Mataeocephalus (Hyostomus) hyostomus (Smith and Radcliffe, 1912)

Figures 17A–B.

Macrourus hyostomus Smith and Radcliffe in Radcliffe, 1912:121–122, pl. 27, fig. 1 (holotype, 280 mm TL, USNM 72938, Lagonoy Gulf, Luzon I., Philippines; Albatross sta. 5470, 560 fm [1024 m]; paratypes from Sibuku Bay, Borneo, 750 m, and Buton Strait, Celebes, 1022 m).

Coryphaenoides (Hyomacrurus) hyostomus: Gilbert and Hubbs, 1920:422–424 (redescription of types; described new subgenus Hyomacrurus).

Hyomacrurus hyostomus: Marshall, 1973:565 (listed).

Mataeocephalus (Hyomacrurus) hyostomus: Sazonov et al., 2003:294–296, fig. 6 (7 spec. [including holotype], 36.5–65.5 HL, 160+–283 TL; Philippines, 760–1100 m).— Shao et al., 2008: table 2 (2 spec., Taiwan [SWT, SCS], 227–1040 m; first record from Taiwan).

MATERIAL EXAMINED (2 spec.).— SCS: ASIZP 65541 (1, 180+ TL), CD 142, 227– 335 m; ASIZP 65550 (1, 220 TL), CD 134, 736– 1040 m .

DISTINGUISHING FEATURES.— BR 6; P i16–i20; V 7–8; inner GR-I 5–8; scales below mid-1D 5.0–7.5; pyl. caeca 8–13. Snout 30–36% HL; orbit 22–25%; interorbital 22–26%; orbit to angle of preopercle 40–44%. Snout broad, moderately pointed and protruding; upper jaws extend posteriorly to below posterior 1 ⁄ 4 to 1 ⁄ 3 of orbit; spinous second ray of 1D weakly serrated near base, prolonged, 1.5 or more times HL; body scales densely covered with slender, slightly flattened, reclined spinules in somewhat convergent to divergent rows; underside of head almost fully scaled; window of light organ scarcely discernible from exterior; periproct relatively moderate in size, situated between V and A but closer to former. Attains at least 283 mm TL. (Adapted from Sazonov et al. 2003.)

DISTRIBUTION.— Known only from the Philippines, Indonesia, and Taiwan in 227–1100 m.

REMARKS.— Our two specimens collected in the South China Sea in 227–1040 m were first recorded from Taiwan and the South China Sea by Shao et al. (2008: table 2). Mataeocephalus hyostomus is closely similar to M. kotlyari Sazonov, Shcherbachev, and Iwamoto, 2003, which is found in the sw. Pacific, but M. hyostomus has more pyl. caeca (16–19 cf. 8–13 in M. kotlyari), V 7, rarely 6 vs. 7–8, rarely 9, and shorter 1D (88–119% HL vs. 124–295%).