TheCranial AnatomyofCricetops dormitor, anOligocene Fossil RodentfromMongolia

A description ofthecranial, mandibular, anddental morphology ofCricetops dornitor, an Oligocene muroidrodent, ispresented. Cricetops exhibits aunique combination ofprimitive muroidcharacters (e.g., thepresence ofalarge hystricomorphous infraorbital foramen) and derived muroid characters (e.g., aprominent metacone intheupperthird molar) that cloudits taxonomic affiliations. Inaddition, Cricetops dormitor lacks manycharacters, including a highly inclined zygomatic plate, that havebeenusedtounite membersofthefamily Muridae. Overall, these results suggest thatthephylogenetic position ofCricetops within theMuroidea needstobereevaluated.