Engyprosopon grandisquama ( Temminck & Schlegel, 1846 )

Amaoka, Kunio & Ho, Hsuan-Ching, 2018, Review of the genus Engyprosopon Günther, 1862 (Pleuronectiformes: Bothidae) from waters off Taiwan, with descriptions of two new species, Zootaxa 4413 (3), pp. 449-481 : 453-456

Engyprosopon grandisquama ( Temminck & Schlegel, 1846)

Figures 2–3 ; Table 1

Rhombus grandisquama Temminck & Schlegel, 1846:183 , figs. 3–4 (type locality: Nagasaki, Japan).

Rhombus poecilurus Bleeker, 1852:293 (type locality: Ambon Island , Molucca Islands, Indonesia).

Rhomboidichthys grandisquama: Günther, 1862:437 .

Platophrys (Arnoglossus) poecilurus: Bleeker, 1870 –75:13, pl.5, fig.1.

Rhomboidichthys spilurus Günther, 1880:47 , pl. 21, fig. A (type locality: South of New Guinea, Zebu , 28 fathoms [51 m]).

Rhomboidichthys spiniceps Macleay, 1881:127 (type locality: Port Jackson, New South Wales, Australia).

Scaeops grandisquama : Jordan & Starks, 1904:627, pl. 8, fig. 2.

Scaeops poecilurus : Jordan & Seale, 1905:803.

Scaeops orbicularis Jordan & Seale, 1907:45 (type locality: Cavite, Luzon Island, Philippines). Oshima, 1927:179.

Engyprosopon grandisquama: Norman, 1926:250 ; Norman, 1934:209, fig. 156; Chen & Weng, 1965:48, fig. 32; Amaoka, 1963:108; Amaoka, 1969:143; Shen, 1983:20, fig. 25; Amaoka et al., 1993:385, fig. 2; Shen, 1993:569, pl. 19-7; Hensley & Amaoka, 2001:3823; Shao et al., 2008:264; Ho et al., 2009:10; Shen & Wu 2012:751, 2 figs.

Material examined. NMMB-P 22233, 1 male, 82.5 mm SL, 11 Mar. 2015; NMMB-P 22235, 4 males, 67.5–78.9 mm SL, 11 Feb. 2015; NMMB-P 22302, 3 females, 65.7–72.6 mm SL, 28 Mar. 2015; NMMB-P 22298, 1 male and 1 female, 70.2–72.0 mm SL, 28 Mar. 28 2015; all collected from Ke-tzu-liao, Kaohsiung, southwestern Taiwan at depths less than 100 m.

Diagnosis. Body deeply ovoid; caudal fin with a pair of black blotches, arranged between the third and fourth fin rays from upper- and lowermost rays in the fin; ocular-side pectoral fin not elongate, and without sexual differences in its length; gill rakers very short, not serrate.

Description. Dorsal-fin rays 81–87, anal-fin rays 61–65, ocular-side pectoral-fin rays 10–12, blind-side pectoral-fin rays 8–10, caudal-fin rays 3 + 11 + 3, ocular-side pelvic-fin rays 6, blind-side pelvic-fin rays 6, scales 40–45 in lateral line, gill rakers 0 + 5–7, vertebrae 10 + 14.

In SL: HL 3.65–4.16, body depth 1.63–1.86. In HL: snout 4.61–5.89, upper eye diameter 2.66–3.32, lower eye diameter 2.69–3.43, interorbital width 2.52–3.47 in males, 4.57–5.31 in females, ocular-side upper jaw 3.07–3.49, blind-side upper jaw 3.12–3.55, ocular-side lower jaw 2.21–2.41, blind-side lower jaw 2.02–2.29, caudal peduncle depth 1.74–2.14, ocular-side pectoral fin 1.01–1.04 in males, 1.03–1.14 in females, blind-side pectoral fin 1.72– 2.04, ocular-side pelvic fin 2.05–2.76, blind-side pelvic fin 2.03–2.44, base of ocular-side pelvic fin 2.17–2.73, base of blind-side pelvic fin 5.72–8.14, longest dorsal fin ray 1.77–2.02, longest anal fin ray 1.69–2.14, middle caudal fin ray 1.02–1.26.

