Gray Rice Rat

Open encyclopedia reference

Eremoryzomys polius, also known as the gray rice rat or the Marañon oryzomys, is a rodent species in the tribe Oryzomyini of the family Cricetidae. Discovered in 1912 and first described in 1913 by Wilfred Osgood, it was originally placed in Oryzomys and named Oryzomys polius. In 2006, a cladistic analysis found that it was not closely related to Oryzomys in the strict sense or to any other oryzomyine then known, so that it is now placed in its own genus, Eremoryzomys. The Brazilian genus Drymoreomys, named in 2011, is probably the closest relative of Eremoryzomys. Eremoryzomys has a limited distribution in the dry upper valley of the Marañón River in central Peru, but may yet contain more than one species. A large, long-tailed rice rat, with head and body length of 138 to 164 mm (5.4 to 6.5 in), E. polius has gray fur and short ears. There are well-developed ungual tufts of hair on the hindfeet. Females have eight mammae. The rostrum (front part of the skull) is long and robust and the braincase is rounded.

Wikipedia contributors, Eremoryzomys; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T08:05:04.049726+00:00. This reference remains separate from the taxonomic record.

Identity & source status

Scientific name

Eremoryzomys polius (Osgood, 1913)

Name authority

(Osgood, 1913)

Common name

Gray Rice Rat

Rank

species

Accepted status

accepted

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Rodentia

Family

Cricetidae

Genus

Eremoryzomys

Extinction status

Recorded extant

Classification family tree

Nested taxonomic groups from the source. This is not a direct-ancestor chain, a dated evolutionary tree or a phylogenetic reconstruction.

1. domainEukaryota (Chatton, 1925) Whittaker & Margulis, 1978
2. kingdomAnimalia
3. phylumChordata
4. subphylumVertebrata
5. infraphylumGnathostomata
6. parvphylumOsteichthyes
7. megaclassTetrapoda
8. classMammalia Linnaeus, 1758
9. subclassTheria Parker & Haswell, 1897
10. infraclassEutheria Gill, 1872
11. orderRodentia Bowdich, 1821
12. suborderMyomorpha Brandt, 1855
13. superfamilyMuroidea Illiger, 1811
14. familyCricetidae Fischer, 1817
15. subfamilySigmodontinae Wagner, 1843
16. genusEremoryzomys Weksler, Percequillo & Voss, 2006
17. speciesEremoryzomys polius (Osgood, 1913)

Close classified relatives

No other member of this genus is present in the selected snapshot.

Browse 593 records assigned to Cricetidae.

Names & synonyms

Names explicitly linked to this accepted taxon in the source. Synonymy can change with revision.

Documented distribution

Source distribution statements, not a complete range map. A listed locality is not necessarily a place of origin.

Source literature & publication evidence

References attached to this source record, including nomenclatural citations where supplied. This is a selected bibliography; abbreviated citations remain in the source’s form.

1. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=972463 Source fields: Taxon.tsv dwc:namePublishedIn, Taxon.tsv dcterms:references

Origins, evidence & remaining research

Name authority and publication references document nomenclature where the source supplies it. They do not establish evolutionary origins or the earliest fossil occurrence.

Specimen-level evidence, morphology, ecological research, phylogenetic studies, a comprehensive bibliography and a located literary passage have not yet been compiled for this record. A suitable sourced image remains to be added.

Dataset citation & attribution

This exact taxon in ChecklistBank · Catalogue of Life 2026-09-11

Catalogue of Life 2026-09-11; dataset 316321; doi:10.48580/dgz5n. https://creativecommons.org/licenses/by/4.0/ . Retrieved 5 October 2026.

Stable key: col:6GG6M. Classification follows source parent identifiers. English common names may vary by region.