Coryphaenoides nasutus Günther, 1877

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 192-196

Coryphaenoides nasutus Günther, 1877

[Japanese name: Hana-sokodara]

( Figs. 122 E–F, 125–126; Appendix 3-7B)

Coryphaenoides nasutus G̹nther, 1877:440 [original description; lectotype (designated herein): BMNH 1887.12.7.78, from “south of Yeddo” (off Cape Omaezaki), Challenger sta. 235, in 565 ftm (1034 m); 1 paralectotype from type locality]; Gilbert & Hubbs 1916:168 (brief description; 45 spec. from Hyuga-nada, off Cape Shionomisaki, Enshu-nada, southwest of Hokkaido, south of Izu Peninsula, and Sagami Bay); Jordan & Hubbs 1925:327 (spec. from Misaki); Okada & Matsubara 1938:449 (in key; Japan); Kamohara 1950:279 (listed; Kochi Pref.); Kamohara 1952:98 (selected counts and measurements; 1 spec. from Kochi Pref.); Matsubara 1955:1310 (in key; Japan; Japanese name: “Hana-sokodara”); Kamohara 1958:73 (listed; Kochi Pref.); Kamohara 1964:95 (listed; Kochi Pref.); Ueno 1965:19 (listed; Pacific off Hokkaido); Wheeler & O’Riordan 1969:96 (comments on type specimens); Okamura 1970a:140, pl. XXXI, text-fig. 56 (description; biological notes; 38 spec. from Pacific from off Hokkaido to Mimase and East China Sea); Ueno 1971:101 (listed; Hokkaido); Kuroda 1971:56 [listed from Suruga Bay after Okamura (1970a)]; Tominaga & Uyeno 1981:489 (listed; Japan); Okamura 1982:165, 351, fig. 99 [brief description; 8 spec. from Tosa Bay; photo based on BSKU spec. (catalog no. unknown)]; Shiogaki 1982:33 (listed; Aomori Pref.); Sawada 1983:113, 195, fig. 64 (brief description; 5 spec. from Pacific off Tohoku; photo based on HUMZ spec. (catalog no. unknown); Ohta 1983: photo 28, tables A–B (listed; Suruga Bay; in situ observation); Yatou 1984:219, 364, fig. 155 [brief description; 10 spec. from Okinawa Trough; photo based on BSKU spec. (catalog no. unknown)]; Okamura 1984b:95, pl. 82, fig. F (compiled); Okamura 1988:95, pl. 82, fig. F (compiled); Iwamoto 1990:216, fig. 496 (synopsis); Maeda & Maruyama 1991:366 (listed; Hokkaido); Nakabo 1993:365 (in key; Japan); Amaoka et al. 1995:103, fig. 153 (compiled; northern Japan); Shinohara et al. 1996:169 (2 spec. listed from Pacific off Tohoku); Okamura 1997:126, fig. 3 (compiled); Shinohara & Matsuura 1997:291 (listed; Suruga Bay); Nakabo 2000:429 (in key; Japan); Shinohara et al. 2001:305 (5 spec. listed from Tosa Bay); Nakabo 2002:429 (in key; Japan); Yoda et al. 2002:11 (listed; East China and Yellow Seas); Maeda & Tsutsui 2003:488 (listed; Hokkaido); Shiogaki et al. 2004:55 (listed; Pacific off Aomori Pref.); Shinohara et al. 2005:417 (listed; Ryukyu Islands); Suetsugu & Ohta 2005: table 3 (listed; Enshu-nada); Senou et al. 2006:420 (listed; Sagami Sea); Kitagawa et al. 2008:41, unnumbered fig. (brief description; spec. from Pacific off Tohoku); Shao et al. 2008b: table 2 (5 spec. listed from northeastern and southeastern Taiwan; first Taiwanese record); Matsuura et al. 2009:24 (1 spec. from Miyagi Pref.); Shinohara et al. 2009:708 (2 spec. listed from Pacific off Tohoku); Amaoka et al. 2011:130, fig. 165 (compiled; Hokkaido); Nakabo & Kai 2013:505 (in key; Japan); Ikeda & Nakabo 2015:320, pl. 65, figs. 9–13 (brief description; 3 spec. from Kii Channel off Wakayama Pref.); Iwamoto et al. 2015:71, fig. 10 (brief description; 9 spec. from northeastern and southeastern Taiwan, South China Sea, and Japan); Amaoka et al. 2020:163, fig. 221 (listed; Hokkaido); Motomura 2020:39 (listed; Japan).