Body deeply ovate, short, body depth greatest at about middle of body, usually equal to more than 1/2 of SL; dorsal and ventral contours almost symmetrical; except for steep anterior profile of head. Caudal peduncle less than 1/4 of body depth. Head small, its length about 1/4 of SL; upper profile of head with distinct concavity anterodorsal to dorsal margin of lower eye; anterior profile steep, nearly vertical in mature males, less so in females and juveniles. Snout short, much shorter than eye diameter. Ocular-side rostral spine present, with round tip in males, rostral spine absent or feeble in females and juveniles. Eyes small, diameter sub-equal to upper jaw length; lower eye slightly in advance of upper eye. No orbital spine in either sex. Interorbital space wide and deeply concave, distinct sexual and ontogenetic differences in width of interorbital space, with males having a wider space than that of females and juveniles. Ocular-side nostrils anterior to upper margin of lower eye; anterior nostril tubular with wide flap posteriorly, posterior nostril a rudimental tube with a short flap; nostrils on blind side very small, closely set below origin of dorsal fin.

Mouth rather small, oblique; maxilla extending ventroposteriorly to below or a little beyond anterior margin of lower eye; anterior tips of both jaws about on same vertical line when mouth closed; rather large, obtuse knob at mandibular symphysis. Teeth on upper jaw biserial, those in outer series larger, stouter, and wider apart than those in inner series; lower jaw teeth uniserial, conical, close-set, curved, almost same size as upper inner teeth. Gill rakers on first arch short and rounded at tip, inside edge not serrate; no gill rakers on upper limb. Ocular-side scales ctenoid with short ctenii; large and greatly deciduous; tips of both jaws and of ocular-side snout naked; scales cycloid on blind side of body.

Dorsal-fin origin on blind side at concavity on head; anal-fin origin ventral to pectoral fin base; both fins without elongate rays. No elongate ocular-side pectoral-fin rays in either sex, but rays of males slightly longer than those of females; blind-side pectoral fin short. Origin of ocular-side pelvic fin at tip of isthmus; space between ocular-side fourth and fifth pelvic-fin ray opposite to first ray of blind-side fin; anterior margin of first ray without skin flap. Tip of isthmus near vertical line through middle of lower eye. Caudal-fin rays branched except for three upper- and three lowermost rays. Tip of pelvic bone extruded anterior to anal-fin origin.

Coloration in alcohol. Ocular side of body uniformly dark greenish without any distinct markings; numerous tiny dark spots before interorbital space; caudal fin with pair of large black blotches arranged between third to fourth fin rays from uppermost and lowermost fin rays, respectively; all fins uniformly dark; blind side of body, except on anterior half, with dark pigment in males; blind side of body uniformly yellowish-white in females.

Sexual dimorphism. This species shows sexual dimorphism in slope of the anterior margin of the head, in interorbital width, presence or absence of a rostral spine, length of the ocular-side pectoral fin, and in coloration on the blind side of the body.

Distribution. Widespread in the Indo-West Pacific Ocean, from East Africa and throughout the Indian Ocean to the Indo-Australian Archipelago and New Caledonia, north to southern Japan. Bathymetric range 7–200 m ( De Bruin et al., 1995), commonly collected at depths less than 100 m off Taiwan.

Remarks. This species resembles E. multisquama in having a pair of black blotches on the caudal fin. It is easily distinguished from the latter in having small black blotches between the third and fourth caudal fin rays, its rather deep body, non-elongate ocular-side pectoral fin, fewer lateral-line scales, and by its somewhat fewer meristic values.

Figures

FIGURE2. Engyprosopon grandisquama (Temminck & Schlegel,1846). Ocular side, A. NMMB-P22235, male, 74.7 mm SL. B. NMMB-P22302, female, 72.6 mm SL.

FIGURE 3. Engyprosopon grandisquama (Temminck & Schlegel, 1846).Blind side, same specimens as those in Figure 2.