Brachirus aspilos ( Bleeker 1852 )

Okamoto, Jo & Motomura, Hiroyuki, 2021, Redescription of Brachirus aspilos (Bleeker 1852), a senior synonym of four nominal species, with a note on the distribution of Dagetichthys marginatus (Boulenger 1900) (Pleuronectiformes: Soleidae), Zootaxa 4908 (3), pp. 354-368 : 355-363

Brachirus aspilos ( Bleeker 1852)

[English name: Dusky Sole; standard Japanese name: Amami-ushinoshita]

Figures 1–5 ; Table 1

Synaptura aspilos Bleeker 1852: 74 (type locality: Singapore).

Synaptura marmoratus Bleeker 1853: 90 (type locality: Lawajong , Solor Island, Indonesia).

Synaptura heterolepis Bleeker 1856: 65 (type locality: Ambon, Molucca Islands , Indonesia).

Brachirus heterolepis: Bleeker 1865 –1871: 20, pl. 236, fig. 2 ( Singapore; Lawajong, Solor Island, Indonesia; Labuha, Bacan Islands, Indonesia; Atapupu, Timor, Indonesia; Wahai, Ceram Islands, Indonesia; Ambon, Molucca Islands, Indonesia); Munroe 2001: 3881 (western central Pacific); Allen & Erdmann 2012: 1054, unnumbered figs. (Sumatra to West Papua, Indonesia); Fricke et al. 2014: 190 (Madang, Papua New Guinea).

Synaptura dicholepis Peters 1877: 844 (type locality: New Hanover , Bismarck Archipelago, Papua New Guinea).

Synaptura sorsogonensis Evermann & Seale 1907: 106 , fig. 22 (type locality: Bacon , Sorsogon, Luzon, Philippines).

Synaptura marginata (not of Boulenger 1900): Ochiai 1984: 340, fig. 319-H (Amami-oshima island to Okinawa Pref., Japan); Iwatsuki et al. 2000: 105 [Makassar, Sulawesi, Indonesia (based on MUFS 18709, 18911)]; Sakai et al. 2001: 123 (Amami to Yaeyama islands, Japan); Allen & Adrim 2003: 64 (Sumatra to Papua, Indonesia); Matsuura et al. 2003: 216, unnumbered fig. (Bitung, Indonesia; fig. based on Japanese specimen); Shao et al. 2008: 265 (southern Taiwan); Motomura & Matsuura 2010: 232 (Yaku-shima island, Osumi Islands, Japan); Ohashi & Motomura 2011: 109 (Yaku-shima island, Osumi Islands, Japan); Nakabo & Doiuchi 2013: 1692, unnumbered figs. (Yaku-shima island and Ryukyu Islands, Japan).

Brachirus aspilos: Munroe 2000: 646 (South China Sea); Munroe 2001: 3881 (western central Pacific); Larson et al. 2013: 226 (Northern Territory, Australia); Voronina 2019: 418.

Brachirus sorsogonensis: Munroe 2000: 646 (South China Sea); Munroe 2001; 3884 ( Philippines and Samoa).

Brachirus dicholepis: Munroe 2001: 3881 (western central Pacific); Fricke et al. 2019: 317 (New Ireland, Papua New Guinea); Voronina 2019: 418.

Brachirus marmoratus: Allen & Erdmann 2012: 1054 , unnumbered figs. (Java, Bali, Nusa Penida, Flores, and Sulawesi, Indonesia).

Dagetichthys marginatus (not of Boulenger 1900): Kottelat 2013: 465 (Mekong delta); Muto 2019: 495, unnumbered figs. [Amami-oshima island (based on KAUM–I. 76287) and Yoron-jima island (based on KAUM–I. 104207), Amami Islands, Japan].

Holotype. BMNH 1862.6 .3.5, 138.2 mm SL, Singapore, P. Bleeker.

Other type specimens examined. BMNH 1862.6 .3.1, holotype of Synaptura heterolepis , 226.2 mm SL, Ambon , Molucca Islands , Indonesia , P. Bleeker; USNM 55916 , holotype of Synaptura sorsogonensis , 193.7 mm SL, Bacon , Sorsogon, Luzon, Philippines , C. Pierson; ZMB 9861 , holotype of Synaptura dicholepis , 274.3 mm SL, New Hanover , Bismarck Archipelago, Papua New Guinea .

