''Ivanantonia'' is the only genus in the extinct rodent family Ivanantoniidae and is represented by a single species, ''Ivanantonia efremovi'', from the early Eocene of Mongolia. ''Ivanantonia'' is poorly known, with only the lower

dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolo ...

represented. The genus is unusual among early rodents in lacking all lower

premolar The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...

s and in showing evidence of propalinal chewing. The relationships of ''Ivanantonia'' are unclear. It was described as a ctenodactyloid. Hartenberger et al. suggested a potential relationship to the muroid '' Nonomys'' but declined to assign Ivanantoniidae to a suborder within Rodentia.

References

* *Shevyreva, N.S. 2007. 1989. New rodents (Ctenodactyloidea, Rodentia, Mammalia) from the Lower Eocene of Mongolia. Paleontological Journal, 3: 60–72.

References

Further reading