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Published: 2009-02-11

A new brooding feather star of the genus Dorometra (Echinodermata: Crinoidea: Comatulida: Antedonidae) from the Ryukyu Islands, southwestern Japan

Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 2-12-1W3-42 Ookayama, Meguro, Tokyo, 152-8551, Japan
10-17 Ikedaminani-machi, Neyagawa-shi, Osaka, 572-0034, Japan
University Education Center, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa, 903-0213 Japan Marine Learning Center, 2-95-101 Miyagi, Chatan-cho, Okinawa, 904-0113, Japan
Echinodermata Comatulid Dorometra sesokonis new species external brooding hermaphroditism


A new comatulid of the family Antedonidae, Dorometra sesokonis n. sp., is described from coral reefs of the Ryukyu Islands, southwestern Japan. The new species is extremely small with ten short arms and a unique pinnulation in which some proximal pinnules are absent or poorly developed in most specimens. Additionally, cirrals and brachials of D. sesokonis are elongated and partly colorless. The combination of these morphological characters makes the new species appear like juvenile specimens, regardless of sexual maturity. This species also has remarkable reproductive habits, exhibiting both external brooding and hermaphroditism.


  1. Clark, A.H. (1907) Descriptions of new species of recent unstalked crinoids from the North Pacific Ocean. Proceedings of the United States National Museum, 33, 69–84.

    Clark, A.H. (1915) A monograph of the existing crinoids. Vol. 1, The Comatulids. Part 1. Bulletin of the United States National Museum, 82 (1), 1–406.

    Clark, A.H. & Clark, A.M. (1967) A monograph of the existing crinoids. Vol. 1, The Comatulids. Pt. 5. Suborders Oligophreata (concluded) and Macrophreata. Bulletin of the United States National Museum, 82 (5), 1–860.

    Gislén, T. (1922) The crinoids from Dr. S. Bock’s expedition to Japan 1914. Nova acta Regiae Societatis Scientarium Upsaliensis, series IV, 5, 1–183.

    Kogo, I. (1998) Crinoids from Japan and its adjacent waters. Osaka Museum of Natural History. Special Publication, 30, 1–148.

    Kogo, I. (2002) Report on the crinoids collected from the Nansei Islands, southern Japan, during a cruise of the training vessel Toyoshio Maru in 1999. Bulletin of the Osaka Museum of Natural History, 56, 1–44.

    Kogo, I. & Fujita, T. (2005) Geographical distribution of crinoids (Echinodermata) in southwestern Japan. In: Hasegawa, K., Shinohara, G. & Takeda, M. (Eds.), National Science Museum Monographs. Vol. 29. Deep-Sea Fauna and Pollutants in Nansei Islands, pp. 297–355.

    Liao, Y. & Clark, A.M. (1995) The Echinoderms of Southern China. Science Press, Beijing. 614pp.

    Messing, C.G. (1997) Living comatulids. In: Waters, J.A. & Maples, C.G. (Eds.), Paleontological Society Papers vol. 3. Geobiology of Echinoderms. Carnegie Museum of Natural History, Pittsburgh, pp. 3–30.

    Messing, C.G. & White, C.M. (2001) A revision of the Zenometridae (new rank) (Echinodermata, Crinoidea, Comatulidina). Zoologica Scripta, 30, 159–180.

    Utinomi, H. & Kogo, I. (1965) On some crinoids from the coastal sea of Kii Peninsula. Publications of Seto Marine Biological Laboratory, 13, 263–286.