Allocyttus folletti Myers, 1960

Hoshino, Koichi, Kosaka, Kunpei, Sawada, Kota & Kiyota, Masashi, 2022, Identification of the Commercially Important Oreosomatid Fish (Zeiformes: Teleostei) of the Emperor Seamounts, with Comments on Diagnostic Characters of the Species, Species Diversity 27 (1), pp. 1-13 : 3-6

Allocyttus folletti Myers, 1960

( Figs 1A, C, E , 2A, C , 3 )

Allocyttus verrucosus (non Gilchrist, 1906): Welander et al. 1957: 245–246 (description; off North Pacific); Abe and Hotta 1962: 152–156, figs 1–8 (description; off Kinkazan, Japan); Kobayashi et al. 1968: 1–5, pl. I (description; western Bering Sea and western North Pacific); Maruyama 1970: 52–54, fig. 9 (description; off Erimo, Japan); Maruyama 1971: 33, fig. 36 (list; off Erimo, Japan); Kido 1983: 126–127, 203, fig. (description: Japan); Machida 1984: 118, pl. 103-A (description; Japan); Ida et al. 1992: 86, fig. (description; off Iwate Pref., Japan); Nakabo 1993: 467, 3 figs (pictorial key); Amaoka et al. 1995: 127, fig. (description; Hokkaido, Japan); Inada 1997: 168, fig. (note on distribution; off Kushiro, Japan); Nakabo 2000: 508, 3 figs. (pictorial key); Nakabo 2002: 508, 3 figs (pictorial key); Tokranov et al. 2004: 210–212, figs 1–3 (distribution, length-weight relationship; Northern Kurile Islands and Southeast Kamchatka); Kitagawa et al. 2008: 50, fig. (diagnosis; Japan); Amaoka et al. 2011: 168, fig. (description; Hokkaido, Japan).

Allocyttus folletti Myers, 1960: 89–98 , fig. 1 (original description; type locality: California); Miller and Lea 1972: 84–85, fig. (diagnosis); Anderson et al. 1979: 262 (meristics; California); Eschmeyer and Herald 1983: 126, pl. 48, fig. 18 (diagnosis); Nagtegaal 1983: 89, fig. 1 (description; British Columbia); Cook and Long 1985: 57 (occurrence; Bering Sea); Gillespie and Saunders 1994: 348 (description; British Columbia); Ward et al. 1996: 41 (diagnosis); Mecklenburg et al. 2002: 327–329, 2 figs (diagnosis; Alaska); Nakabo and Kai 2013: 601, 1902, 3 figs (pictorial key, taxonomic note); Kamikawa 2017: 176, fig. (description; West Coast of U. S. A.); Amaoka et al. 2020: 207, figs (description; Hokkaido, Japan).

Allocyttus sp. : Hart 1973; 266–267, fig. (description of juvenile; mid-Pacific, west of British Columbia).

Material examined. Emperor Seamounts — 21 specimens. SNFR 10560 (n=1), 293.4 mm SL, Koko Seamount, 35°39′N, 171°03′E to 35°38′N, 171°03′E, 361– 355 m deep, 24 July 2007, F/ V Tomi-maru No . 58; SNFR 10561 (n=4), 301–347 mm SL, collected with SNFR 10560 ; SNFR 11127 (n=1), 279.4 mm SL, Kinmei Seamount, 33°40.0′N, 172°00.0′E, 600 m, 13 May 1994; SNFR 18692 (n=1), 537 mm SL, Kinmei Seamount, 33°46′N, 171°54′E, 850–893 m, 27 September 2012, F/ V Shoshin-maru No . 88; SNFR 22400–22408 (n=9), 269.3–300.8 mm SL, Yuryaku Seamount, 32°19.16′N, 172°19.25′E to 32°40.63′N, 172°13.09′E, 486–670 m, 5 February 2019, F/ V Kaiyo-maru No . 38; NSMT-P 72807 (n=1), 337 mm SL, Colahan Seamount, 31°01′N, 175°54′E to 31°02′N, 175°52′E, 285 m, 17 September 2005, F/ V . Yokei-maru No. 5; FAKU72487 (n=1), 328 mm SL, Kinmei Seamount, 33°40′N, 172°00′E, 600 m, 13 May 1994; FAKU72575 (n=1), 397 mm SL, collected with FAKU72487 ; FAKU119906 (n=1), 321 mm SL, Hancock Seamounts, 3 March 1973, R / V Kaiyomaru; FAKU119907 (n=1), 382 mm SL, collected with FAKU119906 .

