The giant tree-rat (''Toromys grandis'') is a species 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 ...

, the spiny rats. It is the only species in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

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 ...

''Toromys''. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, where it occurs in the

flooded forest Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are foun ...

along the banks of the Amazon River and its tributaries. This species was formerly considered to be a member of the genera ''Loncheres'' and ''

Makalata ''Makalata'' is a genus of rodents in the family Echimyidae. Systematics The etymology of this genus name derives from a combination of letters inspired by the Suriname Suriname, officially the Republic of Suriname, is a country in northe ...

''. In 2005 it was reclassified as the only member of the new genus ''Toromys''. The etymology of the genus name derives from the onomatopoeic Portuguese word , referring to the vocalizations of this rodent, and the

ancient greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

word (), meaning "mouse, rat".

Phylogeny

''Toromys'' is the sister genus to ''Pattonomys''. These taxa are closely related to ''Echimys'', ''Phyllomys'', and ''Makalata'', reflecting the fact that '' Toromys grandis'' and '' Pattonomys occasius'' have formerly been placed in ''Makalata'' by some authorities. In turn, these five genera share phylogenetic affinities with a clade containing the bamboo rats ''Dactylomys'', ''Olallamys'', ''Kannabateomys'' together with ''Diplomys'' and ''Santamartamys''.

References

Echimyini Mammals described in 1845 Endemic mammals of Brazil Taxa named by Johann Andreas Wagner {{Echimyidae-stub