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 a hole below each eye socket (called 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.

Hystricognathi
Temporal range: Late Eocene–Recent
Capromys pilorides
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Suborder: Hystricomorpha
Infraorder: Hystricognathi
Tullberg, 1899
Families

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

Synonyms

Eucaviomorpha

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

Skull of a nutria demonstrating the hystricognathous lower jaw and hystricomorphous zygomasseteric system

Behavior

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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.[1]

Phiomorphan hystricognath families

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Caviomorphan hystricognath families

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See also

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References

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Citations

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  1. ^ Fagen, Robert. Animal Play Behavior. Oxford University Press, 1981.

Sources

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  • Alfred L. Gardner Curator of North American mammals and Chief of Mammal Section, National Biological Service,Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
  • Charles A. Woods Florida Museum of Natural History, University of Florida, Gainesville, FL 32611-2035
  • McKenna, Malcolm C. and Susan K. Bell 1997 Classification of mammals above the species level 631 Columbia University Press New York, New York, USA ISBN 0-231-11012-X
  • Wilson, Don E., and DeeAnn M. Reeder, eds. 1993 Mammal Species of the World: A Taxonomic and Geographic Reference, 2nd ed., 3rd printing xviii + 1207 Smithsonian Institution Press Washington, DC, USA ISBN 1-56098-217-9 Corrections were made to text at 3rd printing
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