Alpheus macrocheles (Hailstone, 1835), a species originally described from the northeastern Atlantic, has been reported from Brazil based on material from the north and northeast coasts and Espírito Santo. However, a thorough morphological comparison between Brazilian material reported as A. macrocheles and eastern Atlantic material of A. macrocheles revealed consistent differences, suggesting that the Brazilian specimens belong to an undescribed species. Alpheus ramosportoae sp. nov. is therefore now described based on material from Amapá to Pernambuco, Brazil. Morphological differences between the new species and A. macrocheles s. str. were supported by the clear divergence of 16S rRNA gene sequences (18% of genetic distance), separating the species in two distinct clades. Differences in the color pattern also were observed and illustrated.