Males and females of this species differ from its congeners with the exception of females of P. atrox, by having the following set of characters: postorbital photophore (PO) of moderate size, 21.0-25.3% upper jaw length (UJL), in males greater than 60 mm (vs. PO small, 12.1-20.0% UJL in P. tantillux; large, 26.8-46.6% UJL, in P. atrox and P. lucingens); accessory orbital (AO) of moderate size, 4.9-8.3% UJL, in males greater than 60 mm (vs. AO small, 2.4-4.7% UJL, in P. lucingens); three tooth patches at posterior end of the first, second, and third basibranchials (vs. two basibranchials tooth patches in P. guernei); total of dorsal- and anal-fin rays 49-53, rarely 55 (vs. 57-63, rarely 56, in P. goodyeari); females mature at approximately 100 mm (vs. less than 70 mm in P. tantillux and P. lucingens). Females of P. liemi can not be distinguished from those of P. atrox (Ref. 80463).