Coelorinchus hubbsi Matsubara, 1936

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 73-74

Coelorinchus hubbsi Matsubara, 1936

[Japanese name: Moyo-hige]

( Figs. 46 , 47A ; Appendix 3-2F)

Coelorhynchus hubbsi Matsubara, 1936:358 , figs. 2–3 [original description; single specimen (whereabouts unknown); type locality: Owase, in 100–200 ftm (183–366 m); new Japanese name: “Moyô-hige”]; Kamohara 1936:934 (listed; Kochi); Okada & Matsubara 1938:450 (in key; Japan); Kamohara 1938:73 (brief description; spec. from Kochi Pref.); Kamohara 1950:276 (listed; Kochi and Wakayama Pref.); Matsubara et al. 1951:42 (listed; Mie Pref.); Kamohara 1952:99 (brief description; spec. from Kochi Pref.); Matsubara 1955:1311, pl. 133, fig. 456 (in key; Japan); Kamohara 1958:73 (listed; Kochi Pref.); Okada et al. 1959:83 (listed; Kumano-nada); Kamohara 1964:95 (listed; Kochi Pref.); Tatara et al. 1965:121 (listed; off Shikoku); Matsubara 1965:505 (compiled; Japan); Okamura 1970a:168, pl. XXXVI, text-fig. 68 (description; biological notes; 118 spec. from Pacific off southern Japan from Choshi to Totoro); Kuroda 1971:56 [listed from Suruga Bay after Okamura (1970a)]; Kataoka & Tomida 1981:78 (listed; Mie Pref.); Tominaga & Uyeno 1981:488 (listed; Japan); Ozawa 1983:13 (listed; off Makurazaki, Kagoshima Pref., East China Sea).

Coelorhynchus (Quincuncia) hubbsi : Okamura 1970b: table 1 (listed; Japan).

Coelorinchus hubbsi : Okamura 1984b:96, pl. 82, fig. L (compiled); Okamura 1988:96, pl. 82, fig. L (compiled); Okamura 1997:126, fig. 5 (compiled); Shao et al. 2008b: table 2 (2 spec. listed from northeastern Taiwan); Nakabo & Kai 2013:507 (in key; Japan); Fukui et al. 2015:182, fig. 10 (1 spec. from off Kuro-shima Island, Kagoshima Pref., East China Sea); Ikeda & Nakabo 2015:321, pl. 68, figs. 1–6 (brief description; spec. from Wakayama Pref.); Iwamoto et al. 2015:57 (brief description; 2 spec. from northeastern Taiwan); Motomura 2020:38 (listed; Japan).

Caelorinchus hubbsi : Nakabo 1993:367 (in key; Japan); Shao 1993:169 (compiled; Taiwan); Suzuki & Kataoka 1997:83, pl. 33, fig. 180 (brief description; 1 spec. from off Owase); Shinohara & Matsuura 1997:290, pl. 2-B (listed; Suruga Bay); Nakabo 2000:431 (in key; Japan); Shinohara et al. 2001:304 (76 spec. listed from Tosa Bay); Nakabo 2002:431 (in key; Japan); Yoda et al. 2002:11 (listed; East China and Yellow Seas); Nakajima 2003:54 (brief description; 1 spec. from Enshu-nada); Shinohara et al. 2005:416 (listed; Ryukyu Islands); Iwatsuki et al. 2017:32 (listed; Hyuga-nada).

