Andeancistrus platycephalus is distinguished from its only congener, A. eschwartzae, by having light gray base color of head and body (vs. black to dark gray), uniformly shaped round white to light blue spots smaller smaller than half naris diameter evenly distributed across head, lateral and dorsal surfaces of body and fin rays (vs. irregularly shaped round to vermiculate yellow-gold spots); and by the presence of enlarged clusters of odontodes (keels) at posteromedial apex of most lateral body plates (vs. absence of odontode clusters) (Ref. 104644).