Ondatrini is a

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

of semiaquatic rodents in the family Arvicolinae. They are known as muskrats. They are related to

voles Voles are small rodents that are relatives of lemmings and hamsters, but with a stouter body; a longer, hairy tail; a slightly rounder head; smaller eyes and ears; and differently formed molar (tooth), molars (high-crowned with angular cusps i ...

and lemmings.

Classification

It contains two extant species, each in their own genus, both of which are native to

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

: * Genus '' Neofiber'' ** Round-tailed muskrat, ''N. alleni'' * Genus '' Ondatra'' ** Muskrat, ''O. zibethicus'' Of these, the muskrat (''O. zibethicus'') is found throughout North America aside from the warmer or drier regions, and has been introduced to

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

. The round-tailed muskrat (''N. alleni'') is only found in

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

and adjacent Georgia, just outside of the range of ''O. zibethicus''. Some authorities place both genera in different tribes (Ondatrini for ''Ondatra'', Neofibrini for ''Neofiber''), but the American Society of Mammalogists places both in Ondatrini, and some molecular evidence supports a close relation between both genera. Some phylogenetic evidence indicates that Balkan snow vole (''Dinaromys bogdanovi'') may also be a member of the Ondatrini, but this is uncertain and it is still classified in the Pliomyini by the ASM.

Evolution

Ondatrini likely descends from a lineage of Siberian

that invaded North America about 5 million years ago. The earliest fossils from this tribe are of fossil ''Ondatra'' from the early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Ogmodontomys'' and '' Cosomys'', both from North America, are likely also members of this tribe. The Plio-Pleistocene fossil taxa '' Dolomys'', '' Pliomys'' (of the tribe Pliomyini) and '' Kislangia'' from

have also been classified in this group by some authorities, but this has been disputed. A 2021 phylogenetic study found Ondatrini to form the

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to the Dicrostonychini (defined as including the members of both Dicrostonychini ''sensu stricto'' and Phenacomyini).

References

{{Taxonbar, from= Q16975883 Taxa named by John Edward Gray Voles and lemmings Mammal tribes