Coryphaenoides acrolepis ( Bean, 1884 )

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 141-146

Coryphaenoides acrolepis ( Bean, 1884)

[Japanese name: Ibara-hige]

( Figs. 91 , 92A , 93–94 , 95 A–C; Table 6 ; Appendix 3-5D)

Macururus [sic] acrolepis Bean, 1884:362 [original description; holotype: USNM 32496 , from off Cape Flattery , Washington (from stomach of seal)].

Macrurus firmisquamis Gill & Townsend, 1897:234 (original description; holotype: USNM 48772 , from southwest of Pribilof Islands , Bering Sea).

Chalinura spinulosa Gilbert & Burke, 1912:92 , figs. 36, 36a (original description; holotype: USNM 74397 , from off Avatcha Bay , Albatross sta. 4797).

Coryphaenoides bona-nox Jordan & Thompson, 1914:305 , pl. XXXVIII, figs. 1, 1a [original description; holotype: FMNH 57520 (ex. CM 6462 ), from Sagami Bay ].

Nematonurus bona-nox : Gilbert & Hubbs 1916:162 (new combination; brief description; 2 spec. from Eno-shima Island).

Coryphaenoides altipinnis (not G̹nther 1877): Schmidt 1931:154 (description 1 spec. from Sagami Bay) [re-identified here from description].

Coryphaenoides (Nematonurus) acrolepis: Okada et al. 1935:258 , pl. 154, fig. 3 (first record from Japan; description; 1 spec. probably from Choshi; new Japanese name: “Ibara-hige”).

Coryphaenoides spinulosus: Taranetz 1937:169 (new combination; listed; Soviet Far East); Ueno 1971:101 (listed; northern Kuril Islands; new Japanese name: “Toge-sokodara”).

Coryphaenoides acrolepis: Taranetz 1937:170 (listed; Soviet Far East); Okamura 1970a:125, pl. XXVII, text-fig. 51 (description; biological notes; 11 spec. from Pacific off Japan from Hokkaido to Kamogawa); Ueno 1971:101 (listed; Pacific off Hokkaido); Tominaga & Uyeno 1981:488 (listed; Japan); Shiogaki 1982:33 (listed; Aomori Pref.); Sawada 1983:111, 248, fig. 63 (brief description; 5 spec. from Pacific off Tohoku and Okhotsk Sea; photos based on HUMZ 78122 and HUMZ 79709); Amaoka & Nakaya 1983:44, fig. 59 (compiled; northern Japan); Okamura 1984b:95, pl. 82, fig. C (compiled); Okamura 1988:95, pl. 82, fig. C (compiled); Iwamoto 1990:202, fig. 472 (synopsis); Maeda & Maruyama 1991:366 (listed; Hokkaido); Nakabo 1993:362 (in key; Japan); Masuda & Kobayashi 1994:51, fig. 1 (in situ observation; off Kamaishi); Amaoka et al. 1995:101, fig. 150 (compiled; northern Japan); Hori 1996:28 (listed; Ibaraki Pref.); Shinohara et al. 1996:169 (2 spec. listed from Pacific off Tohoku); Okamura 1997:124, fig. (compiled); Funabashi 1998:85 (listed; Ibaraki Pref.); Nakabo 2000:427 (in key; Japan); Zama 2001:40 (listed; Miyagi Pref.); Nakabo 2002:427 (in key; Japan); Maeda & Tsutsui 2003:488 (listed; Hokkaido); Shiogaki et al. 2004:55 (listed; Pacific off Aomori Pref.); Senou et al. 2006:420 (listed; Sagami Sea); Senou 2008:367, fig. 31.34A–B (in situ observation; east of Hokkaido and Sagami Bay); Kitagawa et al. 2008:40, unnumbered fig. (brief description; spec. from Pacific off Tohoku); Shinohara et al. 2009:708 (1 spec. listed from Pacific off Tohoku); Amaoka et al. 2011:129, fig. 162 (compiled; Hokkaido); Nakabo & Kai 2013:503 (in key; Japan); Ikeda & Nakabo 2015:320, pl. 66, figs. 1–7 (brief description; 3 spec. from Kii Channel off Wakayama Pref.); Shinohara et al. 2020:6 (description; 7 spec. from Kurile-Kamchatka Trench, at midwater depths of 883–1350 m; stomach contents); Amaoka et al. 2020:161, fig. 216 (listed; Hokkaido); Motomura 2020:39 (listed; Japan).

