Two specimens: BSKU 133028, 103.1 mm SL, Tosa Bay, Kochi Prefecture, 23 Feb. 2023, collected at Mimase Fish Market by Yuto Mizumoto, Keiya Kumaki, Yuma Takanashi, Tsubasa Matsunaga, Sota Nakagaito, Minaki Tachibana; KPM-NI 79784, 91.0 mm SL, 34°27'N, 138°10'E, Enshu-nada Sea off Omaezaki, Shizuoka Prefecture, 300 m depth, bottom trawl, 16 Apr. 2024, collected by Hayata Tagawa.

Six specimens: BSKU 15239, 105.5 mm SL, 8°11.8'S, 117°58.0'E, Sulu Sea, 285 m depth, 26 May 1972; HUMZ 193642, 104.0 mm SL, HUMZ 193643, 68.3 mm SL, 8°19.2'S, 109°45.7'E–8°19.1'S, 109°44.7'E, Indian Ocean off Java Island, Indonesia, 400 m depth, 10 May 2005; HUMZ 194499, 80.4 mm SL, 8°19.9'S, 109°45.3'E–8°19.8'S, 109°43.4'E, Indian Ocean off Java Island, Indonesia, 342 m depth, 16 July 2005; NSMT-P 60392, 123.9 mm SL, 24°1.2'S, 112°30.6'E, West coast of Australia, 420 m depth, 6 Nov. 1975; ZSI 13732, holotype of Poecilopsetta maculosa, 71.1 mm SL, Bay of Bengal off Colombo, Sri Lanka, 261–450 m depth, 30 Jan. 1894.

Dorsal-fin rays 48–62; anal-fin rays 46–53; ocular-side pectoral-fin rays 9–12; lateral-line scales 90–124; caudal vertebrae 26–29; body deep, its depth greatest at mid body; both eyes separated by scaled flat interorbital area; ocular-side pectoral fin short, its length 46.9%–69.7% HL (1.4–2.1 in HL); middle pectoral-fin rays on ocular side branched; dorsal-fin origin above and just or slightly posterior to center of upper eye; white spots and transverse bands absent on ocular-side head and body; single large dark blotch on ocular-side pectoral fin; single pair of dark blotches on caudal fin (Günther 1880; Norman 1934; Guibord and Chapleau 2001; Kawai and Amaoka 2006; presently reported study).

Measurements and counts listed in Table 1. Body laterally compressed, deep, deepest at midpoint (Fig. 1). Head moderate, its dorsal profile sloping anteriorly. Dextral eyes large, scaleless, without tentacles; lower orbit slightly ahead of upper orbit; eyes not contiguous, separated by scaled flat interorbital area; upper orbit protruding anterodorsal to dorsal profile of head; lower eye partially covering upper jaw. Nostrils on ocular side anterior to interorbital area; anterior nostril tubular, anteroventral to posterior nostril; tube of anterior nostril not reaching upper jaw when bent anteroventrally; posterior nostril a simple pore. Nostrils on blind side posterodorsal to anterior tip of premaxilla; anterior nostril tubular, anterodorsal to posterior nostril; tube of anterior nostril not reaching upper jaw when bent anteroventrally; posterior nostril a simple pore. Anterior half of snout scaleless, posterior half scaled on ocular side; entire snout scaleless on blind side. Mouth oblique; anterior tip of premaxilla anterior to lower eye; jaws scaleless except for scaled posterior part of maxilla on ocular side; posterior end of maxilla on ocular side extending below anterior margin of lower eye, not reaching below anterior one-third of lower eye. Teeth in bands anteriorly, in one or two rows posteriorly on both jaws (both sides); teeth conical, small on each jaw, except slightly larger canine-like teeth anteriorly on blind-side premaxilla. Vomer and palatine toothless. Gill rakers on first arch leaf-like, without serrations on both sides. Ocular-side scales ctenoid on posterior body, weakly ctenoid on head and anterior body; blind-side scales cycloid on head and body. Lateral line present on ocular side from just behind opercular posterior edge to basal area of caudal fin, upwardly curved above ocular-side pectoral fin, height of curve less than vertical distance between top of curve and dorsal profile of body. Lateral line absent on blind side.

