Lycenchelys albomaculata Toyoshima, 1983

Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, Zootaxa 4762 (1), pp. 1-66 : 6-10

Lycenchelys albomaculata Toyoshima, 1983

(Japanese name: Shirobuchi-hebigenge)

( Figs. 1–4 ; Table 1)

Lycenchelys albomaculatus Toyoshima, 1983: 141 , 269, 333, figs. 16–19, pl. 92, 156 (original description, type locality: off Kamaishi, Iwate Prefecture, Pacific coast of Honshu, Japan); Toyoshima, 1984: 293, pl. 274-C (brief description); Toyoshima, 1985: 159, figs. 6–7, 16–19, 31, table 1 (description); Hatooka, 1993: 904, unnumbered fig. (key to species); Amaoka et al., 1995: 241, pl. 404 (brief description); Imamura, 1997: 60 (species list); Koyanagi, 1997: 538, fig. 1 (brief description); Imamura, 1998: 30, fig. 7 (brief description); Zama, 2001: 86, 133 (species list).

Lycenchelys albomaculata: Anderson, 1994: 112 , 117 (species list); Shinohara et al., 1996: 180 (species list); Hatooka, 2000: 1035, unnumbered fig. (keys to species); Hatooka, 2002: 1035, unnumbered fig. (key to species); Anderson & Fedorov, 2004: 15 (species list); Shiogaki et al., 2004: 71 (species list); Shinohara & Anderson, 2007: 64 (key to species); Kitagawa et al., 2008: 95, unnumbered fig. (brief description); Shinohara et al., 2009: 723 (species list); Amaoka et al., 2011: 319, unnumbered fig. (brief description); Balushkin et al., 2011: 978 (catalog of specimens); Hatooka, 2013: 1229, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name).

Material examined

Holotype: HUMZ 59531 , male, 406.6 mm SL, off Kamaishi , Iwate Prefecture, Tohoku District, northwestern Pacific , 14 Oct. 1976.

Paratypes (19 specimens, 326.8–438.5 mm SL, all from Tohoku District, northwestern Pacific): HUMZ 72538– 39, 1 male and 1 female, 356.0– 356.4 mm SL, off Fukushima Prefecture (38°00’N, 142°10.05’E), 800–810 m depth, 6 Feb. 1978; HUMZ 72645–46, 2 males, 389.5–390.9 mm SL, off Fukushima Prefecture (37°26.5’N, 142°09.5’E), 900 m depth, 20 Jan. 1978; HUMZ 72656–57, 1 male and 1 female, 326.9–397.0 mm SL, off Miyagi Prefecture (38°02’N, 142°29’E), 1100–1150 m depth, 7 Feb. 1978; HUMZ 72708, 1 female, 326.8 mm SL, off Fukushima Prefecture (36°58.8’N, 141°47.5’E), 800 m depth, 19 Jan. 1978; HUMZ 72723, 1 male, 387.4 mm SL, off Fukushima Prefecture (37°11’N, 141°57’E), 810–820 m depth, 18 Jan. 1978; HUMZ 72734, 1 female, 358.2 mm SL, off Miyagi Prefecture (38°04’N, 142°12.2’E), 815–820 m depth, 30 Jan. 1978; HUMZ 78063, 1 male, 413.6 mm SL, off Iwate Prefecture (40°21.6’N, 142°25.6’E to 40°26.8’N, 142°22.1’E), 915–945 m depth, 25 Sep. 1978; HUMZ 78074, 1 male, 405.2 mm SL, off Iwate Prefecture (39°22.7’N, 142°36.5’E to 39°27.9’N, 142°40.2’E), 1290– 1300 m depth, 21 Sep. 1978; HUMZ 78082–83, 2 females, 365.0– 371.2 mm SL, off Iwate Prefecture (39°42.6’N, 142°47.5’E to 39°36.4’N, 142°44.2’E), 1120–1130 m depth, 23 Sep. 1978; HUMZ 78087, 1 female, 393.2 mm SL, off Iwate Prefecture (40°04.5’N, 142°43.5’E to 40°10.0’N, 142°39.3’E), 1095–1100 m depth, 25 Sep. 1978; HUMZ 78142, 1 female, 370.6 mm SL, off Iwate Prefecture (39°04.5’N, 142°22.7’E to 39°10.3’N, 142°25.0’E), 980–1000 m depth, 19 Sep. 1978; HUMZ 78200, 1 male, 436.0 mm SL, off Iwate Prefecture (39°40’N, 142°48.4’E to 39°45.3’N, 142°53’E), 1180–1230 m depth, 23 Sep. 1978; HUMZ 78262, 1 male, 434.5 mm SL, off Aomori Prefecture (40°48.9’N, 142°26.2’E to 40°44.4’N, 142°30.5’E), 1120–1165 m depth, 11 Sep. 1978; HUMZ 78269, 1 female, 413.0 mm SL, off Aomori Prefecture (40°47.6’N, 142°16.7’E to 40°41.5’N, 142°19.2’E), 920–948 m depth, 11 Sep. 1978; HUMZ 78322, 1 male, 438.5 mm SL, off Aomori Prefecture (41°02.4’N, 142°11.9’E to 41°08.1’N, 142°12.2’E), 1200–1205 m depth, 8 Sep. 1978.