Nematonurus acrolepis: Okada & Matsubara 1938:448 , pl. 110, fig. 1 (in key; Japan; C. bonanox a junior synonym of C. acrolepis ); Okada 1955:424, fig. 383; Matsubara 1955:1308 (in key; Japan); Ueno 1965:19 (listed; Pacific off Hokkaido); Matsubara 1965:504 (compiled; Japan); Nakajima 1975:55 (listed; Enshu-nada); Hikita 1981:78, fig. 1 (spec. from Okhotsk Sea off Shiretoko Peninsula).

[?] Coryphaenoides (Chalinura) angustifrons Rass, 1955:331 , fig. 4 (original description; holotype: ZIN 44885, from Okhotsk Sea, 52º20ʹN, 150º20ʹE, 1030 m depth; 9 paratypes from Kuril-Kamchatka Trench and Okhotsk Sea).

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

Nematonwrus [sic] acrolepis: Maruyama 1971:33 (listed; Iwate Pref.).

[?] Coryphaenoides anguistifrons [sic]: Ueno 1971:101 (listed; northern Kuril Islands and southern Okhotsk Sea; new Japanese name: “Chishima-sokodara”).

Ventrifossa sp. 1: Masuda & Kobayashi 1994:50, fig. 4 (in situ observation; Sagami Bay) [re-identified here from figure].

Ventrifossa sp. 2: Masuda & Kobayashi 1994:50, fig. 5 (in situ observation; off Kamaishi) [re-identified here from figure].

Ventrifossa sp. 3: Masuda & Kobayashi 1994:50, fig. 6 (in situ observation; off Kamaishi) [re-identified here from figure].

Diagnosis. Pelvic-fin rays usually 8 (rarely 7 or 9). Snout conical, moderately protruding beyond upper jaw. Tip and lateral angles of snout with stout tubercles; scales along head ridges slightly thickened and enlarged. Mouth large, posterior margin of upper jaw extending to below posterior 1/3 of orbit or beyond; upper-jaw length 33– 40% HL; lateral corner of mouth not restricted by skin folds. Outermost gill slit moderately wide, length 15–21% HL. Barbel well developed, length 11–19% HL. Teeth small, bluntly pointed, in broad bands in both jaws, outer premaxillary series slightly enlarged. Body scales covered with short, reclined, conical spinules in widely divergent rows; tip of last spinule in each row extending well beyond posterior scale margin. Transverse scale rows below first dorsal-fin midbase 7–10. Snout fully scaled dorsally, but variously naked ventrally (underside of snout fully scaled in some larger specimens). Interdorsal space less than first dorsal-fin base length. Height of first dorsal fin less than HL (60–94% HL); second spinous ray not prolonged, finely serrated along its leading edge; first dorsal-fin rays II,8–11. Body uniformly blackish in adults.

