''Paenemarmota'' is an extinct genus of

ground squirrel Ground squirrels are members of the squirrel family of rodents ( Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known ...

from

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Fossils are known from the

Blancan The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years Before Present, BP, a period of .

and

Hemphillian The Hemphillian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 10,300,000 to 4,900,000 years BP. It is usually considered ...

age from localities in

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Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...

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, and

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. At around the size of a beaver, ''Paenemarmota'' is the largest known member of the

squirrel Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

family.

Description

''Paenemarmota'' is the largest known ground squirrel and is nearly twice as large as the largest living

marmots Marmots are large ground squirrels in the genus ''Marmota'', with 15 species living in Asia, Europe, and North America. These herbivores are active during the summer, when they can often be found in groups, but are not seen during the winter, ...

. Weight estimates for ''P. barbouri'' are around on the basis of femur dimensions, or up to kg on the basis of lengths of premolars. On the basis of lengths of premolars, ''P. mexicana'' may have weighed up to , while ''P. sawrockensis'' was smaller, at up to . Although some of its features are primitive, in general morphology it resembles the ground squirrels of the genus ''

Spermophilus ''Spermophilus'' is a genus of ground squirrels in the Sciuridae, squirrel family. As traditionally defined the genus was very species-rich, ranging through Europe, Asia and North America, but this arrangement was found to be paraphyletic to ...

''. The large upper and lower fourth premolars are proportionally very large, a feature shared with modern marmots. The large fourth premolars are exceptions to the general evolutionary trend in the ground squirrels and only in ''Paenemarmota'' and the living ''Marmota'' are these teeth larger than the first molars.

References

{{Reflist Ground squirrels Miocene rodents Pliocene rodents Pleistocene rodents Prehistoric mammals of North America Prehistoric rodent genera