All fins scaleless, except for scaled basal area of caudal fin. Dorsal fin origin almost above center of upper eye; first dorsal-fin ray shorter than second ray; interspace between first and second rays slightly narrower than those of remaining adjacent rays in anterior part of dorsal fin; dorsal- and anal-fin rays unbranched. Caudal fin round; upper and lower lobes each with single outermost unsegmented ray covered by membrane and scales (Fig. 3A); outer two segmented rays on each lobe unbranched, inner thirteen segmented rays branched. Pectoral fin short on both sides, reaching below anterior two-thirds of lateral-line curve; fourth to ninth (KPM-NI 79784) or third to eleventh (BSKU 133028) pectoral-fin rays branched, remainder unbranched on ocular side (Fig. 4A); all rays unbranched on blind side; height of pectoral fin origin similar to that of posterior edge of opercle. Pelvic fin short; pelvic-fin membrane separated from anal-fin membrane; third pelvic-fin rays longest on each side; all rays unbranched; blind-side pelvic fin origin slightly posterior to that of ocular-side pelvic fin. Anus and urogenital papilla damaged.

Two anal-fin proximal pterygiophores between first anal-fin proximal pterygiophore and hemal spine on first caudal vertebrae (Fig. 3B). Five hypurals and first preural centrum autogenous (Fig. 3A).

Coloration in fresh (based on Fig. 1) and recently preserved specimen similar. Head on ocular side pale; body white on body-muscle zone, pale and translucent on dorsal- and anal-fin pterygiophore zones. Many small black dots scattered on ocular-side head and body. Head white on blind side; body white on body-muscle zone, pale and translucent on dorsal- and anal-fin pterygiophore zones. Black spots (aggregated melanophores) in six rows on blind-side body (Fig. 5A); uppermost row, including six (BSKU 133028) or seven (KPM-NI 79784) spots, along dorsal profile of body; second row, including five (KPM-NI 79784) or six (BSKU 133028) spots, along dorsal profile of body-muscle zone; third row, including eight spots, just above horizontal body axis; fourth row, including seven (KPM-NI 79784) or eight (BSKU 133028) spots, just below horizontal body axis; fifth row, including four (BSKU 133028) or five (KPM-NI 79784) spots, along ventral profile of body-muscle zone; sixth row, including five spots, along ventral profile of body; two horizontal spots just above first spot of sixth row present (BSKU 133028) or absent (KPM-NI 79784). Single black spots on dorsal profile of blind-side head, and above blind-side pelvic fin. Dorsal-, anal- and caudal-fin membranes dark gray on basal to middle areas, white distally. Pair of single black spots on caudal fin. Pectoral fin on ocular side light gray, with single large black spot on middle area, uniformly pale on blind side. Pelvic fin black on ocular side, pale and translucent on blind side.

Poecilopsetta colorata has been previously recorded from the tropical and subtropical Indian and western Pacific Oceans (Mozambique Channel, Arabian Sea, Bengal Bay, Andaman Sea, off Java Island, off Lombok Island, northwestern Australia, Kai Islands and South China Sea off Hainan Island and Hong Kong), in depths of 220–730 m (Günther 1880; Alcock 1894; Norman 1927, 1934; Shen 1967; Pokapunt et al. 1983; Evseenko and Suntsov 1993; Li and Wang 1995: Guibord and Chapleau 2001; Hensley 2001; Hoese and Bray 2006; Chen et al. 2016; Ho et al. 2021; Gloerfelt-Tarp and Kailola 2022; Hensley and Amaoka 2022; Chakraborty et al. 2023; Fig. 6A). The presently reported specimens, from 300 m depth in the Enshu-nada Sea and Tosa Bay, Pacific coast of southern Japan (presently reported study: Fig. 6A), represent the first Japanese records of P. colorata, the former location being the northernmost record of the species.

