A new species of Anchoviella (Clupeiformes: Engraulidae) from the western Amazon River in Peru, with comments on congeners in the Peruvian Amazon River.

Anchoviella hernanni sp. nov. is described from the upper Amazon River basin, in tributaries of the Marañon, Ucayali and Madre de Dios river drainages that drain the Peruvian Andes. The new taxon can be distinguished from all congeners except Anchoviella jamesi, Anchoviella manamensis and Anchoviella perezi, by having 12-15 gill rakers in the lower branch of the first gill arch (v·16-35) and from those species by the distance between verticals through the posterior margin of the orbit to the posterior margin of the upper jaw 9·5-14·8% head length; LH (v. up to 6·0% LH ). An updated identification key of all freshwater species of Anchoviella and morphological comparisons between all species of the genus occurring in Peru are provided.