Malacocephalus nipponensis Gilbert and Hubbs, 1916

Iwamoto, Tomio, Nakayama, Naohide, Shao, Kwang-Tsao & Table, Hsuan-Ching Ho, 2015, Synopsis of the Grenadier Fishes (Gadiformes; Teleostei) of Taiwan, Proceedings of the California Academy of Sciences 62 (3), pp. 31-126 : 86-87

Malacocephalus nipponensis Gilbert and Hubbs, 1916

Malacocephalus nipponensis Gilbert and Hubbs, 1916:189–191 , pl. 9, fig. 2 (holotype, USNM 76866, 460 mm TL; e. coast Japan, Albatross st. 4967, 244–253 fm [446–463 m].— Okamura in Okamura et al., 1982:145, 347, fig. 88 (p. 144) (1 spec., 472 mm TL, Kyushu-Palau Ridge, 453 m).— Okamura in Masuda et al., 1984:94, pl. 80–J (compiled).— Okamura in Okamura et al., 1984:144, 360, fig. 145 (p. 202) (18 spec., 270–480 mm TL, East China Sea [Okinawa Trough], 420–550 m).— Shen et al., 1993:172 (descr.).— Chiou et al., 2004b:37, 47 (in key, list).— Shao et al., 2008: table 2 (2 spec., Taiwan [ SCS], 979–1268 m, first record for Taiwan).

Malacocephalus laevis : Okamura, 1970:69–73, pl. IV, text-fig. 29–31(56 spec., 255–520 mm TL; Pacific coast of s. Japan, 350–500 m).— Shao et al., 2008: table 2 (9 spec., NET, ET, SWT).

MATERIAL EXAMINED (20 spec.).— NET: ASIZP 60015 (1, 445 TL), Da-xi ; ASIZP 61312 (1, 336 TL; Nan-fang-ao ; ASIZP 61313 (3, 184–252 TL), Nan-fang-ao ; ASIZP 65517 (1, 68 HL, 405 TL), CD 210 ; ASIZP 70229 (1, 287 TL), Da-xi . SWT: ASIZP 61314 (1, 172 TL), Dong-gang ; ASIZP 62331 (2, 250+-305+ TL), Fong-gang , 200 m ; ASIZP 65517 (1, 405 TL), CD 210, 445– 1185 m ; ASIZP 65597 (2, 360–370 TL), CD 137, 316– 477 m ; ASIZP 70615 (1, 196 TL), Dong-gang ). SCS: ASIZP 58031 (2, 361–389 TL), Tong-sa Islands ); ASIZP 66277 (1, 220+ TL), OCP 312, 517 m ; ASIZP 66745 (1, 178+ TL), CP 314, 506 m ; FRIP 0669 (1, 302 TL) , FRI, 630 m ; NMMSTP 0907 (1, 290+ TL), Tong-sha Islands , 515 m.

DISTINGUISHING FEATURES.— 1D II,10–14; P i16–i22; V 9 (8–10); inner GR-I 2–4+7–9; pyl. caeca 107–130. Snout 23–28%; orbit 29–37%; suborbital 11–14%; interorbital 26–31%; orbit-preopercle 42–50%; upper jaw 45–56%; barbel 18–22%. Snout bluntly pointed; mouth large, upper jaw extends to below hind margin of orbit; orbit large, greater than snout length; suborbital region vertical and smoothly curved; gill openings wide, extend forward to under posterior margin of orbit. Scales small, beset with fine, slender spinules; scales uniformly and smoothly cover head and body; no coarsely modified scales on ridges of head or tip of snout, lower branchiostegal rays scaled, but gular membrane naked. Light organ with anterior dermal window relatively small and round, situated between or slightly anterior to V bases; periproct enclosing posterior dermal window and urogenital openings located between V fins, far removed from A origin. Coloration gray to swarthy with silvery sides, blackish ventrally on head and over abdomen; fins dark dusky to black. Attains> 520 mm TL. (Mostly after Okamura 1970 and from Taiwan specimens.)

DISTRIBUTION.— Pacific coast of s. Japan, East China Sea [Okinawa Trough], Kyushu-Palau Ridge, and Taiwan off ne., sw. coast and in South China Sea in 316–1185 m.

REMARKS.— Malacocephalus nipponensis was first synonymized into M. laevis Lowe, 1843 by Okamura (1970), but later (Okamura in Okamura and Kitajima 1982; Okamura in Okamura et al. 1984) considered it a valid species based on the absence of scales on the gular membrane (usually present in M. laevis ) and the small round anterior dermal window (bean-shaped in M. laevis ). Iwamoto (1979:149) suggested that M. laevis , M. nipponensis , and M. hawaiiensis Gilbert, 1905 may eventually prove to be the same. Although specimens of this species are available in many collections around the world, no one has yet to comprehensively study these collections. A molecular study may prove the easiest and the most-effective approach to resolving this question of how many species are involved in this clade. We have taken a conservative approach and treat these northwestern Pacific specimens as M. nipponensis , following Okamura.