Pristimantis serendipitus is a species of frog in the family Craugastoridae. It is found in the Andes of northern Peru and adjacent southern Ecuador. The specific name refers to serendipitous discovery of this species: collection at the type locality was only made because the road was closed by an accident. Common name Colan Mountains robber frog has been proposed for this species.
Adult males measure 20–21 mm (0.8–0.8 in) in SVL; adult females are unknown but a subadult female measured 22 mm (0.9 in) in SVL. The snout is moderately long. The tympanic annulus is distinct. The fingers and toes bear discs but neither webbing nor lateral fringes. Skin is dorsally finely tuberculate. Coloration in pale gray at night and brown with darker marking by day. The venter is gray while the throat is yellow; both are heavily flecked with gray. The iris is dull bronze with median, horizontal red-brown streak.
