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Lycenchelys ryukyuensis Shinohara & Anderson, 2007 (Japanese name: Ryukyu-hebigenge) (Figs. 36���37; Table 9) Lycenchelys ryukyuensis Shinohara & Anderson, 2007: 59, figs. 1���3, table 1 (original description, type locality: Okinawa Trough, Ryukyu Islands, East China Sea, Japan); Hatooka, 2013: 1225, 2078, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 216 (species list and etymology of scientific name). Materials examined Holotype: NSMT-P 63965, male, 159.3 mm SL, Okinawa Trough, eastern Ryukyu Islands, East China Sea (26��11.34���N, 124��54.27���E to 26��12.65���N, 124��55.47���E), 1493���1533 m depth, 26 Apr. 2002, R/V Tansei-maru, beam trawl. Paratypes (2 specimens): NSMT-P 63966���67, 2 females, 116.9���142.6 mm SL, collected with holotype. Diagnosis. Vertebrae 22���24 + 96���102 = 118���124; head length 14.1���14.4% SL; intertorbital pores and occipital pores absent; postorbital pores usually 3; suborbital pores 6 + 1���2; preoperculomandibular pores 8; vomerine teeth 2���4; palatine teeth 1���2, arranged in single row; opercular flap well developed; pelvic-fin base positioned anterior to lower edge of gill opening; lateral line complete and positioned ventrally; scales absent on pectoral fin and its base; body uniformly grayish brown when fresh. Description. Counts and proportional measurements in Table 9. ....Continued next page Body very elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 3.4���4.0 (3.4)% SL. Head moderately short, oval, dorsal profile of head gently sloping to above pectoral-fin base. Snout short, 133.7���149.7 (149.7)% of eye diameter. Eye ovoid, relatively small. Interorbital space narrow, width 19.7���22.9 (19.7)% of eye diameter. Nostril tube short, not reaching upper lip when depressed. Mouth subterminal. Posterior edge of upper jaw reaching to about vertical through middle of eye in adult male (holotype), reaching to below anterior margin of eye in females (2 paratypes). Labial lobe of lower jaw reduced. Teeth on jaws, vomer and palatine small and conical; upper jaw with 2���3 rows anteriorly and 1���2 rows posteriorly; lower jaw with 2���3 irregular rows anteriorly and 1���2 rows posteriorly; vomerine teeth irregularly arranged; palatine teeth in single row. Lower edge of gill opening about level with lower end of pectoral-fin base. Opercular flap well developed. Gill rakers short and triangular. Pseudobranch filaments extremely short. Lateral line deciduous. Scales small and cycloid, present on body, tail and about basal half of vertical fins. Head, nape, pectoral fin and its base lacking scales. Dorsal-fin origin above middle of pectoral fin; 1st dorsal-fin pterygiophore between neural spines of 7th and 8th vertebrae. Anal-fin origin below 15th or 16th (15th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate abdominal vertebra. Last dorsal-fin pterygiophore between neural spines of 3rd to 5th (between 4th and 5th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 3rd to 5th (between 4th and 5th) preural vertebrae. Caudal fin with 2 epural, 4���5 (4) upper hypural and 3 lower hypural rays. Pectoral fin moderately short, reaching to about middle of abdomen; its posterior margin rounded dorsally and notched ventrally. 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 reaching lower edge of gill opening. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above 1st suborbital pore (Fig. 37A, B). Postorbital pores 3 (Fig. 37A, B); distance between 1st and 2nd pores longest of those between adjacent pores. Suborbital pores 7 or 8 (7); 6 pores below eye and last 1 or 2 (1) pore(s) on ascending part of suborbital canal behind eye; 6th pore behind vertical through posterior margin of eye (Fig. 37A). Preoperculomandibular pores 8; 4 on lower jaw and 4 on preopercle; last preoperculomandibular pore posterior to lower margin of eye (Fig. 37A, C). Interorbital pores and occipital pores absent (Fig. 37B). Color in alcohol. Holotype (Fig. 36; lacking body skin) with dark brown head and pectoral fin, flesh colored body, grayish vertical fins, and pale brown margins on vertical fins. Color when fresh [based on color photograph in Shinohara & Anderson (2007)]. Head and pectoral fin blackish, body grayish, and margins of vertical fins dark brown. Distribution. East China Sea off the eastern Ryukyu Islands and in the Okinawa Trough, at depths of 991���1533 m (Shinohara & Anderson, 2007; Hatooka, 2013; this study). Size. Maximum length 17 cm TL (Hatooka, 2013). The largest specimen examined during this study measured 159.3 mm SL (161.6 mm TL). Remarks. Shinohara & Anderson (2007) compared L. ryukyuensis with Lycenchelys aratrirostris Andriashev & Permitin, 1968, Lycenchelys bellingshausenni Andriashev & Permitin, 1968, Lycenchelys folletti Anderson, 1995, Lycenchelys lonchoura Anderson, 1995 and Lycenchelys maoriensis Andriashev & Fedorov, 1986. Although L. ryukyuensis is similar to these species in sharing a combination of five characters (no interorbital pores and occipital pores, usually 3 postorbital pores, presence of pelvic fins and a single ventrally positioned lateral line; Shinohara & Anderson, 2007), it is distinguishable from L. aratrirostris, L. bellingshausenni, L. folletti and L. lonchoura in having higher numbers of dorsal- and anal-fin rays, and total vertebrae (110���114, 98���104 and 118���124, respectively, in L. ryukyuensis vs. 97���107, 79���89 and 101���110 in L. aratrirostri, 94���103, 82���91 and 102���110 in L. bellingshausenni, 97���104, 83���92 and 102���109 in L. folletti, and 103, 86 and 107 in L. lonchoura), and from L. maoriensis in having 7���8 suborbital pores and no black or brown variegations along the body and tail in males (vs. 6 suborbital pores and black or brown variegations present in L. maoriensis) (Shinohara & Anderson, 2007). On the other hand, Lycenchelys polyodon Anderson & M��ller, 2007 also has the above-mentioned combination of 5 characters, but has not been compared with L. ryukyuensis. The two are difficult to separate on the basis of numbers of dorsal- and anal fin-rays, total vertebrae and suborbital pores (113, 105, 123 and 7, respectively, and no variegations on the body and tail in L. polyodon) (Table 9). However, L. ryukyuensis is clearly distinguished from L. polyodon in having considerably lower numbers of vomerine and palatine teeth (2���4 and 1���2 in L. ryukyuensis vs. 26 and 31���33 in L. polyodon) (Table 9)., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 42-45, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Anderson, M. E. & Moller, P. R. (2007) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. XIII. Two new species of Lycenchelys from the Southwestern Pacific. Species Diversity, 12, 175 - 185. https: // doi. org / 10.12782 / specdiv. 12.175","Anderson, M. E. (1995) The eelpout genera Lycenchelys Gill and Taranetzella Andriashev (Teleostei: Zoarcidae) in the eastern Pacific, with descriptions of nine new species. Proceedings of the California Academy of Science, 49, 55 - 133."]}

Lycenchelys aurantiaca Shinohara & Matsuura, 1998 (Japanese name: Daidai-hebigenge) (Figs. 5���8; Table 2) Lycenchelys aurantiaca Shinohara & Matsuura, 1998: 151, figs. 1���3, table 1 (original description, type locality: off Miyagi Prefecture, Pacific coast of Honshu, Japan); Imamura, 1998: 31, fig. 8 (brief description); Hatooka, 2000: 1033, unnumbered fig. (key to species); Hatooka, 2002: 1033, unnumbered fig. (key to species); Anderson & Fedorov, 2004: 15 (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: 318, unnumbered fig. (brief description); Balushkin et al., 2011: 1026 (species list); Hatooka, 2013: 1227, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Materials examined Holotype: NSMT-P 53147, male, 135.7 mm SL, off Miyagi Prefecture, Tohoku District, northwestern Pacific (37��58.54���N, 142��09.00���E to 37��56.84���N, 142��09.07���E), 700 m depth, 21 Apr. 1997, T/V Tanshu-maru, otter trawl. Other specimens (16 specimens, 91.6���141.3 mm SL): HUMZ 152389���90, 177032���33, 180582 ���83, 180864 ��� 67, 182661, 192779, 206876, 206878, 9 males and 5 females, 91.6���141.3 mm SL, Tohoku District, northwestern Pacific; HUMZ 192380���81, 1 male and 1 female, 102.2���123.8 mm SL, eastern Hokkaido Island, northwestern Pacific. Diagnosis. Vertebrae 19���20 + 66���70 = 85���89; head length 14.3���18.4% SL; interorbital pore 1; occipital pores absent; postorbital pores 4; suborbital pores 5 + 1; preoperculomandibular pores 7 (rarely 8); vomerine teeth 4���10; palatine teeth 8���25, arranged in single row; opercular flap well-developed; pelvic-fin base positioned anterior to lower edge of gill opening; lateral line incomplete and positioned ventrally; scales absent on pectoral fin and its base; body uniformly reddish orange when fresh. Description. Counts and proportional measurements in Table 2. ....Continued next page Body elongate, in cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 3.7���7.7 (4.0)% SL. Head short, ovoid; dorsal profile of head gently sloping to dorsal-fin origin. Cheek more swollen in large specimens (including holotype) than in small specimens. Head of adults longer in males than in females. Snout short, 67.5���111.4 (106.0)% of eye diameter. Eye ovoid, moderately large. Interorbital space narrow, width 10.9���33.7 (26.7)% of eye diameter. Nostril tube short, not reaching upper lip when depressed. Mouth subterminal. Posterior edge of upper jaw about reaching vertical through 5th suborbital pore in adult males (including holotype), reaching below posterior margin of eye in females and juveniles. Labial lobe of lower jaw weak. Teeth on jaws, vomer and palatine small and conical; upper jaw with 2���3 rows anteriorly and single row posteriorly; lower jaw with 2���4 irregular rows anteriorly and single row posteriorly; vomerine teeth irregularly arranged; palatine teeth in single row. Lower edge of gill opening slightly above lower end of pectoral-fin base. Opercular flap well developed. Gill rakers short and slender (Fig. 6). Pseudobranch filaments short. Lateral line deciduous, incomplete and positioned ventrally; originating posterior to last postorbital pore and ending anterior to anus. Scales small and cycloid, present on body, pectoral axilla, tail and about 40���60% vertical fins basally. Head, nape, pectoral fin and its base without scales. Dorsal-fin origin near vertical through posterior edge of opercular flap; 1st dorsal-fin pterygiophore between neural spines of 2nd and 3rd vertebrae. Anal-fin origin below 17th or 18th (18th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate abdominal vertebra. Last dorsal-fin pterygiophore between neural spines of 2nd to 5th (between 3rd and 4th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 2nd to 4th (between 3rd and 4th) preural vertebrae. Caudal fin with 2 epural, 3���4 (4) upper hypural and 4 lower hypural rays. Pectoral fin moderately short, reaching to middle of abdomen; its posterior margin rounded. Upper end of pectoral-fin base on about lateral midline of body. Pelvic fin short; its base anterior to lower edge of gill opening; its posterior margin reaching to or slightly beyond lower edge of gill opening. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above and slightly anterior to vertical through 1st suborbital pore (Fig. 8A, B). Postorbital pores 4; distance between 1st and 2nd pores longest of those between adjacent pores (Fig. 8A, B). Suborbital pores 6; 5 pores located below eye and 6th posterior to center of eye; 5th pore posterior to vertical through 1st postorbital pore (Fig. 8A). Preoperculomandibular pores usually 7 (including holotype); 4 on lower jaw and 3 on preopercle; 4 and 4 on left side of HUMZ 180866; last preoperculomandibular pore located posterior to lower margin of eye (Fig. 8A, C). One interorbital pore on dorsal midline between center of eyes (Fig. 8B). Occipital pores absent (Fig. 8B). Color in alcohol. Holotype (Fig. 7) with light brown head, body and vertical fins; light yellow pectoral fin and brown its ventral margin; light purple opercular region and abdomen. Head and body light brownish yellow and vertical fins whitish in HUMZ 206878. Coloration of other non-type specimens similar to holotype. Color when fresh (based on color photograph of HUMZ 152390; Fig. 5). Head, body and vertical fins uniformly reddish orange. Pectoral fin whitish, its ventral margin light brown. Opercular region and abdomen bluish black. Distribution. Off northwestern Pacific coast of eastern Hokkaido Island and off Tohoku District from Aomori to Fukushima prefectures, at depths of 500���756 m (Shinohara & Matsuura, 1998; Imamura, 1998; Hatooka, 2000, 2002, 2013; Anderson & Fedorov, 2004; Shinohara & Anderson, 2007; Kitagawa et al., 2008; Shinohara et al., 2009; Amaoka et al., 2011; this study). Size. The largest specimen examined during this study measured 141.3 mm SL (143.6 mm TL), exceeding the previously recorded maximum length of 135.8 mm SL (140 mm TL) (Shinohara & Matsuura, 1998; Hatooka, 2000, 2002, 2013; Amaoka et al., 2011). Remarks. Lycenchelys aurantiaca is similar to L. squamosa in having less than 100 total vertebrae, 1 interorbital pore, no occipital pores, 4 postorbital pores and no distinct spots or blotches on the body (vs. without this combination of characters in other species of Lycenchelys) (e.g., Toyoshima, 1983, 1985; Shinohara & Matsuura, 1998; Hatooka, 2000, 2002, 2013; Shinohara & Anderson, 2007; this study). Lycenchelys aurantiaca can be easily separated from L. squamosa in having lower numbers of dorsal-fin rays (82���86 vs. 88���91), anal-fin rays (68���72 vs. 73���77) and pectoral-fin rays (13���16 vs. 17���19), and total vertebrae (85���89 vs. 91���95), respectively. In addition, L. aurantiaca is distinguished from L. squamosa in having a uniformly reddish orange body when fresh and lacking scales on the pectoral fin and its base (vs. body uniformly dark brown when fresh and scales present on the pectoral fin and its base in L. squamosa) (Toyoshima, 1983, 1985; Shinohara & Matsuura, 1998; this study). Lycenchelys aurantiaca has previously been recorded only from off Tohoku District, the northwestern Pacific (Shinohara & Matsuura, 1998; Imamura, 1998; Hatooka, 2000, 2002, 2013; Anderson & Fedorov, 2004; Shinohara & Anderson, 2007; Kitagawa et al., 2008; Shinohara et al., 2009; Amaoka et al., 2011). Two specimens (HUMZ 192380, 192381) collected from off Kiritappu, eastern Hokkaido Island, the northwestern Pacific, and examined for this study, represent the first record of L. aurantiaca from Hokkaido waters., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 10-14, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Shinohara, G. & Matsuura, K. (1998) A new zoarcid, Lycenchelys aurantiaca, from the Pacific coast off northern Japan (Teleostei: Perciformes). Ichthyological Research, 45, 151 - 155. https: // doi. org / 10.1007 / BF 02678557","Imamura, H. (1998) Zoarcid fishes occurring off Pacific of Tohoku District. Researches on Basic Fishes in Tohoku District, 18, 28 - 34. [in Japanese]","Hatooka, K. (2000) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 2 nd edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1590 - 1593. [in Japanese]","Hatooka, K. (2002) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species, English edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1581 - 1583.","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Kitagawa, D., Imamura, H., Goto, T., Ishito, Y., Fujiwara, K. & Ueda, Y. (2008) Field guide of the fishes from the Tohoku District, north-eastern waters of Japan. Tokai University Press, Hadano, 141 pp. [in Japanese]","Shinohara, G., Narimatsu, Y., Hattori, T., Ito, M., Takata, Y. & Matsuura, K. (2009) Annotated checklist of deep-sea fishes from the Pacific coast off Tohoku District, Japan. In: Fujita, T. (Ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Science Museum of Nature and Science Monographs, Tokyo, 39, pp. 683 - 735.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Toyoshima, M. (1983) Zoarcidae. In: Amaoka, K., Nakaya, K., Araya, H. & Yasui, T. (Eds.), Fishes from the north-eastern Sea of Japan and the Okhotsk Sea off Hokkaido. The intensive research of unexploited fishery resources on continental slopes. Japan Fisheries Resource Conservation Association, Tokyo, pp. 136 - 149 + 208 - 210 + 258 - 277 + 329 - 335.","Toyoshima, M. (1985) Taxonomy of the subfamily Lycodinae (family Zoarcidae) in Japan and adjacent waters. Memoirs of the Faculty of Fisheries, Hokkaido University, 32, 131 - 243."]}

