Diagnosis |
Diagnosis: 2 pairs of well-developed barbels; barbels dullcolored, same hue as skin of head where they arise; length of posterior barbel consistently slightly less than diameter of eye, and length of anterior barbel about 1/3-1/2 that of posterior barbel; keratinous tubercles on head small, granular, white spots which project little or not at all above surface of head; adults dull blue dorsally and laterally, whitish ventrally; 37-39 scales in a lateral series to end of hypural plate, 20-24 (usually 24) around caudal peduncle; dorsal fin with 10-11 (usually 11) branched rays, its margin falcate (Ref. 42510).
Description: Lips: rostral flap fimbriated; inner surface of upper lip with numerous transverse plicae formed by minute, confluent papillae; lower lip with numerous large, conical papillae which become larger and harder with growth (Ref. 42510). Eye: position of eye lateral or slightly superolateral, less superolateral than in barbatus (Ref. 42510). Squamation: 37-39 scales in lateral series to end of hypural fan, plus 2-4 more pored scales extending onto base of caudal fin; 6-8 (usually 7) scales between lateral line and pelvic fin insertion; dorsomedian scale row anterior to dorsal fin poorly developed, the scales small, irregularly positioned and often with scaleless gaps between them; first 1-2 dorsolateral scale rows anterior to dorsal fin also reduced in size; squamation of barbatus virtually identical, except that there are usually only 8-9 scales above lateral line, and usually 20-21 (rarely 24) scales around caudal peduncle (Ref. 42510). 20-26 scales around caudal peduncle (Ref. 26190).
Coloration: juvenile coloration: except for striking difference in barbels, coloration of juveniles is very similar to that in barbatus; entire sides of the body exhibit a reticulate pattern of light and dark areas, parallel or complementary to scales; pattern is very similar in barbatus, there may be a difference in that the indistinct darker vertical marks on the scales characteristic of adult barbatus are sometimes more evident in juveniles of barbatus; caudal peduncle bears a dark vertical blotch, surrounded by a poorly defined lighter area; 2-3 scale rows extending onto caudal fin also darkened; no indication of either red spots on scales or a dark midlateral stripe, characteristic features of juvenile coloration in some other species groups of Labeo (Ref. 42510). |