Diagnosis. Ventral light organ externally represented by long dark line, terminated with 1 fossa at each end, one immediately anterior to anus, the other on chest just posterior to isthmus (duct connecting each fossa often difficult to distinguish). Underside of head completely naked except along lateral nasal ridges; dorsal surface of snout almost fully scaled, naked clefts only narrowly developed along each side of median rostral ridge. Snout long, sharply pointed, length 72–85% PRL; dorsal profile of snout slightly concave in lateral view; terminal scute long, slender, spearhead-shaped, length 20–27% PRL; distal portion of snout narrowly attenuated when viewed dorsally; lateral nasal ridge incompletely supported by nasal bone. Interdorsal space less than first dorsal-fin base length. Anal fin originating posterior to vertical through second dorsal-fin origin. First dorsal fin high, but second spinous ray not especially elongate, height of fin 85–130% PRL. Second dorsal fin well developed, its rays as long as opposites of anal fin. Anus immediately anterior to anal-fin origin. Premaxillary teeth small, slender, conical in short, uniformly wide band, none especially enlarged; posterior end of tooth band falling far short of lateral corner of mouth. Body scales covered with short, reclined, needle-like spinules in subparallel to slightly divergent rows; spinules in each row overlapping, but free from one another, with last spinule extending well beyond posterior scale margin; buttresses scarcely developed. Orbit diameter 45–52% PRL; postorbital length 47–56% PRL; upper-jaw length 38–43% PRL; preoral length 64–79% PRL; barbel length 13–19% PRL. Transverse scale rows below first dorsal-fin midbase 4–6.5. Spinules on scales anterior to light organ not rudimentary. Longitudinally elongate dark blotch between lateral line and pectoral fin, extending from above pectoral-fin base to below about second dorsalfin origin; narrow dark stripe extending mid-laterally from pectoral-fin base to middle of tail or beyond; scale pockets on dorsal half of body outlined by dark brown; underside of head dark to dusky, heavily peppered; lips pale; oral cavity blackish; gular and branchiostegal membranes dusky to uniformly black; first dorsal fin pale, with large, black, apical blotch; pelvic fin dark, but outermost ray paler distally.

Material examined. 32 specimens. Japan: BSKU 77924 (1, 42.8 mm HL, 178+ mm TL) , BSKU 97993 (1, 59.5 mm HL, 234+ mm TL), south of Muroto , 33.0790ºN, 134.1645ºE, 414–513 m, R/ V Tansei-maru, cr. KT-05-29, sta. K-500, beam trawl, coll. H. Endo et al., 17 Nov. 2005 ; BSKU 97985 (1, 54.9 mm HL, 232+ mm TL) , BSKU 97988 (1, 49.4 mm HL, 188+ mm TL), Tosa Bay , 300 m, FRV Kotaka-maru, otter trawl, 16 Jul. 1997 ; BSKU 42505 (1, 53.9 mm HL, 216+ mm TL) , BSKU 42509 (1, 28.8 mm HL, 120+ mm TL), Tosa Bay , FRV Kotakamaru, otter trawl, 14 Jan. 1986 ; * BSKU 74229 (1, ca. 18 mm HL, 78+ mm TL), Mimase fish market, bottom trawl, 14 Feb. 2005 ; BSKU 99355 (1, 47.9 mm HL, 193+ mm TL), Mimase fish market, bottom trawl, 11 Jan. 2007 ; BSKU 75645 (1, 34.0 mm HL, 131+ mm TL), Mimase fish market, bottom trawl, 15 Dec. 2004 ; BSKU 57945 (1, 44.9 mm HL, 187+ mm TL), Mimase fish market, bottom trawl, 17 Mar. 2002 ; BSKU 72793 (1, 57.5 mm HL, 238 mm TL), Mimase fish market, bottom trawl, 20 Feb. 2004 ; BSKU 99468 (1, 53.5 mm HL, 216+ mm TL), Mimase fish market, bottom trawl, 26 Mar. 2005 ; BSKU 99302 (1, 34.9 mm HL, 138+ mm TL), Mimase fish market, bottom trawl, 8 Apr. 2007 ; BSKU 99300 (1, 27.1 mm HL, 110+ mm TL), Mimase fish market, bottom trawl, coll. N. Nakayama, 8 Apr. 2007 ; BSKU 94810 (1, 40.2 mm HL, 161+ mm TL), Mimase fish market, F/ V Kosei-maru, bottom trawl, 28 Nov. 2007 ; BSKU 92269 (1, 40.8 mm HL, 169+ mm TL), Mimase fish market, F/ V Kosei-maru, bottom trawl, coll. N. Nakayama, 9 Nov. 2007 ; BSKU 99283 (1, 43.4 mm HL, 178+ mm TL), Mimase fish market, F/ V Seiryo-maru, bottom trawl, coll. N. Nakayama, 14 Nov. 2007 ; * BSKU 95378 (1, 54.0 mm HL, 195+ mm TL), Mimase fish market, F/ V Seiryomaru, bottom trawl, coll. N. Nakayama, 12 Mar. 2008 ; BSKU 97967 (1, 51.9 mm HL, 210+ mm TL) , BSKU 97968 (1, 52.4 mm HL, 216+ mm TL) , BSKU 97969 (1, 56.1 mm HL, 232+ mm TL) , BSKU 97970 (1, 60.3 mm HL, 231+ mm TL) , BSKU 97974 (1, 61.6 mm HL, 244+ mm TL) , BSKU 97975 (1, 57.3 mm HL, 243+ mm TL) , BSKU 97978 (1, 54.4 mm HL, 226 mm TL), Tosa Bay , 33.1412ºN, 133.5388ºE, 295–336 m, FRV Kotakamaru, otter trawl, 18 Jul. 1988 ; BSKU 113676 (1, 46.0 mm HL, 182+ mm TL) , BSKU 113677 (1, 51.0 mm HL, 215+ mm TL) , BSKU 113679 (1, 52.4 mm HL, 200+ mm TL) , BSKU 113680 (1, 48.4 mm HL, 199 mm TL) , BSKU 113681 (1, 43.7 mm HL, 174+ mm TL) , BSKU 113685 (1, 44.4 mm HL, 184+ mm TL), off Okitsu , Tosa Bay, 280–320 m, F/ V Kosei-maru, bottom trawl, coll. N. Nakayama et al., 24 Jan. 2014 ; BSKU 110077 (1, 55.3 mm HL, 221+ mm TL), Suruga Bay , 34.7481ºN, 138.4652ºE, 243–424 m, F/ V Hinode-maru, sta. 3, bottom trawl, coll. N. Nakayama and R. Misawa, 23 Apr. 2013 .