Lycenchelys makushok Fedorov & Andriashev, 1993 (Japanese name: Wakataka-hebigenge) (Figs. 17–20; Table 5) Lycenchelys makushok Fedorov & Andriashev, 1993: 130, figs. 1–2 (original description, type locality: off Iturup, Pacific cost of Kuril Islands); Anderson, 1994: 117 (species list); Shinohara et al., 1996: 180, fig. 2A (description); Imamura, 1997: 60 (species list); Imamura, 1998: 32, fig. 11 (brief description); Hatooka, 2000: 1032, 1590, unnumbered fig. (key to species); Hatooka, 2002: 1032, 1581, unnumbered fig. (key to species); Anderson & Fedorov, 2004: 18 (species list); Shinohara & Anderson, 2007: 63 (key to species); Kitagawa et al., 2008: 95, unnumbered fig. (brief description); Shinohara et al., 2009: 723 (species list); Amaoka et al., 2011: 316, unnumbered fig. (brief description); Balushkin et al., 2011: 981, 1024 (catalog of specimens); Hatooka, 2013: 1226, 2078, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Materials examined Holotype: ZIN 42290, 137.1 mm SL, off Iturup, Kuril Islands, northwestern Pacific (44°39.2’N, 149°02.2’E), 800 m depth, 10 Sep. 1968, R/V Vityaz, trawl. Other specimens (40 specimens, 111.2–168.7 mm SL): HUMZ 152378, 163847, 180633, 182293, 182295, 182383–89, 182395, 182478, 182480–82, 182484–85, 182487–88, 182519, 182636–44, 182646–47, 15 males and 19 females, 111.2–147.2 mm SL, Tohoku District, northwestern Pacific; HUMZ 192427 (4), 196342, 226078, 5 males and 1 females, 133.7–168.7 mm SL, eastern Hokkaido Island, northwestern Pacific. Diagnosis. Vertebrae 24–26 + 107–113 = 132–139; head 10.0–12.9% SL; interorbital pore 1; occipital pore usually 1; postorbital pores 4; suborbital pores usually 7 + 1; preoperculomandibular pores usually 10; vomerine teeth 4–13; palatine teeth 5–12, arranged in single row; opercular flap well developed; pelvic-fin base positioned anterior to lower edge of gill opening; lateral line incomplete and positioned ventrally; scales present or absent on pectoral fin and absent on its base; body uniformly grayish brown when fresh. Description. Counts and proportional measurements in Table 5. Body strongly elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 2.1–3.6% SL (unknown for holotype). Head very short, ovoid, dorsal profile of head gently sloping from above posterior edge of eye to about above last postorbital pore. No sexual dimorphism in head recognized. Snout short, 103.3–162.8 (152.2)% of eye diameter. Eye ovoid, relatively small. Interorbital space narrow, width 10.0–43.5 (43.5)% of eye diameter. Nostril tube short, quite not reaching upper lip when depressed. Mouth subterminal. Posterior edge of upper jaw reaching about to about vertical through anterior margin of pupil in adult males, not reaching vertical through anterior margin of pupil in females and juveniles. Labial lobe of lower jaw weak. Teeth on jaws sharp, anterior teeth large and posterior teeth small; upper jaw with single row, sometimes having additional small teeth behind anteriormost tooth (unknown for holotype); lower jaw with 2–3 irregular rows anteriorly and single row posteriorly; vomerine teeth large and conical, arranged irregularly; palatine teeth smaller than vomerine teeth, arranged in single row. Lower edge of gill opening slightly above lower end of pectoral-fin base. Opercular flap well developed. Gill rakers short and triangular (Fig. 18). Pseudobranch filaments short. Lateral line deciduous, incomplete and positioned ventrally; originating posterior to 5th postorbital pore terminating its end area above about middle of anal fin. Scales small and cycloid, present on body and tail. Scales covering basal portions of dorsal and anal fins anteriorly; extent of scaled areas gradually increasing posteriorly, except at margins. Scales present or absent on pectoral axilla and basal portions of lower pectoral-fin rays (unknown for holotype). Head, nape and pectoral-fin base without scales. ....Continued next page Dorsal-fin origin above middle of pectoral fin; 1st dorsal-fin pterygiophore between neural spines of 3rd to 5th (between 3rd and 4th) vertebrae. Anal-fin origin below 20th to 22nd (20th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate or penultimate (penultimate) abdominal vertebra. Last dorsal-fin pterygiophore between neural spines of 2nd to 5th (between 3rd and 4th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 2nd to 5th (between 3rd and 4th) preural vertebrae. Caudal fin with 2 epurals, 4 upper hypurals and 3–5 (5) lower hypural rays. Pectoral fin moderately short, not quite reaching middle of abdomen; its posterior margin having notches. Upper end of pectoral-fin base about on lateral midline of body. Pelvic fin short; its base anterior to lower edge of gill opening; its posterior margin not reaching vertical through pectoral-fin base. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above 1st suborbital pore (Fig. 20A, B). Postorbital pores 4; distance between 1st and 2nd pores longest of those between adjacent pores (Fig. 20A, B). Suborbital pores usually 8 (8), rarely 9; 7 pores located below eye and last pore posterior to eye; when 9 pores, 8 pores below eye and 9th behind eye on left side in HUMZ 182639 and on right side in HUMZ 182293; 5th below anterior margin of pupil; last pore of those below eye located posterior to vertical posterior to margin of eye (Fig. 20A). Preoperculomandibular pores usually 10 (10), rarely 9; 5 on lower jaw, 2 at junction of lower jaw and preopercle, and 3 on preopercle; 8th and 9th pores united into 1 pore on left side of HUMZ 182479 and counted as 9; last preoperculomandibular pore located posterior to lower margin of eye (Fig. 20A, C). One interorbital pore located on dorsal midline anterior to anterior margin of pupils (Fig. 20B). Usually 1 occipital pore located on dorsal midline at middle of occiput (1); 1 additional pore present on left side of middle pore in HUMZ 182640; 2 additional pores, one on either side of middle pore in HUMZ 182642; occipital pore(s) located anterior to 3rd postorbital pore (Fig. 20B). Color in alcohol. Holotype (based on color photograph; Fig. 19) with uniformly light brown head, body and vertical fins, slightly paler pectoral fin; dark brown opercular region; purplish gray abdomen. Margin of vertical fins in non-type specimens dark brown, but coloration otherwise similar to holotype. Color when fresh (based on color photograph of HUMZ 152378; Fig. 17). Head and margin of vertical fins dark brown; body and vertical fins uniformly grayish brown; pectoral fins gray; abdomen dark purplish gray. Distribution. Off northwestern Pacific coast of the Kuril Islands, eastern Hokkaido Island and Honshu Island from Miyagi to Ibaraki prefectures, at depths of 399–1219 m (Fedorov & Andriashev, 1993; Anderson, 1994; Shinohara et al., 1996; Imamura, 1997, 1998; Hatooka, 2000, 2002, 2013; Anderson & Fedorov, 2004; Shinohara & Anderson, 2007; Kitagawa et al., 2008; Shinohara et al., 2009; Amaoka et al., 2011; Balushkin et al., 2011; this study). Size. Maximum length 180 mm TL (Amaoka et al., 2011; Hatooka, 2013). The largest specimen examined for this study measured 168.7 mm SL (172.2 mm TL). Remarks. Lycenchelys makushok resembles L. hippopotamus, L. melanostomias and L. rassi in having more than 100 total vertebrae, 1 interorbital pore, 1–3 occipital pores, 4 postorbital pores, a single ventral lateral line and no distinct spots or blotches on the body (vs. lacking this combination of this characters in other species of Lycenchelys) (e.g., Toyoshima, 1983, 1985; Fedorov & Andriashev, 1993; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1995; Shinohara et al., 1996; Imamura et al., 2004; Shinohara & Anderson, 2007; this study). See Remarks for L. hippopotamus for a detailed comparison of L. makushok and L. hippopotamus. Lycenchelys makushok is separable from L. melanostomias and L. rassi by the number and position of occipital pores. Lycenchelys makushok always has an occipital pore on the dorsal midline at the middle of the occiput. When 2 or 3 occipital pores are present (2 of 41 specimens observed in this study), the additional pore or two are on the lateral side or sides of the middle pore. In contrast, L. melanostomias and L. rassi usually have 2 occipital pores (1 occipital pore on right side was examined in only 1 specimen of L. melanostomias in this study), that are located on the left and right sides of the midline of the occiput. Lycenchelys makushok is further separable from L. melanostomias in having a higher number of total vertebrae (132–139, vs. 117–124, respectively), and from L. rassi in having a shorter head (head length 10.0–12.9% SL, vs. 13.4–16.4% SL, respectively).

Lycenchelys squamosa Toyoshima, 1983 (Japanese name: Uroko-hebigenge) (Figs. 38���43; Table 10) Lycenchelys squamosus Toyoshima, 1983: 145, figs. 20���22, table 10, pl. 93 (original description, type locality: off Miyagi Prefecture, Pacific coast of Honshu Island, Japan); Toyoshima, 1984: 293, pl. 274-E (brief description); Toyoshma, 1985: 156, figs. 6���7, 12���13, 31, table 1 (description); Hatooka, 1993: 901, unnumbered fig. (key to species); Amaoka et al., 1995: 241, pl. 405 (brief description); Koyanagi, 1997: 538, fig. 5 (brief description); Imamura, 1998: 32, fig. 13 (brief description); Zama, 2001: 86, 133 (species list). Lycenchelys squamosa: Anderson, 1994: 113, 118 (species list); Shinohara et al., 1996: 182 (species list); Imamura, 1997: 60 (species list); Shinohara & Matsuura, 1998: table 1 (comparison with Lycenchelys aurantiaca); Hatooka, 2000: 1033, unnumbered fig. (key to species); Hatooka, 2002: 1033, unnumbered fig. (key to species); Anderson & Fedorov, 2004: 20 (species list); Shiogaki et al., 2004: 71 (species list); Shinohara & Anderson, 2007: 64 (key to species); Kitagawa et al., 2008: 96, unnumbered fig. (brief description); Shinohara et al., 2009: 724 (species list); Amaoka et al., 2011: 318, unnumbered fig. (brief description); Balushkin et al., 2011: 983 (catalog of specimens); Hatooka, 2013: 1227, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Materials examined Holotype: HUMZ 78464, male, 246.1 mm SL, off Miyagi Prefecture, Tohoku District, northwestern Pacific (37��49.7���N, 142��23.7���E to 37��55.4���N, 142��24.5���E), 985���1005 m depth, 8 Oct. 1978. Paratypes (2 specimens, 193.0��� 222.5 mm SL, both from Tohoku District, northwestern Pacific): HUMZ 72563, 1 female, 193.0 mm SL, off Fukushima Prefecture (37��09.4���N, 141��56E), 900���920 m depth, 19 Jan. 1978; HUMZ 78390, 1 female, 222.4 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. Other specimens (6 specimens, 203.0��� 253.1 mm SL): HUMZ 157660, 157669, 181894���95, 192737, 2 males and 3 females, 203.0��� 253.1 mm SL, Tohoku District, northwestern Pacific; HUMZ 177036, 1 female, 241.8 mm SL, eastern Hokkaido Island, northwestern Pacific. Diagnosis. Vertebrae 20 + 71���75 = 91���95; head length 16.3���19.9% SL; interorbital pore 1; occipital pores absent; postorbital pores 4; suborbital pores 5 + 1 (rarely 5 + 2); preoperculomandibular pores 8; vomerine teeth 7���17; palatine teeth 5���25, arranged in 1 or 1���2 rows; opercular flap well-developed; pelvic-fin base positioned below lower edge of gill opening; lateral line incomplete and positioned ventrally; scales present on pectoral fin and its base; body uniformly dark brown when fresh. Description. Counts and proportional measurements in Table 10. Body elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 5.4���6.5 (5.7)% SL. Head moderately long, ovoid; dorsal profile of head gently sloping to dorsal-fin origin. Snout short, 125.8���173.2 (159.3)% of eye diameter. Eye ovoid, relatively large. Interorbital space narrow, width 15.6���35.6 (27.4)% of eye diameter. Nostril tube short, not reaching upper lip when depressed. Mouth subterminal; lower jaw extending slightly beyond upper jaw (holotype) (Fig. 39A), or upper jaw extending slightly (paratypes and non-type specimens, all females) or significantly (non-type males) beyond lower jaw (Fig. 39B, C). Posterior end of upper jaw reaching to or slightly beyond vertical through suborbital pore behind eye in males, reaching below posterior margin of eye in females. Labial lobe of lower jaw weak. Teeth on jaws, vomer and palatine small and conical; upper jaw with 2���3 rows anteriorly and single row posteriorly; lower jaw with 2���4 irregular rows anteriorly and single row posteriorly; vomerine teeth irregularly arranged; all palatine teeth in single row, or in 2 rows anteriorly and single row posteriorly (single row). Lower edge of gill opening slightly above lower end of pectoral-fin base. Opercular flap well developed. Gill rakers short and thin (Fig. 40). Pseudobranch filaments short. Lateral line deciduous, positioned ventrally and incomplete; its origin posterior to last postorbital pore and terminating above middle of anal fin. Scales small and cycloid, present on nape, body, pectoral axilla, about basal half of pectoral fin, pectoral-fin base, tail and vertical fins except at margin. Head without scales. ....Continued next page Dorsal-fin origin near vertical through posterior edge of opercular flap; 1st dorsal-fin pterygiophore between neural spines of 2nd and 3rd vertebrae. Anal-fin origin below 18th to 20th (19th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate abdominal vertebra or hemal spine of 1st caudal vertebra (posterior to parapophysis of ultimate abdominal vertebra). Last dorsal-fin pterygiophore between neural spines of 2nd to 5th (between 4th and 5th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 2nd to 5th (between 3rd and 4th) preural vertebrae. Caudal fin with 1���2 (2) epural, 4 upper hypural and 3���4 (4) lower hypural rays. Pectoral fin relatively long, reaching to about mid-portion of abdomen; its posterior margin rounded. Upper end of pectoral-fin base on about lateral midline of body. Pelvic fin short; its posterior margin slightly beyond lower edge of gill opening. