A New Genus and Species of Phtisicidae (Crustacea: Amphipoda) from Abyssal Depths in the Japan Trench, with Special Reference to Similarities with Southern Ocean Genera. Issue 4 (1st July 2016)

• Record Type: Journal Article
• Authors: Takeuchi, Ichiro; Tomikawa, Ko; Lindsay, Dhugal
• Is Part Of: Journal of crustacean biology. Volume 36:Issue 4(2016)
• Page Start: 495
• Page End: 506
• Publication Date: 2016-07-01
• Subjects: Antarctic Bottom Water -- cold-seep fauna -- Japan Trench -- new genus -- new species -- taxonomy; Crustacea -- Periodicals; Crustacés -- Périodiques; Crustacea; Periodicals; 595.305
• DOI: 10.1163/1937240X-00002457
• Languages: English
• ISSNs: 0278-0372

Abstract

Abstract: Abyssododecas styx, a new genus and new species of Phtisicidae (Amphipoda), is described based on specimens collected from cold-seep sites at abyssal depths between 5313 and $7322\;{\rm{m}}$ in the Japan Trench, North Pacific, using the crewed submersible Shinkai 6500 and the Remotely-Operated Vehicle Kaiko . This is the deepest yet record of a caprellidean amphipod. While A. styx n. gen., n. sp. looks like a member of Caprellidae, this species can be assigned to Phtisicidae through the possession of a normally articulated pereopod 3 and the lack of a molar on the mandible. The distribution of Phtisicidae along the coast of Japan, including deep-sea habitats, is rather rare, whereas genera of Caprellidae are dominant. Abyssododecas n. gen. is most closely-related to Dodecasella K. H. Barnard, 1931, which is distributed in the Southern Ocean, but differs in possessing a 2-articulated flagellum on antenna 2. The present discovery of Abyssododecas n. gen. from the North Pacific suggests a northward-trending distribution pathway over the ocean floor over geological time into the North Pacific through transport by Antarctic Bottom Water.