Origin of Rodents

Abstract

Osborn (1902) viewed the origin of rodents from the primitive Paleocene insectivore family the Mixodectidae for which he proposed the term Proglires. Mixodectids have since been shown to be most closely related to other insectivores (notably the leptictids and tupaiids) and have nothing to do with rodents (Szalay, 1969, pp. 237–239). Other early workers suggested the Meso-zoic and early Tertiary Multituberculata as the ancestors of rodents, noting the enlarged lower incisor and diastema in many families of this Mesozoic and early Tertiary group (Forsyth Major, 1983; Hinton, 1926; Friant, 1932). The multituberculates are, however, specially derived prototherians and cannot be ancestral to any eutherian group. The condition of the incisor and diastema in the multituberculates is only convergent with that of rodents.