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above and slightly anterior to vertical through 1st suborbital pore (Fig. 42A, B). Postorbital pores 4; distance between 1st and 2nd pores longest of those between adjacent pores; 3rd pore slightly higher than others (Fig. 42A, B). Suborbital pores usually 6 (including holotype), rarely 7; 5 pores below eye and last pore behind midline of eye, except for another pore just above 5th pore on left side in HUMZ 181895 and right side in HUMZ 157669; 5th pore behind vertical through 1st postorbital pore (Fig. 42A). Preoperculomandibular pores 8; 4 on lower jaw and 4 on preopercle; last preoperculomandibular pore posterior to lower margin of eye (Fig. 42A, C). One interorbital pore on dorsal midline above middle of eyes (Fig. 42B). Occipital pores absent (Fig. 42B). Color in alcohol. Holotype (Fig. 41) with light purplish brown head, body and vertical fins, color fading somewhat on body, right side of tail and vertical fins. Pectoral fin slightly lighter than body color. Head, body, vertical and pectoral fins dark brown in paratypes. Head and pectoral fin dark brown, body and vertical fins grayish brown, margins of dorsal and anal fins blackish in other specimens. Color when fresh (based on color photograph of HUMZ 192737; Fig. 38). Head and pectoral fin blackish. Body, vertical fins and pectoral-fin base uniformly dark brown. Margins of dorsal and anal fins black. Distribution. The Okhotsk Sea, off northwestern Pacific coast of eastern Hokkaido Island and in the northwestern Pacific from Aomori to Ibaraki prefectures, at depths of 310���1340 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; Shinohara & Matsuura, 1998; 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 examined during this study measured 253.1 mm SL (261.3 mm TL), about equal to the previously recorded maximum length (252 mm SL, 260 mm TL) (Toyoshima, 1983, 1984, 1985; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1994; Amaoka et al., 1995, 2011; Koyanagi, 1997; Shinohara & Matsuura, 1998; Shinohara & Anderson, 2007). Remarks. Lycenchelys squamosa resembles L. aurantiaca in having less than 100 total vertebrae, 1 interorbital pore, no occipital pores, 4 postorbital pores and no distinct spots or blotches on the body (vs. lacking this combination of characters in other species of Lycenchelys) (e.g., Toyoshima, 1983, 1985; Shinohara & Matsuura, 1998; Hatooka, 2000, 2002, 2013; Shinohara & Anderson, 2007; this study). See Remarks under L. aurantiaca for a detailed comparison of L. squamosa with L. aurantiaca. In Lycenchelys squamosa, the upper jaw extends forward slightly beyond the lower jaw in females (including paratypes) (Fig. 39B). In males however, the lower jaw extends slightly (holotype, 246.1 mm SL) (Fig. 39A) or considerably beyond the lower jaw (2 non-types, 217.0 and 253.1 mm SL) (Fig. 39C). According to Toyoshima (1983, 1985), the lower jaw of the holotype (male) protrudes slightly beyond the upper jaw, and the lower jaw is nearly equal to or slightly included in the upper jaw of paratypes (females). He did not mention the variation in the jaw protrusion of males because he was able to examine only 1 male specimen (= holotype). Subsequent studies have not described the variation in males of the species even though the extension of the lower jaw in males of the species as presented by Toyoshima (1985) has been repeated in some studies (e.g., Amaoka et al., 1995, 2011). This study found that the variation in males lies in the length of the upper jaw, not of the lower jaw, although the ratio of the lower jaw length seems to increase with growth (Fig. 43B). In the 3 males examined, the 246.1 mm SL specimen (holotype) with the lower jaw protrusion has a shorter upper jaw, while the largest (253.1 mm SL) and smallest (217.0 mm SL) specimens with the upper jaw protrusion have a longer upper jaw (Fig. 43A). Therefore, the length of the upper jaw may be due to intraspecific variation not associated with change in growth in males of L. squamosa. Further specimens are required to resolve the differences., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 45-50, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Toyoshima, M. (1983) Zoarcidae. In: Amaoka, K., Nakaya, K., Araya, H. & Yasui, T. (Eds.), Fishes from the north-eastern Sea of Japan and the Okhotsk Sea off Hokkaido. The intensive research of unexploited fishery resources on continental slopes. Japan Fisheries Resource Conservation Association, Tokyo, pp. 136 - 149 + 208 - 210 + 258 - 277 + 329 - 335.","Toyoshima, M. (1984) Family Zoarcidae. Eelpouts. In: Masuda, H., Amaoka, K., Araga, C., Uyeno, T. & Yoshino, T. (Eds.), The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo, pp. 291 - 295. [in Japanese]","Hatooka, K. (1993) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. Tokai University Press, Tokyo, pp. 898 - 913 + 1343 - 1345. [in Japanese]","Amaoka, K., Nakaya, K. & Yabe, M. (1995) The fishes of northern Japan. Kita-Nihon Kaiyo Center, Sapporo, 391 pp. [in Japanese]","Koyanagi, M. (1997) Zoarcidae. In: Okamura, O. & Amaoka, K. (Eds.), Sea fishes of Japan, Yama-Kei, Tokyo, pp. 536 - 538. [in Japanese]","Imamura, H. (1998) Zoarcid fishes occurring off Pacific of Tohoku District. Researches on Basic Fishes in Tohoku District, 18, 28 - 34. [in Japanese]","Zama, A. (2001) Fish fauna of Miyagi Prefecture, Japan. Sanwa Publisher, Ishinomaki, 153 pp. [in Japanese]","Anderson, M. E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). Ichthyological Bulletin of the J. L. B. Smith Institute of Ichthyology, 60, 1 - 120.","Shinohara, G., Endo, H. & Matsuura, K. (1996) Deep-water Fishes collection from the Pacific coast of northern Honshu, Japan. Memories of the National Science Museum, Tokyo, 29, 153 - 185.","Imamura, H. (1997) Perciform fish fauna from off Pacific of Tohoku. Researches on Basic Fishes in Tohoku District, 17, 55 - 68. [in Japanese]","Shinohara, G. & Matsuura, K. (1998) A new zoarcid, Lycenchelys aurantiaca, from the Pacific coast off northern Japan (Teleostei: Perciformes). Ichthyological Research, 45, 151 - 155. https: // doi. org / 10.1007 / BF 02678557","Hatooka, K. (2000) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 2 nd edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1590 - 1593. [in Japanese]","Hatooka, K. (2002) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species, English edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1581 - 1583.","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Shiogaki, M., Ishito, Y., Nomura, Y. & Sugimoto, T. (2004) Revised catalog of the fishes collected from the waters of Aomori Prefecture. Bulletin of Aomori Prefectural Fisheries Research Center, (4), 39 - 80. [in Japanese with English abstract]","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Kitagawa, D., Imamura, H., Goto, T., Ishito, Y., Fujiwara, K. & Ueda, Y. (2008) Field guide of the fishes from the Tohoku District, north-eastern waters of Japan. Tokai University Press, Hadano, 141 pp. [in Japanese]","Shinohara, G., Narimatsu, Y., Hattori, T., Ito, M., Takata, Y. & Matsuura, K. (2009) Annotated checklist of deep-sea fishes from the Pacific coast off Tohoku District, Japan. In: Fujita, T. (Ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Science Museum of Nature and Science Monographs, Tokyo, 39, pp. 683 - 735.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Toyoshima, M. (1985) Taxonomy of the subfamily Lycodinae (family Zoarcidae) in Japan and adjacent waters. Memoirs of the Faculty of Fisheries, Hokkaido University, 32, 131 - 243."]}

Lycenchelys melanostomias Toyoshima, 1983 (Japanese name: Ohotsuku-hebigenge) (Figs. 21���25; Table 6) Lycenchelys sp.: Shiogaki, 1982: 23 (species list). Lycenchelys melanostomias Toyoshima, 1983: 271, 333, figs. 25���27, pl. 157 (original description, type locality: southern Okhotsk Sea, Hokkaido Island, Japan); Toyoshima, 1984: 293, pl. 274-A (brief description); Toyoshima, 1985: 170, figs. 6���7, 26���27, 31, tables 1, 4 (description); Hatooka, 1993: 902, unnumbered fig. (key to species); Anderson, 1994: 113, 117 (species list); Amaoka et al., 1995: 240, pl. 402 (brief description); Koyanagi, 1997: 538, fig. 3 (brief description); Hatooka, 2000: 1032, unnumbered fig. (key to species); Hatooka, 2002: 1032, unnumbered fig. (key to species); Anderson & Fedorov, 2004: 18 (species list); Imamura et al., 2004: 84, figs. 1���3, table 1 (synonymy of Lycenchelys melanostomias and Lycenchelys brevimaxillaris); Shiogaki et al., 2004: 71 (species list); Imamura et al., 2005: 1, figs. 1���3, table 1 (synonymy of Lycenchelys melanostomias and Lycenchelys brevimaxillaris); Shinohara & Anderson, 2007: 64 (key to species); Kitagawa et al., 2008: 95, unnumbered fig. (brief description); Shinohara et al., 2009: 724 (species list); Amaoka et al., 2011: 315, unnumbered fig. (brief description); Balushkin et al., 2011: 1026 (species list); Hatooka, 2013: 1226, 2078, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Lycenchelys brevimaxillaris: Toyoshima, 1985: 174, figs. 6���7, 29���30, 31, table 1 (original description, type locality: off Aomori Prefecture, Pacific coast of Honshu, Japan); Hatooka, 1993: 902, unnumbered fig. (key to species); Anderson, 1994: 117 (species list); Imamura, 1998: 31, fig. 9 (brief description); Hatooka, 2000: 1033, unnumbered fig. (key to species); Hatooka, 2002: 1033, unnumbered fig. (key to species); Anderson & Fedorov, 2004: 16 (species list); Imamura et al., 2004: 84, figs. 1���3, table 1 (synonymy of Lycenchelys melanostomias and Lycenchelys brevimaxillaris); Shiogaki et al., 2004: 71 (species list); Imamura et al., 2005: 1, figs. 1���3, table 1 (synonymy of Lycenchelys melanostomias and Lycenchelys brevimaxillaris). Materials examined Holotype: HUMZ 77572, male, 182.3 mm SL, Kitami-Yamato Bank, Okhotsk Sea (44��19.5���N, 145��01���E), 915���925 m depth, 11 Oct. 1978; Other specimens (41 specimens, 119.3���227.6 mm SL): HUMZ 189817 (holotype of Lycenchelys brevimaxillaris), female, 185.8 mm SL, off Aomori Prefecture, Tohoku District, northwestern Pacific (41��13���N, 141��44���E), 690���750 m depth, 18 Jan. 1982; HUMZ 152380, 152384, 152404���05, 152411, 157545, 177188, 178572���75, 182565, 192724, 192804, 4 males and 10 females, 124.0��� 195.1 mm SL, Tohoku District, northwestern Pacific; HUMZ 177263, 192453, 205157, 228057, 228067���68, 228070, 228073, 228089, 5 males and 4 females, 119.3���193.2 mm SL, eastern Hokkaido Island, northwestern Pacific; HUMZ 120346, 121158, 121161, 121461, 124054���55, 124116, 126101, 126215���16, 126219���22, 126230, 126359, 126361, 10 males and 7 females, 120.6���227.6 mm SL, northeastern Hokkaido Island, Okhotsk Sea. Diagnosis. Vertebrae 22���25 + 93���102 = 117���124; head length 11.6���15.0% SL; interorbital pore 1; occipital pores usually 2; postorbital pores usually 4; suborbital pores 6���7 + 2���3; preoperculomandibular pores usually 9; vomerine teeth 3���10; palatine teeth 2���11, usually arranged in single row (sometimes 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 absent on pectoral fin and its base; body uniformly grayish-brown when fresh. Description. Counts and proportional measurements in Table 6. ...Continued next page Body very elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 3.8���7.0 (5.0)% SL. Head short, ovoid; dorsal profile of head sloping extremely gently from posterior edge of eye to above opercular flap. Head of males slightly longer than of females in adults. Snout short, 74.4���131.0% of eye diameter (eye damaged in holotype). Eye ovoid, moderately large. Interorbital space narrow, width 12.7���33.8% of eye diameter (eye damaged in holotype). Nostril tube short, not reaching upper lip when depressed. Mouth subterminal. Posterior edge of upper jaw reaching vertical through posterior part of eye in adult males, reaching vertical through anterior margin of pupil in females and juveniles. Labial lobe of lower jaw tending to be more developed in large males than in females and juveniles (labial lobe of lower jaw damaged in holotype). Teeth on jaws sharp; upper jaw with 2���3 rows anteriorly, 1 or 1���2 rows posteriorly (1); anteriormost teeth larger than other teeth; lower jaw with 2���5 irregular rows anteriorly, 1 or 1���2 rows posteriorly (1); vomerine and palatine teeth small and conical; vomerine teeth irregularly arranged; palatine teeth usually in single row, but sometimes 1���2 rows (no data for holotype). Lower edge of gill opening slightly above lower end of pectoral-fin base. Opercular flap well developed. Gill rakers short and triangular (Fig. 23). Pseudobranch filaments short. Lateral line deciduous, complete and positioned ventrally; originating posterior to last postorbital pore and terminating on tail. Scales small and cycloid, present on body and tail, except for area around pelvic fin. Scales covering basal portions of dorsal and anal fins anteriorly; extent of scaled areas gradually increasing posteriorly, except at margins. Head, nape, pectoral axilla, pectoral fin, pectoral-fin base and area around pelvic fin without scales. Dorsal-fin origin posterior to vertical through pectoral-fin base; 1st dorsal-fin pterygiophore between neural spines of 2nd to 5th (between 2nd and 3rd) vertebrae. Anal-fin origin below 17th to 20th (18th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate or penultimate (penultimate) abdominal vertebra. Last dorsal-fin pterygiophore between neural spines of 2nd to 5th (between 2nd and 3rd) preural vertebrae. Last analfin pterygiophore between hemal spines of 3rd to 5th (between 3rd and 4th) preural vertebrae. Caudal fin with 1���3 (2) epural, 3���4 (4) upper hypural and 3���4 (3) lower hypural rays. Pectoral fin moderately short, not quite reaching middle of abdomen; its posterior margin rounded dorsally and having notches ventrally. Upper end of pectoral-fin base about on lateral midline of body. Pelvic fin short; its base posterior to lower edge of gill opening; its posterior margin reaching about vertical through pectoral-fin base. