"Ptilodontoidea is a group of extinct mammals from the Northern Hemisphere. They were generally small, somewhat rodent-like creatures of the extinct order Multituberculata. Some of these genera boast a great many species, though remains are generally sparse. Ptilodus is among the best known, and there's a tendency to depict it as an analog of a squirrel.Upper Cretaceous remains are known from North America and Europe."@en . "Ptilodontoidea"@en . . . . . . "Fossil" . .