Isothrix

"Brush-tailed rat" redirects here. For the rodent endemic to Chile, see degu. For the Australian rodent Conilurus penicillatus, see brush-tailed rabbit rat.

Isothrix Temporal range: Pleistocene - Recent
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Echimyidae
Subfamily:	Echimyinae
Genus:	Isothrix Wagner, 1845
Species
I. barbarabrownae I. bistriata I. negrensis I. pagurus I. sinnamariensis
Synonyms
Lasiuromys Deville, 1852

The toros or brush-tailed rats, genus Isothrix, are a group of spiny rats found in tropical South America, particularly in the Amazon Basin.

Description

Toros look like large rats with soft fur on the body and long guard hairs on the scaly tail (Emmons, 2005). Head and body is 18-27.5 cm and tail is 17–30 cm (Nowak, 1999). Weight is 320-570 grams.

Natural history

These animals appear to be arboreal, based on the shape of their hind feet (Nowak, 1999). They are thought to spend the day in holes in the ground near trees.

Classification

There are currently five species recognized in the genus. Callistomys pictus was previously considered a member of this genus, but most authors consider it distinct enough to warrant a separate genus (Woods and Kilpatrick, 2005). Although tentatively considered an echimyine, Emmons (2005) and other authors as have suggested that Isothrix may not be particularly closely related to other members of its subfamily. There does, however, appear to be good support for the monophyly of the three species found in this genus (Emmons, 2005).

Species

• Genus Isothrix
  • Isothrix bistriata - Yellow-crowned Brush-tailed Rat
  • Isothrix negrensis - Rio Negro Brush-tailed Rat
  • Isothrix pagurus - Plain Brush-tailed Rat
  • Isothrix sinnamariensis - Sinnamary Brush-tailed Rat
  • Isothrix barbarabrownae

References

• Emmons, L.H. 2005. A Revision of the Genera of Arboreal Echimyidae (Rodentia: Echimyidae, Echimyinae), With Descriptions of Two New Genera. pp. 247–310 in Lacey, E.A. & Myers, P. 2005. Mammalian Diversification: From Chromosomes to Phylogeography (A Celebration of the Career of James L. Patton). University of California Publications in Zoology.
• Nowak, Ronald M. 1999. Walker's Mammals of the World, 6th edition. Johns Hopkins University Press, 1936 pp. ISBN 0-8018-5789-9