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above line of 1st suborbital pore (Fig. 22A, B). Postorbital pores usually 4, rarely 5 (5); when 4, distance between 1st and 2nd pores longest of those between adjacent pores; when 5, 1 additional pore present between 1st and 2nd pores (Fig. 22A, B). Suborbital pores 8���10 (unknown for holotype), 6 or 7 pores located below eye and remaining 2 or 3 pores on ascending part of suborbital canal behind eye; 5th pore below posterior margin of pupil; last pore of those below eye located posterior to vertical through posterior margin of eye (Fig. 22A). Preoperculomandibular pores usually 9 (9), rarely 8; 4 on lower jaw, 2 at junction of lower jaw and preopercle, and 3 on preopercle; 2 pores at junction of lower jaw and preopercle united into 1 pore in some specimens and preoperculomandibular pore series counted as 8; 2nd and 3rd pores united into 1 pore on right side of HUMZ 126361 and series counted as 8; last preoperculomandibular pore located posterior to lower part of eye (Fig. 22A, C). One interorbital pore located on dorsal midline anterior to middle of eyes (Fig. 22B). Occipital pores usually 2 (2), usually positioned on either side of dorsal midline; only 1 pore on right side in HUMZ 182565; occipital pore(s) located anterior to 3rd postorbital pore (Fig. 22B). Two additional unnamed pores present in interorbital space on either side in line with postorbital pores, behind posterior to posterior margin of pupil only in HUMZ 178574 (Fig. 22D). Color in alcohol. Color of holotype (Fig. 24) unknown owing to head, body, and fins lacking skin. Long preserved holotype of L. brevimaxillaris with brownish head, pectoral fin and vertical fins, uniformly grayish brown body and gray abdomen. Other recently preserved specimens with dark brown head, pectoral fin and vertical fins, uniformly pale brown body and blackish abdomen. Color when fresh (based on color photograph of HUMZ 124054; Fig. 21). Head and pectoral fin black; body and vertical fins uniformly grayish brown; margin of vertical fins slightly darker and abdomen pale purplish. Distribution. Southern Okhotsk Sea, off northwestern Pacific coast of eastern Hokkaido Island and in the northwestern Pacific from Aomori to Ibaraki prefectures, at depths of 425���1440 m (Shiogaki, 1982; Toyoshima, 1983, 1984, 1985; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1994; Amaoka et al., 1995, 2011; Koyanagi, 1997; Imamura, 1998; Anderson & Fedorov, 2004; Imamura et al., 2004, 2005; Shiogaki et al., 2004; Shinohara & Anderson, 2007; Kitagawa et al., 2008; Shinohara et al., 2009; this study). Size. The largest specimen examined during this study measured 227.6 mm SL (230.8 mm TL), about equal to the previously recorded maximum length of 23 cm TL (Hatooka, 2013). Remarks. Lycenchelys melanostomias is similar to L. hippopotamus, L. makushok and L. rassi in having more than 100 total vertebrae, 1 interorbital pore, 1���2 occipital pores, 4���5 postorbital pores, a single lateral line positioned ventrally and no distinct spots or blotches on the body (vs. lacking this combination of characters in other species of Lycenchelys) (e.g., Toyoshima, 1983, 1985; Fedorov & Andriashev, 1993; Anderson, 1995; Imamura et al., 2004; Shinohara & Anderson, 2007; this study). See Remarks under accounts of L. hippopotamus, L. makushok and L. rassi for detailed comparisons of L. melanostomias with each. Two additional pores behind the posterior margin of the pupil were found in 1 specimen of L. melanostomias (Fig. 22D). These pores have not been previously described for L. melanostomias, although similar pores are known in Lycenchelys parini Fedorov, 1995 (Fig. 25). Lycenchelys melanostomias also resembles L. parini in having similar counts, proportional measurements and arrangements of head pores (e.g., dorsal-fin rays 111���120 vs. 118, and anal-fin rays 98���107 vs. 105, head length 11.6���15.0 vs. 12.2% SL, postorbital pores usually 4 vs. 4 and suborbital pores 8���10 vs. 9 in L. melanostomias respectively; Table 6) (Fedorov, 1995a; Imamura et al., 2004, 2005; this study). However, L. melanostomias is easily separable from L. parini in having the lateral line positioned ventrally rather than midlaterally on the side (Fedorov, 1995a)., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 27-32, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Toyoshima, M. (1983) Zoarcidae. In: Amaoka, K., Nakaya, K., Araya, H. & Yasui, T. (Eds.), Fishes from the north-eastern Sea of Japan and the Okhotsk Sea off Hokkaido. The intensive research of unexploited fishery resources on continental slopes. Japan Fisheries Resource Conservation Association, Tokyo, pp. 136 - 149 + 208 - 210 + 258 - 277 + 329 - 335.","Shiogaki, M. (1982) A catalogue of the fishes collected from the waters of Aomori Prefecture, Japan. Bulletin of the Fisheries Experimental Station of Aomori Prefecture, 1982, 1 - 36. [in Japanese]","Toyoshima, M. (1984) Family Zoarcidae. Eelpouts. In: Masuda, H., Amaoka, K., Araga, C., Uyeno, T. & Yoshino, T. (Eds.), The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo, pp. 291 - 295. [in Japanese]","Toyoshima, M. (1985) Taxonomy of the subfamily Lycodinae (family Zoarcidae) in Japan and adjacent waters. Memoirs of the Faculty of Fisheries, Hokkaido University, 32, 131 - 243.","Hatooka, K. (1993) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. Tokai University Press, Tokyo, pp. 898 - 913 + 1343 - 1345. [in Japanese]","Anderson, M. E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). Ichthyological Bulletin of the J. L. B. Smith Institute of Ichthyology, 60, 1 - 120.","Amaoka, K., Nakaya, K. & Yabe, M. (1995) The fishes of northern Japan. Kita-Nihon Kaiyo Center, Sapporo, 391 pp. [in Japanese]","Koyanagi, M. (1997) Zoarcidae. In: Okamura, O. & Amaoka, K. (Eds.), Sea fishes of Japan, Yama-Kei, Tokyo, pp. 536 - 538. [in Japanese]","Hatooka, K. (2000) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 2 nd edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1590 - 1593. [in Japanese]","Hatooka, K. (2002) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species, English edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1581 - 1583.","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Imamura, H., Machida, Y. & Ohta, S. (2004) Lycenchelys melanostomias Toyoshima, 1983, a senior synonym of L. brevimaxillaris Toyoshima, 1985 (Teleostei: Zoarcidae). Ichthyological Research, 51, 84 - 88. https: // doi. org / 10.1007 / s 10228 - 003 - 0194 - 2","Shiogaki, M., Ishito, Y., Nomura, Y. & Sugimoto, T. (2004) Revised catalog of the fishes collected from the waters of Aomori Prefecture. Bulletin of Aomori Prefectural Fisheries Research Center, (4), 39 - 80. [in Japanese with English abstract]","Imamura, H., Shinohara, G. & Shiogaki, M. (2005) Rediscovery of the type specimens of Lycenchelys brevimaxillaris (Actinopterygii: Perciformes: Zoarcidae) with taxonomic notes on the species. Species Diversity, 10, 1 - 6. https: // doi. org / 10.12782 / specdiv. 10.1","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Kitagawa, D., Imamura, H., Goto, T., Ishito, Y., Fujiwara, K. & Ueda, Y. (2008) Field guide of the fishes from the Tohoku District, north-eastern waters of Japan. Tokai University Press, Hadano, 141 pp. [in Japanese]","Shinohara, G., Narimatsu, Y., Hattori, T., Ito, M., Takata, Y. & Matsuura, K. (2009) Annotated checklist of deep-sea fishes from the Pacific coast off Tohoku District, Japan. In: Fujita, T. (Ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Science Museum of Nature and Science Monographs, Tokyo, 39, pp. 683 - 735.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Imamura, H. (1998) Zoarcid fishes occurring off Pacific of Tohoku District. Researches on Basic Fishes in Tohoku District, 18, 28 - 34. [in Japanese]","Fedorov, V. V. & Andriashev, A. P. (1993) Lycenchelys makushok sp. nova (Perciformes: Zoarcidae) from the bathyal depths of the Kuril-Kamchatka Trench. Journal of Ichthyology, 33, 130 - 135.","Anderson, M. E. (1995) The eelpout genera Lycenchelys Gill and Taranetzella Andriashev (Teleostei: Zoarcidae) in the eastern Pacific, with descriptions of nine new species. Proceedings of the California Academy of Science, 49, 55 - 133.","Fedorov, V. V. (1995 a) Lycenchelys parini sp. nova (Perciformes: Zoarcidae) from the bathyal region of the Kuril-Kamchatka trench. Journal of Ichthyology, 35, 130 - 134."]}

Lycenchelys rassi Andriashev, 1955 (Japanese name: Rasu-hebigenge) (Figs. 26���31; Table 7) Lycenchelys rassi Andriashev, 1955: 359, figs. 2, 5, 6 (original description, type locality: east coast of Sakhalin Island, Sea of Okhotsk); Andriashev, 1958:172 (description); Peden, 1973: 115, fig. 1, table 1 (description); Toyoshima, 1983: 269, 332, pl. 155 (description); Toyoshima, 1984: 293, pl. 274-B (brief description); Toyoshma, 1985: 149, 173, figs. 6���7, 28, 31, tables 1, 4 (description); Hatooka, 1993: 902, unnumbered fig. (key to species); Anderson, 1994: 113, 117 (species list); Amaoka et al., 1995: 240, pl. 403 (brief description); Anderson, 1995: 98, fig. 15 (description); Koyanagi, 1997: 538, fig. 4 (brief description); Hatooka, 2000: 1033, unnumbered fig. (keys to species); Mecklenburg et al., 2002: 703, unnumbered figs. (brief description); Hatooka, 2002: 1033, unnumbered fig. (keys to species); Anderson & Fedorov, 2004: 19 (species list); Shinohara & Anderson, 2007: 64 (key to species); Amaoka et al., 2011: 316, unnumbered fig. (brief description); Balushkin et al., 2011: 981, 1024 (catalog of specimens); Hatooka, 2013: 1226, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Materials examined Holotype: ZIN 32962, female, 190.6 mm SL, off eastern Sakhalin Island, Okhotsk Sea (54��28���N, 145��21.6���E), 1500 m depth, R/V Vityaz. Other specimens (57 specimens): HUMZ 77747, 119939, 120328, 120330, 120347 ���49, 121156, 121451, 121458 ���59, 121464, 126117���22, 126185, 126187���93, 126195���96, 126198, 126200���05, 126211, 126252, 126257, 126367���75, 126377���86, 28 males and 29 females, 93.5���239.7 mm SL, northeastern Hokkaido Island, Okhotsk Sea. Diagnosis. Vertebrae 23���25 + 98���109 = 122���134; head length 13.3���16.4% SL; interorbital pore 1; occipital pores 2; postorbital pores usually 4; suborbital pores usually 7 + 1; preoperculomandibular pores usually 8; vomerine teeth 3���11; palatine teeth 3���10, usually arranged in single row (sometimes 1���2 rows); opercular flap absent; pelvic-fin base positioned below lower edge of gill opening; lateral line complete and positioned ventrally; scales present or absent on pectoral fin and absent on its base; body uniformly grayish brown when fresh. Description. Counts and proportional measurements in Table 7. Body very elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 2.5���4.8% SL (unknown for holotype). Head moderately long, ovoid; dorsal profile of head sloping extremely gently from posterior edge of eye to above about last postorbital pore. Cheek swollen in some males. Head in adults slightly longer in males than females. Snout short, 90.0���176.1 (141.3)% of eye diameter. Eye ovoid, moderately large. Interorbital space narrow, width 17.9���36.4 (19.0)% of eye diameter. Nostril tube long, reaching upper lip when depressed. Mouth subterminal. Posterior edge of upper jaw reaching vertical through middle to posterior part of eye in adult males, reaching vertical through anterior margin to middle of eye in females and juveniles (middle of eye). Labial lobe of lower jaw developed. Teeth on jaws sharp; upper jaw usually with 2 rows, rarely 3 rows (unknown for holotype) anteriorly, single row posteriorly; anteriormost teeth larger than other teeth; lower jaw with 2���5 irregular rows anteriorly, 1 or 1���2 rows posteriorly (unknown for holotype); vomerine and palatine teeth small and conical; vomerine teeth irregularly arranged; palatine teeth usually in single row, sometimes 1���2 rows (no data for holotype). Lower edge of gill opening slightly above lower end of pectoral-fin base. Opercular flap absent (Fig. 31A, B). Gill rakers short; those on upper limb triangular, many triangular and some blunt on lower limb (Fig. 27). Pseudobranch filaments short. Lateral line deciduous, complete and positioned ventrally; originating posterior to last postorbital pore and terminating on tail. Scales small and cycloid, present on body and tail, except head, nape, pectoral-fin base and area around pelvic fin. Scales covering basal portions of dorsal and anal fins anteriorly; extent of scaled areas gradually increasing posteriorly, except at margins. Scales present or absent on pectoral axilla and basal portions of lower pectoral-fin rays (absent). ....Continued next page Dorsal-fin origin above middle of pectoral fin; 1st dorsal-fin pterygiophore between neural spines of 4th to 6th (between 5th and 6th) vertebrae. Anal-fin origin below 17th to 20th (19th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate or penultimate (penultimate) abdominal vertebra. Last dorsal-fin pterygiophore between neural spines of 3rd to 5th (between 3rd and 4th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 2nd to 5th (between 2nd and 3rd) preural vertebrae. Caudal fin with 1���2 (2) epural, 4���5 (4) upper hypural and 3���4 (3) lower hypural rays. Pectoral fin moderately short, reaching to about middle of abdomen; its posterior margin notched. Upper end of pectoral-fin base about on lateral midline of body. Pelvic fin short; its base at about lower edge of gill opening; its posterior margin not quite reaching pectoral-fin base. