Key to species of Oreonectes

1 Caudal fin forked.........................................................................................................................................2

- Caudal fin rounded or emarginate................................................................................................................................ 3

2 Rear of body with scales; eyes normal ............................................................................... O. furcocaudalis

- Body naked; eyes degenerate with only black pigment .................................................................. O. microphthalmus

3 Eyes absent; body naked .................................................................................................... O. anophthalmus

- Eyes present; body with tiny scales ............................................................................................................................. 4

4 Caudal fin emarginated; cephalic lateral-line system degenerate ........................................ O. retrodorsalis

- Caudal fin rounded; cephalic lateral-line system present ............................................................................................ 5

5 Body with many differently spots; posterior chamber of air-bladder developed, filling the body cavity..... ............................................................................................................................................... O. polystigmus

- Body plain; posterior chamber of air-bladder reduced, reaching vertical of pectoral fin ................... O. platycephalus