Key to the species of Euchiloglanis

1 Distance from the anus to the pelvic-fin insertion equal to about 50% of the distance from the anus to the anal-fin origin (Black River drainage, China and Vietnam)...................................................................... 2

- Anus located midway between the pelvic-fin insertion and the anal-fin origin (upper Yangtze basin, China)............. 4

2 Anal-fin origin closer to the caudal-fin base than to the pelvic-fin insertion...................................... 3

- Anal-fin origin closer to the pelvic-fin insertion than to the caudal-fin base (Song Da (Black River) drainage, Vietnam)................................................................................................ E. dorsoarcus

3 Distance from adipose-fin origin to dorsal-fin insertion about 50% of adipose-fin base length (Lixian-Jiang, upper Black River in Yunnan of China)............................................................................ E. longus

- Distance from adipose-fin origin to dorsal-fin insertion about equal to adipose-fin base length (Song Da (Black River) drainage, Vietnam)........................................................................... E. phongthoensis

4 Maxillary barbel pointed, not elongated as a thread, its tip only reaching to gill opening (Fig. 2 A, 2B, 2D); premaxillary tooth band with one median indentation or without an indentation (Fig. 3 A, 3B)......................................... 5

- Maxillary barbel slender and pointed, elongated as a thread, its tip reaching beyond gill opening (Fig. 2 C); premaxillary tooth band with three indentations (Fig. 3 C) (Jinsha-Jiang and Yalong-Jiang, upper Yangtze River basin, China)....................................................................................................... E. longibarbatus

5 Distance between pelvic-fin insertion and anus equal to 100.0–125.0% of distance between pectoral- and pelvic-fin origins; premaxillary tooth band with median indentation (Fig. 3 A) (Dadu-He and Qingyi-Jiang, branches of Min-Jiang, upper Yangtze River basin, China).............................................................................. E. davidi

- Distance between pelvic-fin insertion and anus equal to 81.5–97.5% of distance between pectoral- and the pelvic-fin origins; premaxillary tooth band without indentation (Fig. 3 B) (upper Min-Jiang of Yangtze River basin, China)....... E. kishinouyei