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above 1st suborbital pore (Fig. 29A, B). Postorbital pores usually 4 (4), rarely 3; when 4, distance between 2nd and 3rd pores longest of those between adjacent pores; when 3, 2nd pore absent (Fig. 29A, B). Suborbital pores usually 8 (8), rarely 7 or 9; when 8, 7 pores below eye and last behind eye; when 9, 8 pores below eye and remaining pore behind eye, or 7 pores below eye and last 2 pores on ascending part of suborbital canal behind eye; 6th and 7th pores united into 1 pore on right side of HUMZ 126384 and counted as 7; 4th pore below vertical through anterior margin of eye; last pore of those below eye posterior to posterior margin of eye (Fig. 29A). Preoperculomandibular pores usually 8 (8), rarely 7 or 9; 4 on lower jaw, 1 at junction of lower jaw and preopercle, and 3 on preopercle; pore at junction of lower jaw and preopercle separated into 2 pores in some specimens and counted as 9; 1st and 2nd pores united into 1 pore on right side of HUMZ 126382, 126378 and 126211, 3rd and 4th pores united into 1 pore on left side of HUMZ 126205, and 4th and 5th pores united into 1 pore on left side of HUMZ 126382 and counted as 7; last preoperculomandibular pore posterior to lower margin of eye (Fig. 29A, C). One interorbital pore on dorsal midline anterior to middle of eyes (Fig. 29B). Occipital pores 2, positioned on either side of dorsal midline; occipital pores located anterior to 3rd postorbital pore (Fig. 29B). Color in alcohol. Holotype (based on color photograph; Fig. 28) with uniformly brown head, body and vertical fins, slightly darker pectoral fin and margin of vertical fins, dark brown opercular region and purplish gray abdomen. Most other specimens similar to holotype, and some uniformly paler than holotype. Color when fresh (based on color photograph of HUMZ 119939; Fig. 26). Head purplish brown; body and vertical fins uniformly grayish brown; margin of vertical fins dark brown; opercular region and pectoral fin blackish; abdomen purplish. Distribution. Okhotsk Sea to the eastern Bering Sea, at depths of 895���1805 m (Andriashev, 1955, 1958; Peden, 1973; Toyoshima, 1983, 1984, 1985; Anderson, 1994, 1995; Amaoka et al., 1995, 2011; Koyanagi, 1997; Hatooka, 2000, 2002, 2013; Mecklenburg et al., 2002; Anderson & Fedorov, 2004; Shinohara & Anderson, 2007; Balushkin et al., 2011; this study). Size. The largest specimen examined during this study measured 239.7 mm SL (242.9 mm TL), slightly exceeding the previously recorded maximum length of 24 cm TL (Amaoka, 2011; Hatooka, 2013). Remarks. Lycenchelys rassi resembles L. hippopotamus, L. makushok and L. melanostomias in having more than 100 total vertebrae, 1 interorbital pore, 2 occipital pores, 3���4 postorbital pores, a single ventrally positioned lateral line and no distinct spots or blotches on the body (vs. lacking this combination of characters in other species of Lycenchelys) (e.g., Andriashev, 1955; Toyoshima, 1983, 1985; Fedorov & Andriashev, 1993; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1995; this study). See Remarks under accounts for L. hippopotamus and L. makushok for detailed comparisons of L. melanostomias with those two species. Although L. rassi has been previously compared with L. melanostomias (Toyoshima, 1983, 1985; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1995; Shinohara & Anderson, 2007), this study found most characters considered to be useful for separating them as not valid for doing so. For example, Anderson (1995) redescribed L. rassi based on 6 specimens and claimed that L. rassi is readily separable from L. melanostomias by the following 5 characters: 3���4 postorbital, 7 + 1 or 8 + 1 suborbital and 8 preoperculomandibular pores (vs. 5, 7 + 2 and 9 pores in L. melanostomias), dorsal-fin origin associated with 5th vertebra (vs. 2nd), and stomach pale (vs. black). However, this study found the interspecific variation in the 5 characters mentioned above to be 3���4 postorbital, 7���8 + 1���2 suborbital and 7���9 preoperculomandibular pores, and 1st dorsal-fin pterygiophore located between neural spines of 4th to 6th vertebrae in L. rassi vs. 4���5, 6���7 + 2���3 and 8���9 pores, and 2nd to 5th vertebrae respctively in L. melanostomias, and the stomach in some alcohol preserved specimens of L. melanostomias is pale. See also Imamura et al. (2004) for color of stomach in the holotype of L. melanostomias. In addition, the number of total vertebrae and the length of the head, which were described as being different between L. rassi and L. melanostomias in recently published papers (Shinohara & Anderson, 2007; Hatooka, 2013), are also insufficient to clearly separate them (total vertebrae 122���134 vs. 117���124 and head length 13.3���16.4% SL vs. 11.6���15.0% SL, respectively) (Anderson, 1995; Imamura et al., 2004, 2005; this study). Therefore, these two species cannot always be separated using previously recognized diagnostic characters. This study distinguishes L. rassi from L. melanostomias by the presence or absence of the opercular flap. All specimens of L. rassi observed in this study lack the opercular flap (Fig. 31A, B), while it is present in all specimens of L. melanostomias examined (Fig. 31C, D). The absence of the opercular flap is rare in species of Lycenchelys, and Andriashev (1955) and Toyoshima (1985) started that the absence of the opercular flap is one of the characters differing between L. rassi and its congeners [vs. L. hippopotamus in Andriashev (1955) and vs. L. brevimaxillaris in Toyoshima (1985)]. Until now, the condition of the opercular flap has not been compared between L. rassi and L. melanostomias. This study concludes that the absence of the opercular flap is very valuable for separating L. rassi from L. melanostomias because it is easy to observe and there is no intraspecific variation in both species. Lycenchelys rassi is further distinguished from L. melanostomias by their different arrangements of the postorbital pores. In specimens having 4 postorbital pores, the typical condition in both species, the distance between the 2nd and 3rd pores is much greater in L. rassi (11.8���18.2% HL) than in L. melanostomias (4.1���9.2% HL) (Fig. 30). This difference is due to the positions of the 2nd pores; the 2nd pore emanates from the sphenotic and 3rd pore from the pterotic in L. rassi, while both pores emanates from the pterotic in L. melanostomias., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 32-35, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Andriashev, A. P. (1955) A review of the fishes of the genus Lycenchelys Gill (Pisces, Zoarcidae) and related forms in the seas of the USSR and adjacent waters. Trudy Instituta Zoologii Akademia Nauk, Azerbaidzhanskoi SSR, 18, 349 - 384. [Translated from Russian in Selected taxonomic papers on northern marine fishes, OTS 61 - 31030]","Andriashev, A. P. (1958) An addition to the review of the fishes of the genus Lycenchelys Gill with descriptions of three new species from the Kuril-Kamchatka Trench. Voprosy Ikhtiologii, 8, 611 - 618. [Translated from Russian in Selected taxonomic papers on northern marine fishes, OTS 61 - 31030]","Peden, A. E. (1973) Records of eelpouts of the genus Lycenchelys and Embryx from the northeastern Pacific Ocean. Syesis, 6, 115 - 120.","Toyoshima, M. (1983) Zoarcidae. In: Amaoka, K., Nakaya, K., Araya, H. & Yasui, T. (Eds.), Fishes from the north-eastern Sea of Japan and the Okhotsk Sea off Hokkaido. The intensive research of unexploited fishery resources on continental slopes. Japan Fisheries Resource Conservation Association, Tokyo, pp. 136 - 149 + 208 - 210 + 258 - 277 + 329 - 335.","Toyoshima, M. (1984) Family Zoarcidae. Eelpouts. In: Masuda, H., Amaoka, K., Araga, C., Uyeno, T. & Yoshino, T. (Eds.), The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo, pp. 291 - 295. [in Japanese]","Hatooka, K. (1993) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. Tokai University Press, Tokyo, pp. 898 - 913 + 1343 - 1345. [in Japanese]","Anderson, M. E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). Ichthyological Bulletin of the J. L. B. Smith Institute of Ichthyology, 60, 1 - 120.","Amaoka, K., Nakaya, K. & Yabe, M. (1995) The fishes of northern Japan. Kita-Nihon Kaiyo Center, Sapporo, 391 pp. [in Japanese]","Anderson, M. E. (1995) The eelpout genera Lycenchelys Gill and Taranetzella Andriashev (Teleostei: Zoarcidae) in the eastern Pacific, with descriptions of nine new species. Proceedings of the California Academy of Science, 49, 55 - 133.","Koyanagi, M. (1997) Zoarcidae. In: Okamura, O. & Amaoka, K. (Eds.), Sea fishes of Japan, Yama-Kei, Tokyo, pp. 536 - 538. [in Japanese]","Hatooka, K. (2000) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 2 nd edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1590 - 1593. [in Japanese]","Mecklenburg, G. W., Mecklenburg, T. A. & Thorsteinson, L. K. (2002) Fishes of Alaska. American Fisheries Society, Bethesda, xxxvii + 1037 pp.","Hatooka, K. (2002) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species, English edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1581 - 1583.","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Toyoshima, M. (1985) Taxonomy of the subfamily Lycodinae (family Zoarcidae) in Japan and adjacent waters. Memoirs of the Faculty of Fisheries, Hokkaido University, 32, 131 - 243.","Fedorov, V. V. & Andriashev, A. P. (1993) Lycenchelys makushok sp. nova (Perciformes: Zoarcidae) from the bathyal depths of the Kuril-Kamchatka Trench. Journal of Ichthyology, 33, 130 - 135.","Imamura, H., Machida, Y. & Ohta, S. (2004) Lycenchelys melanostomias Toyoshima, 1983, a senior synonym of L. brevimaxillaris Toyoshima, 1985 (Teleostei: Zoarcidae). Ichthyological Research, 51, 84 - 88. https: // doi. org / 10.1007 / s 10228 - 003 - 0194 - 2","Imamura, H., Shinohara, G. & Shiogaki, M. (2005) Rediscovery of the type specimens of Lycenchelys brevimaxillaris (Actinopterygii: Perciformes: Zoarcidae) with taxonomic notes on the species. Species Diversity, 10, 1 - 6. https: // doi. org / 10.12782 / specdiv. 10.1"]}

Lycenchelys remissaria Fedorov, 1995 (Japanese name: Kawari-hebigenge) (Figs. 32���35; Table 8) Lycenchelys remissaria Fedorov, 1995b: 135, figs. 1���2 (original description, type locality: off Ibaraki Prefecture, Pacific coast of Honshu Island, Japan); Shinohara et al., 1996: 181, fig. 2B (description); Imamura, 1997: 60 (species list); Imamura, 1998: 32, fig. 12 (brief description); Hatooka, 2000: 1032, 1590, unnumbered fig. (key to species); Hatooka, 2002: 1032, 1581, unnumbered fig. (key to species); Anderson & Fedorov, 2004: 20 (species list); Shinohara & Anderson, 2007: 63, table 1 (comparison with Lycenchelys ryukyuensis and key to species); Kitagawa et al., 2008: 95, unnumbered fig. (brief description); Shinohara et al., 2009: 724 (species list); Amaoka et al., 2011: 317, unnumbered fig. (brief description); Balushkin et al., 2011: 982 (catalog of specimens); Hatooka, 2013: 1225, 2078, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Materials examined Holotype: ZIN 50586, male, 200.5 mm SL, off Miyagi Prefecture, Tohoku District, northwestern Pacific (36��54.4���N, 141��55.7���E), 1020 m depth, 4 Feb. 1981, R/V Mys Dal���niy. Other specimens (4 specimens): HUMZ 180877, NSMT-P 47278, NSMT-P 49022 (2), 1 male and 3 females, 216.1���304.4 mm SL, Tohoku District, northwestern Pacific. Diagnosis. Vertebrae 25���26 + 99���105 = 124���130; head length 14.1���15.3% SL; interorbital pores and occipital pores absent; postorbital pores 3���4; suborbital pores 7 + 1; preoperculomandibular pores 9; vomerine teeth 3���5; palatine teeth 2���4, arranged in single row; opercular flap well developed; pelvic-fin base positioned below 7th suborbital pore; two incomplete lateral lines, positioned mediolaterally and ventrally; scales present on pectoral fin and its base; body uniformly grayish when fresh. Description. Counts and proportional measurements in Table 8. ....Continued next page Body elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 4.4���5.3% SL (unknown for holotype). Head moderately long, ovoid; dorsal profile of head sloping extremely gently to dorsal-fin origin. Snout short, 95.5���106.8% of eye diameter (unknown for holotype). Eye ovoid, moderately large. Interorbital space narrow, width 14.1���21.1 (17.1)% of eye diameter. Nostril tube short, not reaching upper lip when depressed. Mouth terminal. Posterior edge of upper jaw reaching to about vertical through anterior edge of pupil or middle of eye (anterior edge of pupil); no significant sexual dimorphism recognized in upper jaw length. Labial lobe of lower jaw weak. Teeth on jaws, vomer and palatine small and conical; upper jaw with 2 rows anteriorly, and 1 or 1���2 rows posteriorly; lower jaw with 2���4 irregular rows anteriorly, and 1 or 1���2 rows posteriorly (tooth arrangement in jaws unknown for holotype); vomerine teeth irregularly arranged; palatine teeth in single row. Lower edge of gill opening slightly above lower end of pectoral-fin base. Opercular flap weakly developed. Gill rakers short and triangular (Fig. 33). Pseudobranch filaments short. Two lateral lines present, deciduous, incomplete; mediolateral line more deciduous, only visible above pectoral fin; ventral line originating posterior to last postorbital pore and terminating anterior to anus. Scales small and cycloid, present on nape, body, except around pelvic fin, pectoral axilla, about 10���30% of pectoral fin basally, pectoral-fin base, tail and about 70���80 % vertical fins basally (scaled areas unknown for holotype). Head and margins of vertical fins without scales. Dorsal-fin origin above middle of pectoral fin; 1st dorsal-fin pterygiophore between neural spines of 7th to 9th vertebrae (between 7th and 8th). Anal-fin origin below 16th or 17th (17th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate abdominal vertebra. Last dorsal-fin pterygiophore between neural spines of 3rd to 5th (between 3rd and 4th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 3rd to 5th (between 3rd and 4th) preural vertebrae. Caudal fin with 2 epural, 3���4 (4) upper hypural and 4���5 (5) lower hypural rays. Pectoral fin moderately short, reaching to middle of abdomen; its posterior margin rounded dorsally and notched ventrally. Upper end of pectoral-fin base on about lateral midline of body. Pelvic fin relatively long; its base below 7th suborbital pore (Fig. 35A); its posterior margin reaching to or slightly beyond lower edge of gill opening (position of posterior margin of pelvic fin unknown for holotype). Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above and slightly anterior to vertical through 1st suborbital pore (Fig. 35A, B). Postorbital pores 3 (Fig. 35A, B); distance between 1st and 2nd pores longest of those between adjacent pores. Suborbital pores 8; 7 pores below eye and last on ascending part of suborbital canal behind eye; 7th pore above pelvic-fin base; 8th pore slightly higher than other 7 suborbital pores and set posterior edge of cheek (Fig. 35A). Preoperculomandibular pores 9; 5 on lower jaw and 4 on preopercle; last preoperculomandibular pore anterior to upper end of pectoral-fin base (Fig. 35A, C). Interorbital pores and occipital pores absent (Fig. 35B). Color in alcohol. Holotype (based on color photograph; Fig. 34) with dark brown head, pectoral fin and margin of vertical fins and bluish gray body, vertical fins and abdomen. Other specimens with pale chocolate brown head, pectoral fin and margins of vertical fins, pale brown body and vertical fins, and dark brown abdomen. Color when fresh (based on color photograph of HUMZ 180877; Fig. 32). Head, pectoral fin and margin of vertical fins blackish, body and vertical fins uniformly grayish, and abdomen dark gray. Distribution. Off northwestern Pacific coast of Honshu Island from Iwate to Ibaraki prefectures, at depths of 1020���2034 m (Fedorov, 1995b; Shinohara et al., 1996; Imamura, 1997, 1998; Hatooka, 2000, 2002, 2013; Anderson & Fedorov, 2004; Shinohara & Anderson, 2007; Kitagawa et al., 2008; Shinohara et al., 2009; Amaoka et al., 2011; Balushkin et al., 2011; this study). Size. Maximum length 32 cm TL (Hatooka, 2013; Amaoka et al., 2011). The largest specimen examined during this study measured 304.4 mm SL (311.0 mm TL). Remarks. Lycenchelys remissaria resembles Lycenchelys cicatrifer (Garman, 1899) and Lycenchelys novaezealandiae Anderson & M��ller, 2007 in having no interorbital pores and occipital pores, 3���4 postorbital pores, 2 lateral lines and scales on the nape in large specimens (vs. lacking this combination of characters in other species of Lycenchelys) (e.g., Anderson, 1995; Fedorov, 1995b; Shinohara et al., 1996; Hatooka, 2000, 2002, 2013; Anderson & M��ller, 2007; Shinohara & Anderson, 2007; this study). Lycenchelys remissaria is easily distinguished from L. novaezealandiae by its fewer numbers of dorsal-fin rays (116���123 vs. 128���132), anal-fin rays (103���107 vs. 119), and total vertebrae (124���130 vs., 139���141), respectively (Anderson & M��ller, 2007; this study). Lycenchelys remissaria is allied to L. cicatrifer in having similar counts and proportional measurements (e.g., 108���115 dorsal-fin rays, 97���104 anal-fin rays and 116���124 total vertebrae in L. cicatrifer) (Table 8). However, L. remissaria is clearly separable from L. cicatrifer by the position of the pelvic fin. In L. remissaria, the pelvic fin is positioned extremely anteriorly with its base below the the 7th suborbital pore (Fig. 35A). In contrast, the pelvic-fin base of L. cicatrifer is located posterior to the suborbital pores. The position of the pelvic-fin base is also useful for separating L. remissaria from all species of Lycenchelys (except for 6 the species without pelvic fins), which have the more posterior position of the fin., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 38-41, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Fedorov, V. V. (1995 b) Lycenchelys remissaria sp. nova (Perciformes: Zoarcidae) from the bathyal region of the ocean shores of Japan. Journal of Ichthyology, 35, 135 - 139.","Shinohara, G., Endo, H. & Matsuura, K. (1996) Deep-water Fishes collection from the Pacific coast of northern Honshu, Japan. Memories of the National Science Museum, Tokyo, 29, 153 - 185.","Imamura, H. (1997) Perciform fish fauna from off Pacific of Tohoku. Researches on Basic Fishes in Tohoku District, 17, 55 - 68. [in Japanese]","Imamura, H. (1998) Zoarcid fishes occurring off Pacific of Tohoku District. Researches on Basic Fishes in Tohoku District, 18, 28 - 34. [in Japanese]","Hatooka, K. (2000) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 2 nd edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1590 - 1593. [in Japanese]","Hatooka, K. (2002) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species, English edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1581 - 1583.","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Kitagawa, D., Imamura, H., Goto, T., Ishito, Y., Fujiwara, K. & Ueda, Y. (2008) Field guide of the fishes from the Tohoku District, north-eastern waters of Japan. Tokai University Press, Hadano, 141 pp. [in Japanese]","Shinohara, G., Narimatsu, Y., Hattori, T., Ito, M., Takata, Y. & Matsuura, K. (2009) Annotated checklist of deep-sea fishes from the Pacific coast off Tohoku District, Japan. In: Fujita, T. (Ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Science Museum of Nature and Science Monographs, Tokyo, 39, pp. 683 - 735.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Anderson, M. E. (1995) The eelpout genera Lycenchelys Gill and Taranetzella Andriashev (Teleostei: Zoarcidae) in the eastern Pacific, with descriptions of nine new species. Proceedings of the California Academy of Science, 49, 55 - 133.","Anderson, M. E. & Moller, P. R. (2007) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. XIII. Two new species of Lycenchelys from the Southwestern Pacific. Species Diversity, 12, 175 - 185. https: // doi. org / 10.12782 / specdiv. 12.175"]}

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. ....Continued next page 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)., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 6-10, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Toyoshima, M. (1983) Zoarcidae. In: Amaoka, K., Nakaya, K., Araya, H. & Yasui, T. (Eds.), Fishes from the north-eastern Sea of Japan and the Okhotsk Sea off Hokkaido. The intensive research of unexploited fishery resources on continental slopes. Japan Fisheries Resource Conservation Association, Tokyo, pp. 136 - 149 + 208 - 210 + 258 - 277 + 329 - 335.","Toyoshima, M. (1984) Family Zoarcidae. Eelpouts. In: Masuda, H., Amaoka, K., Araga, C., Uyeno, T. & Yoshino, T. (Eds.), The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo, pp. 291 - 295. [in Japanese]","Toyoshima, M. (1985) Taxonomy of the subfamily Lycodinae (family Zoarcidae) in Japan and adjacent waters. Memoirs of the Faculty of Fisheries, Hokkaido University, 32, 131 - 243.","Hatooka, K. (1993) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. Tokai University Press, Tokyo, pp. 898 - 913 + 1343 - 1345. [in Japanese]","Amaoka, K., Nakaya, K. & Yabe, M. (1995) The fishes of northern Japan. Kita-Nihon Kaiyo Center, Sapporo, 391 pp. [in Japanese]","Imamura, H. (1997) Perciform fish fauna from off Pacific of Tohoku. Researches on Basic Fishes in Tohoku District, 17, 55 - 68. [in Japanese]","Koyanagi, M. (1997) Zoarcidae. In: Okamura, O. & Amaoka, K. (Eds.), Sea fishes of Japan, Yama-Kei, Tokyo, pp. 536 - 538. [in Japanese]","Imamura, H. (1998) Zoarcid fishes occurring off Pacific of Tohoku District. Researches on Basic Fishes in Tohoku District, 18, 28 - 34. [in Japanese]","Zama, A. (2001) Fish fauna of Miyagi Prefecture, Japan. Sanwa Publisher, Ishinomaki, 153 pp. [in Japanese]","Anderson, M. E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). Ichthyological Bulletin of the J. L. B. Smith Institute of Ichthyology, 60, 1 - 120.","Shinohara, G., Endo, H. & Matsuura, K. (1996) Deep-water Fishes collection from the Pacific coast of northern Honshu, Japan. Memories of the National Science Museum, Tokyo, 29, 153 - 185.","Hatooka, K. (2000) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 2 nd edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1590 - 1593. [in Japanese]","Hatooka, K. (2002) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species, English edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1581 - 1583.","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Shiogaki, M., Ishito, Y., Nomura, Y. & Sugimoto, T. (2004) Revised catalog of the fishes collected from the waters of Aomori Prefecture. Bulletin of Aomori Prefectural Fisheries Research Center, (4), 39 - 80. [in Japanese with English abstract]","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Kitagawa, D., Imamura, H., Goto, T., Ishito, Y., Fujiwara, K. & Ueda, Y. (2008) Field guide of the fishes from the Tohoku District, north-eastern waters of Japan. Tokai University Press, Hadano, 141 pp. [in Japanese]","Shinohara, G., Narimatsu, Y., Hattori, T., Ito, M., Takata, Y. & Matsuura, K. (2009) Annotated checklist of deep-sea fishes from the Pacific coast off Tohoku District, Japan. In: Fujita, T. (Ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Science Museum of Nature and Science Monographs, Tokyo, 39, pp. 683 - 735.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Gosztonyi, A. E. (1977) Results of the research cruises of FRV \" Walter Herwig \" to South America. XLVIII. Revision of the South American Zoarcidae (Osteichthyes, Blennioidei) with the description of three new genera and five new species. Archiv fur Fischereiwissenshaft, 27, 191 - 249.","Nakamura, I. (1986) Zoarcidae. In: Nakamura, I., Inada, T., Takeda, M. & Hatanaka, H. (Eds.), Important fishes trawled off Patagonia. Japan Marine Fishery Resources Research Center, Tokyo, pp. 232 - 243."]}

Lycenchelys hippopotamus Schmidt, 1950 (Japanese name: Hebigenge) (Figs. 9���13; Table 3) Lycenchelys hippopotamus Schmidt, 1935: 35 (nomen nudum); Taranetz, 1937: 161 (nomen nudum). Lycenchelys hippopotamus Schmidt, 1950: 106, fig 4, pl. IX (original description, type locality: east coast of Sakhalin Island, Sea of Okhotsk); Andriashev, 1955: 354, 361, figs. 2, 7���8 (description); Matsubara, 1955: 774 (key to species); Fedorov, 1976: 8, tables 3���4 (description); Toyoshima, 1983: 267, 332, pl. 154 (description); Toyoshima, 1984: 293, pl. 273-O (brief description); Toyoshma, 1985: 149, 169, figs. 6���7, 24���25, 31, table 1 (description); Hatooka, 1993: 902, unnumbered fig. (key to species); Anderson, 1994: 65, 113, 117 (osteological comments); Amaoka et al., 1995: 239, pl. 401 (brief description); Anderson, 1995: 76 (description); Koyanagi, 1997: 538, fig. 2 (brief description); Hatooka, 2000: 1032, unnumbered fig. (key to species); Hatooka, 2002: 1032, unnumbered fig. (key to species); Mecklenburg et al., 2002: 701, unnumbered figs. (brief description); Anderson & Fedorov, 2004: 17 (species list); Shinohara & Anderson, 2007: 64 (key to species); Amaoka et al., 2011: 315, unnumbered fig. (brief description); Balushkin et al., 2011: 980, 1024 (catalog of specimens); Hatooka, 2013: 1226, unnumbered fig. (key to species); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Materials examined Lectotype: ZIN 24826, female, 206.8 mm SL, east coast of Sakhalin Island, Okhotsk Sea (53��09.5���N, 149��52.1���E), 1150 m depth, 7 Aug. 1932. Paralectotype (2 specimens): ZIN 24826, 1 male and 1 female, 167.7���194.9 mm SL, collected with lectotype. Other specimens (29 specimens): HUMZ 77571, 77573, 77774, 119986���87, 120005, 120285, 120329, 120345, 121155, 121157, 121159 ���60, 121162, 121164, 121193, 121452, 121463, 123979, 124056, 124115, 126116, 126186, 126218, 126223, 126228, 20 males and 9 females, 117.9���211.9 mm SL, northeastern Hokkaido Island, Okhotsk Sea. Diagnosis. Vertebrae 23���24 + 105���115 = 128���138; head length 12.5���15.0% SL; interorbital pores 1���2; occipital pores 2; postorbital pores 3���4; suborbital pores usually 8 + 1; 1st suborbital pore located just below nostril tube; preoperculomandibular pores 8���9; vomerine teeth 3���7; palatine teeth 1���7, arranged in single row; opercular flap well-developed; pelvic-fin base positioned below lower edge of gill opening; lateral line complete and positioned ventrally; scales present or absent on pectoral fin and absent on its base; body uniformly dark chocolate-brown when fresh. Description. Counts and proportional measurements in Table 3. ....Continued next page Body very elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 2.3���4.6% SL (unknown for lectotype). Head moderately long, ovoid; dorsal profile of head gently sloping from posterior edge of eye to above about last postorbital pore. Head of adults generally longer in males than in females. Snout rather short, 127.2���199.8 (172.3)% of eye diameter. Eye ovoid, relatively small. Interorbital space narrow, width 20.0���37.0 (27.8)% of eye diameter. Nostril tube short, reaching 1st suborbital pore when depressed. Mouth subterminal. Posterior edge of upper jaw about reaching vertical through anterior margin of eye in adult males, not reaching vertical through anterior margin of eye in females and juveniles. Labial lobe of lower jaw weak. Teeth on jaws sharp; upper jaw with single row, anterior teeth large and posterior teeth small; 4 females, including lectotype and 1 paralectotype, with additional small teeth behind anteriormost tooth; lower jaw with 2���3 irregular rows anteriorly and single row posteriorly, anterior teeth large and those posteriorly small; vomer and palatine small and conical; vomerine teeth irregularly arranged; palatine teeth in single row. Lower edge of gill opening reaching 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. 10). Pseudobranch filaments relatively 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, tail and about 40���80 % of vertical fins basally. Scales present or absent on basal portion of pectoral-fin rays (present in lectotype). Head, nape, pectoral axil and pectoral-fin base without scales. Dorsal-fin origin posterior to vertical through pectoral-fin base; 1st dorsal-fin pterygiophore between neural spines of 4th to 6th (between 5th and 6th) vertebrae. Anal-fin origin below 17th to 19th (17th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate to antepenultimate abdominal (penultimate) vertebra. Last dorsal-fin pterygiophore between neural spines of 2nd to 5th (between 3rd and 4th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 2nd to 6th (between 3rd and 4th) preural vertebrae. Caudal fin with 2 epural, 4���5 (4) upper hypural and 3���4 (4) lower hypural rays. Pectoral fin moderately short, reaching to about middle of abdomen; its posterior margin rounded dorsally and having notches ventrally. Upper end of pectoral-fin base about on lateral horizontal midline of body. Pelvic fin relatively long; its base below lower edge of gill opening; its posterior margin reaching vertical through pectoral-fin base. