Key to the freshwater genera of Terapontidae

1a. Posttemporal bone covered with skin and scales, not expanded posteriorly, and without serrated edge................... 2

1b. Posttemporal bone exposed posteriorly, expanded and serrate posteriorly.......................................... 5

2a. One spine on the first proximal dorsal pterygiophore.............................................. Leiopotherapon

2b. Two spines on the first proximal dorsal pterygiophore......................................................... 3

3a. Mottling pattern present at caudal base; lack of a foramen for exit of blood vessels from the third hemal arch anterior to the parahypural vertebrae.......................................................................... Amniataba

3b. No mottling pattern present at caudal base; foramen present for exit of blood vessels from the third hemal arch anterior to the parahypural vertebrae.................................................................................. 4

4a. Black blotch on lower caudal fin lobe (found in the Kimberley region)...................................... Hannia

4b. No black blotch on lower caudal fin lobe (found in the Mitchell River [Queensland, Australia] and the Fly River [Papua New Guinea])..................................................................................... Variichthys

5a. 26 vertebrae (found in Sulawesi)................................................................... Lagusia

5b. 25 or 27 vertebrae.................................................................................... 6

6a. Longest dorsal spines are shorter than the longest dorsal rays (in adults). Conic, non-depressible, vertically directed dentition............................................................................................. Hephaestus

6b. Longest dorsal spines are as long as or longer than the longest dorsal rays ( Syncomistes trigonicus is an exception). Depressible dentition, rolled laterally to varying extents................................................................. 7

7a. Body elongate; caudal peduncle distinctly long; small head relative to body length; 20–25 predorsal scales to the occiput; dis- tinctly concave dorsal profile slightly posterior to the orbit.............................................. Bidyanus

7b. Body stout ( S. kimberleyensis, S. trigonicus and S. wunambal are exceptions); caudal peduncle moderately long; moderate sized head relative to body length; mostly <20 predorsal scales to the occiput (up to 25 in some particularly large Syncomistes specimens); dorsal profile straight or convex ( S. butleri and S. bonapartensis are exceptions).......................... 8

8a. Usually with randomly distributed dark body blotches; vomerine teeth; distinctive leathery-textured flesh.......... Scortum

8b. Dark body blotches absent; flattened teeth; flesh not leathery................................................... 9

9a. Small mouth, nearly nonprotractile, with the posterior of the maxillary strongly curved ventrally; two distinct rows of teeth in each jaw, slightly laterally pointed; tooth rows continuous on both jaws..................................... Pingalla

9b. Medium to larger protractile mouth; nearly straight maxillary; single distinct outer row of teeth pointed laterally from lower jaw; lower jaw with dorsally directed, toothless medium bump......................................... Syncomistes