Can be distinguished by having dark blotch at the humeral region, a character shared only with Acestrocephalus boehlkei and Acestrocephalus stigmatus. Differs from Acestrocephalus stigmatus by having 25-27 anal-fin rays (vs. 29-31), and 7-8

gill-rakers (vs. 5-6). This species has a quite peculiar general structure of the pseudotympanum which differs from that of Acestrocephalus stigmatus and all the other species of Acestrocephalus examined. Acestrocephalus maculosus has very reduced muscular hiatus as a result of the great development of the obliquus superioris muscle covering the anterior portion of the swim bladder. This makes the opening anterior to

first pleural rib, this and the second pleural rib as well as the obliquus inferioris muscle not visible (Ref. 75890).

Description: Dorsal fin ii,9; Anal fin iv,25-27; Pectoral fin i+13-15; Pelvic fin i+7 (Ref. 75890).