Description. Meristics are presented in Table 1, and morphometrics as % of SL1 and SL2 are presented in Tables 2 and 3 respectively. Body oval, laterally compressed and deep; deepest at dorsal-fin origin, its depth greater than head length. Predorsal profile usually slightly convex (but sometimes straight) from dorsal-fin origin to vertical through uppermost end of gill opening, slightly concave or straight in front of same vertical. Snout profile steep. Thorax flat ventrally. Midline of abdomen gently keeled between pelvic-fin origin and anus (abdominal edge). Caudal peduncle slender, deeper posteriorly ( Fig. 1C ), deepest at caudalfin base.

Head large, 34.6–39.3% of SL1. Eye large, 12.5–18.4% of SL1. Mouth large, oblique, greatly extensible. Maxillary extending posteriorly nearly to below middle of eye when mouth closed. Opercular bones with radiated bony striations, scaleless, except opercle sparsely scaled. Numerous spinules on all exposed bones on head. Nasal projected anteriorly above anterior nostril, with enlarged spinules (more prominent in larger specimens). Nostrils close together: anterior one circular, oriented anteriorly; posterior one vertically elongate, oriented laterally, immediately anterior to eye. Nasal projected forward above posterior nostril ( Fig. 1E ). Lower surface of dentary with numerous spinules and longitudinal striations. Teeth on both jaws minute, conical, slightly curved inward, in irregular 1–3 rows. Vomerine teeth similar to jaw teeth in shape, size and arrangement. Palatine teeth absent.

Dorsal-, anal-, and pelvic-fin spines robust, densely striated; first dorsal-fin spine about one-third of second spine in length. First anal-fin spine longer than second and third spines. All dorsal-, anal- and pectoral-fin soft rays simple, densely segmented. Spinous and soft-ray portions of anal fin continuous, with low membrane. Pectoral fin small, round- ed, posterior margin falling slightly short of vertical through anal-fin origin. Pelvic fin reaching or extending slightly beyond anus when depressed, its spine reaching or falling slightly short of anus. Caudal fin rounded.

Lateral line gently arched, nearly parallel to dorsal contour in anterior two-thirds, posterior third straight. Scales mostly cycloid and deciduous mid-laterally ( Fig. 2A ), and on caudal peduncle, basal part of caudal fin and lateral line; thickened cycloid or ctenoid with a few spinules on lower side of thorax and abdomen; thickened ctenoid with prominently enlarged and elevated spinules at nape and ventral surface of thorax and abdomen; those on ventral midline of abdomen especially thickened and enlarged in large specimens; row of enlarged scales along base of dorsal and anal fins (S-DFB and S-AFB respectively) forming sheath of scales, with up to 7–12 (margin) and 1–3 (center) elevated spines per scale ( Fig. 2C ). Single row of smaller scales with 1–3 spinules along medial side of S-DFB and S-AFB. Two nearly horizontal rows of scutes (assemblage of somewhat enlarged scales) on abdomen between pectoral and pelvic fins; in upper row enlarged scales forming 1–5 patches, weak or dislodged in some specimens; in lower row, enlarged scales forming continuous row ( Fig. 3A ). Body uniformly dark brown or grayish brown, fins darker; cheek and opercles blueish.

Distribution. Emperor Seamounts ( Mundy 2005; present study), Bering Sea and Pacific Ocean east to Central California and west to Japan (from Hokkaido to Ibaraki Prefecture) ( Mecklenburg et al. 2002; Nakabo and Kai 2013).

Figures

Fig. 1. Lateral view of oreosomatids. A, Allocyttus folletti from the Emperor Seamounts, SNFR 22402, 289.8mm SL; B, Allocyttus verrucosus from New Zealand, NSMT-P 41168, 187.2mm SL; caudal peduncle of A. folletti; C, SNFR 10560, 293.4mm SL, Emperor Seamounts, and that of A. verrucosus; D, NSMT-P 41168, 187.2mm SL, New Zealand; nasal of oreosomatids; E, A. folletti, SNFR 10561, 347mm SL, Emperor Seamounts; F, A. verrucosus, NSMT-P 113107, 238.4mm SL, west coast of Australia. Abbreviations: NA, nasal; PN, posterior nostril.

Fig. 2. Scales on mid-side of body in, (A) Allocyttus folletti, FAKU 72575, 397mm SL, Emperor Seamounts, and (B) Allocyttus verrucosus, NSMT-P 113107, 238.4mm SL, Australia; enlarged scales of dorsal-fin base (S-DFB) in (C) A. folletti, SNFR 22403, 289.3mm SL, Emperor Seamounts, and (D) A. verrucosus, BSKU 48476, 136.5mm SL, off South Africa.

Fig. 3. Lateral aspect (above) and abdomen (below) of Allocyttus folletti. A, SNFR 10560, 293.4mm SL, Emperor Seamounts; B, CAS-SU 15377, holotype of Allocyttus folletti, off California, traced from Myers (1960: fig.1). Arrows indicate the rows of scutes.