This species is distinguished from its congeners by having small plates covered with odontodes randomly distributed on the abdomen (vs. abdomen completely naked) and by color pattern of caudal-fin completely dark with one hyaline bar (vs. variegated blotches corresponding to approximately 3-4 hyaline bars in P. brachyrhyncha and P. rudolphi and hyaline random spots in P. carrancas. It differs from all congeners, except for P. brachyrhyncha, by presence of a minute lateral cusp in teeth (vs. unicuspid teeth in remaining species); from all congeners, except for P. carrancas, by having ventral surfaces of first pectoral, pelvic and anal-fin rays covered by pointed odontodes (vs. conspicuously spatulate odontodes); from P. carrancas by lacking a ridge on the postdorsal surface of trunk (vs. postdorsal surface of trunk with a low, elongate ridge formed by 10-13 raised median unpaired plates), anterior ends of the premaxillae and dentaries gently sloped inwards (vs. strongly sloped); from P. brachyrhyncha by lacking odontodes at the ventral tip of the snout (vs. tip of snout completely covered by odontodes) (Ref. 92077).