Can be diagnosed from other species of Parotocinclus, except P. prata and P. robustus, by its lack of abdominal plates between the pectoral girdle and the anus. Differs from these species by having smaller cleithral width (16.7-20.7 vs. 20.8- 27.6% SL in P. prata and 25.9-28.8% SL in P. robustus). Can be further distinguished from P. prata by the ventral surface of head, behind the lower lip, smooth and unwrinkled in adults (vs. wrinkled and rugose), and by the tip of adpressed pectoral fin not reaching to middle of pelvic fin (vs. pectoral fin reaching to middle of pelvic fin); also from P. robustus by the lack of dark brown dots on body (vs. presence in large specimens of many dark brown dots on dorsal and lateral region of head and trunk). Distinguished also from most other congeners (except P. arandai, P. bahiensis, P. prata, P. robustus, and P. spilurus) by having the rostral plate not visible ventrally (vs. visible in ventral view); and except for P. cearensis, P. cesarpintoi, P. jumbo, P. prata, P. robustus, P. spilosoma, and P. spilurus, by having the pectoral girdle covered by thick skin medially and exposed supporting odontodes only laterally (vs. pectoral girdle exposed and supporting odontodes medially and laterally). Can be further separated from all congeners from the Amazon and Orinoco basins and the Guianas coastal drainages (except P. collinsae), by the absence of a triangular patch of dark pigmentation on the anterior dorsal-fin base (vs. presence). Differs from P. collinsae by the absence of accessory teeth on the premaxilla and dentary (vs. presence) (Ref. 94247).