This species is distinguished from all its congeners except P. pygmaeus by having lower number of teeth in the maxilla 21-30 (vs 32-58) and dentary 26-29 (vs 33-55); differs from P. pygmaeus by the presence of two postcleithra (vs. absence and branched anal-fin rays 22-27 modes 25 and 26 (vs. 19-22, mode 19); differs fom P. nanus and P. varii by having pelvic-fin rays i,5 (vs.i,6) and postcleithrum 3, slender and sinuous (vs. relatively thick and straight); differs from P. ariel by the branched anal-fin rays 22-27 (vs. 16-22) and with two postcleithra (vs. absent); further differs from P. varii by the absence of the adipose fin (vs. presence) and from P. nanus by the absence of the claustrum (vs. presence); with a shorter snout relative to the orbital diameter when compared to all congeners except P. nanus [range of the proportion of snout length in relation to orbital diameter and its mean is 45-59 (mean = 53.6; SD = 3.8) in P. britzi vs. 60-76 (mean = 65.5; SD = 4.9) in P. pygmaeus, 54-81 (mean = 67.0; SD = 5.1) in P. varii and 54-84 (mean = 68.4; SD = 6.3) in P. ariel]. Molecular analyses further support the recognition of the new species (Ref. 124594).