Arnoglossus, Bleeker, 1862

Amaoka, Kunio & Ho, Hsuan-Ching, 2019, The lefteye flounder family Bothidae (Order Pleuronectiformes) of Taiwan, Zootaxa 4702 (1), pp. 155-215 : 157-158

Key to species of Arnoglossus in Taiwan

1A. First to fourth dorsal-fin rays filamentous (> 50 mm SL); a large black spot on rear end of dorsal- and anal-fin bases................................................................................................ A. macrolophus

1B. Anterior four rays of dorsal fin not elongate, except for some anterior rays slightly elongate or only second ray elongate in males; no spots on same region.......................................................................... 2

2A. LLs> 60; D 99–114; A 77–92; gill rakers with serration along inner margin; upper-jaw length 8.3–12.8% SL............ 3

2B. LLs 51–58; D 89–96; A 68–78; gill rakers without serration along inner margin; upper-jaw length 6.7–8.3% SL.... A. tenuis

3A. Upper limb of first gill arch with 1 raker; maxilla extends to anterior margin or anterior 1/3 of lower eye; uppermost and lowermost 2 caudal-fin rays unbranched; anterior few dorsal-fin rays more or less elongate in males............. A. polyspilus

3B. No gill rakers on upper limb of first gill arch; maxilla extends to middle of lower eye, or slightly behind it; uppermost and lowermost 3 caudal-fin rays unbranched; second dorsal-fin ray elongate in males................................... 4

4A. LLs 82–83; D 110–113; A 85–86; vert. 11+35–36=46–47; pectoral fin and pelvic fin with black blotches..... A. oxyrhynchus

4B. LLs 60–72; D 99–108; A 77–84; vert. 10–12+33–34=43–45; pectoral and pelvic fins without black blotch............... 5

5A. Gill rakers short, somewhat palmate; cycloid scales on both sides; shortest distance between upper eye and dorsal margin of head nearly equal to half eye diameter; abdominal vertebrae 10........................................ A. japonicus

5B. Gill rakers slender, distal half of each gill raker with spines; scales weakly ctenoid on ocular side, cycloid on blind side; shortest distance between upper eye and dorsal margin of head about 1/3 of eye diameter; abdominal vertebrae 11–12...................................................................................................... A. yamanakai