Great American Interchange

File:Thylacosmilus Amerika.jpg, a sparassodont]]

After the late Mesozoic breakup of Gondwana, South America spent most of the Cenozoic era as an island continent whose "splendid isolation" allowed its fauna to evolve into many forms found nowhere else on Earth, most of which are now extinct.{{cite book |last=Simpson |first=George Gaylord |author-link=George Gaylord Simpson |title=Splendid Isolation: The Curious History of South American Mammals |publisher=Yale University Press |year=1980 |location=New Haven |url=https://archive.org/details/splendidisolatio0000simp |url-access=registration |isbn=978-0-300-02434-0 |oclc=5219346}} Its endemic mammals initially consisted primarily of metatherians (marsupials and sparassodonts), xenarthrans, and a diverse group of native ungulates known as the Meridiungulata: notoungulates (the "southern ungulates"), litopterns, astrapotheres, pyrotheres and xenungulates.{{refn|group=n|During the Eocene, astrapotheres{{cite journal |last1=Bond |first1=M. |last2=Kramarz |first2=A. |last3=MacPhee |first3=R. D. E. |last4=Reguero |first4=M. |title=A new astrapothere (Mammalia, Meridiungulata) from La Meseta Formation, Seymour (Marambio) Island, and a reassessment of previous records of Antarctic astrapotheres |year=2011 |journal=American Museum Novitates |issue=3718 |pages=1–16 |url=http://digitallibrary.amnh.org/dspace/bitstream/2246/6118/1/N3718.pdf |doi=10.1206/3718.2 |hdl=11336/98139 |s2cid=58908785}} and litopterns{{cite book |author1=M. Bond |author2=M. A. Reguero |author3=S. F. Vizcaíno |author4=S. A. Marenssi |year=2006 |chapter=A new 'South American ungulate' (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula |editor1=J. E. Francis |editor2=D. Pirrie |editor3=J. A. Crame |title=Cretaceous-tertiary high-latitude palaeoenvironments: James Ross Basin, Antarctica |journal=Geological Society, London, Special Publications |publisher=The Geological Society of London |volume=258 |issue=1 |pages=163–176 |doi=10.1144/GSL.SP.2006.258.01.12 |contribution-url=https://www.researchgate.net/publication/249551916_A_new_%27South_American_ungulate%27_Mammalia_Litopterna_from_the_Eocene_of_the_Antarctic_Peninsula |bibcode=2006GSLSP.258..163B |s2cid=140546667}}{{cite journal |last1=Gelfo |first1=J. N. |last2=Mörs |first2=T. |last3=Lorente |first3=M. |last4=López |first4=G. M. |last5=Reguero |first5=M. |last6=O'Regan |first6=H. |title=The oldest mammals from Antarctica, early Eocene of the La Meseta Formation, Seymour Island |journal=Palaeontology |volume=58 |issue=1 |date=2014-07-16 |pages=101–110 |doi=10.1111/pala.12121 |s2cid=140177511 |url=http://urn.kb.se/resolve?urn=urn:nbn:se:nrm:diva-922|doi-access=free }} were also present in Antarctica.}}{{refn|group=n|Sequencing of collagen from fossils of one recently extinct species each of notoungulates and litopterns has indicated that these orders comprise a sister group to the perissodactyls.{{cite journal |last1=Welker |first1=F. |last2=Collins |first2=M. J. |last3=Thomas |first3=J. A. |last4=Wadsley |first4=M. |last5=Brace |first5 =S. |last6=Cappellini |first6=E. |last7=Turvey |first7=S. T. |last8=Reguero |first8=M. |last9=Gelfo |first9=J. N. |last10=Kramarz |first10=A. |last11=Burger |first11=J. |last12=Thomas-Oates |first12=J.