Non-type specimens examined. 48 specimens, 23.6–403.3 mm SL. JAPAN: BSKU 50080, 205.8 mm SL, Shirahama, Iriomote-jima island, Yaeyama Islands , Okinawa, 12 Oct. 2011; BSKU 113945, 160.8 mm SL, BSKU 113946, 304.4 mm SL, Shirahama , Iriomote-jima island , Yaeyama Islands , Okinawa, 14 Apr. 2014; BSKU 114074, 279.5 mm SL, Funaura Port , Iriomote-jima island , Yaeyama Islands , Okinawa, 18 Apr. 2014; KAUM–I. 28461, 278.0 mm SL, KAUM–I. 28462, 275.2 mm SL, KAUM–I. 28463, 324.0 mm SL, off Hirayashiki , Katsuren , Uruma , Okinawa, 26°17′N, 127°55ʹE, Motomura et al., 13 Apr. 2010; KAUM–I. 60781, 259.7 mm SL, off Minatomachi, Naha, Okinawa, 26°13ʹN, 127°40ʹE, H. Iwatsubo, 6 Dec. 2013; KAUM–I. 64921, 170.4 mm SL, Toguchi Beach, Yomitan, Nakagami, Okinawa, 26°22ʹN, 127°44ʹE, Y. Sakurai, 26 Oct. 2013; KAUM–I. 104207, 221.5 mm SL, Chabana Beach, Yoron-jima island , Amami Islands , Kagoshima, 27°03ʹN, 128°24ʹE, 2–4 m, D. Uyeno et al., 2 July 2017; KAUM–I. 116037, 334.1 mm SL, KAUM–I. 116038, 347.3 mm SL, southern Ryukyu Islands from Amami to Yaeyama islands (purchased at Tomari Fish Market), Y. Sakurai, 2 May 2018; KAUM–I. 116039, 326.8 mm SL, southern Ryukyu Islands from Amami to Yaeyama islands (purchased at Tomari Fish Market), Y. Sakurai, 21 Apr. 2018; KAUM–I. 117762, 162.0 mm SL, off Hiyane, Okinawa, 26°18ʹ41ʹʹN, 127°50ʹ03ʹʹE, 2–4 m, Y. Sakurai, 25 May 2018; KAUM–I. 117767, 161.7 mm SL, off Hiyane, Okinawa, 26°18ʹ41ʹʹN, 127°50ʹ03ʹʹE, 2–4 m, Y. Sakurai, 7 June 2018; KAUM–I. 125214, 235.7 mm SL, southern Ryukyu Islands from Amami to Yaeyama islands (purchased at Tomari Fish Market), Y. Sakurai, 19 Oct. 2018; KAUM–I. 125230, 258.6 mm SL, KAUM–I. 125231, 268.7 mm SL, southern Ryukyu Islands from Amami to Yaeyama islands (purchased at Tomari Fish Market), Y. Sakurai, 3 Nov. 2018; KAUM–I. 128765, 291.8 mm SL, southern Ryukyu Islands from Amami to Yaeyama islands (purchased at Tomari Fish Market), Y. Sakurai, 18 Feb. 2019; KAUM–I. 131182, 127.4 mm SL, off Awase, Okinawa, 26°18ʹ47ʹʹN, 127°51ʹ02ʹʹE, 1.5–2.0 m, 6 June 2019; KPM-NI 17684, 403.3 mm SL, KPM-NI 17685, 362.7 mm SL, south of Tokashiku Beach , Tokashiki-jima island , Kerama Islands , Okinawa Islands, Okinawa, Y. Miyazaki, 10 Mar. 2006; KPM-NI 24325 , 274.0 mm SL, Okinawa (purchased at Tomari Fish Market), 11 July 2009; KPM-NI 33316, 102.6 mm SL, Yakata , Okinawa-jima island , Okinawa Islands , Okinawa, H. Senou & M. Aizawa, 7 Sept. 1990; KPM-NI 34050 , 88.3 mm SL, Ishigaki-jima island , Yaeyama Islands , Okinawa, H. Senou et al., 4 Sept. 1991; KPM-NI 34089 , 23.6 