I. barbarabrownae I. bistriata I. negrensis I. pagurus I. sinnamariensis Lasiuromys Deville, 1852 The toros or brush-tailed rats, genus Isothrix, are a group of spiny rats[1] found in tropical South America, particularly in the Amazon Basin.

[2] Toros look like large rats with soft fur on the body and long guard hairs on the scaly tail.

The etymology of the genus name Isothrix corresponds to the two ancient greek words ἴσος (ísos), meaning "of equal length", and θρίξ, τριχός (thríx, trikhós), meaning "hair".

[8] Although tentatively considered an echimyine, it has been suggested that Isothrix may not be particularly closely related to other members of its subfamily.

[3] This is confirmed by molecular phylogenies in which Isothrix appears as a distant relative of the three clades of Echimyini: (i) Echimys, Phyllomys, Makalata, Pattonomys, and Toromys ; (ii) the bamboo rats Dactylomys, Olallamys, Kannabateomys together with Diplomys and Santamartamys ; and (iii) the arboreal eumysopines Mesomys and Lonchothrix.