Macrurus nasutus : G̹nther 1887:132, pl. XXX, fig. B (description; 11 spec. from Enshu-nada and Sagami Bay).

[?] Macrurus altipinnis : G̹nther 1887:138 (description; in part, 1 spec., BMNH 1887.12.7.91; Enshu-nada) .

Macrourus nasutus : Jordan & Snyder 1901:120 (listed; Japan); Jordan & Gilbert in Jordan & Starks 1904:616 (brief description; 16 spec. from Sagami Bay and “off the shore of Izu”); Franz 1910:26 (5 spec. from Aburatsubo); Jordan et al. 1913:417 (listed; Japan; new Japanese name: “Hana-nagasokodara”); Jordan & Thompson 1914:306 [selected counts; 3 spec. from Misaki (FMNH 57384, 2 spec.) and Sagami Bay]; Kamohara 1938:72 (selected counts and measurements; 1 spec. from Kochi Pref.).

Coryphaenoides (Coryphaenoides) nasutus: Okamura 1970b : table 1 (listed; Japan).

Diagnosis. Pelvic-fin rays 8–10 (usually 9). Snout conical, moderately protruding beyond upper jaw. Tip and lateral angles of snout armed with prominent enlarged tubercles; scales along head ridges not coarsely modified. Mouth small, posterior margin of upper jaw not extending beyond vertical through midorbit; upper-jaw length 28– 32% HL; lateral corner of mouth moderately restricted by skin folds. Outermost gill slit greatly restricted, length 4–8% HL. Barbel short, slender, length 5–8% HL. Teeth all small, conical, in wide bands in both jaws, none especially enlarged. Body scales covered with short, greatly reclined, needle-like spinules in tightly packed convergent rows; tip of last spinule in each row scarcely extending beyond posterior scale margin. Transverse scale rows below first dorsal-fin midbase 4.5–7.5. Dorsal and ventral surfaces of snout broadly naked along leading edges. Height of first dorsal fin 78–125% HL; second spinous ray moderately prolonged, finely serrated along its leading edge; first dorsal-fin rays II,9–12. Pelvic fin well separated, interspace greater than base length of each fin. Body dusky brown overall.

