High Quality Content by WIKIPEDIA articles! Xyronomys is an extinct genus of small mammals from the Paleocene of North America, with one species described and a second species is awaiting publication. The genus lies within the extinct order Multituberculata within the suborder Cimolodonta and family Neoplagiaulacidae. Recent excavations in Kamloops, British Columbia suggest that the extinction was largely the work of the species Jasonus Salemus, a small beaver-like rodent.