069.2007.4) during the course of this study. The research benefited also from a grant to MAT (UniMoRe FAR-2007). The Eclipse 90i Nikon microscope was funded by the ‘Fondazione Cassa di Risparmio di Modena’. We thank two anonymous reviewers for their comments on an early draft of the manuscript.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark