hind feet have only four toes, owing to the suppression of the first, in place of which they have a fleshy pad on the inner side of the foot; between this pad and the toes, branches and other objects can be firmly grasped as with a hand. These three genera are often united into a single genus Coendou. Genus Chaetomys, distinguished by the shape of its skull and the greater complexity of its teeth, contains C. subspinosus, a native of the hottest parts of Brazil. This animal is often considered a member of Echimyidae on the basis of its premolars. However, a molecular phylogeny based on the mitochondrial gene coding for cytochrome b combined to karyological evidence actually suggests the bristle-spined rat is more closely related to the Erethizontidae than to the Echimyidae, and is the sister group of all other Erethizontidae. Classification Extant genera and species Family Erethizontidae Subfamily Chaetomyinae Genus Chaetomys Bristle-spined rat C. subspinosus Subfamily Erethizontinae Genus Coendou – prehensile-tailed porcupines Baturite porcupine - C. baturitensis - discovered in 2013 Bicolored-spined porcupine - C. bicolor Streaked dwarf porcupine - C. ichillus Bahia porcupine - C. insidiosus Black-tailed hairy dwarf porcupine - C. melanurus Mexican hairy dwarf porcupine - C. mexicanus Black dwarf porcupine - C. nycthemera Brazilian porcupine - C. prehensilis Frosted hairy dwarf porcupine - C. pruinosus Andean porcupine - C. quichua Rothschild's porcupine - C. rothschildi Roosmalen's dwarf porcupine - C. roosmalenorum Stump-tailed porcupine - C. rufescens Santa Marta porcupine - C. sanctamartae Coandumirim - C. speratus - discovered in 2013 Paraguaian hairy dwarf porcupine - C. spinosus Brown hairy dwarf porcupine - C. vestitus Genus Erethizon North American porcupine - E. dorsatum Fossil genera †Branisamyopsis †Cholamys †Eopululo †Hypsosteiromys †Microsteiromys †Neosteiromys †Palaeosteiromys †Paradoxomys †Parasteiromys †Protosteiromys References External links Erethizontidae, Mammal Species of the World, 3rd edition. Extant Chattian first appearances Mammals described in 1845 Taxa named by Charles Lucien Bonaparte