Parabothus taiwanensis Amaoka & Shen, 1993

Amaoka, Kunio & Ho, Hsuan-Ching, 2019, The lefteye flounder family Bothidae (Order Pleuronectiformes) of Taiwan, Zootaxa 4702 (1), pp. 155-215 : 202-203

Parabothus taiwanensis Amaoka & Shen, 1993

Taiwan flounder; ûjfľ

Figures 9 A–B; Table 11

Parabothus taiwanensis Amaoka & Shen, 1993:1042 (Type locality: Kaohsiung, Taiwan). Shen & Wu, 2012:754.

Parabothus chlorospilus (not of Gilbert, 1905): Shen, 1983:13.

Parabothus sp.: Shen, 1983:13; Shen in Shen et al., 1993:571.

Crossorhombus sp.: Shen, 1983:19.

Specimens examined. NMMB-P23214 (1 female, 101.6), Ke-tzu-liao, 17 Mar. 2016 ; NMMB-P23219 (2, 73.0– 85.5), Ke-tzu-liao, 30 Apr. 2015 ; NMMB-P23232 (3 males, 1 female, 91.8–132.2), Ke-tzu-liao, 31 Mar. 2016 ; NMMB-P23272 (1 male, 1 female, 116.3–129.6), Ke-tzu-liao, 28 Feb. 2016 ; NMMB-P23305 (1 male, 1 female, 92.7–95.6), Ke-tzu-liao, 18 Mar. 2016 ; NMMB-P24854 (1 male, 1 female, 116.7–124.8) , NMMB-P25710 (1 male, 117.6) , NMMB-P25713 (2 males, 100.8–123.9), Ke-tzu-liao, 2 Apr. 2015 ; NMMB-P25725 (2 males, 98.8–122.3), Ke-tzu-liao, 11 Mar. 2017 . More specimens deposited in NMMB-P.

Diagnostic features. D 98–110; A 77–87; P 11–14; C 2+13+2=17; LLs 61–67; GR 0+7–8=7–8; vert. 10+28– 30=38–40.

Body elliptical, deepest at anterior 1/3 of body (36.8–45.6% SL). Head slightly longer than half of body depth (22.0–28.1% SL); upper profile of head with deep concavity in front of interorbital space. Snout much shorter than eye diameter. Rostral spine on snout tip blunt in males, absent in females and juveniles. Eye diameter slightly shorter than upper-jaw length. Orbital spine absent in either sex. Interorbital space narrow, deeply concave, its width narrower than eye diameter, wider in males than females and juveniles, 3.0–3.5% SL in males, 2.3–2.6% SL in females, 1.2–1.3% SL in juveniles.

Mouth moderate, upper-jaw length 7.4–12.7% SL; maxilla extending to slightly beyond anterior margin of lower eye. Prominent knob on mandibular symphysis in males, feeble or absent in females and juveniles. Teeth on upper jaw biserial, those in outer series stronger and more widely spaced than those in inner series; some anterior teeth canine-like; teeth on lower jaw uniserial, nearly equal in size and spacing to inner-row teeth of upper jaw. Gill rakers only on lower limb, moderate in size, not serrate.

Scales on ocular side ctenoid with long ctenii; scales on blind side cycloid. Pectoral fin on ocular side very short (13.5–22.3% SL).

Coloration. Ocular side of body grayish brown without any distinct color pattern (body pale purple when scales are removed); body on blind side grayish white. All fins on both sides uniformly grayish brown without any noticeable spots or blotches.

Size. Reaching 130 mm SL in Taiwan; up to 153 mm SL in East China Sea ( Yamada et al., 2007).

Distribution. Northeastern and southwestern Taiwan, at depth not deeper than 100 m (present study); East China Sea ( Yamada et al., 2007).

Remarks. This species can be easily separated from P. polylepis in having more dorsal- and anal-fin rays, and from Parabothus kiensis and P. coarctatus in having clearly fewer lateral-line scales. This species exhibits sexually dimorphism and ontogenetic changes of interorbital width and presence or absence of a rostral spine and mandibular knob. Parabothus sp. and Crossorhombus sp. reported by Shen (1983) may in fact represent the same species.

Figures

FIGURE 9. A–B. Parabothus taiwanensis, NMMB-P 25725, male, 122.3 mm SL (A) and NMMB-P 23214, female, 101.6 mm SL (B). C. Psettina gigantea, NMMB-P23236, 98.2 mm SL. D. Psettina iijimae, NMMB-P26402, 68.3 mm SL. E. Psettina tosana, NMMB-P 23211, 81.5 mm SL. F. Psettina variegata, NMMB-P23202, 121.9 mm SL.