The presently reported specimens (BSKU 133028 and KPM-NI 79784) are distinctly different from eight species of Poecilopsetta in the numbers of lateral-line scales (100 or 109), as follows: ca. 140 lateral-line scales in Poecilopsetta albomaculata Norman, 1939; and fewer than 89 scales in Poecilopsetta beanii (Goode, 1881), Poecilopsetta dorsialta Guibord et Chapleau, 2001, Poecilopsetta inermis (Breder, 1927), Poecilopsetta macrocephala Hoshino, Amaoka et Last, 2001, Poecilopsetta natalensis Norman, 1931, Poecilopsetta vaynei Quéro, Hensley et Maugé, 1988, and Poecilopsetta plinthus Jordan et Starks, 1904 (Goode 1881; Jordan and Starks 1904; Gilbert 1905; Breder 1927; Norman 1931, 1934, 1939; Reid 1934; Amaoka 1964; Quéro et al. 1988; Foroshchuk and Fedorov 1992; Hoshino 2000; Guibord and Chapleau 2001, 2002; Hensley 2001; Hoshino et al. 2001; Kawai and Amaoka 2006; Nielsen and Casey 2008; Voronina and Volkova 2019; Hensley and Amaoka 2022). Additionally, the numbers of dorsal- and anal-fin rays (56–62 and 52, respectively) are incongruent with those of Poecilopsetta multiradiata Kawai, Amaoka et Séret, 2010 (70–73 and 58–62) (Kawai et al. 2010). On the other hand, the above characters of the presently reported specimens from Japan were consistent with or close to those of the remaining six species (P. colorata, Poecilopsetta hawaiiensis Gilbert, 1905, Poecilopsetta normani Foroshchuk et Fedorov, 1992, Poecilopsetta pectoralis Kawai, Amaoka et Séret, 2006, P. praelonga and Poecilopsetta zanzibarensis Norman, 1939). However, the presently reported specimens differed from five of the six species as follows: body deep and round vs. body narrow and oblong in P. praelonga and P. zanzibarensis; pectoral fin short, its length 50.5%–54.7% HL (1.8–2.0 in HL) vs. pectoral fin long, its length 82.6%–109.9% HL (0.9–1.2 in HL) in P. pectoralis; number of ocular-side pectoral-fin rays 11–13 vs. 14–17 in P. normani and 8 in P. pectoralis; middle pectoral-fin rays branched on ocular side vs. all pectoral-fin rays simple in P. hawaiiensis, P. pectoralis, and P. praelonga; and eyes well separated from each other vs. eyes contiguous in P. praelonga and P. zanzibarensis (see Gilbert 1905; Norman 1927, 1934, 1939; Foroshchuk and Fedorov 1992; Kawai and Amaoka 2006; Voronina and Volkova 2019; Hensley and Amaoka 2022; Figs 1, 4; Tables 1, 3). In contrast, because these characters of the presently reported specimens are consistent with those previously described for P. colorata (see diagnosis; Tables 1, 3), the former were confidently identified as that species.

The ocular-side coloration of P. colorata is known to change with growth, the large round black spots scattered on the head and body in larvae and juveniles (Alcock 1894: fig. 2 in pl. 7; Evseenko and Suntsov 1993: fig. 4a; Ho et al. 2021: fig. E in pl. 9; Chakraborty et al. 2023: fig. 1b; presently reported study: Fig. 7B, C) being lost in adults (Günther 1880: fig. B in pl. 22; Ho et al. 2021: fig. B in pl. 9; Chakraborty et al. 2023: fig. 1a; presently reported study: Figs 1, 7A). Accordingly, the presently reported specimens were considered to be adults, due to the lack of large round black spots on the ocular-side head and body (Fig. 1).