mm SL, mouth of Miyara River , Ishigaki-jima island , Yaeyama Islands , Okinawa, H. Senou et al., 5 Sept. 1991; KPM-NI 37533, 159.8 mm SL, Awase , Nakagusuku Bay , Okinawa-jima island , Okinawa Islands , Okinawa, 0.5 m, K. Matsuzaki, 28 May 2014; NSMT-P 34102, 213.2 mm SL, Sakinome , Setouchi , Amami-oshima island , Amami Islands , Kagoshima, 28°11ʹ06ʹʹN, 129°16ʹ12ʹʹE, 5 m, 14 Sept. 1989; NSMT-P 59151, 184.1 mm SL, Yonada River , Iriomote-jima island , Yaeyama Islands , Okinawa, Mar. 1997; HUMZ 63002, 197.1 mm SL, Naha, Okinawa (purchased at Makishi Market), July 1993; HUMZ 101193, 312.3 mm SL, Ishikawa, Okinawa (purchased at fish market), 15 Apr. 1984; URM-P 19794, 334.8 mm SL, Onna, Kunigami, Okinawa, 14 Aug. 1988; URM-P 43494, 249.6 mm SL, Itoman, Okinawa (purchased at fish market), K. Shimada, 28 Oct. 2005; URM-P 43563, 283.8 mm SL, Yonajou, Okinawa (purchased at fish market), K. Shimada, 5 Oct. 2005. TAIWAN: NMMBP 2297, 342.7 mm SL, Hou-bi-hwo, Pingtung, trawl, 0–1.0 m, J.-P. Chen, 7 Dec. 2001. PHILIPPINES: BMNH 1933.3 .11.792, 182.3 mm SL, Culion, A. Herre; UPVMI 2521, 257.4 mm SL, UPVMI 2522, 266.9 mm SL, off Estancia, Iloilo, Panay Island , Visayas (purchased at Estansia Fish Market), J. Okamoto, 25 July 2018; USNM 445291, 179.2 mm SL, USNM 445293, 209.4 mm SL, USNM 445295, 221.4 mm SL, off Tayabas Bay , Quezon, Luzon (purchased at Pagbilao Market), J. Williams et al., 26 Oct. 2017. SINGAPORE: BMNH 1933.7 .31.21, 144.5 mm SL, BMNH 1933.7 .31.22, 142.1 mm SL, purchased at fish market; ZRC 55760, 2 specimens, 98.1–99.6 mm SL, intertidal lagoon next to Tanah Merah Ferry Terminal, Tenah Merah, H.-H. Tan et al., 12–15 Jan. 2017; ZRC 30305, 268.6 mm SL, reef flat at southeast coast of Sentosa, D.-G. -B. Chia et al., 21 May 1992; ZRC 47351, 282.6 mm SL, Changi Beach, 24 Jan. 2002, ZRC 60307, 194.5 mm SL, purchased at fish market, H.-C. Ho et al., 7 Aug. 2018. INDONESIA: BMNH 1858.4 .29.4, 155.6 mm SL, Ambon, G. Frank; NSMT-P 63024, 175.1 mm SL, west coast of Batsulubang, Lembeh Island, Bitung , North Sulawesi , 01°26ʹ00ʹʹN, 125°11ʹ30ʹʹE, 1 m; NSMT-P 62035, 107.7 mm SL, west coast of Tanjung Lampu, Lembeh Island , Bitung, North Sulawesi , 01°26ʹ00ʹʹN, 125°11ʹ18ʹʹE, 1.5 m. PAPUA NEW GUINEA: BMNH 1881.10 .18.17, 150.5 mm SL, New Britain Island, Bismarck Archipelago. AUSTRALIA: WAM P.29052-017, 90.6 mm SL, Middle Island , Ashmore Reef, Western Australia, 12°16ʹS, 123°02ʹE, 0.1–0.4 m, G. Allen, 16 Sept. 1986; WAM P.14816-001, 133.4 mm SL, Shark Bay , Western Australia, 25°21ʹS, 113°44ʹʹE, R. McKay, July 1958 .

