Abstract

Indian Ocean hydrothermal vents are believed to represent a novel biogeographic province, and are host to many novel genera and families of animals, potentially indigenous to Indian Ocean hydrothermal systems. In particular, since its discovery in 2001, much attention has been paid to a so-called 'scaly-foot' gastropod because of its unique iron-sulfide-coated dermal sclerites and the chemosynthetic symbioses in its various tissues. Despite increasing interest in the faunal assemblages at Indian Ocean hydrothermal vents, only two hydrothermal vent fields have been investigated in the Indian Ocean. Here we report two newly discovered hydrothermal vent fields, the Dodo and Solitaire fields, which are located in the Central Indian Ridge (CIR) segments 16 and 15, respectively. Chemosynthetic faunal communities at the Dodo field are emaciated in size and composition. In contrast, at the Solitaire field, we observed faunal communities that potentially contained almost all genera found at CIR hydrothermal environments to date, and even identified previously unreported taxa. Moreover, a new morphotype of 'scaly-foot' gastropod has been found at the Solitaire field. The newly discovered 'scaly-foot' gastropod has similar morphological and anatomical features to the previously reported type that inhabits the Kairei field, and both types of 'scaly-foot' gastropods genetically belong to the same species according to analyses of their COI gene and nuclear SSU rRNA gene sequences. However, the new morphotype completely lacks an iron-sulfide coating on the sclerites, which had been believed to be a novel feature restricted to 'scaly-foot' gastropods. Our new findings at the two newly discovered hydrothermal vent sites provide important insights into the biodiversity and biogeography of vent-endemic ecosystems in the Indian Ocean.

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Authors

Nakamura K, Watanabe H, Miyazaki J, Takai K, Kawagucci S, Noguchi T, Nemoto S, Watsuji TO, Matsuzaki T, Shibuya T, Okamura K, Mochizuki M, Orihashi Y, Ura T, Asada A, Marie D, Koonjul M, Singh M, Beedessee G, Bhikajee M, Tamaki K

Institution

Precambrian Ecosystem Laboratory (PEL), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, Japan. kentaron@jamstec.go.jp

Source

PloS one 7:3 2012 pg e32965

MeSH

Animals
Biodiversity
Body Size
Dermis
Gastropoda
Geography
Hydrothermal Vents
Indian Ocean
Iron
Molecular Sequence Data
Rheology
Stress, Mechanical
Sulfides

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22431990