The Mylagaulidae or mylagaulids are a prehistoric family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of sciuromorph

Sciuromorpha

The term Sciuromorpha has referred to numerous groups of rodents, but the only family common to all variations is the Sciuridae, the squirrels. Most definitions also include the Mountain Beaver....

 rodent

Rodent

Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

s. They are known from the Neogene

Neogene

The Neogene is a geologic period and system in the International Commission on Stratigraphy Geologic Timescale starting 23.03 ± 0.05 million years ago and ending 2.588 million years ago...

 of North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

. The oldest member is the Late Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 Trilaccogaulus montanensis from living some 29 mya (million years ago), and the youngest was Ceratogaulus hatcheri - formerly in Epigaulus - which was found barely into the Pliocene

Pliocene

The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

, some 5 mya.

Systematics

Three subfamilies are recognized. The taxonomy

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 of Galbreathia is not resolved; it might belong in Mylagaulinae but lacks the characteristic apomorphies.

Promylagaulinae

• Genus Crucimys
• Genus Promylagaulus
• Genus Trilaccogaulus

Mesogaulinae

• Genus Mesogaulus - includes Mylagaulodon

Mylagaulinae

• Genus Alphagaulus (paraphyletic)
• Genus Ceratogaulus - includes Epigaulus
• Genus Hesperogaulus
• Genus Mylagaulus
• Genus Pterogaulus
• Genus Umbogaulus

incertae sedis

Incertae sedis

, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

• Genus Galbreathia - basal in Mylagaulinae?