Hexacorals (Anthozoa: Actiniaria, Zoanthidea) from hydrothermal vents in the south-western Pacific

Abstract

Four new species of sea anemones are described from the Eastern Lau Spreading Center, with notes on three additional Hexacorallia. Cyananthea hourdezi sp. nov. and Alvinactis chessi sp. nov. (Actinoscyphiidae) extend the range of the two previously monotypic, vent-endemic genera from the East Pacific Rise. Chondrophellia orangina sp. nov. (Hormathiidae) is the third species of its genus; it inhabits both hydrothermal vents and non-venting sites. Similarly, Sagartiogeton erythraios sp. nov. (Sagartiidae) was collected from non-vent settings, but is documented on video from near diffuse-flow hydrothermal vents. In addition, we report two species from families Actinostolidae and Hormathiidae whose identity could not be established based on the existing material, and provide a new record of a member of order Zoanthidea from a hydrothermal vent. The ecological context of the sites at the Eastern Lau Spreading Center containing sea anemones is described.

Keywords:

• Actiniaria
• Cnidaria
• deep sea
• diversity
• new species
• Pacific Ocean
• vents

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

Specimens were collected by KAZ and Stacy Kim, with the assistance from the crew of the R/V Melville, ROV Jason II, and supported through NSF Grant OCE 003403953 to C.R. Fisher. All in situ photographs are courtesy of C. R. Fisher & Ridge (2000). Comparative material was provided by R. Van Syoc of the California Academy of Sciences, J. Voight of the FMNH, S. Cairns and T. Coffer of the USNM, O. Tendal of the ZMUC, and C. Lüter of the Museum für Naturkunde of Berlin. Comments from V. Häussermann, D. Fautin, and an anonymous reviewer improved this manuscript. We thank A. Reft for her useful advice and comments on cnidae. KAZ was supported through a Training Award for New Investigators (TAWNI) from the Biogeography of Chemosynthetic Ecosystems (ChEss) project of the Census of Marine Life (CoML). MD and ER are supported by NSF EF-0531763; MD is also supported by NSF DEB 041527.

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