Can be easily distinguished from all congeners except Ancistrus reisi and A. jataiensis by lacking adipose fin. A series of 3 to 5 median, unpaired platelets forming a low crest is present in place of adipose fin. Platelets are followed by at least two dermal plates (more often three) of the dorso-lateral series that join dorsally, vs. platelets nearly immediately followed by the plate-like procurrent caudal rays in A. reisi and A. jataiensis. It further differs from all species of Ancistrus by the unique combination of the following characters: naked margin of snout large and tentacles usually absent in both sexes, body very narrow (cleithral width 27.5-31.2% SL, mean 29.4), and long caudal peduncle particularly depressed (depth 8.3-9.2% SL, mean 8.7) (Ref. 54498).

Description: D i,7; P i,6; V i,5; A i,4; C i,13,i or C i,14,i (Ref. 54498).