|author12-link=Jane Thomas-Oates |last13=Ashford |first13=D. A. |last14=Ashton |first14=P. D. |last15=Rowsell |first15=K. |last16=Porter |first16=D. M. |last17=Kessler |first17=B. |last18=Fischer |first18=R. |last19=Baessmann |first19=C. |last20=Kaspar |first20=S. |last21=Olsen |first21=J. V. |last22=Kiley |first22=P. |last23=Elliott |first23=J. A. |last24=Kelstrup |first24=C. D. |last25=Mullin |first25=V. |last26=Hofreiter |first26=M. |last27=Willerslev |first27=E. |last28=Hublin |first28=J.-J. |last29=Orlando |first29=L. |last30=Barnes |first30=I. |last31=MacPhee |first31=R. D. E.|author2-link=Matthew Collins (academic)|author17-link=Benedikt Kessler|author27-link=Eske Willerslev |title=Ancient proteins resolve the evolutionary history of Darwin's South American ungulates |journal=Nature |date=2015-03-18 |issn=0028-0836 |doi=10.1038/nature14249 |volume=522 |issue=7554 |pages=81–84 |pmid=25799987 |bibcode=2015Natur.522...81W |hdl=11336/14769 |s2cid=4467386 |url=http://eprints.whiterose.ac.uk/91438/1/Welker_postprint.docx|hdl-access=free }}{{cite journal |last=Buckley |first=M. |title=Ancient collagen reveals evolutionary history of the endemic South American 'ungulates' |journal=Proceedings of the Royal Society B: Biological Sciences |volume=282 |issue=1806 |date=2015-04-01 |pages=20142671 |doi=10.1098/rspb.2014.2671 |pmid=25833851 |pmc=4426609}} Mitochondrial DNA obtained from Macrauchenia corroborates this and gives an estimated divergence date of 66 Ma ago.{{cite journal |last1=Westbury |first1=M. |last2=Baleka |first2=S. |last3=Barlow |first3=A. |last4=Hartmann |first4=S. |last5=Paijmans |first5=J. L. A. |last6=Kramarz |first6=A. |last7=Forasiepi |first7=A. M. |last8=Bond |first8=M. |last9=Gelfo |first9=J. N. |last10=Reguero |first10=M. A. |last11=López-Mendoza |first11=P. |last12=Taglioretti |first12=M. |last13=Scaglia |first13=F. |last14=Rinderknecht |first14=A. |last15=Jones |first15=W. |last16=Mena |first16=F. |last17=Billet |first17=G. |last18=de Muizon |first18=C. |last19=Aguilar |first19=J. L. |last20=MacPhee |first20=R. D. E. |last21=Hofreiter |first21=M. |title=A mitogenomic timetree for Darwin's enigmatic South American mammal Macrauchenia patachonica |journal=Nature Communications |volume=8 |date=2017-06-27 |pages=15951 |doi=10.1038/ncomms15951 |pmid=28654082 |pmc=5490259 |bibcode=2017NatCo...815951W}}}} A few non-therian mammals – monotremes, gondwanatheres, dryolestids and possibly cimolodont multituberculates – were also present in the Paleocene; while none of these diversified significantly and most lineages did not survive long, forms like Necrolestes and Patagonia remained as recently as the Miocene.{{cite journal |last1=Chimento |first1=Nicolás R. |last2=Agnolin |first2=Federico L. |last3=Novas |first3=Fernando E. |year=2015 |title=The bizarre 'metatherians' Groeberia and Patagonia, late surviving members of gondwanatherian mammals |journal=Historical Biology: An International Journal of Paleobiology |volume=27 |issue=5 |pages=603–623 |doi=10.1080/08912963.2014.903945 |bibcode=2015HBio...27..603C |s2cid=216591096|hdl=11336/85076 |hdl-access=free }}

