Hystricognathi

Taxobox
name = Hystricognaths
fossil_range = Late Eocene - Recent

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image_width = 250px
image_caption = "Capromys pilorides"
regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Rodentia
subordo = Hystricomorpha
infraordo = Hystricognathi
infraordo_authority = Tullberg, 1899
subdivision_ranks = Families
subdivision =
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

Anatomy

Hystricognathi is an infraorder of rodents. Hystricognaths are 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.

There are 18 families within the Hystricognathi, divided into two infraorders, the Phiomorpha and the Caviomorpha. The Caviomorpha are mostly native to South America, with a few species in North America, while the Phiomorpha occur in the Old World.

Behavior

Play behavior has been observed in seven hystricognath families. The caviomorphs chase each other, play-wrestle, and gallop. The longer-legged species chase more often than the shorter-legged species. They also rotate their heads and body muscles as a form of play (Fagen 1981).

Phiomorphan hystricognath familiæ

* Bathyergidae
* Hystricidae
* Petromuridae
* Thryonomyidae

Caviomorphan hystricognath familiæ

* Abrocomidae
* Agoutidae
* Capromyidae
* Caviidae
* Chinchillidae
* Ctenomyidae
* Dasyproctidae
* Dinomyidae
* Echimyidae
* Erethizontidae
* Myocastoridae
* Octodontidae

External links

http://animaldiversity.ummz.umich.edu/site/topics/mammal_anatomy/rodent_jaws.html

References

Fagen, Robert. "Animal Play Behavior". Oxford University Press, 1981.

ee also

* Sciurognathi
* Hystricomorpha