日本初記録のセキトリイワシ科魚類セダカヤジリイワシ（新称）Conocara werneri

抄録

The alepocephalid genus Conocara Goode and Bean, 1896 is characterized by the dorsal-fin origin located posterior to the anal-fin origin, dorsal-fin base shorter than the anal-fin base, body covered with small scales (> 80 in longitudinal row above the lateral line), tubular lateral line scales, the maxilla toothless, upper jaw equal to or longer than the snout, and photophores absent. Six specimens of Conocara werneri Nybelin, 1947, collected from Hyuga-nada Sea, Japan in a depth of 1,453–1,481 m, on 3 April 1991, are distinguished from all congeners by the following combination of characters: 17–20 dorsal-fin rays, 30–34 anal-fin rays, 159–179 longitudinal series scales above the lateral line, 19–22 scales between the dorsal fin insertion and lateral line, 25–32 scales between the anal fin insertion and lateral line, premaxillary bony crests present, the upper jaw reaching a vertical through the orbit anterior margin, an uninterrupted inner row of gill rakers on the first gill arch, the absence of palatine teeth, and raised insertions of the dorsal and anal fins with well-developed anterior cariniform skin folds. The gut contents of the six specimens represented the following higher taxa: Amphipoda, Copepoda, Ostracoda, Gastropoda (conch), Diatoma, Pyrosomata, and Foraminiferida. Four specimens possessed 113–550 developed ovarian eggs (maximum diameter 4.6 mm). Conocara werneri has been recorded previously only from subtropical zones of the eastern Atlantic and off New Zealand (south-western Pacific), the present specimens therefore representing the first record of the species from Japanese waters and northernmost record in the Pacific Ocean. The new standard Japanese name “Sedaka-yajiri-iwashi” is proposed for the species.