Utah Department of Natural Resources
A jaw of a newly discovered mouse fossil (Basirepomys robertsi) from central Utah rests on a fingertip.
A newly published report describes the discovery of two new prehistoric rodents in Utah believed to be about 8 million years old.
The site, in central Utah near Sevier, has since been the site of the discovery of several hundred vertebrate fossils, including those belonging to extinct camels, carnivores and elephants.
Jeff and Denise Roberts, amateur naturalists from Annabella, Sevier County, first discovered the fossil site in 1996 in the Sevier River Formation. One of the new fossils, a relative of the modern-day deer mouse, has been named Basirepomys robertsi in honor of the Robertses.
Don DeBlieux, the report's co-author and a paleontologist with the Utah Geological Survey, said the findings have significance because previously, Utah had been a "hole" in that geologic time frame in western North America for fossil mammals.
"The uplift and erosion of the Colorado Plateau, which makes Utah such a good place for finding dinosaur fossils, means that younger rocks and fossils, such as those from the Miocene epoch, which lasted from 23 million to 5 million years ago, have been washed away."
The article, published in the January edition of the Journal of Vertebrate Paleontology, highlights the significance of the finding.
"These are the first fossils to be reported from this formation, and we wanted to acknowledge the important role the Robertses played in bringing this site to the attention of scientists," DeBlieux said. The second new species, a relative of the spiny pocket mouse, was named Metaliomys sevierensis for the area in which the fossils were found. The fossils will eventually go the Utah Museum of Natural History.
— Amy Joi O'Donoghue