Coelorinchus jordani Smith & Pope, 1906, 1984

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 84-87

Coelorinchus jordani Smith & Pope, 1906

[Japanese name: Kyushu-hige]

( Figs. 55–56 , 57 A–B; Appendix 3-3B)

[?] Coelorhynchus australi s (not Richardson 1893): Ishikawa & Matsuura 1897:26 [listed; spec. from Awa (= Chiba Pref.)]; Jordan & Snyder 1901:120 (listed; Japan; local name: “Hige”).

Coelorhynchus jordani Smith & Pope, 1906:494 , fig. 11 (original description; holotype: USNM 55609, from Kagoshima); Jordan et al. 1913:419, fig. 389 (listed; Japan; new Japanese name: “Kiusiu-hige”); Gilbert & Hubbs 1916:173 (supplementary description; 24 spec. from Kagoshima market, East China Sea, and Kagoshima Bay; comparison with C. kishinouyei ); Schmidt 1931:156 (brief description; 11 spec. from Kagoshima); Okada & Matsubara 1938:450 (in key; Japan); Kamohara 1950:277 (listed; Kochi and Wakayama Pref.); Kamohara 1952:99 (spec.from Kochi Pref.); Matsubara 1955:1310 (in key; Japan); Kamohara 1958:73 (listed; Kochi Pref.); Kamohara 1964:95 (listed; Kochi Pref.); Okamura 1970a:175 (description; 31 spec. from Pacific off southern Japan from Suruga Bay to Mimase); Kuroda 1971:56 [listed from Suruga Bay after Okamura (1970a)]; Tominaga & Uyeno 1981:488 (listed; Japan); Ozawa 1983:13 (listed; off Makurazaki, Kagoshima Pref., East China Sea).

Coelorhynchus (Paramacrurus) jordani : Okamura 1970b: table 1 (listed; Japan).

Coelorinchus jordani : Yatou 1984:229, 367, fig. 162 [brief description; 10 spec. from Okinawa Trough; photo based on BSKU 37574 (from Kagoshima Bay)]; Okamura 1984b:96, pl. 83, fig. B (compiled); Yamada 1986:101 (brief description; East China Sea); Okamura 1988:96, pl. 83, fig. B (compiled); Okamura 1997:126, fig. 10 (compiled); Nakabo & Kai 2013:508 (in key; Japan); Iwatsubo & Motomura 2017:59, unnumbered fig. (listed; Kagoshima Bay); Motomura 2020:38 (listed; Japan).

Caelorinchus jordani : Nakabo 1993:368 (in key; Japan); Shinohara & Matsuura 1997:290 (listed; Suruga Bay); Nakabo 2000:432 (in key; Japan); Shinohara et al. 2001:305 (listed; Tosa Bay); Nakabo 2002:432 (in key; Japan); Yoda et al. 2002:11 (listed; East China and Yellow Seas); Shinohara et al. 2005:416 (listed; Ryukyu Islands); Yamada et al. 2007:315, pl. 14, fig. 6 (brief description; 1 spec.; East China Sea; biological notes); Furuhashi et al. 2010: table 2 (1 spec. listed from northern Okinawa Trough); Iwatsuki et al. 2017:32 (listed; Hyuga-nada).

Diagnosis. Light organ moderately long, externally represented by narrow black streak immediately anterior to anus (covered with scales), its anterior margin extending forward to line connecting outer pelvic-fin bases, but falling far short of isthmus. Underside completely naked; dorsal surface of snout posterior to lateral nasal ridges broadly naked. Snout moderately long, length 51–65% PRL, its dorsal profile slightly concave in lateral view; terminal scute small but broad, dorsoventrally flattened; lateral nasal ridge completely supported by nasal bone, broadly convex in dorsal view. Length of chin barbel 12– 19% PRL. Anus separated from anal-fin origin by several scale rows. Premaxillary teeth small, conical, arranged in short, uniformly wide band, none especially enlarged; posterior margin of tooth band falling far short of lateral corner of mouth. Body scales covered with short, greatly reclined, needle-like spinules in tightly packed parallel rows; spinules in each row greatly overlapping, but free from one another; buttresses absent.Body silvery white but darker dorsally; small dorsoventrally elongate dark spot between lateral line and pectoral-fin base (occasionally absent or indistinct); lips and oral cavity whitish; gular membrane prominently blackish; chest mostly pale; anal fin pale except for dark anterior margin.

