Coryphaenoides filifer ( Gilbert, 1896 )

Nakayama, Naohide, 2020, Grenadiers (Teleostei: Gadiformes: Macrouridae) of Japan and adjacent waters, a taxonomic monograph, Megataxa 3 (1), pp. 1-383 : 164-166

Coryphaenoides filifer ( Gilbert, 1896)

[Japanese name: Kitano-sokodara]

( Figs. 92B , 107–109 ; Appendix 3-6C)

Chalinura filifera Gilbert, 1896:458 [original description; 3 syntypes, from off Queen Charlotte Island, Albatross sta. 3342, in 1588 ftm (2904 m)].

Macrurus dorsalis Gill & Townsend,1897:233 [original description; holotype: USNM 48770 , from southwest of Pribilof Islands , Bering Sea, Albatross sta. 3640, in 1401 ftm (2562 m)].

Macrurus lepturus Gill &Townsend, 1897:233 [original description; holotype: USNM 48770 , from southwest of Pribilof Islands , Bering Sea, Albatross sta. 3640, in 1401 ftm (2562 m)].

Coryphaenoides filifer: Gilbert & Hubbs 1916:143 (listed); Endo et al. 1994:330, fig. 2 (first record from Japan; brief description; 2 spec. from Okhotsk Sea; new Japanese name: “Kitanosokodara”); Amaoka et al. 1995:102, fig. 151 (compiled; northern Japan); Okamura 1997:125, fig.7 (compiled); Nakabo 2000:426 (in key; Japan); Nakabo 2002:426 (in key; Japan); Maeda & Tsutsui 2003:488 (listed; Hokkaido); Amaoka et al. 2011:129, fig. 163 (compiled; Hokkaido); Nakabo & Kai 2013:502 (in key; Japan); Amaoka et al. 2020:162, fig. 219 (listed; Hokkaido).

Macrourus albatrossus Townsend & Nichols, 1925:17 , pl. IV, fig. 2 [original description; holotype: USNM 87555 (ex. AMNH 8345 ), from off northern Baja California, northeastern Pacific, Albatross sta. 1692, in 1076 ftm (1968 m)].

Coryphaenoides filiferus: Motomura 2020:39 (listed; Japan).

Diagnosis. Pelvic-fin rays 9–10. Snout short, slightly protruding beyond upper jaw. Tip and lateral angles of snout armed with enlarged tubercles; no scute-like scales along head ridges. Snout width 19–22% HL; internasal width 16–18% HL. Mouth large, posterior margin of upper jaw extending to about vertical through hind rim of orbit; upper-jaw length 38–43% HL; lateral corner of mouth not restricted by skin folds. Outermost gill slit moderately wide, length 19–23% HL. Barbel short, slender, length 8–11% HL. Teeth small, conical, in narrow bands in both jaws; outer premaxillary series slightly enlarged. Body scales covered with short, reclined, needle-like spinules in narrowly divergent rows; tip of last spinule in each row extending distinctly beyond posterior scale margin. Transverse scale rows below first dorsal-fin midbase 6–11.5. Snout fully scaled dorsally, narrowly naked ventrally. Height of first dorsal fin 91–105% HL; second spinous ray slightly elongate, weakly serrated along its leading edge; first dorsal-fin rays II,12–15. Outer pelvicfin ray greatly prolonged, its tip extending well beyond anal-fin origin. Body dark overall.

