Description. Morphometric data in Table 12. Head depressed; body slender, subcylindrical. Dorsal profile rising evenly from tip of snout to origin of dorsal fin, then sloping gently ventrally from origin of dorsal fin to end of caudal peduncle. Ventral profile straight to anal-fin base, then sloping gently dorsally from anal-fin base to end of caudal peduncle. Anus and urogenital openings located at vertical through middle of adpressed pelvic fin. Skin tuberculate, with tubercles of even size on sides of body. Lateral line complete and midlateral. Vertebrae 16 + 18 = 34 (1), 17 + 17 = 34 (8), 16 + 19 = 35 (1), 17 + 18 = 35 (12), 17 + 19 = 36 (4) or 18 + 18 = 36 (5). Head depressed and broad, triangular when viewed laterally. Snout prominent. Anterior and posterior nares large and separated only by base of nasal barbel. Gill opening broad, extending from ventral margin of posttemporal to isthmus. First branchial arch with 2 + 5 (1), 2 + 6 (14) or 2 + 7 (5) rakers. Bony elements of dorsal surface of head covered with thick, tuberculate skin. Eye ovoid, horizontal axis longest; located entirely in dorsal half of head. Barbels in four pairs. Maxillary barbel long and slender, extending to middle of pectoral-fin base. Nasal barbel slender, extending to midway between its base and anterior orbital margin. Inner mandibular-barbel extending to midway between its base and that of pectoral spine. Outer mandibular barbel extending to two-thirds of distance between its base and that of pectoral spine. Mouth inferior, premaxillary tooth band partially (approximately two-thirds) exposed when mouth is closed. Oral teeth small and villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary teeth appearing in single broad semilunate band. Dentary teeth in a single crescentic band, consisting of two separate halves tightly bound at midline. Thoracic adhesive apparatus consisting of keratinized striae in an elliptical field extending from isthmus to just beyond posterior limit of pectoral-fin base (Fig. 3 l). Anteromedial striae absent. Narrow, v-shaped medial pit on posterior half. Dorsal fin located above anterior third of body, with I, 6 (20) rays; fin margin concave; spine short and straight, smooth on anterior and posterior margins. Adipose fin with anterior margin straight or slightly concave and posterior margin straight. Caudal fin strongly forked, with lower lobe slightly longer than upper lobe and i, 7,8, i (20) principal rays. Procurrent rays symmetrical and extending only slightly anterior to fin base. Anal-fin base vertically opposite adipose-fin base. Anal fin with straight anterior margin and straight or slightly concave posterior margin; with iv, 8 (3), iv, 8, i (5), iv, 9 (5) or iv, 9, i (7) rays. Pelvic-fin origin at vertical through posterior limit of dorsal-fin base. Pelvic fin with slightly convex margin and i, 5 (20) rays; tip of adpressed fin not reaching anal-fin origin. Pectoral fin with I, 8 (1), I, 8, i (18) or I, 9 (1) rays; posterior fin margin slightly concave; anterior spine margin smooth, posterior margin with 6 – 14 serrations. Coloration. In 70 % ethanol: Dorsal and lateral surfaces of head, and body brown to brownish gray, fading to beige on ventral surfaces. A dark, diffuse midlateral stripe running along lateral line; lateral line without such pigmentation in some individuals, causing it to show up as paler stripe within darker stripe. Body often with four long, elliptical pale patches: first above lateral line and spanning region between dorsal and adipose fins, second below lateral line and first spot, third on anterior half of caudal peduncle above lateral line and fourth on anterior half of caudal peduncle below lateral line, with pale patches imparting appearance of dark vertical band on body between adipose and anal fins. Dorsal fin with brown base and broad subdistal triangular brown mark. Pectoral fin hyaline, with brown melanophores forming a diffuse broad, transverse band subdistally. Pelvic fin hyaline, with faint transverse brown band in middle. Anal fin with brown base and brown melanophores forming V-shaped subdistal mark on anterior half of fin; rest of fin hyaline. Adipose fin brown to brownish gray, with hyaline distal margin. Caudal fin brown to brownish gray, tips and posterior margins of lobes hyaline. Maxillary barbel brown to brownish gray dorsally, beige ventrally.
