Archolaemus blax Korringa 1970

Distinguished from other congeners in having the following combination of characters: gape relatively long and rictus extending posteriorly beyond the vertical through the posterior naris; length of coronomeckelian bone less than 20% the length of Meckel’s cartilage; length of the posterior ceratohyal 1.5 times the length of the ventral hypohyal; approximately six irregularly distributed teeth on the internal surface of the endopterygoid; anteroposterior length of premaxilla greater than the transverse width; teeth on the dentary restricted to the anterior half or slightly more of the dorsal margin; depth of the caudal filament 5.0-6.5% CL; presence of a narrow dark stripe along the lateral line and a broad dusky to dark band of pigmentation overlying the basal pterygiophores of the anal fin; pectoral-fin rays 19-22; total number of anal-fin rays 193-222 (Ref. 93148).Description: Pectoral-fin rays ii, 19 to ii, 22; anal fin with 23-27 unbranched rays and 193-222 total fin rays (Ref. 93148).

Analsoft rays: 193 - 222

Its elongated, laterally compressed body is completely covered with scales and is without a caudal fin (Ref. 27188).

Archolaemus blax is a species of glass knifefish endemic to Brazil where it is found in the Rio Tocantins.