| Uintasorex | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Plesiadapiformes |
| Family: | † Microsyopidae |
| Subfamily: | † Uintasoricinae |
| Genus: | † Uintasorex |
| Type species | |
| †Uintasorex parvulus Matthew, 1909 | |
| Species | |
| |
Uintasorex is a genus of primate which lived in North America during the Eocene epoch. [1] Fossils belonging to Uintasorex have been dated to the Bridgerian and Uintan stages, roughly 50.3 to 42 million years ago.
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.
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 enamel allowed Uintasorex teeth to endure long enough after death to undergo fossilization, and much of what is known about the genus comes from dental remains. A defining feature of microsyopids is a distinctive twinning between the hypoconulid-entoconid cusps of the molars, and within the family this feature is most developed in Uintasorex. Well-defined crests on the upper and lower molars suggest the presence of interradicular fibers, a trait seen in other uintasoricinids. [4] Uintasorex sp. is distinguished from U. parvulus by a larger tooth size.
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.
Uintasorex was described by William Diller Matthew in 1909 and assigned to Apatemyidae because of its resemblance to Apatemys , Phenacolemur , Trogolemur , and some other fossil tarsiers. [4] William King Gregory supported this classification when he proposed the order Soricomorpha in 1910, as did Edward Troxell in June 1923. [7] In the coming decades, however, the genus was shuffled among a number of families including Anaptomorphidae (Gazin 1958; Robinson 1966, 1968; Simons 1963; Simpson 1940, 1959); Chiromyidae (Teilhard 1922); Plesiadapidae (Scholosser 1923, Abel 1931); and Primates, incertae sedis (Simpson 1945). [2] For much of the 20th century, there was much controversy over whether microsyopsids belonged to Primates or Insectivora, but the latter is now considered a wastebasket taxon. [8]
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.
Branisella is an extinct genus of New World monkey from the Salla Formation of what is now Bolivia during the Late Oligocene, approximately 26 million years ago (Deseadan), comprising only the species Branisella boliviana. Together with the Peruvian genus Canaanimico, it is the oldest fossil New World monkey discovered.
Indopithecus giganteus is an extinct species of large ape that lived in the late Miocene of the Siwalik Hills in northern India. Although frequently assigned to the more well-known genus Gigantopithecus, recent authors consider it to be a distinct genus in its own right.
Altanius is a genus of extinct primates found in the early Eocene of Mongolia. Though its phylogenetic relationship is questionable, many have placed it as either a primitive omomyid or as a member of the sister group to both adapoids and omomyids. The genus is represented by one species, Altanius orlovi, estimated to weigh about 10–30g from relatively well-known and complete dental and facial characteristics.
Catopithecus is an early catarrhine fossil. It is known from more than 16 specimens of a single species, Catopithecus browni, found in the Jebel Qatrani Formation of the Fayum Province, Egypt. The Jebel Qatrani Formation has been divided into two main faunal zones based on the fact that the fauna found in the lower portion of the quarry appear to be more primitive than those found in the upper section. The upper zone has been dated to older than 31 ± 1 myr based on the dating of a basalt layer that lies immediately above the formation and Nicolas Steno’s Law of Superposition. The lower zone contains the late Eocene green shale unit called Locality-41 (L-41) in which all the specimens of Catopithecus browni have been found. The relative dating of L-41 based on paleomagnetic correlations places it at 36 Myr according to Simons et al (1999), but Seiffert (2006) suggests this should be revised to 34.8-33.9 Myr.
Lufengpithecus is an extinct genus of ape in the subfamily Ponginae. It is known from thousands of dental remains and a few skulls and probably weighed about 50 kg (110 lb). It contains three species: L. lufengensis, L. hudienensis and L. keiyuanensis. Lufengpithecus lufengensis is from the Late Miocene found in China, named after the Lufeng site and dated around 6.2 Ma. It is the latest Miocene fossil ape that has been discovered in the entire world. Some researchers believe that genus Lufengpithecus could be an ancestor to African apes.