Other specimens (40 specimens, 141.4–508.0 mm SL): HUMZ 72495, 72537, 72610–11, 72648, 72704, 72733, 72738, 180859, 180870, 180879, 180883, 180900, 182282, 182314, 182316, 182318–19, 182326, 209261, 214430–31, 214626, 226944, 12 males and 12 females, 141.1–386.4 mm SL, Tohoku District, northwestern Pacific; HUMZ 119854–55, 120153, 123913, 126048, 126353–55, 4 males and 4 females, 195.3– 508.0 mm SL, eastern Hokkaido Island, northwestern Pacific; HUMZ 133184, 196387–88, 205185, 205192, 205194, 215072, 228077, 4 males and 4 females, 397.5–454.1 mm SL, northeastern Hokkaido Island, Okhotsk Sea.

Diagnosis. Vertebrae 22–25 + 99–105 = 122–128; head length 14.3–20.4% SL; interorbital pore 1; occipital pores 3; postorbital pores 4; suborbital pores 7–9 + 2–3; preoperculomandibular pores usually 9; vomerine teeth 2–10; palatine teeth 2–18, arranged in 1 or 1–2 rows; opercular flap well developed; pelvic-fin base positioned posterior to lower edge of gill opening; lateral line complete and positioned ventrally; scales present on pectoral fin and its base; body blackish brown when fresh; 6–10 white blotches present above upper edge of gill opening and on dorsal fin extending onto dorsal part of body.

Description. Counts and proportional measurements in Table 1.

Body elongate, cross section oval anteriorly, compressed posteriorly; its width at anal-fin origin 3.1–6.0 (5.6)% SL. Head moderately long, ovoid, dorsal profile of head sloping extremely gently to dorsal-fin origin. Cheek swol- len in large males (including holotype), more so than in females and small males. Head of adults longer in males than in females. Snout short, 72.5–219.1 (145.1)% of eye diameter. Eye ovoid, relatively large. Interorbital space relatively narrow in adults, wide in juveniles; its width 8.9–29.6 (17.5)% of eye diameter. Nostril tube short, not reaching upper lip when depressed. Mouth subterminal. Posterior edge of upper jaw reaching vertical through posterior margin of eye in adult males (including holotype), reaching below middle or posterior part of eye in females and juveniles. Labial lobe of lower jaw developed in adults (including holotype). Teeth on jaws, vomer and palatine small and conical; upper jaw with single row, sometimes having some additional teeth behind anterior teeth (including holotype); lower jaw with 2–4 irregular rows anteriorly and 1–2 rows posteriorly; vomerine teeth irregularly arranged; palatine teeth in 1 or 1–2 rows (1). Lower edge of gill opening below lower end of pectoral-fin base. Opercular flap well developed. Gill rakers short; those on upper limb triangular, many triangular and some blunt on lower limb ( Fig. 2 ). Pseudobranch filaments long. Lateral line deciduous, complete and positioned ventrally; originating posterior to last postorbital pore and terminating on tail. Scales small and cycloid, present on body, pectoral axilla, about basal half of pectoral fin, pectoral-fin base, tail and most of vertical fins except margins. Scales covering nape in adults (including holotype), but not in some juveniles. Head without scales.

Dorsal-fin origin above middle of pectoral fin; 1st dorsal-fin pterygiophore between neural spines of 3rd to 5th (unknown for holotype) vertebrae. Anal-fin origin below 17th to 20th (unknown for holotype) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate or penultimate abdominal vertebra (unknown for holotype). Last dorsal-fin pterygiophore between neural spines of 2nd to 5th (unknown for holotype) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 2nd to 4th (unknown for holotype) preural vertebrae. Caudal fin with 1–2 epural, 4–5 upper hypural and 3–5 lower hypural rays (unknown for holotype). Pectoral fin moderately long in juveniles, becoming relatively short in adults (including holotype); tip reaching or over middle of abdomen in juveniles, not quite reaching middle portion of abdomen in adults (including holotype); its posterior margin rounded. Upper end of pectoral-fin base on about lateral midline of body. Pelvic fin short; its base posterior to lower edge of gill opening; its posterior margin not reaching pectoral-fin base in adults (including holotype), reaching pectoral-fin base in some juveniles.

