Clyomys

Clyomys is a South American rodent genus in the family Echimyidae. It contains two species, found in tropical savannas and grasslands from circa 100 m to 1100 m elevation in central Brazil and eastern Paraguay.

The term Clyomys derives from the two ancient greek words (, or clyo), meaning "to listen, to prick up one's ears", and , meaning "mouse, rat".

The Clyomys  species are as follows:
 * Broad-headed spiny rat (Clyomys laticeps)
 * † Clyomys riograndensis

Phylogeny
Clyomys is the sister genus to Euryzygomatomys. 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 Clyomys — and also Euryzygomatomys — may be associated with Carterodon. However, molecular data suggest the polyphyly of this assemblage of fossorial genera.