Diagnosis: sucker huge and rounded, longer than broad; mandibular barbels very small, no auxiliary mandibular barbels; premaxillary teeth large in up to 7 rows; mandibular teeth usually in 2 rows, with 13+13 to 15+15 teeth; eye very small; adipose fin long and low, its origin well in advance of a vertical through anal fin origin; caudal peduncle moderately deep; caudal fin moderately forked with lobes rounded, nearly equal; no sexual dimorphism of anal fin, caudal fin or humeral process of pectoral girdle (Ref. 81251).

Coloration: preserved specimens with numerous large melanophores more or less uniformly distributed over entire dorso-lateral surface of body, rapidly becoming sparser toward middle of abdomen; dark vertical bar on base of caudal fin as well as one in its middle (Ref. 81251).