This species can be distinguished within the group by a set of characteristics: mesial series of premaxillary teeth in a single row, with 2-4 teeth (vs. medial series in 3-4 rows, with 20 or more teeth in P. scriptus, P. cephalus, P. sagamianus, and P. cordilluminatus); dentary teeth in 2 series, lateral and medial, each with a single row (vs. 2 series, lateral in single row and mesial with three or more rows); teeth at the anterior edge of premaxilla recurved, dentary inserted on the ventral edge of the bone and pointing mesially or caudally (vs. teeth at lateral series extremely curved with anterior teeth inserted in the lateral edge of bone, turned outwards) (Ref. 85782).