A new species of Moenkhausia (Characiformes, Characidae) from the I?á River, Amazon Basin, northern Brazil

摘要

A new species of the genus Moenkhausia is described from the I?á River, Amazon Basin. Moenkhausia britskii sp. n. is most similar to M. grandisquamis and M. xinguensis. From these two species it is readily distinguished by the pigmentation pattern of the humeral spot. Moenkhausia britskii further differs from M. xinguensis by the pattern of radii on the scales, which curve upward and downward (vs. scales with straight radii). Discussions on the putative relationship of the new species with M. grandisquamis and M. xinguensis, and on the peculiar upward and downward arched scale radii are provided.