Asterorhombus intermedius (Bleeker, 1865)

Intermediate flounder; ÑƖ¥6ľ

Figures 2 C–D; Table 3

Platophrys (Arnoglossus) intermedius Bleeker, 1865:47 (Type locality: Surawesi, Celebes, Indonesia).

Asterorhombus intermedius: Amaoka, 1969:111; Lin et al., 1995:27; Shen & Wu, 2012:748.

Specimens examined. ASIZP 57100 (1, 87.7), Dawulun, Keelung, northern Taiwan, 28 Apr. 1993 . Other localities: BSKU 8376 (1 male, 122.0), Mimase, Kochi Prefecture, Japan, 1 Jul. , 1958; FAKU 17541 (1 female, 103.5), Miya, Aichi Prefecture, Japan, 15 Mar. 1952; HUMZ 124783 (1 female, 108.8), Belep Island, New Caledonia, 24 Oct. 1989 ; HUMZ 142681–142682 and MNHN 1995- 1174 – 1177 (3 males, 3 females, 54.8–101.7), Bellona Plateau, Coral Sea, 25 Jul. 1984 ; MNHN 1995-1178 (1 female, 119.1), Fairway Ridge, Coral Sea, 15 Jul. 1984 ; MNHN 1995-1179 (1 female, 97.8), Belep Island, New Caledonia, 2 Jul. 1986 ; MNHN 1995-1180 (1 male, 76.8), New Caledonia, 20 Aug. 1985 l; MNHN 1995-1181 (1 female, 98.4), Chesterfield Plateau, Coral Sea, 24 Jul. 1988 ; HUMZ 142683–142684 and MNHN 1995-1185 (1 male, 2 females, 81.2–98.6), Chesterfield Plateau, 24 Jul. 1988 ; MNHN 1995-1186 (male, 95.0), Bellona Plateau, 22 Aug. 1988 ; MNHN 1995-1187 (1 male, 78.8), Chesterfield Plateau, 28 Jul. 1988 ; MNHN 1995-1188 (1 male, 91.7), New Caledonia, 22 Apr. 1988; MNHN 1995-1189 (1 female, 50.3), Chesterfield Plateau, 17 July 1984 ; MNHN 1995-1190 (1 female, 90.2), Chesterfield Plateau, 28 Jul. 1988 ; MNHN 1995-1191 (1 male, 57.6), Bellona Plateau, 24 Jul. 1984 ; MNHN 1995-1192 (1 male, 72.7), Chesterfield Plateau., 18 Jul. 1984 ; HUMZ 142685, MNHN 1995-1193, (1 male, 1 female, 47.0–82.5), Nereus Reef, 68–75 m, 22 Jul. 1988 ; HUMZ 142686, MNHN 1995-1194 (2 males, 43.0–65.1), New Caledonia, 23 Aug. 1984; MNHN 1995-1195 (1 female, 53.5), New Caledonia, 20 Aug. 1984; MNHN 1995-1196 (1 male, 50.5), New Caledonia, 21 Aug. 1984 .

Diagnostic features. D 83 (80–85, from other localities); A 63 (58–65); P 10 (10–12); C 2+13+2=17(1– 3+11+15+21–2=17); LLs 55 (50–57); GR 0+8 (0+8–11); vert. 10+28=38 (10+26–28=36–38).

Body ovate, greatest depth at middle part of body 44.7 (41.3–50.8)% SL. Head much longer than half of body depth 24.7 (26.2–29.7)% SL; upper profile of head with slight concavity in front of lower margin of upper eye; head profile moderately steep. Snout round and mounded, snout length about 1.5 times of eye diameter. Eyes small, separated by deep and narrow space; interorbital width about 1/3 of eye diameter.

Mouth large, curved; upper-jaw length 9.6 (10.7–12.9)% SL; maxilla extending to or slightly beyond anterior margin of lower eye. Teeth on both jaws uniserial, upper-jaw teeth small, somewhat enlarged anteriorly; teeth on lower jaw slightly larger than lateral teeth on upper jaw. Gill rakers only on lower limb, short and palmate with 5–8 spines.

Scales on ocular side rather small, ctenoid with short ctenii; cycloid scales on blind side; snout, both jaws and interorbital area scale-less. First dorsal-fin ray elongate 16.3 (8.4–19.5)% SL, and separated from remaining rays; pectoral fin short on ocular side 15.4 (13.0–17.8)% SL.

Coloration. Ocular side of body uniformly dark brownish, 2–3 dark (blue in fresh specimens) blotches, larger than eye, along dorsal and ventral edges of body, obtuse blotches on lateral line, and many scattered small blotches on head and body. All fins with many dark small blotches and spots except for pectoral fin; blind side of body uniformly whitish.

Size. Reaching 87.7 mm SL in Taiwan; up to 150 mm total length (Hensley & Amaoka, 2001).

Distribution. Northern Taiwan and an underwater photograph taken from around Orchid Island, southern Taiwan; widespread in the Western Indian and Western Pacific oceans (Amaoka, 2016).

Remarks. Asterorhombus intermedius resembles A. filifer in the coloration of the body and body form, but it differs from A. filifer in having a short first dorsal-fin ray, a rough edge of the fin membrane of the first dorsal-fin ray and few scales along the lateral line (Hensley, 2005). Asterorhombus filifer is not reported from Taiwanese waters.