Dinopithecus is an extinct genus of very large primate closely related to the baboon that lived during the Pliocene to the Pleistocene epoch of South Africa and Ethiopia. It was named by British paleontologist Robert Broom in 1937. The only species currently recognized is Dinopithecus ingens, as D. quadratirostris has been reassigned to the genus Soromandrillus. It is known from several infilled cave sites in South Africa, all of early Pleistocene age, including Skurweberg, Swartkrans, and Sterkfontein.
Rooneyia viejaensis is a relatively small primate belonging to the extinct monotypic genus Rooneyia. Rooneyia viejaensis is known from the North American Eocene of the Sierra Vieja of West Texas; the species is only known from the type specimen. The lack of additional fossils at this time makes it difficult to hypothesize where and how Rooneyia may have evolved. The minimal wear upon the molar teeth of the specimen has led to the assumption that the type specimen is that of a young adult. Rooneyia does not consistently fall within any one group of fossil or extant primates.
Biretia is an extinct genus of Old World monkey belonging to the extinct family Parapithecidae. Fossils are found from Late Eocene strata in Egypt.
Solimoea acrensis is a prehistoric ateline monkey from the Late Miocene Solimões Formation of Brazil. It is the only known species of the genus Solimoea.
Anaptomorphinae is a pre-historic group of primates known from Eocene fossils in North America and Europe and later periods of Paleocene Asia, and are a sub-family of omomyids. The anaptomorphines is a paraphyletic group consisting of the two tribes Trogolemurini and Anaptomorphini. Anaptomorphine radiation in Wyoming, one of the most detailed records of changes within populations and between species in the fossil record, has provided remarkable evidence of transitional fossils.
The Wasatch Formation (Tw) is an extensive highly fossiliferous geologic formation stretching across several basins in Idaho, Montana Wyoming, Utah and western Colorado. It preserves fossils dating back to the Early Eocene period. The formation defines the Wasatchian or Lostcabinian, a period of time used within the NALMA classification, but the formation ranges in age from the Clarkforkian to Bridgerian.
The Bridger Formation is a geologic formation in southwestern Wyoming. It preserves fossils dating back to the Bridgerian and Uintan stages of the Paleogene Period. The formation was named by American geologist Ferdinand Vandeveer Hayden for Fort Bridger, which had itself been named for mountain man Jim Bridger. The Bridger Wilderness covers much of the Bridger Formation's area.
Sivaladapis is a genus of adapiform primate that lived in Asia during the middle Miocene.
Saimiri fieldsi is an extinct species of New World monkey in the genus Saimiri from the Middle Miocene. Its remains have been found at the Konzentrat-Lagerstätte of La Venta in the Honda Group of Colombia.
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Ignacius is a genus of extinct mammal from the early Cenozoic era. This genus is present in the fossil record from around 62-33 Ma. The earliest known specimens of Ignacius come from the Torrejonian of the Fort Union Formation, Wyoming and the most recent known specimens from Ellesmere Island in northern Canada. Ignacius is one of ten genera within the family Paromomyidae, the longest living family of any plesiadapiforms, persisting for around 30 Ma during the Paleocene and Eocene epochs. The analyses of postcranial fossils by paleontologists suggest that members of the family Paromomyidae, including the genus Ignacius, most likely possessed adaptations for arboreality.
Canaanimico is an extinct genus of medium-sized New World monkeys from the Late Oligocene fossiliferous fluvio-lacustrine Chambira Formation of the Ucayali Basin in Amazonian Peru. The genus was described by Marivaux et al. in 2016 and the type species is C. amazonensis.
Apatemys is a member of the family Apatemyidae, an extinct group of small and insectivorous placental mammals that lived in the Paleogene of North America, India, and Europe. While the number of genera and species is less agreed upon, it has been determined that two apatemyid genera, Apatemys and Sinclairella, existed sequentially during the Eocene in North America. The genus Apatemys, living as far back as 50.3 million years ago (mya), existed through part of the Wasatchian and persisted through the Duchesnean, and Sinclairella followed, existing from the Duchesnean through the Arikareean. Examinations of specimens belonging to the genus Apatemys suggest adaptations characteristic of arboreal mammals.
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