Careproctus longidigitus, a new snailfish (Liparidae) from the southern Sea of Okhotsk

Abstract

A new snailfish, Careproctus longidigitus, is described on the basis of four specimens collected off the Shiretoko Peninsula, Hokkaido, Japan. The new species is most similar to C. notosaikaiensis Kai, Ikeguchi, and Nakabo 2011 (Sea of Japan) and C. rausuensis Machi, Nobetsu, and Yabe 2012 (southern Sea of Okhotsk), having similar numbers of dorsal- (50–53 in C. longidigitus vs. 52 and 50–55, respectively) and anal-fin rays (45–47 vs. 46–47 and 45–48, respectively), similar number of vertebrae (58–59 vs. 57–58 and 56–59, respectively), the pectoral fin with a distinct notch, trilobed teeth, chin pores in a single pit, and a moderately sized pelvic disk (disk length: 5.7–6.5% SL vs. 5.6–7.0% SL, 5.7–6.7% SL, respectively). However, the former differs from both in having fewer pectoral-fin rays (28–32 vs. 35–37 and 34–37, respectively), lower 4 or 5 pectoral-fin rays filamentous and nearly completely free of membrane (vs. strongly exserted), and a pale stomach (vs. black stomach). The large sequence divergences in COI between C. longidigitus and C. notosaikaiensis/C. rausuensis (0.093 and 0.080 in uncorrected p-distance, respectively) also support the validity of the new species.