This species is distinguished from P. glaucostigmus in having a nasal tassel, uniform coloration, a slightly narrower maximum disc width and disc width at anterior orbit, longer head, longer snout, shorter anterior nasal flap, smaller nostril length, and a smaller body width at first dorsal-fin origin; differs from P. leucorhynchus in having a nasal tassel, brown rostrum, shorter distance from snout to first dorsal-fin origin, shorter distance from snout to lower caudal-fin origin, slightly narrower disc width at anterior orbit, a narrower body at first dorsal-fin origin, shorter anterior nasal flap base length, and shorter nostril length. It is most similar to P. productus but differs in having a narrower disc width 30-35% (vs. 36-38% TL range), shorter distance from nostril to disc margin 2.8-4.0% (vs. 4.2-5.2% TL range), narrower disc width at anterior orbit 12-19% (vs. 20-22% TL range), narrower tip of snout width 3% (vs. 4-6% TL average), and no prominent thorns as a juvenile (Ref. 125697).