Uintasorex
Uintasorex | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Plesiadapiformes |
Family: | †Microsyopidae |
Subfamily: | †Uintasoricinae |
Genus: | †Uintasorex |
Type species | |
†Uintasorex parvulus Matthew, 1909
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Species | |
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Uintasorex is a genus of
, roughly 50.3 to 42 million years ago.Etymology
The genus name derives from the Latin word for "shrew" (-sorex), combined with a reference to the Uinta Mountains where the holotype fossils were discovered.
Description
Like other microsyopids, the most discussed feature of Uintasorex is its extremely tiny size. It is thought to have been smaller than the mouse lemur, the smallest extant primate.[2] Uintasorex was once thought to have been insectivorous based on its body mass and the principle of Kay's threshold,[2] which suggested that primates lighter than 500 grams tend to be insectivorous and those heavier than 500 grams are folivorous,[3] but the validity of this rule has come into question and can no longer be considered valid.
The hardness of their
Discovery and species
The first specimen of Uintasorex (YPM VP 013519) was discovered by John W. Chew and L. Lamothe in July 1874.[5] The fossils were uncovered at the Henry's Fork locality of the Bridger Formation in Sweetwater County, Wyoming.[4] Other specimens of Uintasorex have been recovered from the Bridger Formation at the Hypsodus Hill, Twin Buttes, and Tabernacle Butte locality, as well as the Friars Formation, Green River Formation, Tepee Trail Formation, and Wasatch Formation.
The type species of Uintasorex is U. parvulus. Other species include U. montezumicus[2] and an as-yet unnamed species tenatively known as "Uintasorex sp.".[4] U. montezumicus is defined by UCMP 104179, a tooth recovered from the Solstice Hill locality of the Friars Formation in California.[6] Uintasorex sp. is based on a collection of tiny Uintasorex teeth recovered from the Green River Formation in Utah which went uncatalogued in the archives of the Carnegie Museum of Natural History until they were rediscovered and described by Charles L. Gazin in 1958.
Classification
Uintasorex was described by
In 1969 two genera, Uintasorex and Niptomomys, were reassigned by anthropologist Frederick Szalay to Uintasoricinae, a new subfamily within Microsyopidae.[4] The suggestion that Uintasorex had been a microsyopid was first privately put forward by Donald E. Russell in 1965, and the idea that the species represented a distinct family from the other taxa it was being grouped received its first mention as a footnote in a 1958 paper by Charles L. Gazin. The relationship was formally established when Szalay assigned previously-unstudied dental fragments to specimen AMNH 55664, Uintasorex teeth collected from the Tabernacle Butte locality in Wyoming, identifying the distinct dental features that are now considered ubiquitous in the family Uintasoricinae. Alveojunctus, Berruvius, Navajovius, and Palenochtha have also been included in Uintasoricinae.
References
- ^ "Uintasorex". Fossilworks.org. Retrieved 17 December 2021.
- ^ a b c d Gunnell, Gregg F. (30 November 1989). "Evolutionary history of Microsyopoidea (Mammalia, ?Primates) and the relationship between Plesiadapiformes and Primates" (PDF). University of Michigan Papers on Paleontology. 27. Retrieved 24 November 2020.
- ISBN 9780120586707. Retrieved 24 November 2020.
- ^ a b c d e Szalay, Frederick (10 March 1969). "Uintasoricinae, A New Subfamily of Early Tertiary Mammals (?Primates)". American Museum Novitates (2363): 1–36. Retrieved 24 November 2020.
- ^ "Uintasorex parvulus Matthew, 1909". collections.peabody.yale.edu. Yale Peabody Museum of Natural History. Retrieved 24 November 2020.
- ^ "Uintasorex montezumicus". Fossilworks.org. Retrieved 17 December 2021.
- . Retrieved 24 November 2020.
- S2CID 21132866. Retrieved 24 November 2020.