This species belong to the 'uarnacoides' complex, characterized by the following: lateral disc shape with pectoral fin apices broadly rounded rather than narrowly rounded or angular; color plain (usually uniform light to dark brown dorsally, and pale or whitish ventrally with or without a dark margin; a long and slender whiplike tail and platelike denticles in a broad dorsal band in adults. This species differs from H. hortlei in having a highly protrusible mouth and a pelvic girdle with prominent lateral prepelvic processes (Ref. 58327).