''Saimiri fieldsi'' is an extinct

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

New World monkey New World monkeys are the five families of primates that are found in the tropical regions of Mexico, Central and South America: Callitrichidae, Cebidae, Aotidae, Pitheciidae, and Atelidae. The five families are ranked together as the Ceboid ...

in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

'' Saimiri'' (squirrel monkeys) from the Middle Miocene (

Laventan The Laventan ( es, Laventense) age is a period of geologic time (13.8 to 11.8 Ma) within the Middle Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Colloncuran and precedes the ...

in the

South American land mammal age The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as age ...

s; 13.8 to 11.8 Ma). Its remains have been found at the Konzentrat-Lagerstätte of

La Venta La Venta is a pre-Columbian archaeological site of the Olmec civilization located in the present-day Mexican state of Tabasco. Some of the artifacts have been moved to the museum "Parque - Museo de La Venta", which is in nearby Villahermos ...

in the Honda Group of Colombia.''Saimiri fieldsi''
at

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.org

Description

More than 200 fossil specimens of ''Saimiri fieldsi'', formerly described as ''Neosaimiri fieldsi'', were recovered from the Middle Miocene Villavieja Formation, that has been dated to the

, about 13 to 12 Ma, during fieldwork in 1989 and 1990. The holotype of ''Saimiri'' which was recovered in 1949, is an incomplete mandible and dentition, while later materials include not only lower but also upper dentition and deciduous teeth.Takai, 1994 The fossils were differentiated from ''Saimiri'' in the proportions of tooth series, with smaller

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, w ...

s and larger molars; in the structure of the P4

hypocone A cusp is a pointed, projecting, or elevated feature. In animals, it is usually used to refer to raised points on the crowns of teeth. The concept is also used with regard to the leaflets of the four heart valves. The mitral valve, which has two ...

; and in the morphology of M1-2, which shows strong polymorphism. Also the species has been described as more robust than the extant ''Saimiri''.Defler, 2004, p.31 This led researchers to identify an independent genus, ''Neosaimiri'', as a Middle Miocene ancestor of ''Saimiri''. ''Laventiana annectens'', which was recovered at the same location in 1988, has been concluded to be a junior synonym of ''Neosaimiri'', placed later in the same genus as '' Saimiri annectens''. The lower molars of the fossil ''Saimiri'' resemble those of '' Dolichocebus'', from

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

.Tejedor, 2013, p.24 An estimated body mass of has been suggested for ''Saimiri fieldsi''.Pérez et al., 2013, p.9Silvestro et al., 2017, p.14

Evolution

The evolutionary split in New World monkeys between ''

Cebus Gracile capuchin monkeys are capuchin monkeys in the genus ''Cebus''. At one time all capuchin monkeys were included within the genus ''Cebus''. In 2011, Jessica Lynch Alfaro ''et al.'' proposed splitting the genus between the robust capuchin ...

'' and ''Saimiri'' has been estimated at 16.7 Ma.Takai et al., 2001, p.304

Habitat

The

Lagerstätte A Lagerstätte (, from ''Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These for ...

of the Honda Group, and more precisely the "Monkey Beds", are the richest site for fossil primates in South America.Rosenberger & Hartwig, 2001, p.3 It has been argued that the monkeys of the Honda Group were living in habitat that was in contact with the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technolog ...

and Orinoco Basins, and that La Venta itself was probably seasonally dry forest.Lynch Alfaro et al., 2015, p.520 Other fossil New World primates uncovered from the same locality are '' Aotus dindensis'', '' Cebupithecia'', '' Mohanamico'' and '' Stirtonia tatacoensis''.Luchterhand et al., 1986, p.1753Wheeler, 2010, p.133Setoguchi et al., 1986, p.762

References

Bibliography

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Description

Evolution

Habitat

See also

References

Bibliography

Further reading