The Atlantic spiny rats are all found in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Trinomys''. They are a group of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

n spiny-rats in the family

Echimyidae Echimyidae is the family of neotropical spiny rats and their fossil relatives. This is the most species-rich family of hystricognath rodents. It is probably also the most ecologically diverse, with members ranging from fully arboreal to terr ...

Extant species of ''Trinomys''

Based on Natureserve.InfoNatura: Animals and Ecosystems of Latin America eb application 2007. Version 5.0 . Arlington, Virginia (USA): NatureServe. Available

/ref> The species of spiny rats in the genus ''Trinomys'' are apparently all Brazilian. In particular many of them are endemic to the Atlantic Forest of southeastern Brazil. Not much is known for certain about their ranges however, which still are being investigated, with frequent extensions to the recorded distributions of several species in various ecological classes of forest and dry land. They do not however appear to occur at high altitudes, and several of their ranges appear to be parapatric. Most species of ''Trinomys'' are terrestrial and ambulatory, though ''Trinomys yonenagae'' is unusual that it is semi-

fossorial A fossorial animal () is one that is adapted to digging and which lives primarily (but not solely) underground. Examples of fossorial vertebrates are Mole (animal), moles, badgers, naked mole-rats, meerkats, armadillos, wombats, and mole salamand ...

, living in colonial burrows, and exhibits incipient specializations for

saltatorial This glossary of entomology describes terms used in the formal study of insect species by entomologists. A–C A synthetic chlorinated hydrocarbon insecticide, toxic to vertebrates. Though ...

locomotion.

Phylogeny

Genus level

''Trinomys'' is the sister genus to the

genera ''Clyomys'' and ''Euryzygomatomys''. In turn, these three genera — forming the clade of

Euryzygomatomyinae Euryzygomatinae is a subfamily of rodents, proposed in 2017, and containing three extant genera of spiny Echimyidae: '' Clyomys'', '' Euryzygomatomys'', and '' Trinomys''. Members of this echimyid subfamily all share an origin in the eastern par ...

— share phylogenetic affinities with a clade containing ''

Carterodon Owl's spiny rat (''Carterodon sulcidens'') is a rodent species in the family Echimyidae found in Brazil. It is the only species in the genus ''Carterodon''. Owl's spiny rat has evolved characteristics such as a heightened ability to dig in open ...

'' and members of the family Capromyidae.

References

Rodent genera Taxa named by Oldfield Thomas {{Echimyidae-stub