The Raigón Formation is a geologic formation in

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

dated between the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Middle Pleistocene The Chibanian, more widely known as the Middle Pleistocene (its previous informal name), is an Age (geology), age in the international geologic timescale or a Stage (stratigraphy), stage in chronostratigraphy, being a division of the Pleistocen ...

Overview

In 1966, Uruguayan geologists Héctor Goso and Jorge Bossi defined the Raigón Formation, which they subdivided into the San José

Member Member may refer to: * Military jury, referred to as "Members" in military jargon * Element (mathematics), an object that belongs to a mathematical set * In object-oriented programming, a member of a class ** Field (computer science), entries in ...

(the same as Francis and Mones' San José Formation) below and the San Bautista Member above. In 1988,

Álvaro Mones Álvaro Jaime Mones Sibillotte (born 7 August 1942 in Montevideo) is a Uruguayan biologist and paleontologist.Uruguaya ...

identified

Lower Pleistocene The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span th ...

levels in the San José Member. In 2002, American geologist H. McDonald and Uruguayan paleontologist Daniel Perea suggested the formation may represent a wide timespan from the Montehermosan all the way to the Ensenadan. A notable finding was ''J. monesi'', recovered ''in situ'' from a boulder originating in the San José Member. The boulder is made up of

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility. Although its permeabil ...

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone and shale. Most of the particles of which the stone is composed are less than and are too small to ...

, and medium- grained and medium-to- conglomeratic

psammite Psammite (Greek: ''psammitēs'' "(made) from sand", from ''psammos'' "sand") is a general term for sandstone. It is equivalent to the Latin-derived term areniteU.S. Bureau of Mines Staff (1996) ''Dictionary of Mining, Mineral, & Related Terms.'' ...

(a type of

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

) intercalated with siltstone.

Fossil content

The following fossils have been reported from the formation: * '' Charruatoxodon'' * ''

Desmodus draculae ''Desmodus draculae'' is an extinct species of vampire bat that inhabited Central and South America during the Pleistocene, and possibly the early Holocene. It was 30% larger than its living relative the common vampire bat (''Desmodus rotund ...

'' * ''

Trigodon ''Trigodon'' is an extinct genus of the family Toxodontidae, a large bodied notoungulate which inhabited South America during the Late Miocene to Early Pliocene ( Mayoan to Montehermosan in the SALMA classification), living from 11.61 to 4.0 ...

'' sp. * '' Catonyx tarijensis'' * '' Pronothrotherium figueirasi'' * ''

Glyptodon ''Glyptodon'' (; ) is a genus of glyptodont, an extinct group of large, herbivorous armadillos, that lived from the Pliocene, around 3.2 million years ago, to the early Holocene, around 11,000 years ago, in South America. It is one of, if not th ...

'' * ''

Plaxhaplous ''Plaxhaplous'' was a genus of glyptodont, an extinct relative of the modern armadillo. It lived in the Pleistocene epoch. The type species is ''Plaxhaplous canaliculatus''. ''Plaxhaplous canaliculatus'' fossils were found in Argentina, near Luj ...

'' * '' Giganhinga'' * ''

Josephoartigasia monesi ''Josephoartigasia'' is an extinct genus of enormous dinomyid rodent from the Early Pliocene to Early Pleistocene of Uruguay. The only living member of Dinomyidae is the pacarana. ''Josephoartigasia'' is named after Uruguayan national hero Jo ...

'' * '' Pronothrotherium''''Pronothrotherium''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org * ''Uruguayurus'' * ''Cardiatherium talicei'' * '' Uruguayodon'' * ''

Platygonus ''Platygonus'' ("flat head" in reference to the straight shape of the forehead) is an extinct genus of herbivorous peccaries of the family Tayassuidae, endemic to North and South America from the Miocene through Pleistocene epochs (10.3 millio ...

'' sp. *

Phorusrhacinae Phorusrhacids, colloquially known as terror birds, are an extinct family of large carnivorous, mostly flightless birds that were among the largest apex predators in South America during the Cenozoic era. Their definitive fossil records range from ...

(possibly ''

Devincenzia ''Devincenzia'' is an extinct genus of giant flightless predatory birds in the family (biology), family Phorusrhacidae or "terror birds" that lived during the Miocene, Early Miocene (Deseadan) Fray Bentos Formation of Uruguay, Miocene, Late Mioc ...

'') *

Homotherini Homotherini (Machairodontini) is a tribe (or subtribe) of saber-toothed cats of the family Felidae (true cats). The tribe is commonly known as scimitar-toothed cats. These saber-toothed cats were endemic to North America, Europe, Asia, Africa, a ...

- previously assigned to cf. ''

Xenosmilus ''Xenosmilus'' is an extinct genus of homotherin machairodontine (saber-toothed cat) that roamed the North America from the Early Pleistocene. The type species of the genus, ''X. hodsonae,'' is known from Early Pleistocene deposits in Florida ...

'' sp., but its generic attribution is uncertain.

References

Geologic formations of Uruguay Fossiliferous stratigraphic units of South America Paleontology in Uruguay Montehermosan Huayquerian Miocene Uruguay Siltstone formations {{SouthAm-geologic-formation-stub

Overview

Fossil content

See also

References