Rodents from the Lower Oligocene of the Bierzo Basin (Leon, Spain)

The Bierzo Basin is one of a series of Tertiary basins, located in the NW of the Iberian Peninsula linked to the Alpine Pyrenean oro geny. So far, its exact age was unknown because no paleontological data were available. Two new fossiliferous localities between Fresnedo and Tombrio de Arriba in the Bierzo Basin (Leon, Spain) permit such a dating for the first time. The fossil rodent collection from REY1, includes Issiodoromys bergidensis sp. nov., Protechimys cf. truci, Pseudocricetodon simplex, and Gliravus majori. Its age is late Early Oligocene (MP24). The second locality, REY3B, contains Issiodoromys minor, Protechimys cf. gracilis, Allocricetodon sp. no v., Pseudocricetodon simplex, Heterocricetodon aff. schlosseri, and Oligodyromys planus. Its age is latest Early Oligocene age (MP25).