Parodon magdalenensis differs from all congeners by presenting a completely dark ground portion above black lateral stripe that lacks projections or spots extending dorsally, in adults (vs. base color white to yellow above lateral stripe which often has projections or spots extending dorsally); base color below lateral stripe to level of axillary scale gray (vs. body below lateral stripe same color as base color of rest of body, usually white or yellow); adults with well defined black spot from middle of pectoral fin to its tip (not reaching base), absent in juveniles (vs. chromatophores present on pectoral fin not forming well-defined spot, nor bar and often present in juveniles); no dark brown spots on dorsal part of sides above lateral stripe (vs. dark brown spots present); branched pectoralfin rays 11-14 (vs. 14-16; except P. buckleyi which has 13-15 branched pectoral rays). Parodon magdalenensis differs from P. bifasciatus by the higher number of cusps in premaxillary teeth (11-15 vs. 7-12) and the lower number of post-adipose scales (6-8 vs. 7-10, as well as from P. hilarii and P. nasus which have the same count as P. bifasciatus). It is differentiated from P. guyanensis by the number of teeth on the premaxilla (4 vs. 5) and can be distinguished from P. pongoensis and P. moreirai by the presence of a lateral band with projections above and below (vs. absence of projections in such band) and the number of scales in the lateral line (35-38 vs. 40-42 in P. moreirai), and normal sized teeth in the maxilla (vs. teeth minute or absent). It can be distinguished from most P. carrikeri by the number of scales in the lateral line (35-38 vs. 38-39), and the dark coloration along the body including most of the head (vs. ground and general color of body light in P. magdalenensis). It differs from P. suborbitalis by the lower number of cusps in premaxillary teeth (11-15 vs. 15-17) (Ref. 88955).