Diagnosis. A species of Brachirus with the following combination of characters: dorsal-fin rays 64–76 (mode 71), anal-fin rays 51–62 (56), pored scales on straight portion of lateral line 93–126 (118); vertebrae 41–44 (43); pectoral-fin rays 4–7 (6) and 4–7 (5) on ocular and blind sides, respectively; pelvic-fin rays 4–6 (5) and 4 or 5 (4) on ocular and blind sides, respectively; caudal-fin rays 13–15 (14); body slightly elongate, its depth 40.0–51.0 (mean 45.5)% SL; head length 16.1–23.9 (18.6)% SL; pectoral fin on ocular side longer than that on blind side, 5.3–7.6 (6.6)% SL and 4.0–6.0 (4.8)% SL, respectively; pelvic fin on ocular side longer than that on blind side, 4.9–7.4 (6.0)% SL and 4.3–7.5 (5.8)% SL, respectively; body depth below lateral line 21.7–27.1 (23.4)% SL; lips without labial papillae; eyes separated by scaled interorbital space; cycloid or weakly ctenoid scales on blind side; body on ocular side uniformly brown or grey with dark vermiculation, some small white blotches along dorsal- and anal-fin bases, or without remarkable pattern.

Description. Frequency data of selected meristic characters and proportional measurements as percentages of SL given in Table 1. Dorsal-fin rays all branched at tips (except small individuals), uppermost quadruple-branched, number of branches tending to increase with growth, a papilla in front of 1st dorsal ray; anal-fin rays all branched at tips (except small individuals), uppermost ray quadruple-branched, number of branches tending to increase with growth; caudal-fin rays all branched at tips (except small individuals), uppermost ray quadruple-branched, number of branches tending to increase with growth; pectoral fin rays on ocular side all double-branched at tips; pelvic-fin rays on ocular side all double- or triple-branched at tips, third rays longest on both sides; curved lateral line scales on ocular side of head curved; dorsal pterygiophore formula (number of proximal pterygiophores inserted onto dorsal edge of erisma) 4 or 5 (5), number of pterygiophores attached to or directly over cranium and dorsoposterior surface of neural spine of second vertebra 0 and 3–5 (3), respectively. Body moderately extended and wider compared to other soles; body thin (juveniles very thin); eyes small (much larger relative size much greater in juveniles), sometimes with about 7 short-hairy cirri-like eyelashes; a narrow concave interorbital space covered with scales; relative to long axis of body upper and lower eyes overlapping by about one-fourth eye diameter; upper end of gill opening horizontally level with ventral margin of lower eye.

Mouth interior, jaws strongly curved; maxilla extending posteriorly to vertical through lower eye anterior margin; jaws on blind side with a band of villiform teeth (about 2 rows in widest portion); anterior-nostril tube on front of lower eye slender, short, its length about half eye diameter, posterior-nostril tube on ocular side with small aperture, shorter and wider than anterior tube; a single nostril tube on blind side surrounded with hairy membrane located behind eye.

Scales ctenoid on ocular side of body, with 9–14 cteni (juveniles and small individuals with fewer cteni), cycloid or weakly ctenoid on blind side of body, with 1 (rarely 2 or 3) cteni (most juveniles or small individuals with cycloid scales only on blind side, Fig. 3 ); scales progressively smaller towards head and bases of dorsal and anal fins; number of cteni tending to increase towards posterior base of anal fin; cteni smaller than cirri (sensory papillae); many short cirri scattered on ocular side of body, fewer short cirri on blind side; scales on ocular side of head and caudal fin rays small, with cteni; a dense circular mass of papillae forming reticulate pattern on blind side of head before vertical through pelvic-fin base; dorsal, anal and caudal fin rays on ocular side covered with 2 scale rows, their size diminishing distally, scales with about 3 cteni; 17–20 (18) scale rows between posterior margin of lower eye and upper opening of operculum on ocular side; many cirri scattered on ocular side of head; opercular edge of gill opening on both sides with developed membrane; uppermost gill opening at base of pectoral fin; lateral line straight along midline of body on both sides, lateral line on head on ocular side curved, below 9–10th to 14–16th dorsal-fin bases; medio-lateral line on blind side of body continuing on head along upper edge of operculum and connecting with curved line extending to 15th dorsal ray, continuous with many branches of cephalic lateral line system.

Dorsal and anal fin bases at level of 20th anal- and dorsal-fin rays, respectively, on ocular side covered with 1 or 2 and 8–10 scale rows, respectively; scales present on blind side (difficult to count in juveniles and small individuals); ocular side of caudal fin base mostly covered with scales (12–14 rows), scales progressively smaller posteriorly, fewer scales on blind side; pectoral-fin base on ocular side covered by 2 or 3 scale rows with 2 or 3 lines, pectoral-fin rays on both sides not covered with scales (ocular side pelvic-fin base scaled in juveniles and small individuals, scales absent on blind side); membrane of dorsal and anal fins on both sides connected, progressively shorter posteriorly; some cirri scattered randomly on all fin rays on ocular side (many cirri in larger individuals); genital papilla just anterior to anal-fin origin; anus small, at anterior of 1st anal-fin ray, between genital papilla and blind side pelvic fin base.