The two Japanese P. colorata specimens examined had many black dots scattered on the ocular-side head and body (Fig. 1), being similar to the coloration of the holotype of the species shown in the original description (Günther 1880: fig. B in pl. 22), and a single specimen from the South China Sea (Shen 1967: fig. 73). However, no such dots were observed in the comparative adult specimens examined here (HUMZ 193642: Fig. 7A; NSMT-P 60392) or other adult specimens previously described (Chen et al. 2016: fig. 2; Ho et al. 2021: fig. B in pl. 9; Gloerfelt-Tarp and Kailola 2022; unnumbered fig.; Chakraborty et al. 2023: fig. 1a). Therefore, it is considered that adult individuals of P. colorata may vary in the presence or absence of black dots on the ocular-side head and body. Poecilopsetta normani apparently also varies intraspecifically in the presence or absence of many black dots on the ocular side (Foroshchuk and Fedorov 1992; Voronina and Volkova 2019: fig. 25; Corbari et al. 2025: fig. 12B).

The new standard Japanese name “Gomafu-kawara-garei”, referring to the black dots scattered on the ocular-side head and body of the presently reported specimens, is proposed for Poecilopsetta colorata based on KPM-NI 79784.

Single specimen: KPM-NI 79783, 104.5 mm SL, 34°27'N, 138°10'E, Enshu-nada Sea off Omaezaki, Shizuoka Prefecture, Japan, 300 m depth, bottom trawl, 16 Apr. 2024, collected by Hayata Tagawa.

Five specimens: BSKU 15238, 103.5 mm SL, 8°11.8'S, 117°58.0'E, Sulu Sea, 285 m depth, 26 May 1972; HUMZ 193990, 84.7 mm SL, 8°15.5'S, 110°22.0'E–8°14.8'S, 110°20.3'E, Indian Ocean off Java Island, Indonesia, 290 m depth, 11 May 2005; HUMZ 194542, 110.7 mm SL, 8°22.5'S, 109°43.4'E–8°21.9'S, 109°40.3'E, Indian Ocean off Java Island, Indonesia, 409 m depth, 17 July 2005; ZSI 13733, ZSI 13734, syntypes, 70.1–70.3 mm SL, Bay of Bengal off Colombo, Sri Lanka, 260–732 m depth.

Dorsal-fin rays 57–65; anal-fin rays 45–55; ocular-side pectoral-fin rays 6–11; lateral-line scales 91–111; caudal vertebrae 29–32; body slender, its depth 33.3%–47.2%SL (2.1–3.0 in SL), highest anterior to mid body; eyes contiguous; anterior margin of lower eye below and in front of anterior margin of upper eye; ocular-side pectoral fin short, its length 25.6%–66.7% HL (1.5–3.9 in HL); all pectoral-fin rays simple on both sides; dorsal fin origin above posterior part of upper eye; lateral line straight section about three times the width of lateral-line curve; white or black spots absent on ocular-side head and body; pectoral fin uniformly blackish; caudal fin with two pairs of dark blotches or without blotches (Alcock 1894, 1896; Norman 1934, 1939; Hoshino et al. 2000; Guibord and Chapleau 2001; Kawai and Amaoka 2006; presently reported study).

Measurements and counts listed in Table 2. Body laterally compressed; body narrow, oblong, deepest at anterior one-third (Fig. 2). Head small; dorsal profile sloping anteriorly. Dextral eyes large, scaleless, without tentacles; lower orbit anterior to upper orbit; eyes contiguous; dorsal margin of upper orbit protruding anterodorsally beyond dorsal profile of head; lower eye dorsally over middle of upper jaw, and posterior half of posterior nostril. Nostrils on ocular side anterior to lower eye; both nostrils tubular; anterior nostril longer than posterior one, well below horizontal line through posterior nostril, not reaching upper jaw when bent anteroventrally. Nostrils on blind side posterodorsal to anterior tip of premaxilla; anterior nostril tubular, slightly above horizontal line through posterior nostril, reaching upper jaw when bent anteroventrally; posterior nostril a simple pore only. Pores of nasal bone absent on ocular side; two pores present above nostrils on blind side. Snout scaleless on both sides. Mouth oblique; anterior tip of premaxilla anterior to center of lower eye; both jaws scaleless on both sides; posterior end of maxilla extending below anterior one-third of lower eye, not reaching below center of lower eye. All teeth conical and small, in bands anteriorly, in one or two rows posteriorly on all four jaws; teeth on both blind side jaws more numerous and longer than those on ocular side. Vomer and palatine toothless. Gill rakers on first arch of both sides leaf-like, without serrations. Lateral line present on ocular side, running from just behind opercular posterior edge to basal area of caudal fin, curved upwardly above ocular-side pectoral fin; height of curve almost similar to, or slightly narrower than, vertical distance between top of curve and dorsal profile of body; straight section about three times longer than width of lateral-line curve. Lateral line absent on blind side. Scales on ocular side almost lost, except weakly ctenoid on lateral line; scales on blind side almost lost, except cycloid anteriorly on head and along middle horizontal line of body.

