Guiara

Euryzygomatomys is a genus of South American rodents, commonly called guiaras, in the family Echimyidae. It contains two extant and one fossil species, found in Argentina, Brazil and Paraguay. They are as follows:
 * Brandt's guiara (Euryzygomatomys guiara)
 * Fischer's guiara (Euryzygomatomys spinosus)
 * †Euryzygomatomys hoffstetteri Goeldi 1901 - Tarija Formation, Bolivia

Etymology
The genus name Euryzygomatomys derives from the three Ancient Greek words (, or eury), meaning "wide, or which extends in width",  or , meaning "a part of the forehead, or the zygomatic bone", and  , meaning "mouse, rat".

Phylogeny
Euryzygomatomys is the sister genus to Clyomys. Both taxa are closely related to the genus Trinomys. In turn, these three genera — forming the clade of Euryzygomatomyinae — share phylogenetic affinities with a clade containing Carterodon and members of the family Capromyidae.

Analyses of craniodental characters proposed that Euryzygomatomys — and also Clyomys — may be associated with Carterodon. However, molecular data suggest the polyphyly of this assemblage of fossorial genera.