Adults: 18-31 cm TL. Body wet weight of individuals measuring 18.7-22.5 cm TL, 21.3-26.3 g. Body proportions, as percentage of TL [based on 54 specimens, TL range inferred to be roughly 18-31 cm TL, Álvarez del Villar (1966)]: prebranchial length, 10.9-15.7; branchial length, 8.2-13.6; trunk length, 41.0-50.3; tail length, 27.2-34.3. Trunk myomeres, 60-65. Dentition: supraoral lamina, 2 unicuspid teeth, but 20% of individuals had 1-2 additional unicuspid teeth on the bridge; infraoral lamina, 5-9 unicuspid teeth, of which 4-5 are large and 0-4 are small (84% of specimens possess both large and small cusps); 4 endolaterals on each side, exceptionally 3 or 5; endolateral formula, typically 2-2-2-2, rarely, one of the teeth is tricuspid; 3 rows of anterials; first row of anterials, 6 unicuspid teeth; 1 row of exolaterals; 1 rows of posterials; first row of posterials, 21 unicuspid teeth; transverse lingual lamina weakly u-shaped, 17-22 unicuspid teeth, the median one or two unicuspid teeth slightly enlarged; longitudinal lingual laminae parentheses-shaped, each with 24-25 unicuspid teeth. Velar tentacles, 19-21, with tubercles; the dorsal wings are long, reaching the median tentacle. Lateral line neuromasts unpigmented. Caudal fin pigmentation, 75% or more. Caudal fin shape, spade-like. Oral fimbriae, 109-136. Oral papillae, 13-27.