Material examined. 15 specimens. Syntype of Chalinura filifera : * USNM48626 (1,badly disintegrated), off Queen Charlotte Island , British Columbia , Canada, northeastern Pacific, 52.6608ºN, 132.6333ºW, 1588 ftm (2905 m), Albatross sta. 3342, large beam trawl, 3 Sept. 1890 . Non-types : Japan : HUMZ 126365 (1, 92.5 mm HL, 506+ mm TL), northwest of Shiretoko Peninsula , Okhotsk Sea, 44.5450ºN, 145.0867ºE, 1348 m, bottom trawl, coll. D. Tsutsui, 26 May 1993 ; HUMZ 126444 (1, 116 mm HL, 626+ mm TL), northwest of Shiretoko Peninsula , Okhotsk Sea, 44.5067ºN, 145.0767ºE, 1285 m, bottom trawl, coll. D.Tsutsui, 27 May 1993 . Northeastern Pacific : FMNH 117113 (5, 83.6–104 mm HL, 412+–557+ mm TL), off Newport , 44.7617ºN, 125.5214ºW, 2800 m, R/ V Wecoma, cr. W9704A, sta. 9, 40-ft otter trawl, coll. J. Voightt, 19 Apr. 1997 ; FMNH 117112 (5, 78.8–102 mm HL, 400–511+ mm TL), off Newport , 44.7658ºN, 125.5289ºW, 2850 m, R/ V Wecoma, cr. W9704A, sta. 3, 40-ft otter trawl, coll. J. Voightt, 17 Apr. 1997 ; FMNH 117111 (1, 99.1 mm HL, 487+ mm TL), off Newport , 44.7594ºN, 125.5311ºW, 2850 m, R/ V Wecoma, cr. W9704A, sta. 2, 40-ft otter trawl, coll. J. Voightt, 17 Apr. 1997 ; FMNH 119802 (1, 105 mm HL, 557+ mm TL), off Newport , 44.7594ºN, 125.5311ºW, 2850 m, R/ V Wecoma, sta. 2, otter trawl, coll. J. Voightt, 17 Apr. 1997 .

Counts and measurements. Based on 14 specimens (78.8–116 mm HL, 400–626+ mm TL). Counts: first dorsal-fin rays II,12–15; pectoral-fin rays i20–i24; pelvic-fin rays 9–10; gill rakers on first arch (outer/inner) 6–12/12–16, on second arch 12–16/12–15; longitudinal scales 40–50; transverse scale rows below first dorsal-fin origin 8.5–13.5, below first dorsal-fin midbase 6–11.5, below second dorsal-fin origin 8–12, above anal-fin origin 36.5–37.5.

The following measurements are in % of HL, followed by those in % of PRL in parentheses: snout length 25–27 (33–37); orbit diameter 24–29 (32–38); postorbital length 48–53 (64–69); postrostral length 74– 77; orbit–preopercle distance 42–46 (56–61); suborbital width 10–13 (13–17); upper-jaw length 38–43 (50–57); length of rictus 33–37 (43–48); length of premaxillary tooth band 29–33 (37–43); preoral length 11–13 (15–18); distance between tip and lateral angle of snout 12–16 (16– 20); snout width 19–22 (25–29); internasal width 16–18 (21–24); interorbital width 24–28 (32–37); body width over pectoral-fin bases 45–60 (60–78); body depth at first dorsal-fin origin 70–83 (93–111); body depth at anal-fin origin 54–72 (71–97); prepelvic length 98–108 (129–144); preanus length 141–163 (182–218); preanal length 146– 169 (189–226); isthmus–pelvic distance 38–47 (51–62); isthmus–anus distance 108 (145); isthmus–anal distance 87–115 (116–154); pelvic–anal distance 46–72 (61–96); anus–anal distance 7 (10); pelvic-fin length 76–103 (99– 140); pectoral-fin length 56–70 (74–91); predorsal length 98–116 (133–152); height of first dorsal fin 91–105 (121–139); length of first dorsal-fin base 28–36 (37–48); interdorsal length 11–27 (15–36); length of gill slit 19–23 (25–31); length of posterior nostril 8–10 (10–14); barbel length 8–11 (11–15).

Size. Attains about 66 cm TL ( Mecklenburg et al. 2002).

Development. Descriptions of larvae and juveniles were given by Stein (1980).

