Umbogaulus
| Umbogaulus Temporal range: Miocene
| |
|---|---|
| Reconstruction of U. galushai. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | †Mylagaulidae |
| Genus: | †Umbogaulus Korth, 2000 |
| Species | |
| |
Umbogaulus is a genus of mylagaulid rodent from Miocene North America.[1]
Description
Crania
Umbogaulus, much like other mylagaulids, have thickened nasals, though they lack the horns of Ceratogaulus.[2] Umbogaulus has large bosses on the anterior end of the nasals, similar to the related Hesperogaulus. The premaxilla of Umbogaulus are splayed laterally, to accommodate the nasal bosses. The skull is generally heavier built than other mylagaulids, and the shape of the mandibular ramus is deep and compressed.[3] In terms of dentition, the teeth of Umbogaulus are highly adapted. The fourth premolar is considerably wider than those of related mylagaulids,[4] and all premolars are patterned with complex holes and divots. The teeth are so diagnostic that they have been used to assign one species, U. monodon, to the genus.[5] The molars of U. monodon are greatly enlarged, and there is no cementum lining the external enamel ring.[6] The post-canine diastema is short.[3]
Paleoenvironment
Umbogaulus has been found in the mid-Miocene Fort Randall Formation. Being a fluvial depositional site composed of claystone, the Fort Randall Formation was a meandering river environment during the middle Miocene. The location was highly biodiverse, with 29 named species and 300 specimens known from the area. Some species that lived alongside Umbogaulus include the canine Tomarctus, the horses Merychippus and Archaeohippus, the garter snake Thamnophis and a fragmentary proboscidean.[1][7] Umbogaulus has also been found in the Olcott Formation, another fluvial deposition site.[5][8]
Classification
Umbogaulus is currently grouped within Mylagaulinae, the more derived subfamily of mylagaulids. U. monodon was originally classified as a species of the related Mylagaulus, though dental similarity has caused it to be moved to Umbogaulus.[5][6]
References
- ^ a b Weiler, Matthew W (2010-04-01). "Paleontology and Geology of the Fort Randall formation at Feyereisen Gap, Gregory County, South Dakota". go.gale.com.
- ^ Hopkins, Samantha (2005-08-01). "The evolution of fossoriality and the adaptive role of horns in the Mylagaulidae (Mammalia: Rodentia)". Proceedings of the Royal Society. 272 (1573). doi:10.1098/r. ISSN 0962-8452. Archived from the original on 2026-02-09.
- ^ a b Cope, Edward Drinker (1881). Review of the Rodentia of the Miocene Period of North America ... United States Geological and Geographical Survey.
- ^ Korth, William W. (2013-09-01). "Mylagaulid Rodents (Mammalia: Rodentia: Mylagaulidae) from the Middle Miocene (Barstovian) of New Mexico". Annals of Carnegie Museum. 81 (4). doi:10.2992/007.081.0403.short. ISSN 0097-4463. Archived from the original on 2026-02-18.
- ^ a b c Korth, William W (2000-11-29). "Review of Miocene (Hemingfordian to Clarendonian) mylagaulid rodents (Mammalia) from Nebraska". Annals of the Carnegie Museum. v.69 (2000:Feb.-Nov.). ISSN 0097-4463. Archived from the original on 2022-10-25.
- ^ a b Matthew, William Diller; Brown, Barnum (1902-01-01). "A horned rodent from the Colorado Miocene ; with, A revision of the Mylagauli, beavers, and hares of the American Tertiary". digitallibrary.amnh.org. Retrieved 2026-02-28.
- ^ Pagnac, Darrin (2012). "Additions to the Vertebrate Faunal Assemblage of the Middle Miocene Fort Randall Formation in the Vicinity of South Bijou Hill, South Dakota, U.S.A." The Mountain Geologist. 49 (1): 19–34.
- ^ Skinner, Morris F.; Skinner, Shirley M.; Gooris, Raymond J. (1977-05-26). "Stratigraphy and biostratigraphy of late Cenozoic deposits in central Sioux County, western Nebraska. Bulletin of the AMNH ; v. 158, article 5". digitallibrary.amnh.org. Retrieved 2026-02-28.