Counts and measurements. Based on 30 specimens (27.1–61.6 mm HL, 110+–244+ mm TL). Counts: first dorsal-fin rays II,8–9; pectoral-fin rays i15–i19; pelvicfin rays 7; gill rakers on first arch (outer/inner) 0/8–9, on second arch 5–7/8–9; longitudinal scales 30–38; transverse scale rows below first dorsal-fin origin 5.5–8, below first dorsal-fin midbase 4–6.5, below second dorsal-fin origin 5–7, above anal-fin origin 13.5–19.

The following measurements are in % of HL, followed by those in % of PRL in parentheses: snout length 42–46 (72–85); orbit diameter 25–30 (45–52); postorbital length 27–31 (47–56); postrostral length 54– 59; orbit–preopercle distance 28–31 (49–54); suborbital width 11–14 (21–24); upper-jaw length 21–25 (38–43); length of rictus 16–19 (28–34); length of premaxillary tooth band 7–11 (13–20); preoral length 37–43 (64–79); length of terminal snout scute 11–15 (20–27); length of lateral nasal ridge 29–34 (50–62); length of suborbital ridge 91–96 (157–174); snout width 25–30 (43–52); internasal width 17–23 (31–39); interorbital width 20–24 (36–42); occipital width 9–12 (15–20); body width over pectoral-fin bases 33–48 (58–85); body depth at first dorsal-fin origin 40–54 (69–95); body depth at anal-fin origin 31–44 (53–77); prepelvic length 100–113 (174– 201); preanus length 137–158 (238–278); preanal length 139–160 (243–285); isthmus–pelvic distance 25–33 (43– 56); isthmus–anus distance 62–80 (108–143); isthmusanal distance 66–85 (114–152); pelvic–anal distance 41– 58 (72–103); anus–anal distance 2–6 (3–10); pelvic-fin length 33–46 (59–79); pectoral-fin length 39–44 (67–76); predorsal length 107–113 (185–202); height of first dorsal fin 48–71 (85–130); length of first dorsal-fin base 16–22 (29–39); interdorsal length 8–14 (14–25); length of gill slit 10–14 (18–23); length of posterior nostril 6–9 (11– 16); barbel length 7–11 (13–19).

