The cricetid rodent genus Rhipidomys belongs to the tribe Thomasomyini, subfamily Sigmodontinae, whose distribution covers high- and lowlands areas of South America. In a number of contributions to the taxonomy and systematics of the genus, 24 species of Rhipidomys were recognized by different authors until now. Here we identify 13 species of the lowland “leucodactylus” section from Brazil and named two new forms of this genus based on morphological and molecular data. One of these forms is only found at municipality of Bezerros, Pernambuco state, while the other has a more extensive distribution, being recorded in northern Goiás, west of Tocantins, southern Piauí, western portion of Bahia and northern region of Minas Gerais states. These two new species can be distinguished from the others of the genus by qualitative and quantitative characters although, like most other Brazilian species of Rhipidomys, they do not exhibit an autapomorphic characters. These species are diagnosed by unique combinations of character states that are operational and useful for species recognition. In general, the most valuable character sets to differentiate Rhipidomys species are found in the skull, external morphology being strongly variable and showing overlapping sets of characters. We compared the two new species with all Brazilian species of the “leucodactylus” section and added taxonomic comments and their phylogenetic relationships.