NATURAL HISTORY · CATALOGUE RECORD
Mesopotamian Fat-tailed Opossum
Thylamys citellus (Thomas, 1912)
Source-backed taxonomic record
Accepted species in Catalogue of Life’s 11 September 2026 base release. This preserves the source classification and available supporting data; it is not a completed species monograph.
Mesopotamian Fat-tailed Mouse Opossum (Thylamys citellus)
Pablo H Capovilla · CC BY-SA 4.0 · Image sourceProvider-generated thumbnail requested at 800 pixels; no local editing Local WebP display rendition; resized without cropping.
Open encyclopedia reference
Thylamys citellus, commonly known as the Mesopotamian fat-tailed opossum (or comadreja litoraleña in Spanish), is a small, nocturnal marsupial belonging to the family Didelphidae. Native to the Mesopotamian region of South America, this species was historically grouped as a subspecies or synonym of the common fat-tailed mouse opossum (Thylamys pusillus), but genetic and morphological revisions have firmly established it as its own distinct, monotypic species.
Wikipedia contributors, Thylamys citellus; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T12:17:13.161647+00:00. This reference remains separate from the taxonomic record.
Identity & source status
- Scientific name
- Thylamys citellus (Thomas, 1912)
- Name authority
- (Thomas, 1912)
- Common name
- Mesopotamian Fat-tailed Opossum
- Rank
- species
- Accepted status
- accepted
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Mammalia
- Order
- Didelphimorphia
- Family
- Didelphidae
- Genus
- Thylamys
- 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.
- domainEukaryota (Chatton, 1925) Whittaker & Margulis, 1978
- kingdomAnimalia
- phylumChordata
- subphylumVertebrata
- infraphylumGnathostomata
- parvphylumOsteichthyes
- megaclassTetrapoda
- classMammalia Linnaeus, 1758
- subclassTheria Parker & Haswell, 1897
- infraclassMetatheria Huxley, 1880
- orderDidelphimorphia Gill, 1872
- familyDidelphidae Gray, 1821
- subfamilyDidelphinae Gray, 1821
- tribeThylamyini Hershkovitz, 1992
- genusThylamys Gray, 1843
- speciesThylamys citellus (Thomas, 1912)
Close classified relatives
These entries share the source’s genus, Thylamys. They are not necessarily the closest relatives established by molecular evidence.
| Species | Classification | Source status |
|---|---|---|
| Dwarf Fat-tailed Mouse OpossumThylamys velutinus (Wagner, 1842) | DidelphidaeChordata | Accepted speciesRecorded extant |
| Buff-bellied Fat-tailed Mouse OpossumThylamys venustus (Thomas, 1902) | DidelphidaeChordata | Accepted speciesRecorded extant |
| Elegant Fat-tailed Mouse OpossumThylamys elegans (Waterhouse, 1839) | DidelphidaeChordata | Accepted speciesRecorded extant |
| Karimi's Fat-tailed Mouse OpossumThylamys karimii (Petter, 1968) | DidelphidaeChordata | Accepted speciesRecorded extant |
| Pallid Fat-tailed OpossumThylamys pallidior (Thomas, 1902) | DidelphidaeChordata | Accepted speciesRecorded extant |
| Argentine Fat-tailed Mouse OpossumThylamys sponsorius (Thomas, 1921) | DidelphidaeChordata | Accepted speciesRecorded extant |
| Tate's Fat-tailed Mouse OpossumThylamys tatei (Handley, 1957) | DidelphidaeChordata | Accepted speciesRecorded extant |
Names & synonyms
Names explicitly linked to this accepted taxon in the source. Synonymy can change with revision.
| Recorded name | Source status |
|---|---|
| Marmosa citella Thomas, 1912 Thomas, 1912 | synonym |
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.
- https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=1255452 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.
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:DTCSQ. Classification follows source parent identifiers. English common names may vary by region.