Japan Geoscience Union Meeting 2015

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Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS30] Evolution of the Pelagic Realm

Tue. May 26, 2015 11:00 AM - 12:45 PM 304 (3F)

Convener:*Atsushi Matsuoka(Department of Geology, Faculty of Science, Niigata University), Toshiyuki Kurihara(Graduate School of Science and Technology, Niigata University), Yasuhiro Kato(Department of Systems Innovation, Graduate School of Engineering, University of Tokyo), Tetsuji Onoue(Earth and Environmental Sciences, Graduate School of Science and Technology, Kumamoto University), Katsunori Kimoto(Japan Agency for Marine-Earth Science and Technology), Tatsuo Nozaki(Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology), Hayato Ueda(Department of Geology, Niigata University), Kenta Kobayashi(Department of Geology, Faculty of Science, Niigata University), Takashi Hasegawa(Division of Global Environmental Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University), Chair:Tetsuji Onoue(Earth and Environmental Sciences, Graduate School of Science and Technology, Kumamoto University), Atsushi Matsuoka(Department of Geology, Faculty of Science, Niigata University)

12:00 PM - 12:20 PM

★ [MIS30-12] Molluscs in pelagic realm: general characteristics in morphology and ecology

*Takenori SASAKI1 (1.The University Museum, The University of Tokyo)

Keywords:pelagic realm, Mollusca

Molluscs are the most thriving living animals in the ocean, and their fossil records are rich and continuous from the Cambrian to Holocene. The majority of molluscan groups are benthic, but part of them have adapted to a planktonic or pelagic life. Notable examples include pteropods, heteropods, janthiniids and several genera of nudibranchs in gastropods. In cephalopods, many species are pelagic or actively swim. These non-benthic molluscs segregate their habitats from the epipelagic to abyssopelagic zones, and a large number of species are known to migrate vertically. Their life habit is regulated by numerous environmental factors such as light, nutrients, temperature and water pressure. A specialized mode of life often has severe constraints in morphological diversity: species in pelagic realm are characterized by a thin-shelled or shelless body, a limited spectrum of coloration, sensitivity to illumination, and buoyancy control. These general characteristics are manifested particularly by comparison with those of benthic species.