Diagnosis |
This species has a characteristic dark bluish-gray band from the head to the origin of the dorsal fin; 5-9 opercular odontodes, and the anterior and posterior fontanels separated but connected by a narrow channel; body elongated, deeper than wide, gradually deeper from trunk toward caudal peduncle; convex dorsal profile of trunk; straight ventral profile of trunk; dorsal and ventral profiles of caudal peduncle slightly convex; thick integument with lateral cutaneous folds forming vertical rings between pectoral and anal fins in specimens preserved in alcohol; wide head, trapezoidal, and depressed in dorsal view; straight dorsal profile of head, the ventral and lateral profiles convex; eye small, black, rounded, well defined, with variable diameter, positioned dorsally on anterior half of head; subterminal mouth, the corners oriented backwards; lower lip with distinct fleshy lateral lobes; teeth conical and curved, arranged in 3-4 irregular rows on upper jaw and 3 rows on lower jaw; jaw muscles not particularly developed and not bulging from surface of head; thick branchial membranes, united to isthmus anteromedially and forming free fold across isthmus; wide gill opening; nasal and maxillary barbels surpassing base of pectoral fin; the maxillary barbel is longer than nasal barbel; the anterior nostril is surrounded by slightly raised thick integument, continuous with nasal barbel, both forming a tubular-shaped structure around nostril; the posterior nostril oriented transversally, its anterior edge delimited by thin and long flap of integument; pectoral fin rounded with i,8 rays, the first ray thin and fragile, prolonged as a long filament; dorsal-fin is rounded and located posterior to vertical through midbody, with iv,7 rays (only 2 unbranched rays are externally visible); pelvic-fin rays i,4, with a lateral splint, its origin anterior to vertical through dorsal-fin origin and its posterior edge slightly surpasses urogenital opening, the pelvic-fin bases not widely separated; anal-fin similar to dorsal fin, but smaller, with ii, 5 rays, its origin at level of last dorsal-fin ray; caudal-fin rays i, 5+6, i, caudal-fin edge slightly convex, with uppermost rays larger (Ref. 79018). |