著者

金子 奈都美 窪寺 恒己

出版者

日本動物分類学会

雑誌

タクサ:日本動物分類学会誌 (ISSN:13422367)

巻号頁・発行日

vol.22, pp.38-43, 2007-02-20 (Released:2018-03-30)

参考文献数

14

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Specimens of two small octopus species collected from intertidal waters of the Ryukyus were identified as species of Abdopus, based on the following combination of characters: small to medium body (<70mm ML) with long arms (>4×ML), arm autotomy, number of gill lamellae (6-7 per demibranch), enlarged suckers on second and third arms of male, hectocotilized arm with small ligula (<2.3% of hectocotylized arm), and highly sculptured skin. Two specimens collected at Oku and Sesoko, northern parts of Okinawa Island were identified as A. abaculus due to the presence of large circular white spots on dorsal mantle and dorsal arm surfaces. Four specimens collected from Awase at Okinawa Island, Kabira at Ishigaki Island, and Nakano at Iriomote Island were identified as A. aculeatus by their brownish yellow body color, comparatively large body (37.7-51.0mm), long arms (6-9×ML), and highly sculptured skin with primary papillae on dorsal mantle and above eyes. Abdopus aculeatus had been confused with Octopus oliveri in the Japanese literature. These two species were distinguished by arm length (<5×ML in O. oliveri), number of gill lamellae (7-8 in O. oliveri), body color (dark purple in O. oliveri), presence of papillae above the eyes (absent in O. oliveri), and shape of penis (V-shape in O. oliveri versus linear in A. aculeatus). These specimens are the first records of Abdopus from Japanese waters as well as the northern-most records for both species.