Hystricognathi

Hystricognathi Temporal range: Late Eocene–Recent PreЄ Є O S D C P T J K Pg N
Capromys pilorides
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Suborder:	Hystricomorpha
Infraorder:	Hystricognathi Tullberg, 1899
Families
Hystricidae †Bathyergoididae Bathyergidae †Myophiomyidae †Diamantomyidae †Phiomyidae †Kenyamyidae Petromuridae Thryonomyidae Erethizontidae Chinchillidae †Neoepiblemidae Dinomyidae †Cephalomyidae †Eocardiidae Caviidae Dasyproctidae Cuniculidae Ctenomyidae Octodontidae Abrocomidae Echimyidae Myocastoridae Capromyidae †Heptaxodontidae

Hystricidae
†Bathyergoididae
Bathyergidae
†Myophiomyidae
†Diamantomyidae
†Phiomyidae
†Kenyamyidae
Petromuridae
Thryonomyidae
Erethizontidae
Chinchillidae
†Neoepiblemidae
Dinomyidae
†Cephalomyidae
†Eocardiidae
Caviidae
Dasyproctidae
Cuniculidae
Ctenomyidae
Octodontidae
Abrocomidae
Echimyidae
Myocastoridae
Capromyidae
†Heptaxodontidae

The Hystricognathi are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls. The masseter medialis (a jaw muscle) passes partially through the infraorbital foramen and connects to the bone on the opposite side. This, together with their lack of an infraorbital plate and the relative size of the infraorbital foramen, distinguishes hystricognaths from other rodent groups.