Type species. Protomyzon pachychilus Chen 1980b (Figs. 1, 2A, 3A).

Etymology. The generic name is derived from the Dayaoshan, the mountain from where the type species was recorded. Gender feminine.

Diagnosis. Yaoshania is distinguished from all other genera of Balitoridae by: a unique enlarged lip lamina at angle of mouth (Fig. 3A), connecting the upper lip and maxillary. Other characters useful to diagnose the genus, but not unique to it are: gill opening large, with the ventral extremity reaching lower extremity of pectoral-fin base (Fig. 2A); upper lip and rostral fold separated by a groove, rostral fold with four notches to accommodate rostral barbels; two pairs of rostral barbels and one pair of maxillary barbels; a small fleshy lobe present posterior to each maxillary barbel; pectoral fin with one simple and 17–18 branched rays; pelvic fin with one simple and 8–9 branched rays; side of body lacking vertical blotches in adult; lateral line with 71–75 scales.

We retain the wording 'lip lamina' (as used by Chen 1980a) for the flange of skin originating under the lateral part of the upper lip and continuous with the maxillary barbel. This flange appears as if pinched between the rostral fold and the upper lip. We have not observed significant ontogenetic differences in the development of the lamina in our material.