Diagnostic Description
provided by Fishbase
Distinguished from all congeners, among other characters, by approximately equal uncinate process and anterior arm and reduced anteroventral expansion of epibranchial 1 (vs. uncinate process narrower and complete anteroventral expansion in the other two species), a dorso-ventrally flattened maxillary process of the palatine (vs. cylindrical in the other two species), cycloid (vs. ctenoid) scales in the opercular, postorbital, lateral chest and anal-genital regions, the absence of a mid-lateral spot, and a diffuse dark area covering the dorsal portion of the head giving the impression of a 'black cap'. Possessess a unique juvenile pattern of seven vertical dark bars partially preserved in adults. Bars 3-6 in antero-caudal direction are most visible in juveniles and medium-sized specimens but become fainter and almost disappear in adults. Many specimens show only bar number 3 (midlateral bar) (Ref. 91746).
Morphology
provided by Fishbase
Dorsal spines (total): 15 - 17; Dorsal soft rays (total): 8; Analspines: 3; Analsoft rays: 7 - 8; Vertebrae: 26
Biology
provided by Fishbase
Abundant in the entire upper Mazaruni River basin, and especially in tributaries with rocky substrates and rich in rapids. Collected from black water sites with fairly high transparency (0.55-1.0 m Secchi depth), none to relatively fast currents (0-0.6 m/s), temperature (21.7- 24.5°C), pH (4.4-4.8), dissolved oxygen (5.2- 9.3 mg/L) and very low conductivity (
