New records of the abyssal grenadiersCoryphaenoides armatus andC. yaquinae from the western North Pacific

Abstract

The abyssal grenadier, Coryphaenoides armatus, was first described by Hector (1875) from off New Zealand at a depth of 400 fathoms (732 m). It is known as the only cosmopolitan rattail recorded from all oceans except the Arctic (e.g., Grey, 1956; Nybelin, 1957). C. yaquinae is very closely related to C. armatus, and was confused with the latter in the eastern North Pacific until Iwamoto and Stein (1974) described it as a new species. Wilson and Waples (1983, 1984) discussed in detail the distribution, depth range, morphology, ecology, biochemical genetics and nomenclature of the two species. Both have been recorded from the Pacific Ocean except in the northwestern area. C. arrnatus is distributed vertically at depths of about 2000-4300 m and C. yaquinae at about 3400-5800m (Wilson and Waples, 1983). Our material agrees well with the descriptions of Iwamoto and Stein (1974). These are the first records of C. armatus (new Japanese name: Yoroidara) and C. yaquinae (new Japanese name: Shinkaiyoroi-dara) from the western North Pacific around the Japan trench. Moreover, the capture depth of 6380-6450m for C. yaquinae is the deepest record for a macrourid. Methods for taking meristic and morphometric data follow Hubbs and Lagler (1958) and Okamura (1970) except for the pelvic fin ray counts (i.e., total number of both sides) which follow Wilson and Waples (1984). Institutional abbreviations follow Leviton et al. (1985).