Head pores small and distinct. Usually 2 nasal pores (including holotype); anterior pore in front of nostril tube, posterior pore about above 1st suborbital pore; third pore present above nostril tube on left side in HUMZ 78087 and on both sides in HUMZ 214430 ( Fig. 4A, B ). Postorbital pores 4; distance between 1st and 2nd pores longest of those between adjacent pores ( Fig. 4A, B ). Suborbital pores 9–11 (10); 7–9 (8) pores located below eye and remaining 2 or 3 (2) pores on ascending part of suborbital canal behind eye; 5th pore about below anterior margin of pupil; last pore below eye located posterior to vertical through posterior margin of eye ( Fig. 4A ). Preoperculomandibular pores usually 9 (including holotype), 4 on lower jaw, 2 on junction of lower jaw and preopercle, and 3 on preopercle; some specimens with 8 pores having only 1 pore on junction of lower jaw and preopercle; HUMZ 72734 having 10 pores with 4 pores on preopercle of right side; last preoperculomandibular pore located posterior to lower part of eye ( Fig. 4A, C ). One interorbital pore located anterior to center of eyes ( Fig. 4B ). Occipital pores 3; 1 on midline of occiput, and remaining 2 on left and right sides; middle pore located slightly posterior to other two; all pores located anterior to 3rd postorbital pore ( Fig. 4B ).

Color in alcohol. Holotype ( Fig. 3 ) with head, body and vertical fins brown, opercular region and pectoral fin darker; nine white blotches present dorsally, 1 above upper edge of gill opening and 8 on dorsal fin extending onto dorsal part of body. Paratypes and long preserved non-type specimens with coloration similar to holotype but more recently preserved specimens darker than holotype with one white blotch above upper edge of gill opening and another 5–9 on dorsal fin and dorsal part of body. Juveniles having narrower white blotches than adults.

Color when fresh (based on color photograph of HUMZ 228077; Fig. 1 ). Head, body, pectoral-fin base and vertical fins blackish brown, pectoral fin and margin of vertical fins darker. Ten white blotches; 1 above upper edge of gill opening, 9 on dorsal fin extending onto dorsal part of body.

Distribution. The Okhotsk Sea and off the northwestern Pacific coast of the Kuril Islands, and the eastern side of Hokkaido Island to the Ibaraki Prefecture, at depths of 400–1505 m ( Toyoshima, 1983, 1984, 1985; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1994; Amaoka et al., 1995, 2011; Shinohara et al., 1996; Imamura, 1997, 1998; Koyanagi, 1997; Zama, 2001; Anderson & Fedorov, 2004; Shiogaki et al., 2004; Shinohara & Anderson, 2007; Kitagawa et al., 2008; Shinohara et al., 2009; Balushkin et al., 2011; this study).

Size. The largest specimen recorded during this study was 508.0 mm SL (518.6 mm TL), exceeding the previously recorded maximum length of 50 cm TL ( Amaoka et al., 1995, 2011; Koyanagi, 1997; Imamura, 1998).

Remarks. Lycenchelys albomaculata is characterized by the presence of white blotches on the body. Although Lycenchelys bachmanni Gosztonyi, 1977 also has paler blotches on the body (vs. paler blotches absent in other species of Lycenchelys ), its blotches are yellowish ( Gosztonyi, 1977; Nakamura, 1986). In addition, L. albomaculata is easily separable from L. bachmanni in having a scaled and dark pectoral fin (vs. naked and yellowish white in L. bachimanni ) ( Gosztonyi, 1977; Nakamura, 1986). Furthermore, L. albomaculata has a higher number of gill rakers (1–3 + 11–14 = 13–17 in L. albomaculata vs. 2 + 8 = 10 in L. bachimanni ) ( Gosztonyi, 1977; Nakamura, 1986; this study).

Toyoshima (1983, 1985) described the occipital pores of L. albomaculata to be “absent”. However, this study found 3 occipital pores in all specimens of L. albomaculata , including the holotype ( Fig. 4B ).

Figures

FIGURE 1. Lycenchelys albomaculata, HUMZ 228077, 454.1 mm SL, fresh condition.

FIGURE 2. Lycenchelys albomaculata, HUMZ 180789, 216.0 mm SL, male, gill rakers on 1st gill arch (right side). White arrows point to uppermost and lowermost gill rakers. Bar = 0.5 mm.

FIGURE 3. Lycenchelys albomaculata, HUMZ 59531, holotype, 406.6 mm SL, male, in alcohol.

FIGURE 4. Lycenchelys albomaculata, HUMZ 228077, 454.1 mm SL, male, views of head showing positions of head pores. (A) Lateral, (B) dorsal and (C) ventral.