First endomyarian sea anemone (Cnidaria, Actiniaria) putatively from chemosynthetic environments: a new deep-sea genus and species from the North Pacific

Abstract

A new genus and species of deep-sea sea anemone is described and illustrated from the vicinity of a cold seep in the North Pacific Ocean. Henactis seepala gen. nov. et sp. nov. is characterized by an endodermal marginal sphincter, smooth column with 24 marginal projections of two kinds alternately arranged, equal numbers of mesenteries proximally and distally, five cycles of mesenteries regularly arranged with only the first cycle perfect, diffuse retractor musculature and well-developed basilar muscles. Henactis seepala gen. et sp. nov. is the first sea anemone of the group Endomyaria putatively reported from chemosynthetic environments. The discovery of H. seepala gen. et sp. nov. is the first evidence that sea anemones from chemosynthetic environments are the product of at least two radiations.

Keywords:

• Anthozoa
• cold seep
• deep sea
• systematics

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

Special thanks to J. Voight (FMNH) and M. Daly (Ohio State University) for making access to this material possible. Janet Voight, D. Clague (Monterey Bay Aquarium Research Institute, MBARI) and J. Paduan (MBARI) are also thanked for facilitating the ecological information related to the habitat. MBARI provided the in-situ images of Henactis seepala gen. et sp. nov. Yuri Kantor (Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences, Moscow) is thanked for the gastropod identification. Louise Crowley (AMNH) helped in the lab with some of the sequences. Verena Häussermann is thanked for the material of Isotealia for the molecular study. The manuscript was improved through feedback from D. Fautin and one anonymous reviewer. Support was partly provided by NSF EF-0531763 to M. Daly.

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