Editing New World monkey (section)

== Evolutionary history ==

About 40 million years ago, the [[Simiiformes]] infraorder split into the parvorders Platyrrhini (New World monkeys) and [[Catarrhini]] (apes and [[Old World monkey]]s) somewhere on the African continent.<ref name=PQ>{{cite book | title = Primates in Question | publisher = Smithsonian Institution Press | year = 2003 | author1 = Robert W. Shumaker | author2 = Benjamin B. Beck | name-list-style = amp | isbn = 978-1-58834-176-1 | url-access = registration | url = https://archive.org/details/primatesinquesti00shum}}</ref> Platyrrhini are currently conjectured to have dispersed to [[South America]] on a [[Oceanic dispersal|raft of vegetation]] across the Atlantic Ocean during the [[Eocene]] epoch, possibly via several intermediate now submerged islands. Several other groups of animals made the same journey across the Atlantic, notably including [[caviomorph]] rodents.<ref name=":0">{{cite book |last1=Oliveira |first1=Felipe Bandoni de |chapter=Paleogeography of the South Atlantic: a Route for Primates and Rodents into the New World? |title=South American Primates |pages=55–68 |location=New York |publisher=Springer |isbn=978-0-387-78704-6 |last2=Molina |first2=Eder Cassola |last3=Marroig |first3=Gabriel|year=2009 |doi=10.1007/978-0-387-78705-3_3}}</ref><ref>{{cite book |last=Defler |first=Thomas |chapter=Platyrrhine Monkeys: The Fossil Evidence |date=2019 |title=History of Terrestrial Mammals in South America |series=Topics in Geobiology |volume=42 |pages=161–184 |place=Cham |publisher=Springer International |doi=10.1007/978-3-319-98449-0_8 |isbn=978-3-319-98448-3 |s2cid=91938226}}</ref> At the time the New World monkeys dispersed to South America, the [[Isthmus of Panama]] had not yet formed, so [[ocean current]]s, unlike today, favoured westward dispersal, the climate was quite different, and the width of the Atlantic Ocean was less than the present {{convert|2800|km|mi|abbr=on}} width by about a third (possibly {{convert|1000|km|mi|-2|abbr=on}} less, based on the current estimate of the Atlantic [[mid-ocean ridge formation process]]es spreading rate of {{Convert|25|mm/year|in/year|0|abbr=}}).<ref name=":0" />

The non-platyrrhini ''[[Ucayalipithecus]]'' of Amazonian Peru who might have rafted across the Atlantic between ~35–32 million years ago, are nested within the extinct [[Parapithecoidea]] from the [[Eocene]] of Afro-Arabia, suggesting that there were at least two separate dispersal events of primates to South America,<ref>{{cite journal |last1=Seiffert |first1=Erik R. |last2=Tejedor |first2=Marcelo F. |last3=Fleagle |first3=John G.|last4=Novo |first4=Nelson M. |last5=Cornejo |first5=Fanny M. |last6=Bond |first6=Mariano |last7=de Vries |first7=Dorien |last8=Campbell Jr. |first8=Kenneth E. |year=2020 |title=A parapithecid stem anthropoid of African origin in the Paleogene of South America |journal=[[Science (journal)|Science]] |volume=368 |issue=6487 |pages=194–197 |doi=10.1126/science.aba1135 |pmid=32273470 |bibcode=2020Sci...368..194S |s2cid=215550773 }}</ref> ''[[Parvimico]]'' and ''[[Perupithecus]]'' from Peru appear to be at the base of the Platyrrhini,<ref>{{Cite bioRxiv |last1=Vries|first1=Dorien de|last2=Beck|first2=Robin M. D.|date=2021-10-22|title=Total evidence tip-dating phylogeny of platyrrhine primates and 27 well-justified fossil calibrations for primate divergences |language=en |biorxiv=10.1101/2021.10.21.465342}}</ref> as are ''[[Szalatavus]]'', ''[[Lagonimico]]'', and ''[[Canaanimico]]''.<ref name=Silvestro/>

Possible evidence for a third transatlantic dispersal event comes from a fossil molar belonging to ''[[Ashaninkacebus simpsoni]]'', which has strong affinities with stem [[Simian|anthropoid]] primates of South Asian origin, the [[Eosimiidae]].<ref>{{cite journal |last1=Marivaux |first1=Laurent |title=An eosimiid primate of South Asian affinities in the Paleogene of Western Amazonia and the origin of New World monkeys |journal=Proceedings of the National Academy of Sciences |date=July 3, 2023 |volume=120 |issue=28 |pages=e2301338120 |doi=10.1073/pnas.2301338120 |pmid=37399374 |pmc=10334725 |bibcode=2023PNAS..12001338M }}</ref>

The chromosomal content of the ancestor species appears to have been 2n = 54.<ref name="deOliveira2012">de Oliveira EH, Neusser M, Müller S (2012). "Chromosome evolution in New World Monkeys (Platyrrhini)." ''Cytogenetic and Genome Research'' https://doi.org/10.1159/000339296</ref> In extant species, the 2n value varies from 16 in the [[titi monkey]] to 62 in the [[woolly monkey]].

A [[Bayesian inference in phylogeny|Bayesian]] estimate of the most recent common ancestor of the extant species has a 95% [[credible interval]] of {{Ma|27}}-{{Ma|31}}.<ref name=Perez2013>Perez SI, Tejedor MF, Novo NM, Aristide L (2013) "Divergence times and the evolutionary radiation of New World monkeys (Platyrrhini, Primates): An analysis of fossil and molecular Data". ''PLoS One'' 8(6):e68029.</ref>