Origin of dorsal fin above anterior margin of lower eye joined with anterior edge of upper lip; first dorsal-fin ray 8.0–19.7 (13.7) % HL; origin of anal fin about level with 13th –15th dorsal-fin ray; pre-anal fin length 12.1–19.9 (15.3) % SL; first anal-fin ray 15.1–28.5 (21.2) % HL; 3rd pectoral-fin largest on both sides; pelvic fins close together on ventral edge of body, base of pelvic fin on ocular side slightly wider, reaching or just short of base of 4th anal-fin ray, 3rd ray longest on both sides.

Coloration when fresh. Based on color photographs of fresh specimens ( Fig. 4 A–F). The color pattern difference appear not to depend on sexes from examination of gonads, but probably depends on substrate of the habitat. Body color on ocular side variegated, highly variable, generally greyish or brownish, mottled with irregularly scattered, variously-sized pale or light greyish or brownish blotches and irregular vertical dark brown bands (some individuals with 4 or 5 bands on midbody along lateral line ( Figs. 2D , 4A, D ); occasionally tortoiseshell-like patterns of pale spots and lines ( Figs. 2B , 4A , D–E), or scattered white blotches (sometimes absent in juveniles and adults), usually with a series of small white blotches along entire dorsal- and anal-fin bases and lacking dark grey vertical bands ( Fig. 4 D–E); sometimes varying from whitish-grey to blackish ( Fig. 4 A–C). Body on blind side pale yellow with dark brown dorsal, anal and caudal fins; inside of mouth greyish. Head greyish or brownish; sometimes ca. 5 semicircular spots above upper eye. Opercular membrane light grey. All cirri on both sides of body translucent brown. Several blackish to brownish blotches with thin dark borders along dorsal- and anal-fin bases ( Figs. 2D , 4A, D ). Dorsal, anal and caudal fin colors on both sides similar to that of ocular side of body, greyish to brownish ( Fig. 4 ); tips of dorsal, anal and caudal fins with white margin; pectoral fin uniformly translucent white, sometimes with black small spots above central area on blind side, tips sometimes with white to yellow margin; pelvic fins generally greyish or brownish, tips on ocular side whitish, uniformly translucent white on blind side.

Distribution. Currently known from tropical to subtropical waters in the southeastern Indian and western Pacific oceans, having been recorded from Japan, East China Sea, Taiwan, Philippines, Vietnam, Singapore, Indonesia, Papua New Guinea, Samoa, and Australia ( Bleeker 1852, 1853, 1856; Peters 1877; Evermann & Seale 1907; Munroe 2000, 2001; Hoese & Bray 2006; Kottelat 2013; Larson et al. 2013; Frick et al. 2014; this study: Fig. 5 ). Specimens of B. aspilos examined in the present study had been collected from shallow marine and estuarine waters in depths less than 5 m. However, underwater photographs have shown individuals on shallow sandy bottoms between 2–30 m depth ( Allen & Erdmann 2012; this study).

Figures

FIGURE 1. Holotype of Brachirus aspilos (BMNH 1862.6.3.5, 138.2 mm SL, Singapore). A, ocular side; B, blind side.

FIGURE 2. Holotypes of nominal species identified as Brachirus aspilos in this study. A, BMNH 1862.6.3.1, holotype of Synaptura heterolepis, 226.2 mm SL, Indonesia; B, ZMB 9861, holotype of Synaptura dicholepis, 274.3 mm SL, Papua New Guinea; C, USNM 55916, holotype of Synaptura sorsogonensis, 193.7 mm SL, Philippines.

FIGURE 3. Blind side midbody scales from below the lateral line in Brachirus aspilos (BSKU 114074, 279.5 mm SL). A, whole scale; B, cycloid scale; C, ctenoid scale with single ctenii; D, ctenoid scale with three ctenii.

FIGURE 4. Fresh specimens of Brachirus aspilos. A, KAUM–I. 76287, 170.4 mm SL, Amami Islands, Japan; B, UPVMI 2521, 257.4 mm SL, Panay Island, Philippines; C, KAUM–I. 28462, 275.2 mm SL, Okinawa Islands, Japan; D, KAUM–I. 131182, 127.4 mm SL, Okinawa Islands, Japan; E, KAUM–I. 125230, 258.6 mm SL, southern Ryukyu Islands, Japan; F, KAUM–I. 116037, 334.1 mm SL, southern Ryukyu Islands, Japan.

FIGURE 5. Distributional records of Brachirus aspilos. Blue circles indicate records based on specimens examined in this study. Red, yellow, green, purple, and orange circles indicate type localities of Synaptura aspilos, S. dicholepis, S. heterolepis, S. marmoratus, and S. sorsogonensis, respectively.