The Mylagaulidae or mylagaulids are an extinct clade of sciuromorph

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

s nested within the family

Aplodontiidae The family Aplodontiidae also known as Aplodontidae, Haplodontiidae or Haploodontini is traditionally classified as the sole extant family of the suborder Protrogomorpha. It may be the sister family of the Sciuridae. There are fossils from the O ...

. They are known from the

Neogene The Neogene ( ,) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period million years ago. It is the second period of th ...

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 ...

and

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. The oldest member is the Late

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

'' Trilaccogaulus montanensis'' that lived some 29

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

(Mya), and the youngest was ''

Ceratogaulus hatcheri Horned gophers are extinct rodents from the genus ''Ceratogaulus'', a member of the extinct fossorial rodent clade Mylagaulidae. ''Ceratogaulus'' is the only known rodent genus with horns, and is the smallest known horned mammal. ''Ceratogaulus' ...

''—formerly in the invalid genus "''Epigaulus"'' —which was found barely into the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58subfamilies In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zool ...

are recognized. The

taxonomy image:Hierarchical clustering diagram.png, 280px, Generalized scheme of taxonomy Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme o ...

of '' Galbreathia'' is not resolved; it might belong in Mylagaulinae, but lacks the characteristic

apomorph In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ha ...

ies. Promylagaulinae *Genus '' Crucimys'' *Genus '' Promylagaulus'' *Genus '' Trilaccogaulus'' *Genus '' Simpligaulus'' Mesogaulinae *Genus '' Mesogaulus'' - includes ''Mylagaulodon'' Mylagaulinae *Genus '' Alphagaulus'' (

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

) *Genus ''

Ceratogaulus Horned gophers are extinct rodents from the genus ''Ceratogaulus'', a member of the extinct fossorial rodent clade Mylagaulidae. ''Ceratogaulus'' is the only known rodent genus with horns, and is the smallest known horned mammal. ''Ceratogaulus' ...

'' - includes "''Epigaulus"'' *Genus '' Hesperogaulus'' *Genus ''

Mylagaulus ''Mylagaulus'' is an extinct genus of rodents in the family Mylagaulidae. ''Mylagaulus'' lived in the Americas during the middle to late Miocene. The genus contains the following species: *''M. cambridgensis'' *''M. cornusaulax'' Czaplewski, 20 ...

'' *Genus ''Notogaulus'' *Genus '' Pterogaulus'' *Genus '' Umbogaulus'' ''

incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

'' * Genus '' Galbreathia'' - basal in Mylagaulinae?

Footnotes

References

* (2005): The evolution of fossoriality and the adaptive role of horns in the Mylagaulidae (Mammalia: Rodentia). '' Proc. R. Soc. B'' 272(1573): 1705–1713. PDF fulltext
* (1997): ''Classification of Mammals Above the Species Level''. Columbia University Press. Sciuromorpha Prehistoric rodent families Chattian first appearances Zanclean extinctions Taxa named by Edward Drinker Cope {{paleo-rodent-stub