Material examined. 39 specimens. Holotype of Macururus [sic] acrolepis : * USNM 32496 (badly deteriorated; originally 365 mm TL, fide Bean 1884:362), off Cape Flattery , Washington (from stomach of seal), USA, northeastern Pacific, coll. J.G. Swan, 1 Feb.1883. Holotype of Coryphaenoides bonanox: FMNH 57520 (ex. CM 6462, 141 mm HL, 581+ mm TL), Sagami Bay, Kanagawa Pref., Japan, date unknown. Holotype of Chalinura spinulosa: USNM 74397 (badly deteriorated; originally 41 cm TL, fide Gilbert & Burke 1912:92), off Avacha Bay, east coast of Kamchatka, northwestern Pacific, 52.6250ºN, 158.8333ºE, 682 ftm (1248 m), Albatross sta. 4797, 9ft Albatross-Blake beam trawl, 20 Jun. 1906. Non-types: Japan: BSKU 49891 (1, 92.1 mm HL, 462+ mm TL), BSKU 49893 (1, 166 mm HL, 808+ mm TL), BSKU 49894 (1, 130 mm HL, 655+ mm TL), BSKU 49895 (1, 142 mm HL, 710+ mm TL), BSKU 49896 (1, 103 mm HL, 512+ mm TL), BSKU 49899 (1, 148 mm HL, 776+ mm TL), 1500 m, R/V Hakuho-maru, cr. KH-91-6, sta. 12, 16 Nov. 1991; BSKU 83765 (1, 78.1 mm HL, 316+ mm TL), off Tohoku, 450 m, FRV Wakataka-maru, sta. E, otter trawl, Oct. 1997; BSKU 19556 (1, 107 mm HL, 565 mm TL), off Ito, Sagami-nada, 34.9467ºN, 139.3500ºE, 1470–1500 m, FRV Soyo-maru, sta. T21, beam trawl, 15 Dec. 1964; BSKU 103028 (1, 138 mm HL, 714+ mm TL), off Manazuru, Sagami Bay, 450 m, rod and reel, coll. T. Okamoto, date unknown; BSKU 14188 (1, 104 mm HL, 478+ mm TL), BSKU 14192 (1, 91.2 mm HL, 430+ mm TL), off Odawara, Sagami Bay, 35.2014ºN, 139.2003ºE, 670–750 m, 14 Apr. 1969; BSKU 97738 (1, 77.5 mm HL, 385+ mm TL), southeast of Cape Erimomisaki, Japan Trench, 41.2353ºN, 144.0357ºE, 2977–3014 m, R/V Tansei-maru, cr. KT-93-15, sta. M7, 3-m beam trawl, coll. Y. Machida, 17 Nov. 1993; BSKU 35672 (1, 168 mm HL, 867+ mm TL), off Kuji, 40.3683ºN, 143.3800ºE, 1970–2000 m, R/V Hakuho-maru, cr. KH-81- 4, sta. 3, 10 Jul. 1981; BSKU 35681 (1, 83.9 mm HL, 422+ mm TL), BSKU 35682 (1, 108 mm HL, 520+ mm TL), BSKU 35684 (1, 138 mm HL, 683+ mm TL), BSKU 35685 (1, 147 mm HL, 717+ mm TL), BSKU 35688 (1, 141 mm HL, 734+ mm TL), off Kinkazan, 38.7333ºN, 143.1850ºE, 1950–1960 m, R/V Hakuho-maru, cr. KH-81-4, sta. 8, 25 Jul. 1981; BSKU 96504 (1, 147 mm HL, 705+ mm TL), off Kinkazan, 38.4640ºN, 143.0518ºE, 1853–1906 m, R/V Tansei-maru, cr. KT-08-27, sta. K-2, 3-m ORE beam trawl, coll.H. Endo and N.Nakayama, 23 Oct.2008; BSKU 96421 (1, 80.4 mm HL, 398 mm TL), * BSKU 96425 (1, 62.1 mm HL, 323+ mm TL), off Miyako, 39.5668ºN, 142.9008ºE, 1586–1617 m, R/V Tansei-maru, cr. KT-08-27, sta. M-2, 3-m ORE beam trawl, coll. H. Endo and N. Nakayama, 21 Oct. 2008; BSKU 97783 (1, 67.2 mm HL, 348 mm TL), off Miyako, 39.5747ºN, 142.6852ºE, 1132–1170 m, R/V Tansei-maru, cr. KT-93-15, sta. O4, 3-m ORE beam trawl, coll. Y. Machida, 13 Nov. 1993; BSKU 97743 (1, 85.4 mm HL, 403+ mm TL), off Kuji, 40.0613ºN, 142.6825ºE, 1005–1016 m, R/V Tansei-maru, cr. KT-93-15, sta. M3, 3-m beam trawl, coll. Y. Machida, 18 Nov. 1993; BSKU 97841 (1, 78.2 mm HL, 365+ mm TL), BSKU 97846 (1, 67.9 mm HL, 332+ mm TL), off Otsuchi, 39.0538ºN, 142.6342ºE, 1195–1202 m, R/V Tansei-maru, cr. KT-89- 03, sta. SR91, 10 Mar. 1989; BSKU 97820 (1, 90.8 mm HL, 408+ mm TL), off Otsuchi, 39.1444ºN, 142.3748ºE, 847–935 m, R/V Tansei-maru, cr. KT-89-03, sta. SR89, 10 Mar. 1989; * BSKU 45528 (1, 45.0 mm HL, 206+ mm TL), BSKU 45529 (1, 71.9 mm HL, 363 mm TL), off Otsuchi, 39.1444ºN, 142.3748ºE, 847–935 m, R/V Tansei-maru, cr. KT-89-03, sta. SR89, 3-m ORE beam trawl, 10 Mar. 1989; BSKU 97728 (1, 52.2 mm HL, 277 mm TL), BSKU 97729 (1, 59.1 mm HL, 297+ mm TL), BSKU 97784 (1, 90.2 mm HL, 440+ mm TL), BSKU 97785 (1, 72.1 mm HL, 360+ mm TL), BSKU 97786 (1, 78.6 mm HL, 382+ mm TL), south-southeast of Akkeshi, 42.6052ºN, 144.9938ºE, 1113–1161 m, R/V Tansei-maru, cr. KT-93-15, sta. T8, 3-m ORE beam trawl, coll. Y. Machida, 16 Nov. 1993; BSKU 96393 (1, 98.0 mm HL, 476+ mm TL), BSKU 96394 (1, 146 mm HL, 727+ mm TL), BSKU 96395 (1, 129 mm HL, 663+ mm TL), south of Cape Erimomisaki , 41.6675ºN, 143.3268ºE, 2022–2027 m, R/ V Tansei-maru, cr. KT-08- 27, sta. S-2, 3-m ORE beam trawl, coll. H. Endo and N. Nakayama, 20 Oct. 2008.

