Rattus norvegicuss (Linnaeus 1758) is the living rat and a member of the clade Rodentia. The mandible slides forward to gnaw and backward to chew. Note the maxilla takes over much of the skull formerly occupied by the jugal, which is a mere sliver.. The incisors grow continually and are worn down by gnawing. Contra all prior studies, the Multituberculates are derived from rodents like Shenshou. Rodents are derived from armboreal forms like Carpolestes and Plesiadapis.
Mus musculus (Linneaus 1758) is the living mouse, a sister to Rattus and derived from Paramys and Shenshou. Mus is smaller that Rattus, with a rounder skull, a relatively larger braincase and only two molars (x4).
Eliomys quercinus (Linneaus 1758) is the living dormouse. Here this arboreal rodent with a fuzzy tail nests with the more terrestrial house mouse. Though similar, the skulls show distinct traits.
Leidy J 1871. Remains of extinct mammals from Wyoming. Proceedings of the Academy of Natural Sciences 23: 113–116.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
Matthew WD 1910. On the osteology and relationships of Paramys and the affinities of the Ischyromyidae. Bulletin of the American Museum of Natural History, 28:43–72.
