Malacocephalus Günther, 1862

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 238-239

Genus Malacocephalus Günther, 1862

[Japanese name: Manjudara-zoku]

Malacocephalus G̹nther, 1862:396 (type species: Macrourus laevis Lowe, 1843 , by original designation).

Pawnurus Parr, 1946:27 (as subgenus of Malacocephalus ; type species: Malacocephalus occidentalis Goode & Bean, 1885 , by original designation) Diagnosis. Anus closer to pelvic-fin bases than to anal-fin origin; periproct moderately broad; 2 dermal windows of light organ, one small, immediately anterior to anus, the other large, between pelvic-fin bases. Infraorbital ridge not connected with preopercular ridge, separated by distinct gap. Leading edge of second spinous ray of first dorsal fin smooth or serrated. Chin barbel well developed. Teeth in 2 rows or narrow broad in upper jaw, with outer series greatly enlarged; lower jaw teeth arranged in uniserial row. Body scales covered with long, erect, needle-like spinules in quincunx order; buttresses of spinules scarcely developed; reticulate structure absent. Grooved lateral line present. Cephalic sensory canals lacking open pores. Pyloric caeca numerous, about 50–100. Branchiostegal rays 7. Body gray to swarthy, with silvery reflection when fresh. [Modified from Sazonov & Iwamoto (1992), Iwamoto & Merrett (1997), and Iwamoto & Graham (2001).]

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Malacocephalus nipponensis Gilbert & Hubbs, 1916

[Japanese name: Nihon-manjudara]

( Figs. 160–162 ; Appendix 3-9F)

Malacocephalus nipponensis Gilbert & Hubbs, 1916:189 , pl. 9, fig. 2 [original description; holotype: USNM 76866, from “off the east coast of central Hondo” (off Cape Shionomisaki), Albatross sta. 4967, in 244–253 ftm (447–463 m)]; Okada & Matsubara 1938:452, pl. 111, fig. 1 (in key; Japan; new Japanese name: “Nihon-manju-dara”); Kamohara 1938:72 (brief description; 9 spec. from Kochi Pref.; new Japanese name: “Bôzu-dara”); Kamohara 1950:279 (listed; Kochi and Wakayama Pref.); Kamohara 1952:98 (selected counts and measurements; spec. from Kochi Pref.); Matsubara 1955:1315 (in key; Japan); Kamohara 1958:74 (listed; Kochi Pref.); Kamohara 1964:96 (listed; Kochi Pref.); Okamura 1982:145, 347, fig. 88 (brief description; 1 spec. from Tosa Bay; BSKU 29516); Okamura 1984a:203, 360, fig. 145 (brief description; 18 spec. from Okinawa Trough; photo based on BSKU 29587); Okamura 1984b:93, pl. 80, fig. J (compiled); Okamura 1988:93, pl. 80, fig. J (compiled); Nakabo 1993:356 (in key; Japan); Okamura 1997:128, fig. 6 (compiled); Nakabo 2000:420 (in key; Japan); Shinohara et al. 2001:306 (listed; Tosa Bay); Nakabo 2002:420 (in key; Japan); Yoda et al. 2002:11 (listed; East China and Yellow Seas); Shinohara et al. 2005:418 (listed; Ryukyu Islands); Shao et al. 2008b: table 2 (2 spec. listed from South China Sea; first record from Taiwan); Nakabo & Kai 2013:496 (in key; Japan); Ikeda & Nakabo 2015:319, pl. 65, figs. 1–5 (brief description; spec. from Wakayama Pref.); Iwamoto et al. 2015:86 (brief description; 20 spec. from northeastern and southwestern Taiwan, and South China Sea); Iwatsuki et al. 2017:32 (listed; Hyuga-nada).

Remarks. According to Iwamoto (1990), Malacocephalus comprises two subgenera: Malacocephalus and Pawnurus Parr, 1946 . The subgenus Malacocephalus includes four nominal species, viz., M. hawaiiensis Gilbert, 1905 confined to Hawaii; M. luzonensis Gilbert & Hubbs, 1920 so far known only from the Philippines; M. nipponensis Gilbert & Hubbs, 1916 recorded from Japan and Taiwan; and M. laevis ( Lowe, 1843) widespread in tropical and temperate waters of the world’s oceans (see also the Remarks of M. nipponensis ). On the other hand, the subgenus Pawnurus includes three valid species: M. boretzi Sazonov, 1985 endemic to the Emperor Seamounts; M. occidentalis Goode & Bean, 1885 distributed in both sides of the Atlantic; and M. okamurai Iwamoto & Arai, 1987 known only from the Atlantic coast of South America.

Figures

FIGURE 160. Fresh specimens of Malacocephalus nipponensis. (A) BSKU 112433, 46.3 mm HL, 274+ mm TL, Tosa Bay off Susaki, Kochi Pref., Pacific, 320–380 m depth; (B–D) BSKU 112450, 70.9 mm HL, 415+ mm TL, collected with BSKU 112433. (A–B) Lateral views; (C) dorsal and (D) ventral views of the head and trunk. [Photos: N. Nakayama]

FIGURE 161. Holotype of Malacocephalus nipponensis. USNM 76866, 69.1 mm HL, 400+ mm TL, off Cape Shionomisaki, Wakayama Pref., Pacific, 447–463 m depth. (A) Lateral view; (B) dorsal and (C) ventral views of the head and trunk. Preserved condition. [Photos: N. Nakayama]

FIGURE162.Scanningelectronmicrographsshowingabodyscale(fromthedorsumbelowtheinterdorsal space)ofMalacocephalus nipponensis. BSKU 13317, 65.3 mm HL. (A) View from above; (B) oblique view. [Photos: N. Nakayama]