A new species of Corydoras from the Rio Urucu basin, a right-bank tributary of the Rio Solimões is described. The new species shares a distinctive pigmentation pattern with Corydoras arcuatus, C. gracilis, and C. narcissus, composed of a uniform light ground color on the body, and a dark, arched stripe from tip of snout to caudal-fin base along the upper portion of the dorsolateral body plates. The new species is readily distinguished from these congeners by the absence of a continuation of the arc-like stripe onto the snout. It also differs from Corydoras gracilis and C. narcissus by the posterior part of the arc-stripe reaching the base of the lower caudal-fin rays, and from C. arcuatus and C. narcissus by the distinctly rounded profile of the snout in lateral view, a greater preadipose distance, and the position of the posterior limit of the cleithrum. Despite the general resemblance, investigation about the position of the new species in light of previous phylogenetic hypotheses concerning this subfamily indicates that the arc-striped coloration pattern was independently acquired.