Engyprosopon Günther, 1862

Amaoka, Kunio & Ho, Hsuan-Ching, 2019, The lefteye flounder family Bothidae (Order Pleuronectiformes) of Taiwan, Zootaxa 4702 (1), pp. 155-215 : 183

Genus Engyprosopon Günther, 1862

Engyprosopon Günther, 1862:431 . Type species: Rhombus mogkii Bleeker, 1854 .

Diagnostic features. Body shallow to deeply ovate. Tip of isthmus below middle of lower eye. Usually sexual dimorphism and growth changes on head profile, head spines, interorbital width, and length of pectoral-fin rays. Rostral spine strong, or feeble (rarely absent) in males, feeble or absent in females and juveniles. Front margin of head steep in mature males, less steep in females and juveniles, or rarely with the same steepness in both sexes. Interorbital space narrow to very broad, concave to almost ridge-like, becoming wider with growth; the space wider in males than in females and juveniles.

Mouth usually moderate or occasionally large in size, upper-jaw length on ocular side 2.0– 3.6 in HL. Teeth on upper jaw uniserial or biserial; uniserial on lower jaw. Scales ctenoid on ocular side with one row of feeble ctenii along posterior margin; cycloid on blind side; lateral line on ocular side curved above pectoral fin, with 36–61 scales; absent on blind side.

Dorsal fin originating on blind side, anterior to upper margin of lower eye. Anal fin originating below anterior base of pectoral fin on ocular side. Pelvic fin on ocular side originating at tip of isthmus, fourth or fifth fin ray of ocular side opposite to first ray of blind side. Vent on blind side, just before origin of anal fin, and urogenital pore on ocular side, opposite side of vent. Caudal skeleton with four plates, including parhypural and three hypurals, all plates with deep clefts.

Remarks. Engyprosopon is closely related to Asterorhombus in having cleft plates on the parhypural and three hypurals. But Engyprosopon is well distinguished from Asterorhombus in lacking a lure on the first dorsal-fin ray and palmate-like gill rakers.