Japonolaeops dentatus Amaoka, 1969

Amaoka, Kunio & Ho, Hsuan-Ching, 2019, The lefteye flounder family Bothidae (Order Pleuronectiformes) of Taiwan, Zootaxa 4702 (1), pp. 155-215 : 191

Japonolaeops dentatus Amaoka, 1969

Lanceolate toothed flounder; ıƾÉľ

Figure 7A ; Table 10

Japonolaeops dentatus Amaoka, 1969:202 (Type locality: Mimase, Kochi Prefecture, Japan). Shen, 1983:31; Shen in Shen et al., 1993:570; Shen & Wu, 2012:752.

Specimens examined. NMMB-P02173 (1, 153.9), Taiwan, no date ; NMMB-P07140 (1 female, 137.1), Dong-gang , 26 Dec. 2003 ; NMMB-P11568 , (2, 98.2–130.6), Taiwan, 13 Jun. 1983 ; NMMB-P12618 (3, 133.2–138.5), Donggang , 25 Mar. 2011 ; NMMB-P13769 (2 males, 133.3–133.5), Dong-gang , 26 Aug. 2011 ; NMMB-P21093 (2, 98.1– 102.9), Dong-gang , 30 Mar. 2014 ; NMMB-P21130 (1 female, 139.3), Ke-tzu-liao, 2 Ari. 2014 ; NMMB-P21614 (1, 118.8), Dong-gang , 25 Feb. 2014 ; NMMB-P22109 (1, 143.4), Dong-gang , 22 Feb. 2014 ; NMMB-P23205 (1, 122.0), Dong-gang , 5 Mar. 2016 ; NMMB-P23279 (1 female, 139.8), Dong-gang , 3 Apr. 2015 ; NMMB-P23281 (1, 130.0), Dong-gang , 16 Apr. 2015 ; NMMB-P25676 (1, 146.6), Dong-gang , 8 Jan. 2017 . More specimens deposited in NMMB-P.

Diagnostic features. D 111–118; A 93–97; P 14–15; C 3+10–11+3–4=17; LLs 94–105; GR 5–8+6–10=13–16; vert. 11+39–42=50–53.

Body elongated and strongly compressed, greatest at near anterior 1/3 part of body, its depth 31.1–36.8% SL. Caudal peduncle narrow. Head small, more than 1/2 of body depth (18.1–20.6% SL); front of head with deep concavity anterior of upper eye; head profile gently curved. Snout short, protruding, snout length much shorter than eye diameter. Eyes small, diameter slightly longer than upper jaw; upper eye extremely close to dorsal margin of head. Interorbital space low and narrow; inner margins of each eye with bony ridge extending from anterior margin of lower eye to posterior interorbital space.

Mouth small and asymmetrical, upper-jaw length on ocular side about 4.5–6.2% SL; maxilla extending to or slightly beyond anterior margin of lower eye. Teeth present on both sides of both jaws; uniserial in upper jaw, teeth on blind side somewhat larger than those on ocular side; anterior teeth on lower jaw biserial, posterior teeth uniserial. Gill rakers on lower limb slender and pointed without inner serration; those on upper limb small. Scales very small and deciduous, cycloids on both sides.

Dorsal and anal fins very low anteriorly and posteriorly. Pectoral fin on ocular side very short, slightly longer than half of head (10.8–13.7% SL); that on blind side relatively short. Caudal fin round and slender.

Coloration. Ocular side of body uniformly dark yellowish without distinct blotches or spots; all fins uniformly pale dark without distinct spots and blotches; middle part of caudal fin black except for basal part. Blind side of body uniformly yellowish white.

Size. Reaching 153.9 mm SL in Taiwan; up to about 200 mm SL elsewhere ( Hensley & Amaoka, 2001).

Distribution. Western and southwestern Taiwan; widespread in Indian and Western Pacific oceans, including South China Sea to southern Japan, and Coral Sea ( Amaoka, 2016).

Remarks. This species resembles members of Laeops in the small mouth and general appearance, but can be easily separated in the presence of teeth on both jaws of both sides and the anterior two dorsal-fin rays not being separated from the remaining fin rays. Moreover, this species is closely related to Laeops gracilis Fowler, 1934 , but it differs from the latter in having smaller head and deeper body (Amoaka, 2016).

Figures

FIGURE 7. A. Japonolaeops dentatus, NMMB-P 23281, 130 mm SL. B–C. Kamoharaia megastoma, NMMB-P 17856, 186.6 mm SL(B) and NMMB-P21088, juvenile, 105 mm SL (C). D–E. Laeops kitaharae, NMMB-P21087, female, 130.8 mm SL (D) and NMMB-P22276, male, 150 mm SL (E).