Sigmodontinae

… species belong to the subfamily Sigmodontinae of the “true” mouse family, Muridae, within the order Rodentia. Today’s Onychomys species are related to grasshopper mice represented by four-million to five-million-year-old fossils that extend the evolutionary history of the genus back to the Early Pliocene Epoch (5.3 million to 3.6 million years…