Distribution. Widely distributed in the North Pacific from the Okhotsk Sea off Hokkaido (Appendix 3-6C), north to Alaska, and east to southern California ( Iwamoto & Stein 1974; Endo et al. 1994; Mecklenburg et al. 2002; this study). Depth range 1285‾ 1348 m in Japan, but much greater in other parts of its range (2065–2904 m; Iwamoto & Stein 1974). Very rare in Japanese waters.

Remarks. Coryphaenoides filifer was originally described by Gilbert (1896) based on three specimens collected from the northeastern Pacific off Queen Charlotte Island, Canada. One of these specimens deposited at the Smithsonian Institution (USNM 48626) is in poor condition, with the head and body badly deteriorated into many parts ( Fig. 92B ), which made it impossible to reconfirm the species’ diagnostic features. Unfortunately, the other two types were not found in the course of this study. This species was first recorded from Japan by Endo et al. (1994) based on two specimens collected from the Kitami-Yamato Bank in the southern margin of the Okhotsk Sea. For further morphological information see Iwamoto & Stein (1974) and Endo et al. (1994).

Nomenclatural discussion. The spelling of the specific epithet of this species is open to discussion. Although most previous authors used “ filifer ” (e.g., Gilbert & Hubbs 1916; Iwamoto & Stein 1974; Iwamoto 1990; Nakabo 1993, 2000, 2002; Eschmeyer 1998; Mecklenburg et al. 2002; Nakabo & Kai 2013; Nakabo & Hirashima 2015), some recent authors considered “ filiferus ” to be grammaticallycorrect(Fricke etal. 2020; Motomura2020). As a species of the feminine nominal genus Chalinura Goode & Bean, 1883 (= Fuyangia Whitley, 1931 ; see the Relationships of C. leptolepis ), Gilbert (1896) originally described the species as Ch. filifera . This specific epithet is considered a feminine form of “ filifer ”, which is derived from the combination of the Latin noun filum, meaning a thread, and the Latin adjectival suffix -fer (-fera, -ferum), denoting carrying (probably in allusion to the species’ elongate outer pelvic-fin ray). However, filifera can also be regarded as a feminine form of “ filiferus ”, because the suffix -fer is occasionally modified to -ferus (-fera, -ferum; Glare 1968:685). Because Gilbert (1896) did not mention the etymology of his filifera , the masculine form of this Latin adjective is currently unclear. However, the spelling “ filifer ” is considered to have priority in this case for the following three reasons: 1) Gilbert & Hubbs (1916), who were the first to recognize the species under a masculine genus ( Coryphaenoides ), inflected the spelling of the word as “ filifer ”; 2) the spelling “ filifer ” has been consistently used for the species for more than a century (with Coryphaenoides ); and 3) the suffix -ferus can be regarded as a supplementary modification of -fer [in the Oxford Latin Dictionary ( Glare 1968:685) the explanation of -ferus appears within the heading of -fer], and there are no grammatical reasons to choose -ferus, rather than -fer, for the species.

Relationships and comparisons. Coryphaenoides filifer belongs to the subgenus Coryphaenoides (sensu Iwamoto 1990) . It is superficially similar to two Japanese congeners, C. altipinnis G̹nther, 1877 and C. cinereus ( Gilbert, 1896) . For comparisons with the latter two species see the Relationships and comparisons of C. altipinnis and C. cinereus .

Figures

FIGURE 107. Fresh specimen of Coryphaenoides filifer. HUMZ 126365, 92.5 mm HL, 506+ mm TL, northwest of Shiretoko Peninsula, Hokkaido, Okhotsk Sea, 1348 m depth. Lateral view. [Photo: HUMZ]

FIGURE 108. Preserved specimen of Coryphaenoides filifer. HUMZ 126365, 92.5 mm HL, 506+ mm TL, northwest of Shiretoko Peninsula, Hokkaido, Okhotsk Sea, 1348 m depth. (A) Lateral view; (B) dorsal and (C) ventral views of the head and trunk. [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]

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]