This species is distinguished from its congeners by the following characters: in fresh specimens, with a conspicuous dark spot over the eyes, from snout to nape (vs. indistinct marking); pre-caudal vertebrae 11-12 (vs. 13 or more, rarely 12 except P. xanthurus); total vertebrae 28-29 (vs. 30 or more in P. medius, P. ovatus, P. simillimus, P. snyderi); body height 58.5?74.1% SL (vs. 33.0?52% SL in P. burti, P. ovatus, P. simillimus, P. snyderi, P. triacanthus); dorsal fin moderately falcate (vs. not falcate in P. triacanthus, or conspicuously falcate in P. paru); anal fin falcate (vs. not falcate in P. simillimus, P. ovatus, P. snyderi, P. burti, P. triacanthus); front half of the body under the dorsal fin without series of pores (vs. 17?25 conspicuous pores in P. triacanthus); differs from sympatric P. crenulatus by having an orbital diameter of 1.6?5.0 in anal-fin height (vs. 5.1-8.0) for individuals smaller than 11.0 cm SL and 3.2-5.2 (vs. 5.5-9.2) for specimens larger than 10.9 cm SL; orbital diameter 3.2-3.8 in pectoral-fin height (vs. 3.9-5.9), in the specimens larger than 10.9 cm SL; and orbital diameter 1.1-1.4, rarely 1.5 in post-orbital length (vs. 1.5-2.3) (Ref. 116249).