Material examined. 32 specimens. Lectotype of Coryphaenoides nasutus (designated herein): BMNH 1887.12 .7.78 (81.2 mm HL, 337+ mm TL), off Cape Omaezaki, Enshu-nada, Japan , 34.1167ºN, 138.0000ºE, 565 ftm (1034 m), Challenger sta. 235, trawl, 4 Jun. 1875 . Paralectotype of C. nasutus (designated herein): BMNH 1887.12 .7.79 (1, 72.2 mm HL, 365 mm TL), collected with lectotype. Non-types: Japan : BSKU 26668 (1, 97.8 mm HL, 429+ mm TL), west of Yaku-shima Island, Okinawa Trough , 30.0300ºN, 128.3650ºE, 900 m, F/ V Yuryo-maru, No. 8, tr. 16-1, bottom trawl, coll. Y. Kinoshita and S. Hagino, 3 Feb. 1978 ; BSKU 28493 (1, 95.6 mm HL, 455+ mm TL) , BSKU 28495 (1, 88.7 mm HL, 437+ mm TL), northwest of Amami-oshima Island, Okinawa Trough , 29.7333ºN, 128.0500ºE, 815 m, F/ V Ryoan-maru, No. 28, tr. 74, bottom trawl, coll. Y. Kinoshita and S. Hagino, 20 Mar. 1978 ; BSKU 28076 (1, 105 mm HL, 477+ mm TL) , BSKU 28079 (1, 98.0 mm HL, 478+ mm TL), northwest of Amami-oshima Island, Okinawa Trough , 28.8833ºN, 127.3000ºE, 820–830 m, F/ V Ryoan-maru, No. 28, tr. 60, bottom trawl, coll. Y. Kinoshita and S. Hagino, 16 Mar. 1978 ; BSKU 47158 (1, 73.9 mm HL, 361+ mm TL) , BSKU 47159 (1, 71.8 mm HL, 358+ mm TL) , BSKU 47163 (1, 64.7 mm HL, 335+ mm TL) , BSKU 47164 (1, 75.3 mm HL, 376+ mm TL), off Tosa Bay , 32.8953ºN, 133.6777ºE, 996–1010 m, R/ V Tansei-maru, cr. KT-89- 06, sta. T1, beam trawl, 8 Nov. 1989 ; BSKU 95207 (1, 63.0 mm HL, 237+ mm TL) , BSKU 95213 (1, 61.5 mm HL, 315+ mm TL) , BSKU 95215 (1, 58.1 mm HL, 279+ mm TL) , BSKU 95219 (1, 60.1 mm HL, 325+ mm TL) , BSKU 95221 (1, 53.6 mm HL, 240+ mm TL) , BSKU 95226 (1, 34.6 mm HL, 185+ mm TL), Tosa Bay , 750 m, FRV Kotaka-maru, otter trawl, 13 Sept. 1988 ; BSKU 43456 (1, 67.2 mm HL, 351+ mm TL), south-southwest of Okino-shima Island , 32.5450ºN, 132.4750ºE, 1075–1092 m, R/ V Tansei-maru, cr. KT-86-16, sta. C, 3-m beam trawl, 2 Nov. 1986 ; BSKU 103041 (1, 64.0 mm HL, 337+ mm TL) , BSKU 103042 (1, 78.5 mm HL, 383+ mm TL), Suruga Bay , coll. A. Fukui and M. Takami, 10 Sept. 2007 ; BSKU 103030 (1, 69.3 mm HL, 342+ mm TL), Suruga Bay , coll. A. Fukui and M. Takami, 14 Nov. 2007 ; BSKU 103031 (1, 69.9 mm HL, 329+ mm TL), Suruga Bay , coll. A. Fukui and M. Takami, 3 Dec. 2008 ; BSKU 97868 (1, 56.9 mm HL, 286+ mm TL) , BSKU 97872 (1, 82.3 mm HL, 422+ mm TL) , BSKU 97873 (1, 55.2 mm HL, 288+ mm TL) , BSKU 97887 (1, 74.9 mm HL, 381 mm TL) , BSKU 97888 (1, 88.2 mm HL, 419+ mm TL) , BSKU 97890 (1, 70.4 mm HL, 361+ mm TL) , BSKU 97893 (1, 77.2 mm HL, 373+ mm TL) , BSKU 97900 (1, 46.8 mm HL, 242+ mm TL) , BSKU 97901 (1, 48.2 mm HL, 209+ mm TL) , BSKU 97903 (1, 41.5 mm HL, 212+ mm TL), off Kamaishi , 39.1444ºN, 142.3748ºE, 847–935 m, R/ V Tansei-maru, cr. KT-89-3, sta. SR89, 3-m beam trawl, 10 Mar. 1989 .

Counts and measurements. Based on 32 specimens (34.6–105 mm HL, 185+–478+ mm TL). Counts: first dorsal-fin rays II,9–12; pectoral-fin rays i19–i24; pelvicfin rays 8–10; gill rakers on first arch (outer/inner) 3–5/8– 11, on second arch 8–10/8–9; longitudinal scales 37–45; transverse scale rows below first dorsal-fin origin 6.5– 9.5, below first dorsal-fin midbase 4.5–7.5, below second dorsal-fin origin 6.5–9, above anal-fin origin 19.5–27.5.

The following measurements are in % of HL, followed by those in % of PRL in parentheses: snout length 28–33 (38–47); orbit diameter 25–31 (34–42); postorbital length 41–49 (57–67); postrostral length 69–75; orbit–preopercle distance 37–44 (53–60); suborbital width 11–15 (16–21); upper-jaw length 28–32 (39–43); length of rictus 21–29 (29–38); length of premaxillary tooth band 17–22 (24– 30); preoral length 14–22 (20–31); distance between tip and lateral angle of snout 16–21 (21–30); snout width 26– 32 (35–46); internasal width 18–22 (24–30); interorbital width 17–25 (24–34); body width over pectoral-fin bases 40–63 (57–90); body depth at first dorsal-fin origin 65–86 (91–122); body depth at anal-fin origin 53–76 (74–109); prepelvic length 103–125 (141–178); preanus length 142–168 (196–240); preanal length 147–179 (206–249); isthmus–pelvic distance 34–45 (47–61); isthmus–anus distance 70–94 (97–134); isthmus–anal distance 63–104 (88–145); pelvic–anal distance 41–68 (57–97); anus–anal distance 4–13 (6–18); pelvic-fin length 40–83 (57–117); pectoral-fin length 45–56 (62–80); predorsal length 110–122 (154–174); height of first dorsal fin 78–125 (104–175); length of first dorsal-fin base 23–32 (33–44); interdorsal length 34–114 (48–159); length of gill slit 4–8 (6–12); length of posterior nostril 5–10 (7–14); barbel length 5–8 (6–11).