Size. To about 26 cm TL ( FRLM 8636, 255+ mm TL, Owase, Japan).

Distribution. Restricted to Japan and Taiwan (Appendix 3-2F). Known from the Pacific off southern Japan from Hitachi (36.60ºN; Ibaraki Pref.) southward to Cape Ashizurimisaki (133.02ºE), off the Izu Islands, and the East and South China Seas off Taiwan, at depths of 240–555 m ( Chiou et al. 2004b; Shao et al. 2008b; this study). Common on the upper continental slope off the Pacific coasts of southern Japan, but rare in the east of the Boso Peninsula (139.89ºE) as well as in Taiwan.

Remarks. Coelorinchus hubbsi was originally described from a single male specimen (224 mm TL) collected from off Owase, Mie Pref., Japan. In the original description of this species, Matsubara (1936) indicated neither the catalog number of the holotype nor the whereabouts of the specimen. Unfortunately, the holotype is presumed to be destroyed during WWII (see also the Comments on holotype of C. hige ).

For a full description see Okamura (1970a). Coelorinchus hubbsi is moderately common in the Pacific off southern Japan, with a great abundance in Tosa Bay (author’s pers. observ.). It is also known from the Senkaku Islands, off northwestern Taiwan (Iwamoto et al. 2015). Surprisingly, despite intensive collecting efforts, no specimens of this species have been obtained in the East China Sea by Japanese researchers (e.g., Okamura & Kitajima 1984; Okamura 1985; Yamada 1986; Yamada et al. 2007; Shinohara et al. 2005; Furuhashi et al. 2010).

Relationships and comparisons. Coelorinchus hubbsi is a distinctive species of the C. hubbsi group (see the Relationships of C. brevirostris ), and unlikely to be confused with any other congeners except when young. Its characteristic dark stripes on the body ( Fig. 46A ) readily distinguish the species from the other species of the C. hubbsi group. In young specimens of C. hubbsi , the horizontal stripes are less pronounced, whereas the saddles are more or less distinct ( Fig. 46D ). These features may lead to an erroneous identification of the species as C. matsubarai Okamura, 1982 . However, the pectoral blotch of young C. matsubarai is circular and not elongated horizontally, as seen in adults of the species ( Fig. 70 ).

Figures

FIGURE 46. Fresh specimens of Coelorinchus hubbsi collected from the Mimase fish market, Kochi Pref., Pacific. (A–C) BSKU 95378, 54.0 mm HL, 195+ mm TL; (D) BSKU 74229, ca. 18 mm HL, 78+ mm TL. (A, D) Lateral views; (B) dorsal and (C) ventral views of the head and trunk. [Photos: N. Nakayama]

FIGURE 47. Scanning electron micrographs showing body scales (from the dorsum below the interdorsal space) of two species of the Coelorinchus hubbsi group. (A) C. hubbsi, BSKU 97970, 60.3 mm HL; (B) C. matsubarai, BSKU 32226, paratype, 75.5 mm HL. Views from above. [Photos: N. Nakayama]

FIGURE 70. Fresh specimens of Coelorinchus matsubarai. (A) ZMUT unknown, Kyushu-Palau Ridge, Pacific; (B) BSKU 29440, holotype, 86.6 mm HL, 308+ mm TL, Kyushu-Palau Ridge, Pacific, 550–600 m depth. Lateral views. [Photos: (A) ZMUT; (B) BSKU]