Material examined. 31 specimens. Holotype of Coelorhynchus jordani: USNM 55609 (39.5 mm HL, 172+ mm TL), Kagoshima, Kagoshima Pref., Japan , coll. H.M. Smith, 16 Jun. 1903. Non-types : Japan: BSKU 37574 (1, 44.7 mm HL, 207+ mm TL), BSKU 37579 (1, 39.8 mm HL, 189 mm TL), off Furue , Kagoshima Bay , 13 Oct. 1982 ; BSKU 47208 (1, 52.7 mm HL, 222+ mm TL), off Ibusuki , Kagoshima Bay , 190 m, 24 May 1989 ; BSKU 50884 (1, 46.7 mm HL, 205+ mm TL), off Nomaike , Kagoshima, East China Sea , F / V Maruko-maru, bottom trawl, coll. M. Yamashita and Y. Ohashi, 10 Sept. 2010 ; BSKU 109023 (1, 38.7 mm HL, 181+ mm TL), BSKU 109024 (1, 34.9 mm HL, 160+ mm TL), BSKU 109027 (1, 27.8 mm HL, 107+ mm TL), BSKU 109042 (1, 42.0 mm HL, 208+ mm TL), east of Kasayama Bank , 32.3884ºN, 129.0505ºE, 304–312 m, T/ V Nagasaki-maru, cr. N365, sta. A3, 3-m ORE beam trawl, coll. N. Nakayama, 19 Nov. 2012 ; BSKU 27725 (1, 48.3 mm HL, 181+ mm TL), north-northwest of Okinawa Island, Okinawa Trough, 28.5000ºN, 127.0000ºE, 225–235 m, F/ V Ryoan-maru, No. 28, tr. 51, bottom trawl, coll. Y. Kinoshita and S. Hagino, 12 Mar. 1978 ; BSKU 92878 (1, 57.1 mm HL, 241+ mm TL), off Kannoura, Mimase fish market, F/ V Kosei-maru, bottom trawl, 9 Dec. 2007 ; BSKU 91920 (1, 44.3 mm HL, 227+ mm TL), Mimase fish market, bottom trawl, coll. N. Nakayama, 29 Oct. 2007 ; BSKU 99349 (1, 50.8 mm HL, 230+ mm TL), BSKU 99350 (1, 59.2 mm HL, 247+ mm TL), Mimase fish market, F/ V Koseimaru, bottom trawl, coll. N. Nakayama, 9 Dec. 2007 ; BSKU 87825 (1, 41.8 mm HL, 204+ mm TL), Mimase fish market, bottom trawl, 14 Jan. 2004 ; BSKU 51770 (1, 53.9 mm HL, 242+ mm TL), BSKU 51772 (1, 64.3 mm HL, 279+ mm TL), Mimase fish market, bottom trawl, 18 Nov. 1999 ; BSKU 68922 (1, 55.5 mm HL, 274+ mm TL), Mimase fish market, bottom trawl, 20 Jan. 2004 ; BSKU 54045 (1, 51.7 mm HL, 217+ mm TL), Mimase fish market, bottom trawl, 4 Sept. 1999 ; BSKU 36133 (1, 48.8 mm HL, 252+ mm TL), Mimase fish market, bottom trawl, 5 Dec. 1981 ; BSKU 58380 (1, 55.3 mm HL, 252+ mm TL), Mimase fish market, bottom trawl, 6 Dec. 2001 ; BSKU 89341 (1, 50.0 mm HL, 222+ mm TL), BSKU 99357 (1, 47.2 mm HL, 193+ mm TL), Mimase fish market, bottom trawl, coll. N. Nakayama, 11 Jan. 2007 ; BSKU 76501 (1, 46.2 mm HL, 227+ mm TL), Mimase fish market, bottom trawl, coll. N. Nakayama, 30 Nov. 2005 ; BSKU 112513 (1, 54.1 mm HL, 238+ mm TL), off Okitsu, Tosa Bay, 380 m, F/ V Kosei-maru, bottom trawl, coll. N. Nakayama et al., 11 Mar. 2014 ; * BSKU 101167 (1, 56.2 mm HL, 275+ mm TL), Mimase fish market, F/ V Kosei-maru, bottom trawl, coll. N. Nakayama, 5 Nov. 2009 ; BSKU 110421 (1, 32.5 mm HL, 166 mm TL), Suruga Bay, 34.7651ºN, 138.4880ºE, 200–450 m, F/ V Hinode-maru, sta. 4, bottom trawl, coll. N. Nakayama and R. Misawa, 23 Apr. 2013 ; BSKU 111216 (1, 68.2 mm HL, 281+ mm TL), BSKU 111219 (1, 57.1 mm HL, 223+ mm TL), BSKU 111222 (1, 61.6 mm HL, 298+ mm TL), BSKU 111224 (1, 55.0 mm HL, 269+ mm TL), Isshiki fish market, coll. S. Ohashi, 14 Feb. 2010.