Counts and measurements. See Table 6 .

Size. Attains about 97 cm TL ( NSMT-P 102193, 973+ mm TL, off Boso Peninsula, Japan).

Development. Larval morphology was described by Stein (1980).

Distribution. Widely distributed in the North Pacific from Japan to North America including the Okhotsk and Bering Seas as well as the Emperor Seamounts ( Iwamoto & Stein 1974; Borets 1986; Iwamoto 1990; Mecklenburg et al. 2002; this study). A single specimen also recorded from the southwestern Atlantic off the Falkland Islands ( Laptikhovsky et al. 2013). Depth range about 300–3000 m. In Japanese waters, known from off the Pacific coasts southward to Cape Omaezaki (138.22ºE) and the southern Okhotsk Sea at depths of 450‾ 3014 m (Appendix 3-5D). Common, especially in the north of Choshi (35.74ºN; Chiba Pref.).

Remarks. Coryphaenoides acrolepis was originally described by Bean (1884) based on a single specimen obtained from the stomach of a seal found in the northeastern Pacific off Cape Flattery, Washington, United States. As mentioned by Bean (1884:362), the holotype is “mutilated” and “a small portion of the tail is wanting, and the belly is almost wholly digested” ( Fig. 92A ).

Coryphaenoides acrolepis has been well described by previous authors; for a full description see Okamura (1970a) and Iwamoto & Stein (1974). This species is one of the most common grenadiers in the North Pacific ( Iwamoto 1990:202).

Nomenclatural discussion. Jordan & Thompson (1914) described Coryphaenoides bonanox (originally spelled as “ bona-nox ”) from a single specimen collected in Sagami Bay ( Fig. 93 ), and many authors synonymized the species with C. acrolepis without explanation (e.g., Okada & Matsubara 1938; Okamura 1970a; Iwamoto & Stein 1974; Iwamoto 1990; Mecklenburg et al. 2002). The holotype of C. bonanox was examined here to investigate this synonymy. In the original description of C. bonanox , Jordan & Thompson (1914:305) wrote that “the dentition and scales of this species distinguish it from previously known forms”. Examination of the holotype confirmed that teeth of the specimen are small, sharp, slightly incurved, arranged in long tapered bands in the both jaws, with an outer row of premaxillary teeth enlarged. Also, its body scales are covered with short, reclined, conical spinules in 7–9 widely divergent rows. These features are typically found in the C. acrolepis specimens examined, and thus the two species cannot be distinguished by these characters. Counts and measurements also show no significant differences between the two species ( Table 6 ). This study reconfirms that C. bonanox is a junior synonym of C. acrolepis .

Gilbert & Burke (1912) described Coryphaenoides spinulosus (as Chalinura spinulosa ) from a single specimen collected from off Avacha Bay, southern Kamchatctka ( Fig. 94 ). This is a poorly known grenadier, and no additional specimens have been found since the original description. According to Fricke et al. (2020), the species is a junior synonym of C. acrolepis , but no published data exist to support this synonymy.Although C. spinulosus has not been recorded from Japanese waters, the holotype of this species was examined here to determine its taxonomic status. Unfortunately, the specimen is badly deteriorated ( Fig. 94 ), and it was impossible to obtain meristic and morphometric characters except for fin ray and scale row counts. However, adequate information is available from its original description, with excellent illustrations of the holotype and a body scale from the dorsum of the body ( Gilbert & Burke 1912: figs. 36, 36a). According to Gilbert & Burke’s (1912) description, C. spinulosus can be distinguished from C. acrolepis by having a somewhat shorter snout (26% HL vs. 27–32%; Table 6 ), but otherwise the two species are very similar to each other. Their figure also shows that the snout of C. spinulosus is relatively high and only slightly protrudes beyond the upper jaw (fig. 36). In C. acrolepis , the snout is usually much longer, giving a more conical appearance to the anterior portion of the head ( Fig. 91 ). However, these subtle differences most likely reflect individual variation or the poor condition of the holotype of C. spinulosus . Consequently, C. spinulosus is herein regarded as a junior synonym of C. acrolepis .

