Systematics of the genus Euryoryzomys Weksler et al., 2006 (Rodentia: Cricetidae): integrative analysis reveals a new species from north-eastern Brazil

The genus Euryoryzomys encompasses six species found across Cis-Andean lowland and montane rainforests in South America. One of the most enigmatic forms of the genus is found in the Brejos de altitude of north-eastern Brazil, where enclaves of dense rainforest in mountain ranges sharply contrast with surrounding semi-arid Caatinga. Here we analyse morphological and molecular data, and demonstrate that these populations are members of a new species, which is described and contrasted with other Euryoryzomys. Phylogenetic analyses based on mitochondrial cytochrome b gene, coupled with morphometrics and comparative anatomy analyses, show that the new species differs from its sister-species, Euryoryzomys lamia from the Cerrado of Central Brazil, and from other forms of the genus, corroborating previous perspectives based on karyological data. The new species of the genus occurs in two distinct areas in the state of Ceara, Serra de Ibiapaba and Serra de Baturite, and one isolated range in Paraiba state. The recovered biogeographic pattern of Brejos de altitude-Cerrado sister-group relationship is novel among studied vertebrates, as most species from Brejos are more closely related to taxa from Amazon and Atlantic Forest. Further taxonomic efforts are necessary to uncover the total diversity within Euryoryzomys, especially for the nominal taxa E. emmonsae, E. macconnelli, and E. nitidus.

Automated summary

This study discovered a new species of the genus Euryoryzomys in the Brejos de altitude of north-eastern Brazil, which is distinct from other species and has a unique geographical distribution.