Counts and measurements. Based on 30 specimens (27.8–68.2 mm HL, 107+–298+ mm TL). Counts: first dorsal-fin rays II,8–10; pectoral-fin rays i13–i17; pelvicfin rays 7–8; gill rakers on first arch (outer/inner) 0/8– 10, on second arch 6–8/7–9; longitudinal scales 27–37; transverse scale rows below first dorsal-fin origin 4.5–6, below first dorsal-fin midbase 3.5–5, below second dorsal-fin origin 3.5–5, above anal-fin origin 11.5–17.

The following measurements are in % of HL, followed by those in % of PRL in parentheses: snout length 34–40 (51–65); orbit diameter 29–36 (46–56); postorbital length 30–36 (46–55); postrostral length 61–67; orbitpreopercle distance 36–41 (56–66); suborbital width 12– 15 (19–22); upper-jaw length 24–29 (36–43); length of rictus 18–23 (28–34); length of premaxillary tooth band 10–13 (16–20); preoral length 28–38 (41–59); length of terminal snout scute 4–8 (7–12); length of lateral nasal ridge 24–28 (35–46); length of suborbital ridge 90–100 (134–162); snout width 28–32 (43–50); internasal width 17–21 (27–33);interorbital width19–23 (30–36); occipital width 10–12 (15–19); body width over pectoral-fin bases 37–53 (59–79); body depth at first dorsal-fin origin 54–72 (83–115); body depth at anal-fin origin 42–67 (65–102); prepelvic length 106–117 (163–186); preanus length 128–148 (200–235); preanal length 136–160 (211–254); isthmus–pelvic distance 30–41 (47–65); isthmus–anus distance 50–70 (77–111); isthmus–anal distance 56–84 (87–133); pelvic–anal distance 29–47 (46–75); anus–anal distance 7–16 (11–25); pelvic-fin length 37–48 (55–78); pectoral-fin length 45–59 (68–87); predorsal length 111– 119 (168–186); height of first dorsal fin 59–79 (93–122); length of first dorsal-fin base 20–27 (31–42); interdorsal length 29–45 (43–74); length of gill slit 11–14 (17–23); length of posterior nostril 8–13 (13–21); barbel length 7–13 (12–19).

Size. To about 32 cm TL ( ZMUT 856, 323+ mm TL, Sagami Bay, Japan).

Development. The early life stages of C. jordani were fully described by Fukui et al. (2010), with a complete series of eggs and larvae.

Distribution. So far known only from the Pacific off southern Japan northward to Hitachi (36.60ºN; Ibaraki Pref.), Kagoshima Bay, and the Okinawa Trough, at depths of 110–550 m (Appendix 3-3B). Common, especially in Kagoshima Bay ( Ohtomi 2006).

Remarks. Coelorinchus jordani was described by Smith & Pope (1906) based on a single specimen collected from Kagoshima Pref., Japan ( Fig. 56 ). This species has been well described by previous authors, and thus does not need repeating here. For further morphological details see the original description ( Smith & Pope 1906) and Okamura (1970a). It is one of the most abundant demersal fishes in Kagoshima Bay ( Ohtomi 2006), but not so in other parts of its range.