Relationships and comparisons. Coryphaenoides acrolepis belongs to the subgenus Coryphaenoides (sensu Iwamoto 1990) . According to Iwamoto (1990:203), the species is closely related to C. filifer ( Gilbert, 1896) with which it occurs sympatrically in the North Pacific. In meristic and morphometric features, C. acrolepis differs from C. filifer in having lower counts of first dorsal-fin rays (II,8–11 vs. II,12–15) and a slightly longer chin barbel (11–19% HL vs. 8–11%). Spinulation of body scales further distinguishes the two species, with C. acrolepis having much stouter spinules than C. filifer ( Fig. 95 A–C vs. Fig. 109 ). Furthermore, small but conspicuous pores are present along each canal of the cephalic sensory system in C. acrolepis , whereas the pores of C. filifer are too tiny to observe without a microscope, and none appear to be present along the postorbital and supratemporal canals.

Figures

FIGURE 91. Fresh specimens of Coryphaenoides acrolepis. (A) BSKU 45528, 45.0 mm HL, 206+ mm TL, KT-89-03, sta. SR89; (B) BSKU 96425, 62.1 mm HL, 323+ mm TL, off Miyako, Iwate Pref., Pacific, 1586–1617 m depth; (C) BSKU 96421, 80.4 mm HL, 398 mm TL, collected with BSKU 96425; (D) BSKU 96393, 98.0 mm HL, 476+ mm TL, south of Cape Erimomisaki, Hokkaido, Pacific, 2022–2027 m depth; (E–G) BSKU 103028, 138 mm HL, 714+ mm TL, Sagami Bay, Pacific, 450 m depth. (A– E) Lateral views; (F) dorsal and (G) ventral views of the head and trunk. [Photos: (A) BSKU; (B–D) H. Endo and N. Nakayama; (E–G) N. Nakayama]

FIGURE 93. Preserved specimen of Coryphaenoides acrolepis. FMNH 57520, holotype of C. bonanox, 141 mm HL, 581+ mm TL, Sagami Bay, Pacific. (A) Lateral view; (B) dorsal and (C) ventral views of the head and trunk. [Photos: N. Nakayama]

FIGURE 94. Preserved specimen of Coryphaenoides acrolepis. USNM 74397, holotype of Chalinura spinulosa, not measured due to its poor condition, off Avacha Bay, east of Kamchatka, Pacific, 1247 m depth. (A) Lateral view; (B) dorsal and (C) ventral views of the head and trunk. [Photos: N. Nakayama]

FIGURE 95. Scanning electron micrographs showing body scales (from the dorsum below the interdorsal space) of two species of Coryphaenoides. (A–B) Co. acrolepis, BSKU 103028, 138 mm HL; (C) Co. acrolepis, USNM 74397, holotype of Chalinura spinulosa, not measured due to its poor condition; (D) Co. altipinnis, BMNH 1887.12.7.90, holotype, 102 mm HL. (A, C–D) Views from above; (B) oblique view. [Photos: (A–B) NSMT; (C–D) N. Nakayama]

FIGURE92.Type specimens of twospecies of Coryphaenoides. (A) Holotype of Macururus [sic] acrolepis, USNM 32496, badly deteriorated, off Cape Flattery, Washington, USA, northeastern Pacific; (B) syntype of Chalinura filifera, USNM 48626, disintegrated, off Queen Charlotte Island, British Columbia, Canada, northeastern Pacific, 2905 m depth. [Photos: N. Nakayama]

FIGURE109. Scanning electronmicrographsshowingbodyscales (fromthe dorsumbelowthe interdorsal space) ofCoryphaenoides filifer. (A) HUMZ 126365, 92.5 mm HL; (B) HUMZ 126444, 116 mm HL. Views from above. [Photos: N. Nakayama]