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above 2nd suborbital pore (Fig. 11A, B). Postorbital pores usually 3 (3) (Fig. 11A, B); distance between 1st and 2nd pores longest of those between adjacent pores; 1 additional small pore present just behind 1st pore on both sides in HUMZ 121157. Suborbital pores usually 9 (9), 8 pores located below lower margin of eye and 9th behind eye; when 10 pores, 9 pores below eye and last behind eye on left side in HUMZ 77571 and 121160, and both sides in HUMZ 126194; 5th pore below vertical through anterior margin of eye; last pore of those below eye slightly posterior to vertical through 1st postorbital pore (Fig. 11A). Preoperculomandibular pores 8���9 (8); 4 on lower jaw, 1���2 (1) on junction of lower jaw and preopercle, and 3 on preopercle; last preoperculomandibular pore located posterior to lower margin of eye (Fig. 11A, C). Interorbital pores 1 or 2 (1); when 2, anterior pore located above 4th suborbital pore, and posterior pore between center or slightly posterior to center of eyes (Fig. 11B); when 1, anterior pore absent and posterior pore located slightly posterior to center of eyes. Occipital pores 2, pores on either side of dorsal midline anterior to 2nd postorbital pore (Fig. 11B). Color in alcohol. Lectotype (based on color photograph; Fig. 13) with dark brown head, pectoral fin and margin of vertical fins, slightly paler body and vertical fins; purplish gray abdomen. Non-type specimens similar to lectotype, except HUMZ 77571, 77573 and 77774, which have uniformly pale brown head and body and black dots on pectoral fin (HUMZ 121157 and 121159). Color when fresh (based on color photograph of HUMZ 124056; Fig. 9). Head and pectoral fin blackish. Body and vertical fins uniformly dark chocolate brown. Distribution. Southern Okhotsk Sea to the northwestern Bering Sea, at depths of 408���1800 m (Schmidt, 1950; Andriashev, 1955; Matsubara, 1955; Fedorov, 1976; Toyoshima, 1983, 1984, 1985; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1994, 1995; Amaoka et al., 1995, 2011; Koyanagi, 1997; Mecklenburg et al., 2002; Anderson & Fedorov, 2004; Shinohara & Anderson, 2007; Balushkin et al., 2011; this study). Size. Maximum length 223 mm TL (Anderson, 1995; Mecklenburg et al., 2002). The largest specimen examined for this study was 211.9 mm SL (216.3 mm TL). Remarks. Lycenchelys hippopotamus is similar to L. makushok, L. melanostomias and L. rassi in having more than 100 total vertebrae, 1���2 interorbital pores, 2 occipital pores, 3���4 postorbital pores, single ventral lateral line and no distinct spots or blotches on the body (vs. lacking this combination of characters in other species of Lycenchelys) (e.g., Schmidt, 1950; Andriashev, 1955; Toyoshima, 1983, 1985; Fedorov & Andriashev, 1993; Hatooka, 1993, 2000, 2002, 2013; Anderson, 1995; Shinohara et al., 1996; this study). Lycenchelys hippopotamus is distinguished from these three species by the position of the 1st suborbital pore. In L. hippopotamus, it is located just below the nostril tube (Fig. 12A), while it is located behind the nostril tube in L. makushok, L. melanostomias and L. rassi (Fig. 12B, C, D). In addition, L. hippopotamus has 1���2 interorbital pores, and when only the middle pore is present, it is located between the middle of the eyes or slightly posterior. In contrast, L. makushok, L. melanostomias and L. rassi, always have only 1 pore in the interorbital space, and it is located anterior to the middle of the eyes., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 14-19, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Schmidt, P. Y. (1950) Fishes of the Sea of Okhotsk. Transaction of the Pacific Committee of the Academy of Science of the U. S. S. R., 6, 1 - 370. [in Russian]","Schmidt, P. Y. (1935) The Sea of Okhotsk and its fish fauna. Vestnik Akademii Nauk USSR, 5, 30 - 38. [in Russian] https: // doi. org / 10.2307 / 1436107","Taranetz, A. J. (1937) Hand book for identification of fishes of the Soviet far east and adjacent waters. Bulletins of the Pacific Science Institute, 11, 1 - 200. [in Russian]","Andriashev, A. P. (1955) A review of the fishes of the genus Lycenchelys Gill (Pisces, Zoarcidae) and related forms in the seas of the USSR and adjacent waters. Trudy Instituta Zoologii Akademia Nauk, Azerbaidzhanskoi SSR, 18, 349 - 384. [Translated from Russian in Selected taxonomic papers on northern marine fishes, OTS 61 - 31030]","Matsubara, K. (1955) Fish morphology and hierarchy. Ishizaki-Shoten, Tokyo, 1605 pp. [in Japanese]","Fedorov, V. V. (1976) New data on the eel-like likods (Pisces, Zoarcidae) from the northwestern Pacific Ocean and Bering Sea. Izvestiya TINRO, 100, 3 - 18. [in Russian]","Toyoshima, M. (1983) Zoarcidae. In: Amaoka, K., Nakaya, K., Araya, H. & Yasui, T. (Eds.), Fishes from the north-eastern Sea of Japan and the Okhotsk Sea off Hokkaido. The intensive research of unexploited fishery resources on continental slopes. Japan Fisheries Resource Conservation Association, Tokyo, pp. 136 - 149 + 208 - 210 + 258 - 277 + 329 - 335.","Toyoshima, M. (1984) Family Zoarcidae. Eelpouts. In: Masuda, H., Amaoka, K., Araga, C., Uyeno, T. & Yoshino, T. (Eds.), The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo, pp. 291 - 295. [in Japanese]","Hatooka, K. (1993) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. Tokai University Press, Tokyo, pp. 898 - 913 + 1343 - 1345. [in Japanese]","Anderson, M. E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). Ichthyological Bulletin of the J. L. B. Smith Institute of Ichthyology, 60, 1 - 120.","Amaoka, K., Nakaya, K. & Yabe, M. (1995) The fishes of northern Japan. Kita-Nihon Kaiyo Center, Sapporo, 391 pp. [in Japanese]","Anderson, M. E. (1995) The eelpout genera Lycenchelys Gill and Taranetzella Andriashev (Teleostei: Zoarcidae) in the eastern Pacific, with descriptions of nine new species. Proceedings of the California Academy of Science, 49, 55 - 133.","Koyanagi, M. (1997) Zoarcidae. In: Okamura, O. & Amaoka, K. (Eds.), Sea fishes of Japan, Yama-Kei, Tokyo, pp. 536 - 538. [in Japanese]","Hatooka, K. (2000) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 2 nd edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1590 - 1593. [in Japanese]","Hatooka, K. (2002) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species, English edition. Tokai University Press, Tokyo, pp. 1028 - 1044 + 1581 - 1583.","Mecklenburg, G. W., Mecklenburg, T. A. & Thorsteinson, L. K. (2002) Fishes of Alaska. American Fisheries Society, Bethesda, xxxvii + 1037 pp.","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Toyoshima, M. (1985) Taxonomy of the subfamily Lycodinae (family Zoarcidae) in Japan and adjacent waters. Memoirs of the Faculty of Fisheries, Hokkaido University, 32, 131 - 243.","Fedorov, V. V. & Andriashev, A. P. (1993) Lycenchelys makushok sp. nova (Perciformes: Zoarcidae) from the bathyal depths of the Kuril-Kamchatka Trench. Journal of Ichthyology, 33, 130 - 135.","Shinohara, G., Endo, H. & Matsuura, K. (1996) Deep-water Fishes collection from the Pacific coast of northern Honshu, Japan. Memories of the National Science Museum, Tokyo, 29, 153 - 185."]}

Lycenchelys tohokuensis Anderson & Imamura, 2002 (Japanese name: Kitagawa-hebigenge) (Figs. 44���49; Table 11) Lycenchelys tohokuensis Anderson & Imamura, 2002: 355, figs. 1���2 (original description, type locality: off Fukushima Prefecture, Pacific coast of Honshu Island, Japan); Anderson & Fedorov, 2004: 20 (species list); Shinohara & Anderson, 2007: 63 (key to species); Kitagawa et al., 2008: 95, unnumbered fig. (brief description); Shinohara et al., 2009: 724 (species list); Amaoka et al., 2011: 317, unnumbered fig. (brief description); Balushkin et al., 2011: 1026 (species list); Hatooka, 2013: 1227, 2078, unnumbered fig. (key to species); Yamanaka & Ito, 2014: 4 (species list); Nakabo & Hirashima, 2015: 217 (species list and etymology of scientific name). Materials examined Holotype: HUMZ 156757, male, 269.8 mm SL, off Fukushima Prefecture, Tohoku District, northwestern Pacific (37��31.55���N, 142��12.69���E to 37��32.94���N, 142��13.31���E), 697���705 m depth, 18 Apr. 1998, T/V Tanshu-maru, otter trawl. Paratypes (4 specimens, 195.3���265.1 mm SL, all from Tohoku District, northwestern Pacific): HUMZ 152369, 1 female, 259.8 mm SL, off Aomori Prefecture (40��42.42���N, 142��09.06���E to 40��41.04���N, 142��09.95���E), 661���667 m depth, 22 Oct. 1997, R/V Wakataka-maru, otter trawl; HUMZ 171668, 1 male, 195.3 mm SL, off Fukushima Prefecture, (36��42.43���N, 141��26.10���E to 36��47.68���N, 141��27.22���E), 582���591 m depth, 11 June 2000, R/V Wakatakamaru, otter trawl; NSMT-P 64042, 1 female, 237.9 mm SL, off Fukushima Prefecture (36��36.25���N, 141��18.23���E to 36��38.91���N, 141��23.67���E), 557���599 m depth, 11 June 2000, R/V Wakataka-maru, otter trawl; HUMZ 178280, 1 female, 265.1 mm SL, off Fukushima Prefecture (37��00.94���N, 141��40.59��� E to 36��57.83���N, 141��36.70��� E), 543���546 m depth, 19 Oct. 2001, R/V Wakataka-maru, otter trawl. Other specimens (3 specimens): HUMZ 177071, 192808, 206820, 1 male and 2 females, 208.1���270.1 mm SL, Tohoku District, northwestern Pacific. Diagnosis. Vertebrae 27���29 + 88���91 = 116���119; head length 13.4���14.4% SL; interorbital pore 1; occipital pores 3; postorbital pores 5; suborbital pores 5 + 2; preoperculomandibular pores 8; vomerine teeth 7���11; palatine teeth 8���15, arranged in 2 rows anteriorly and single row posteriorly; opercular flap well developed; pelvic-fins absent; two complete lateral lines, positioned mediolaterally and ventrally; scales present on pectoral fin and its base; body uniformly brown when fresh. Description. Counts and proportional measurements in Table 11. .....Continued next page Body elongate, cross section oval anteriorly, compressed laterally near tail; its width at anal-fin origin 4.2���5.6 (5.9)% SL. Head relatively short, ovoid; dorsal profile of head gently sloping to above upper edge of gill opening or dorsal-fin origin (above upper edge of gill opening). Snout short, 99.0���142.4 (99.0)% of eye diameter. Eye rounded or slightly oval (rounded), relatively small. Interorbital space moderately narrow, width 23.8���45.4 (23.8)% of eye diameter. Nostril tube long, reaching upper lip when depressed. Mouth subterminal. Posterior edge of upper jaw reaching to about vertical through posterior margin of pupil. Labial lobe of lower jaw developed. Teeth on jaws, vomer and palatine small and conical; upper jaw with 2���3 rows anteriorly and single row posteriorly; lower jaw with 2���3 or 3���4 irregular rows (3���4) anteriorly and single row posteriorly; vomerine teeth irregularly arranged; palatine teeth in 2 rows anteriorly and single row posteriorly. Lower edge of gill opening reaching to or slightly above lower end of pectoral-fin base (above lower end of pectoral-fin base). Opercular flap well developed. Gill rakers, short; those on upper limb triangular, many blunt and some triangular rakers on lower limb (Fig. 45). Pseudobranch filaments relatively long. Two lateral lines, deciduous, complete; mediolateral line origin above about middle portion of abdomen and terminating on tail; ventral lateral line origin posterior to last postorbital pore and terminating on tail. Scales small and cycloid, present on body, pectoral axilla, about basal quarter of pectoral fin, pectoral-fin base, tail and most regions of vertical fins except near margins. Nape with few scales or naked (with few scales). Head without scales. Dorsal-fin origin nearly above pectoral-fin base; 1st dorsal-fin pterygiophore between neural spines of 3rd and 4th vertebrae. Anal-fin origin below 23rd to 25th (24th) dorsal-fin ray; 1st anal-fin pterygiophore posterior to parapophysis of ultimate or penultimate (penultimate) abdominal vertebra. Last dorsal-fin pterygiophore between neural spines of 3rd to 5th (between 4th and 5th) preural vertebrae. Last anal-fin pterygiophore between hemal spines of 2nd to 4th (between 2nd and 3rd) preural vertebrae. Caudal fin with 2 epural, 4 upper hypural and 4 lower hypural rays. Pectoral fin moderately short, reaching to anterior or middle portion of abdomen; its posterior margin rounded dorsally and notched ventrally. Upper end of pectoral-fin base slightly below lateral midline of body. Pelvic fins absent. Head pores well developed and distinct. Nasal pores 2; anterior pore in front of nostril tube, posterior pore above 1st suborbital pore (Fig. 46A, B). Postorbital pores 5 (Fig. 46A, B); holotype with extremely small additional pore posterior to 5th pore on right side. Suborbital pores 7; 5 pores below eye and 2 pores on ascending part of suborbital canal behind eye; 5th pore behind vertical through posterior margin of eye (Fig. 46A). Preoperculomandibular pores 8; 4 on lower jaw and 4 on preopercle; last preoperculomandibular pore posterior to lower margin of eye (Fig. 46A, C). One interorbital pore on dorsal midline between anterior margins of pupils (anterior margin of pupils) (Fig. 46B). Occipital pores 3; 1 on dorsal midline of occiput, and remaining 2 on either side; 3 pores transversely aligned or middle pore slightly posterior to those on either side (middle pore located slightly behind side pores); all pores located anterior to 4th postorbital pore (Fig. 46B). Color in alcohol. Holotype (Fig. 47) with brownish head and uniformly paler body, pectoral fin and vertical fins; dark brown margins of pectoral and vertical fins and grayish abdomen. Body purplish brown in HUMZ 171668. Coloration of other specimens similar to holotype. Color when fresh (based on color photograph of HUMZ 152369; Fig. 44). Head, body and vertical fins uniformly brown, pectoral fin paler; margins of pectoral and vertical fins, and opercular region blackish; abdomen grayish. Distribution. Off northwestern Pacific coast of Tohoku District from Aomori to Fukushima prefectures, at depths of 543���905 m (Anderson & Imamura, 2002; Anderson & Fedorov, 2004; Shinohara & Anderson, 2007; Kitagawa et al., 2008; Shinohara et al., 2009; Amaoka et al., 2011; Hatooka, 2013; Yamanaka & Ito, 2014; this study). Size. The largest specimen examined during this study measured 270.1 mm SL (HUMZ 192808, 275.2 mm TL), about equal to the previously recorded maximum length (HUMZ 156757, holotype, 270 mm SL) (Anderson & Imamura, 2002). Remarks. Other than L. tohokuensis, only five species of Lycenchelys are known to lack pelvic fins: Lycenchelys fedorovi Anderson & Balanov, 2000, Lycenchelys hureaui (Andriashev, 1979), Lycenchelys monstrosa Anderson, 1982, Lycenchelys nanospinata Anderson, 1988 and Lycenchelys xanthoptera Anderson, 1991 (Anderson, 1982a, 1988, 1991; Anderson & Balanov, 2000; Anderson & Imamura, 2002). Lycenchelys tohokuensis is distinguished from the five species in having two lateral lines and palatine teeth arranged in two rows anteriorly (vs. having a single lateral line in all five species and palatine teeth arranged in a single row in L. fedorovi, L. hureaui, L. monstrosa and L. nanospinata, or lacking palatine teeth in L. xanthoptera) (Anderson, 1982a, 1988, 1991; Anderson & Balanov, 2000; Anderson & Imamura, 2002). Lycenchelys tohokuensis also differs from L. fedorovi, L. hureaui, L. monstrosa and L. nanospinata in having 116���119 total vertebrae (vs. 132���139 in L. fedorovi, 104���112 in L. hureaui, 126���132 in L. monstrosa and 105 in L. nanospinata), from L. hureaui, L. monstrosa, L. nanospinata and L. xanthoptera in having 1 interorbital pore and 3 occipital pores (vs. interorbital pores and occipital pores absent in the four), and from L. monstrosa in having vomerine teeth (vs. usually absent in L. monstrosa) (Anderson, 1982a, 1988, 1991; Anderson & Balanov, 2000; Anderson & Imamura, 2002; this study). Although the Lycodinae are recognized as having an L-shaped series of suborbital bones (Anderson, 1994), they are arranged in a semicircular series in L. tohokuensis (Fig. 45A). The latter configuration also occurs in the other three subfamilies: Lycozoarcinae Andriashev, 1939, Zoarcinae Gill, 1862 and Gymnelinae Gill, 