Eugnathogobius, Smith, 1931

Larson, Helen K., 2009, Review Of The Gobiid Fish Genera Eugnathogobius And Pseudogobiopsis (Gobioidei: Gobiidae: Gobionellinae), With Descriptions Of Three New Species, Raffles Bulletin of Zoology 57 (1), pp. 127-181 : 132-133

KEY TO SPECIES OF EUGNATHOGOBIUS

1 Segmented caudal fin rays 16 .............................................. 3

– Segmented caudal fin rays 17 .............................................. 2

2 Caudal fin pale, conspicuously barred with dark pigment, five elongate black or brown blotches along midside of body; headpores present; lateral scales 22–24 .................................. .................................................... E. siamensis ( Fowler, 1934) ( Thailand, Malaysia, Singapore, Borneo)

– Caudal fin plain greyish to translucent, darker at base, side of body without brown blotches or bars; no distinct elongate dark blotches along midside of body; headpores absent; lateral scales 24–27 ................... E. microps Smith, 1931 ( Thailand)

3 Upper jaw teeth in single row, teeth compressed and even in height, with tips pointed, indented and bent to one side, lower jaw teeth conical, pointed ......... E. variegatus ( Peters, 1869) ( Thailand, Singapore, Indonesia, Papua New Guinea)

– Upper jaw teeth in at least two rows, all teeth conical and pointed .................................................................................. 4

4 Lateral scales 27–39; headpores present or absent; first dorsal fin spines always VI; all fins well-developed ..................... 6

– Lateral scales 48–63; headpores always absent; first dorsal fin spines VI, V or less; fish small and slender with very low fins ........................................................................................ 5

5 Back and upper sides with small distinct black spots in both sexes, no distinct black spot on upper base of caudal fin; nape always naked; first dorsal fin spines V or fewer .................... .......... E. stictos , new species (Northern Territory, Australia)

– Body indistinctly mottled, males with black spot on upper base of caudal fin; predorsal scales modally absent, may be 2-16 present; first dorsal fin spines VI, rarely V ............................. ................................................. E. polylepis (Wu & Ni, 1985) ( China, Taiwan, Malaysia, Singapore, northern Australia)

6 Headpores always absent; jaws greatly enlarged in males; head with at least two dark stripes, each body scale with fine brown bar or spot ....................................... E. kabilia ( Herre, 1940) ( Thailand, Malaysia, the Philippines)

– Headpores present or absent; jaw length not greatly dissimilar between males and females; body with small but distinct brown or blackish spots and mottling ............................................. 7

7 All nape scales small and equal in size, reaching forward as far as over preopercular margin, but not reaching to behind eyes; headpores always absent; about 10 narrow bars or saddles across dorsum, side of body with dark stripe along midline; no distinctive bars or stripes on face ...................................... ....... E. indicus new species ( Kenya, Mozambique, Aldabra)

– Nape scales reaching forward to close behind eyes, anteriormost scale often enlarged; headpores present or absent; dark stripes or broad dusky bars present on snout and/or side of head ..... ............................................................................................... 8

8 First three dorsal spines often elongate in males; four to five oblique dark brown lines cross side of head; headpores modally absent; anteriormost nape scale enlarged, occasionally all nape scales small, equal in size ............. E. mindora ( Herre, 1945) ( Fiji, Queensland, the Philippines, Thailand)

– No dorsal spines elongate in males, second or third spine longest; two or three broad irregular dusky bands cross snout and cheek; headpores modally present; anteriormost nape scale often enlarged ..................................... E. illotus Larson 1999 ( Thailand, Singapore, Brunei, the Philippines)