Size. Attains about 52 cm TL ( FAKU 102252, 524 mm TL, off Fukushima Pref., Japan) .

Distribution. Restricted to Japan and Taiwan.Known from the Pacific off Japan northward to Muroran (42.32º, Hokkaido), Okinawa Trough, and northern South China Sea, at depths of 450‾ 2056 m ( Shao et al. 2008a, 2008b; this study; Appendix 3-7B). Abundant on the upper slope of the Pacific off southern Japan.

Comments on type specimens. Coryphaenoides nasutus was originally described by G̹nther (1877) from the “south of Yeddo” (= Tokyo), Japan. Although G̹nther (1877) did not indicate how many specimens were involved in the original description, he (1887:132) subsequently noted that five specimens were collected from the above locality ( Challenger sta. 235). Two syntypes ( BMNH 1887.12.7.78–79, 337+– 365 mm TL; Fig. 126 ) were examined in this study, whereas the remaining three are presumed to be lost. G̹nther (1887) also reported six additional specimens from “off Inoshima” (= Eno-shima Island ), Sagami Bay , Japan (Challenger sta. 232), but these specimens do not have any type status. While Bailly et al. (1999) considered MNHN 1890-123 (from Challenger sta. 232) as a syntype of this species, this specimen is also obviously a non-type. One of the syntypes examined ( BMNH 1887.12.7.78; Fig. 126 ) is herein designated as the lectotype of C. nasutus , and thus the other specimens used in the original description automatically become paralectotypes of the species .

Remarks. For a full description see Okamura (1970a). Although Okamura (1982:165, 351) described the number of branchiostegal rays as seven, this is likely a mistype of six. Among the FAKU collection is a single specimen of C. nasutus from off Minamidaito-jima Island (FAKU 13367, 1 spec., 29.2 mm HL, 137+ mm TL). However, the register of FAKU indicates its locality with a question mark. This record was excluded from the distribution of the species in this study. Coryphaenoides nasutus appears to be restricted to the upper continental slope along Japan and Taiwan, and its occurrence on the Philippine Plate is doubtful.

Relationships and comparisons. Coryphaenoides nasutus belongs to the subgenus Coryphaenoides (sensu Iwamoto 1990) , and closely resembles C. hoskynii ( Alcock, 1890) known from the Indian Ocean. However, the two species are readily distinguished by spinulation of the body scales: in C. nasutus , the tip of the last spinule in each row barely overlaps the posterior scale margin ( Fig. 122 E–F), whereas those of C. hoskynii extend well beyond this level. Coryphaenoides nasutus further differs from C. hoskynii in having a narrower snout (internasal width 18–22% HL vs. 24–33%) and much smaller scales (longitudinal scales 37–45 vs. 31–34, scale rows below the first dorsal-fin midbase 4.5–7.5 vs. 3.5–4.5, below the second dorsal-fin origin 6.5–9 vs. 4–5). [Data for C. hoskynii are from Shcherbachev & Iwamoto (1995).]

Among Japanese congeners, C. nasutus is most similar to C. marginatus Steindachner & D̂derlein, 1887 in general appearance, but the two species are clearly separable by the positions of the pelvic fins, body-scale spinulation, head squamation, and fin color (see the Comparisons of C. marginatus ).

Figures

FIGURE 122. Scanning electron micrographs showing body scales (from the dorsum below the interdorsal space) of three species of the Coryphaenoides marginatus group. (A–B) C. marginatus, BSKU 103048, 71.4 mm HL; (C–D) C. microps, ASIZP 66413, 43.7 mm HL; (E–F) C. nasutus, BSKU 103042, 78.5 mm HL. (A, C, E) Views from above; (B, D, F) oblique views. [Photos: NSMT]

FIGURE 126. Lectotype of Coryphaenoides nasutus, BMNH 1887.12.7.78, 81.2 mm HL, 337+ mm TL, off Cape Omaezaki, Enshu-nada, Pacific, 1034 m depth. (A) Lateral view; (B) dorsal and (C) ventral view of head and trunk. Preserved condition. [Photos: N. Nakayama]