1864 (Anderson, 1994). Lycenchelys tohokuensis clearly differs from species of Lycozoarcinae (including only Lycozoarces regani Popov, 1933) and Zoacinae (only Zoarces Cuvier, 1829 with six species) in having scales, and teeth on the vomer and palatine, and lacking the pelvic fins and dorsal-fin spines (vs. having pelvic fins and lacking scales in the Lycozoarcinae, and having pelvic fins and dorsal-fin spines, and lacking vomerine and palatine teeth in the Zoarcinae) (Anderson, 1994). When compared with genera of Gymnelinae, L. tohokuensis mostly resembles Ericandersonia Shinohara & Sakurai, 2006 [only 1 species, Ericandersonia sagamia Shinohara & Sakurai, 2006 (Fig 48)] in having similar numbers of dorsal-fin rays (112���116 vs. 113���116), anal-fin rays (93���94 vs. 93���95), pectoral-fin rays (14 vs. 14), and total vertebrae (116���119 vs.117���118), respectively (Anderson & Imamura, 2002; Shinohara & Sakurai, 2006; this study). Furthermore, numbers and arrangements of head pores in the two species are the same (2 nasal, 5 postorbital, 7 suborbital, 4 mandibular, 4 preopercular, 1 interorbital and 3 occipital pores) (Figs. 46A, B, C, 49A, B, C) (Anderson & Imamura, 2002; Shinohara & Sakurai, 2006; this study). The two are distinguishable, however, by the presence of 2 lateral lines, and a developed labial lobe on the lower jaw, and the lower edge of the gill opening set slightly above the lower end of the pectoral-fin base in L. tohokuensis (vs. lateral line single and mediolateral, labial lobe of lower jaw absent, and lower edge of the gill opening not reaching lower end of pectoral-fin base in E. sagamia) (Anderson & Imamura, 2002; Shinohara & Sakurai, 2006; this study). In addition, E. sagamia is characterized by the presence of a weak ridge (= pseudosubmental crest sensu Shinohara & Sakurai, 2006) on the ventral surface of the mandibula, which is absent in other zoarcid species (Shinohara & Sakurai, 2006; this study). The question of retaining Lycenchelys tohokuensis in Lycenchelys because of its peculiar arrangement of the suborbital bones, relative to that of other members of the subfamily needs to be tested by a phylogenetic study of the entire group., Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 50-55, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Anderson, M. E. & Imamura, H. (2002) A new species of Lycenchelys (Perciformes: Zoarcidae) from the Pacific coast of northern Japan. Ichthyological Research, 49, 355 - 357. https: // doi. org / 10.1007 / s 102280200053","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Kitagawa, D., Imamura, H., Goto, T., Ishito, Y., Fujiwara, K. & Ueda, Y. (2008) Field guide of the fishes from the Tohoku District, north-eastern waters of Japan. Tokai University Press, Hadano, 141 pp. [in Japanese]","Shinohara, G., Narimatsu, Y., Hattori, T., Ito, M., Takata, Y. & Matsuura, K. (2009) Annotated checklist of deep-sea fishes from the Pacific coast off Tohoku District, Japan. In: Fujita, T. (Ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Science Museum of Nature and Science Monographs, Tokyo, 39, pp. 683 - 735.","Amaoka, K., Nakaya, K. & Yabe, M. (2011) Fishes of Hokkaido. The Hokkaido Shimbun Press, Sapporo, 482 pp. [in Japanese]","Balushkin, A. V., Sheiko, B. A. & Fedorov, V. V. (2011) Catalog of archival collection of the Zoological Institute, Russian Academy of Sciences: class Osteichthyes (bony fishes), order Perciformes, family Zoarcidae. Journal of Ichthyology, 51, 950 - 1034. https: // doi. org / 10.1134 / S 0032945211100031","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]","Yamanaka, T. & Ito, K. (2014) Additional records and revisions to the revised catalog of the fishes collected from the waters of Aomori Prefecture-I. Bulletin of Aomori Prefectural Industrial Technology Research Center Fisheries Institute, 8, 1 - 10. [in Japanese]","Nakabo, T. & Hirashima, Y. (2015) Scientific names of Japanese fishes: etymology. Tokai University Press, Hadano, xv + 372 pp. [in Japanese]","Anderson, M. E. & Balanov, A. A. (2000) Lycenchelys fedorovi: a new species of eelpout (Teleostei: Zoarcidae) from the northern Pacific Ocean. Copeia, 2000, 1056 - 1061. https: // doi. org / 10.1643 / 0045 - 8511 (2000) 000 [1056: LFANSO] 2.0. CO; 2","Andriashev, A. P. (1979) First finding of fishes of the families Zoarcidae and Liparididae near Kerguelen Islands. Biologiya Morya, 6, 28 - 34. [in Russian]","Anderson, M. E. (1988) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. I. The Antarctic and subantarctic regions. Antarctic Research Series, 47, 59 - 113. https: // doi. org / 10.1029 / AR 047 p 0059","Anderson, M. E. (1991) Studies on the Zoarcidae (Teleostei: Perciformes) of the souththern hemisphere. V. Two new species from the Weddell Sea, Antarctica. Cybium, 15, 151 - 158.","Anderson, M. E. (1982 a) A new eelpout (Teleostei: Zoarcidae) from the eastern tropical Pacific Ocean. Bulletin of Marine Science, 32 (1), 207 - 212.","Anderson, M. E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). Ichthyological Bulletin of the J. L. B. Smith Institute of Ichthyology, 60, 1 - 120.","Shinohara, G. & Sakurai, H. (2006) Ericandersonia sagamia, a new genus and species of deep waters eelpouts (Perciformes: Zoarcidae) from Japan. Ichthyological Research, 53, 172 - 178. https: // doi. org / 10.1007 / s 10228 - 006 - 0333 - 7"]}

Genus Lycenchelys Gill, 1884 (Japanese name: Hebigenge-zoku) Lycenchelys Gill, 1884: 180 (type species by subsequent designation: Lycodes muraena Collett, 1878). Lycodophis Vaillant, 1888: 311 (type species by monotypy: Lycodes albus Vaillant, 1888). Embryx Jordan & Evermann, 1898: 2458 (type species by original designation: Lycodopsis crotalinus). Lyciscus Evermann & Goldsborough, 1907: 342 (type species by monotypy: Lycodopsis crotalinus Gilbert, 1890). Apodolycus Andriashev, 1979: 29 (type species by original designation: Apodolycus hureaui Andriashev, 1979). Diagnosis. Vertebrae 19���30 + 66���118 = 85���144; suborbital bones 6���10; suborbital pores 6���11; 1st dorsal-fin pterygiophores associated with vertebrae 2���21, with 0���16 free pterygiophores; palatopterygoid series weak; oral valve weak; pseudobranch, pelvic fins, and vomerine and palatine teeth usually present; scales, pyloric caeca and lateral line(s) present (Anderson, 1994; Shinohara & Matsuura, 1998; Shinohara & Anderson, 2007; this study). Distribution. Widespread in the Pacific (mainly in northwestern and eastern), Atlantic, Arctic and Southern oceans, and around the Kerguelen Islands (Anderson, 1994, 2006; Anderson & Fedorov, 2004; Anderson & M��ller, 2007; Shinohara & Anderson, 2007; Thiel et al., 2018; this study). Maximum collection depth 5320 m, in the Peru- Chile Trench (holotype of Lycenchelys atacamensis Andriashev, 1980) (Andriashev, 1980; Anderson, 1988, 1995; Anderson & Fedorov, 2004). Remarks. The genus Lycenchelys currently includes about 60 species (Anderson & Fedorov, 2004; Anderson, 2006; Anderson & M��ller, 2007; Shinohara & Anderson, 2007; Nelson et al., 2016; Thiel et al., 2018). This study recognizes 11 species of Lycenchelys in Japanese waters, in accordance with recent studies (i.e., Shinohara & Anderson, 2007; Hatooka, 2013). The diagnosis of the genus above mainly follows Anderson (1994), except for the numbers of suborbital pores and total vertebrae, variations in which were reported by Shinohara & Matsuura (1998), Shinohara & Anderson (2007) and this study. Keys to species of genus Lycenchelys from Japanese waters 1a. Interorbital pores absent............................................................................... 2 1b. Interorbital pores present............................................................................... 3 2a. Pelvic-fin base positioned below 7th suborbital pore; suborbital pores 7 + 1; preoperculomandibular pores 9; lateral lines 2; pectoral fin and its base having scales............................................................ L. remissaria 2b. Pelvic-fin base set posterior to suborbital pores; suborbital pores 6 + 1���2; preoperculomandibular pores 8; lateral line 1; pectoral fin and its base lacking scales............................................................. L. ryukyuensis 3a. Occipital pores absent................................................................................. 4 3b. Occipital pores present................................................................................ 5 4a. Total vertebrae 85���89; pectoral-fin rays 13���16; pectoral fin and its base lacking scales; body reddish orange when fresh.............................................................................................. L. aurantiaca 4b. Total vertebrae 91���95; pectoral-fin rays 17���19; pectoral fin and its base having scales; body dark brown when fresh................................................................................................. L. squamosa 5a. Distinct spots or blotches present on body.................................................................. 6 5b. Distinct spots or blotches absent on body.................................................................. 7 6a. Six to 10 white blotches present above upper edge of gill opening and on dorsal fin extending onto dorsal part of body; total vertebrae 122���128....................................................................... L. albomaculata 6b. Blackish irregular blotches on most portions of dorsal fin and dorsal part of body; total vertebrae 137���142...... L. maculata 7a. Pelvic fins present; suborbital bone arrangement L-shaped; a single lateral line.................................... 8 7b. Pelvic fins absent; suborbital bone arrangement semicircular; two lateral lines........................... L. tohokuensis 8a. First suborbital pore located just below nostril tube; interorbital pores 1���2, when 1 interorbital pore present, located between middle centers of eyes or slightly posteriorly................................................... L. hippopotamus 8b. First suborbital pore located behind nostril tube; interorbital pore 1, located anterior to center of eyes................... 9 9a. Occipital pore usually 1 (rarely 2 or 3), 1 pore always present on midline of occiput; preoperculomandibular pores 9���10; total vertebrae 132���139.......................................................................... L. makushok 9b. Occipital pores usually 2 (rarely 1), located on left and/or right sides of occiput; preoperculomandibular pores 7���9; total vertebrae 117���134....................................................................................... 10 10a. Opercular flap absent; distance between 2nd and 3rd postorbital pores long, 11.8���18.2% HL.................... L. rassi 10b. Opercular flap present; distance between 2nd and 3rd postorbital pores short, 4.1���9.2% HL............. L. melanostomias, Published as part of Kawarada, Shumpei, Imamura, Hisashi, Narimatsu, Yoji & Shinohara, Gento, 2020, Taxonomic revision of the genus Lycenchelys (Osteichthyes: Zoarcidae) in Japanese waters, pp. 1-66 in Zootaxa 4762 (1) on pages 4-5, DOI: 10.11646/zootaxa.4762.1.1, http://zenodo.org/record/3743698, {"references":["Gill, T. N. (1884) On the anacanthine fishes. Proceedings of the Academy of Natural Sciences of Philadelphia, 36, 167 - 183.","Vaillant, L. (1888) Expeditions scientifiques du \" Travailleur \" et du \" Talisman \" pendant les annees 1880, 1881, 1882, 1883. Masson, Paris, 406 pp. https: // doi. org / 10.5962 / bhl. title. 13677","Jordan, D. S. & Evermann, B. W. (1898) The fishes of North and Middle America: A descriptive catalogue of the species of fishlike vertebrates found in the waters of North America north of the Isthmus of Panama. Bulletin of the United States National Museum, 47, 2183 - 3136. https: // doi. org / 10.5962 / bhl. title. 39716","Evermann, B. W. & Goldsborough, E. L. (1907) The fish of Alaska. Bulletin of the Bureau of Fisheries, 26, 219 - 360. https: // doi. org / 10.5962 / bhl. title. 60330","Andriashev, A. P. (1979) First finding of fishes of the families Zoarcidae and Liparididae near Kerguelen Islands. Biologiya Morya, 6, 28 - 34. [in Russian]","Anderson, M. E. (1994) Systematics and osteology of the Zoarcidae (Teleostei: Perciformes). Ichthyological Bulletin of the J. L. B. Smith Institute of Ichthyology, 60, 1 - 120.","Shinohara, G. & Matsuura, K. (1998) A new zoarcid, Lycenchelys aurantiaca, from the Pacific coast off northern Japan (Teleostei: Perciformes). Ichthyological Research, 45, 151 - 155. https: // doi. org / 10.1007 / BF 02678557","Shinohara, G. & Anderson, M. E. (2007) Lycenchelys ryukyuensis sp. nov. (Perciformes: Zoarcidae) from the Okinawa Trough, Japan. Bulletin of the National Museum of Nature and Science, Series A (Zoology), Supplement 1, 59 - 66.","Anderson, M. E. (2006) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. XII. Two new lycodine species from off Peru. Species Diversity, 11, 183 - 190. https: // doi. org / 10.12782 / specdiv. 11.183","Anderson, M. E. & Fedorov, V. V. (2004) Family Zoarcidae Swainson, 1839 eelpouts. California Academy of Sciences, Annotated Checklists of Fishes, 34, 1 - 58.","Anderson, M. E. & Moller, P. R. (2007) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. XIII. Two new species of Lycenchelys from the Southwestern Pacific. Species Diversity, 12, 175 - 185. https: // doi. org / 10.12782 / specdiv. 12.175","Thiel, R., Knebelsberger, T. & Eidus, I. (2018) Description and DNA barcoding of Lycenchelys lenzeni, a new species of eelpout (Perciformes: Zoarcidae) from the deep sea off the Kuril Archipelago. Zootaxa, 4370 (1), 45 - 56. https: // doi. org / 10.11646 / zootaxa. 4370.1.3","Andriashev, A. P. (1980) On the deepest occurrence of a species of the fish family Zoarcidae Lycenchelys atacamensis sp. n. from the Atacama Trench. Zoologicheskii Zhurnal, 59, 1105 - 1108. [in Russian with English summary]","Anderson, M. E. (1988) Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. I. The Antarctic and subantarctic regions. Antarctic Research Series, 47, 59 - 113. https: // doi. org / 10.1029 / AR 047 p 0059","Anderson, M. E. (1995) The eelpout genera Lycenchelys Gill and Taranetzella Andriashev (Teleostei: Zoarcidae) in the eastern Pacific, with descriptions of nine new species. Proceedings of the California Academy of Science, 49, 55 - 133.","Nelson, J. S., Grande, T. C. & Wilson, M. V. (2016) Fishes of the world, 5 th edition. John Wiley and Sons, New York, xli + 707 pp. https: // doi. org / 10.1002 / 9781119174844","Hatooka, K. (2013) Zoarcidae. In: Nakabo, T. (Ed.), Fishes of Japan with pictorial keys to the species. 3 rd edition. Tokai Uni- versity Press, Hadano, pp. 1220 - 1237 + 2076 - 2082. [in Japanese]"]}

Phuket Marine Biological Center Research Bulletin, 77, 1, 25-31