Key to Chinese species of Niwaella

1a. Lower jaw unexposed or fully covered by lower lip.......................................................... 2

1b. Lower jaw exposed or separated from lower lip............................................................. 4

2a. Transverse black bars on dorsum and upper part of flank (Ding-Jiang).................................... N.tigrina

2b. A row of transverse black blotches on dorsum and vermicular black marks on upper part of flank...................... 3

3a. Four branched anal-fin rays (Dongtiao-Xi)........................................................ N.brevipinna

3b. Six branched anal-fin rays (Xin-Jiang)......................................................... N. xinjiangensis

4a. A distinct blackish mid-dorsal stripe from behind head to caudal-fin basin, and 8–10 brownish or black vertical bars on lower part of flank......................................................................................... 5

4b. An indistinct blackish mid-dorsal stripe from behind head to caudal-fin basin, and more no fewer than 15 brownish or black vertical bars on lower part of flank........................................................................ 6

5a. Suborbital spine straight, with shorter processus latero-caudalis less than one-fifth of processus medio-caudalis (Dongtiao-Xi).......................................................................................... N. fimbriata

5b. Suborbital spine curved, with longer processus latero-caudalis more than one-third of processus medio-caudalis (Shuai-Shui)........................................................................................... N.nigrolinea

6a. Seven branched dorsal-fin rays (Qu-Jiang)...................................................... N. qujiangensis

6b. Six branched dorsal-fin rays............................................................................ 7

7a. Barbels shorter than eye diameter(Yong-Jiang)................................................. N. laterimaculata

7b. Barbels longer than or equal to eye diameter (Cao’e-Jiang).......................................... N. longibarba