All fins scaleless, except scaled basal area of caudal fin. Dorsal fin origin almost above posterior one-third of upper eye; first dorsal-fin ray shorter than second ray; interspaces between first and second rays slightly narrower than those of other adjacent rays anteriorly on dorsal fin; all dorsal- and anal-fin rays simple. Caudal fin round; single outermost ray on upper and lower lobes unsegmented (Fig. 3C); unsegmented rays entirely covered by fin membrane and scales; two outer segmented rays on each lobe simple, fourteen inner segmented rays branched, middle rays longest. Both pectoral fins short, origins at similar height to posterior edge of opercle; ocular-side pectoral fin reaching below anterior three-fourths of lateral-line curve; all pectoral-fin rays simple on both sides (Fig. 4B). Pelvic fin short, membrane separated from anal-fin membrane; all rays simple, third pelvic-fin rays longest on both sides; blind-side pelvic fin origin slightly posterior to ocular-side origin. Anus between pelvic and anal fin origins, slightly closer to latter. Urogenital papilla posterior to anus, and closer to anal fin origin.

Two anal-fin proximal pterygiophores between first anal-fin proximal pterygiophore and hemal spine on first caudal vertebrae (Fig. 3D). Five hypurals and first preural centrum autogenous (Fig. 3C).

Coloration of fresh (based on Fig. 2) and recently preserved specimens similar. Head and body on ocular side pale, with four faint brown transverse bands on latter. Head and body on blind side pale on body-muscle zone, pale on pterygiophore zone, and partially brown around dorsal and ventral margins of head and on caudal peduncle. Black spots (aggregated melanophores) in six rows on blind-side body (Fig. 5B); uppermost row, including six spots, along dorsal profile of body; second row, including five spots, along dorsal profile of body-muscle zone; third row, including seven spots, just above horizontal axis; fourth row, including five spots, just below horizontal axis; fifth row, including five spots, along ventral profile of body-muscle zone; sixth row, including three spots, along ventral profile anteriorly on body. Dorsal and anal fins dark gray on basal to middle areas, white distally. Caudal fin white basally and distally, its intermediate area dark gray. Two pairs of black spots on caudal fin, one on outer branched rays, the other on inner branched rays. Pectoral fin on ocular side uniformly dark gray, that on blind side uniformly pale. Pelvic fin grayish white on ocular side, pale and translucent on blind side.

Poecilopsetta praelonga has been previously recorded from tropical and subtropical waters in the eastern Indian Ocean and western Pacific (Bay of Bengal, Gulf of Mannar, Andaman Sea, Sumatra Island, Java Island, northwestern Australia, Timor Sea, Sunda Strait, Philippines and southern Taiwan) in depths of 216–732 m (Alcock 1894, 1896, 1899; Norman 1927, 1934; Shen 1982; Li and Wang 1995; Hoshino et al. 2000; Guibord and Chapleau 2001; Hensley 2001; Hoese and Bray 2006; Ho et al. 2021; Gloerfelt-Tarp and Kailola 2022; Hensley and Amaoka 2022: Fig. 6B). The presently reported specimen, from 300 m in the Enshu-nada Sea, Pacific coast of Honshu Island, Japan (presently reported study: Fig. 6B), represents the first Japanese record and northernmost record of the species.