Relationships. Coelorinchus jordani is one of 12 species closely related to C. argus Weber, 1913 .According to Iwamoto et al. (2015), this complex also includes: C. dorsalis Gilbert & Hubbs, 1920 ; C. kishinouyei Jordan & Snyder, 1900; C. macrolepis Gilbert & Hubbs, 1920 ; C. maculatus Gilbert & Hubbs, 1920 ; C. notatus Smith & Radcliffe in Radcliffe, 1912; C. sexradiatus Gilbert & Hubbs, 1920 ; C. thurla Iwamoto & Williams, 1999 ; C. triocellatus Gilbert & Hubbs, 1920 ; C. velifer Gilbert & Hubbs, 1920 ; and C. sp. cf. notatus (sensu Iwamoto et al. 2015) . Gilbert & Hubbs (1920) classified most of these species under the subgenus Paramacrurus Bleeker, 1874 . However, this subgenus was originally established with the type species C. australis ( Richardson, 1839) that is now considered a member of the C. fasciatus group as defined by Iwamoto & Graham (2008). Therefore, the complex is called here the C. argus group, which is defined by the following combination of features: light organ moderately long, extending to or slightly beyond line connecting inner bases of pelvic fins; lateral nasal ridge completely supported by nasal bone; anus slightly separated from anal-fin origin; body scales covered with parallel to slightly divergent rows of greatly reclined, needle-like spinules; dark blotch between lateral line and pectoral-fin base (in most species). The C. argus group differs most notably from the C. fasciatus group in that the lateral nasal ridge is incompletely supported by the nasal bone.

Comparisons. Among the C. argus group, C. jordani differs from all but C. kishinouyei in that the spinules on the body scales are arranged in tightly packed parallel rows (vs. moderately separated, parallel to slightly divergent rows). The species also differs from all, except C. argus , C. kishinouyei , C. macrolepis , C. thurla , and C. sp. cf. notatus , in that the second spinous ray of the first dorsal fin is not especially elongate (vs. greatly prolonged; see Iwamoto 1990: figs. 284–292). Coelorinchus jordani is most similar to C. kishinouyei , the only other species of the group occurring in the Pacific off southern Japan. However, C. jordani differs from C. kishinouyei in that the dark spot between the lateral line and the pectoralfin base is small and rudimentary, and even absent in some specimens (vs. large and prominent). Apart from the difference in coloration, C. jordani is distinguished from that species by the position of the light organ: in C. jordani , the anterior margin of the light organ extends forward beyond a line connecting the outer pelvic-fin bases, whereas that of C. kishinouyei only reaches this line. Compared with C. kishinouyei , C. jordani has a longer barbel [2.6–4.1 in orbit (12–19% PRL) vs. 4.2– 7.9 (7–13%)], and a somewhat smaller orbit [0.8–1.2 in postorbital length (usually 1.0–1.1) vs. 0.8–1.1 (usually 0.8–0.9)]. In addition, dorsal surfaces of the snout posterior to the leading edges are broadly naked in most specimens of C. jordani , whereas the areas are variously scaled in C. kishinouyei (rarely lacking scales).

Figures

FIGURE 55. Fresh specimens of Coelorinchus jordani. (A) BSKU 109042, 42.0 mm HL, 208+ mm TL, Okinawa Trough, East China Sea, 304–312 m depth; (B–D) BSKU 101167, 56.2 mm HL, 275+ mm TL, Mimase fish market, Kochi Pref., Pacific. (A–B) Lateral views; (C) dorsal and (D) ventral views of the head and trunk. [Photos: N. Nakayama]

FIGURE 56. Holotype of Coelorhynchus jordani (= Coelorinchus jordani). USNM 55609, 39.5 mm HL, 172+ mm TL, Kagoshima, Pref. (A) Lateral view; (B) dorsal and (C) ventral views of the head and trunk. Preserved condition. [Photos: N. Nakayama]

FIGURE 57. Scanning electron micrographs showing body scales (from the dorsum below the interdorsal space) of two species of the Coelorinchus argus group. (A–B) C. jordani, BSKU 101167, 56.2 mm HL; (C–D) C. kishinouyei, BSKU 111224, 55.0 mm HL. (A, C) Views from above; (B, D) oblique views. [Photos: NSMT]