The presently reported specimen (KPM-NI 79783) was consistent with P. colorata, P. hawaiiensis, P. normani, P. pectoralis, P. praelonga, and P. zanzibarensis in having 62 dorsal- and 51 anal-fin rays and 100 lateral-line scales (Alcock 1894; Gilbert 1905; Norman 1934, 1939; Hoshino et al. 2000; Guibord and Chapleau 2001; Kawai and Amaoka 2006; Hensley and Amaoka 2022; presently reported study: Tables 2, 3; see also Remarks under P. colorata for numbers of these elements in other species). However, the following characters differentiated the specimen from five of the above species: ocular-side pectoral-fin rays 11 (vs. 14–17 in P. normani and 8 in P. pectoralis); body narrow, oblong (vs. body deep, round in P. colorata, P. hawaiiensis, and P. pectoralis); eyes contiguous (vs. eyes well separated from each other in P. colorata, P. hawaiiensis, and P. normani); upper margin of lower eye distinctly anterior to that of upper eye (vs. slightly anterior in P. colorata, P. hawaiiensis, P. normani, P. pectoralis, and P. zanzibarensis); all pectoral-fin rays simple on ocular side (vs. middle pectoral-fin rays branched on ocular side in P. colorata and P. normani); pectoral fin short, its length 59.2% HL (1.7 in HL) [vs. long, 82.6%–109.9% HL (0.9–1.2 in HL) in P. pectoralis]; straight section of lateral line about three times width of lateral-line curve (vs. 3.3–3.7 times in P. zanzibarensis) (Günther 1880; Alcock 1894; Gilbert 1905; Norman 1934, 1939; Foroshchuk and Fedorov 1992; Kawai and Amaoka 2006; Voronina and Volkova 2019; Hensley and Amaoka 2022). Because the characters of the presently reported specimen conformed to those of P. praelonga (see diagnosis; Table 3), we can confirm its identity as that species.

The presence or absence of ocular-side transverse bands in adults has been considered as species-specific in Poecilopsetta, transverse bands being present in P. dorsialta, P. hawaiiensis, P. pectoralis and P. normani, and absent in the other species (e.g., Norman 1939; Foroshchuk and Fedorov 1992; Guibord and Chapleau 2001; Kawai and Amaoka 2006; Hensley and Amaoka 2022; Table 3). However, KPM-NI 79783 had faint transverse bands on the ocular-side body (Fig. 2), although such transverse bands have been considered absent in other adult P. praelonga previously examined (Alcock 1894: fig. 2 in pl. 7; Alcock 1897: fig. 5 in pl. 7; Ho et al. 2021: fig. D in pl. 9; Fig. 8A, B). This suggests some intraspecific variation in the presence or absence of ocular-side transverse bands in P. praelonga (Table 3), a situation paralleled in P. zanzibarensis, which lacked transverse bands in the holotype (Norman 1939: fig. 33) [vs. present in a specimen from Mozambique (Hensley and Amaoka 2022: unnumbered fig. in pl. 94)].

The presence, or absence, and number of black blotches on the caudal fin has been recognized as diagnostic for several Poecilopsetta species: e.g., blotch absent in P. macrocephala, four blotches present in P. pectoralis, and two in other species, except for P. praelonga) (e.g., Alcock 1894; Norman 1934; Kawai and Amaoka 2006). Some earlier studies inferred that P. praelonga lacked blotches on the caudal fin (Norman 1934; Kawai and Amaoka 2006), including the original description (Alcock 1894: fig. 2 in pl. 7), whereas several specimens of P. praelonga examined in other studies had two pairs of black blotches (Alcock 1897: fig. 5 in pl. 7; Hoshino et al. 2000: fig. 3; Ho et al. 2021: pl. 9D), as well as the presently reported specimen from the Enshu-nada Sea (Fig. 2). Accordingly, it must be concluded that P. praelonga is subject to intraspecific variation in the presence or absence of caudal-fin blotches.

The new standard Japanese name “Hōba-kawara-garei”, referring to the body shape reminiscent of a leaf of the Japanese bigleaf magnolia Magnolia obovata Thunberg (“hōba” in Japanese), is proposed for Poecilopsetta praelonga based on KPM-NI 79783.