File:Monito del Monte ps6.jpg, Dromiciops gliroides, South America's only australidelphian marsupial]]

File:AstrapotheriumDB.jpg]]

Marsupials appear to have traveled via Gondwanan land connections from South America through Antarctica to Australia in the late Cretaceous or early Tertiary.{{cite journal

|last1=Nilsson |first1=M. A. |last2=Churakov |first2=G. |last3=Sommer |first3=M. |last4=Van Tran |first4=N. |last5=Zemann |first5=A. |last6=Brosius |first6=J. |last7=Schmitz |first7=J.

|title=Tracking Marsupial Evolution Using Archaic Genomic Retroposon Insertions

|journal=PLOS Biology |volume=8 |issue=7 |pages=e1000436

|date=2010-07-27

|pmid=20668664 |pmc=2910653 |doi=10.1371/journal.pbio.1000436 |doi-access=free }}{{refn|group=n|Once in Australia, facing less competition, marsupials diversified to fill a much larger array of niches than in South America, where they were largely carnivorous.}} One living South American marsupial, the monito del monte, has been shown to be more closely related to Australian marsupials than to other South American marsupials (Ameridelphia); however, it is the most basal australidelphian,{{refn|group=n|It is the sister group to a clade containing all other extant australidelphians (roughly 238 species).}} meaning that this superorder arose in South America and then dispersed to Australia after the monito del monte split off. Monotrematum, a 61-Ma-old platypus-like monotreme fossil from Patagonia, may represent an Australian immigrant.{{cite journal |last1=Pascual |first1=R. |last2=Archer |first2=M. |last3=Jaureguizar |first3=E. O. |last4=Prado |first4=J. L. |last5=Godthelp |first5=H. |last6=Hand |first6=S. J. |title=First discovery of monotremes in South America |journal=Nature |volume=356 |issue=6371 |year=1992 |pages=704–706 |doi=10.1038/356704a0 |bibcode=1992Natur.356..704P |s2cid=4350045}}{{cite journal |last1=Pascual |first1=R. |last2=Goin |first2=F. J. |last3=Balarino |first3=L. |last4=Sauthier |first4=D. E. U. |title=New data on the Paleocene monotreme Monotrematum sudamericanum, and the convergent evolution of triangulate molars |journal=Acta Palaeontologica Polonica |volume=47 |issue=3 |pages=487–492 |date=2002 |url=https://www.app.pan.pl/archive/published/app47/app47-487.pdf |access-date=2020-01-21}} Paleognath birds (ratites and South American tinamous) may have made a similar migration around the same time to Australia and New Zealand.{{cite journal |last=Briggs |first=J. C. |date=August 2003 |title=Fishes and Birds: Gondwana Life Rafts Reconsidered |journal=Syst. Biol. |volume=52 |issue=4 |pages=548–553 |doi=10.1080/10635150390218385 |jstor=3651142 |pmid=12857645}}{{cite journal |last1=Yonezawa |first1=T. |last2=Segawa |first2=T. |last3=Mori |first3=H. |last4=Campos |first4=P. F. |last5=Hongoh |first5=Y. |last6=Endo |first6=H. |last7=Akiyoshi |first7=A. |last8=Kohno |first8=N. |last9=Nishida |first9=S. |last10=Wu |first10=J. |last11=Jin |first11=H. |last12=Adachi |first12=J. |last13=Kishino |first13=H. |last14=Kurokawa |first14=K. |last15=Nogi |first15=Y. |last16=Tanabe |first16=H. |last17=Mukoyama |first17=H. |last18=Yoshida |first18=K. |last19=Rasoamiaramanana |first19=A. |last20=Yamagishi |first20=S. |last21=Hayashi |first21=Y. |last22=Yoshida |first22=A. |last23=Koike |first23=H. |last24=Akishinonomiya |first24=F. |last25=Willerslev |first25=E. |last26=Hasegawa |first26=M. |title=Phylogenomics and Morphology of Extinct Paleognaths Reveal the Origin and Evolution of the Ratites |journal=Current Biology |volume=27 |issue=1 |date=2016-12-15 |pages=68–77 |doi=10.1016/j.cub.2016.10.029 |pmid=27989673 |s2cid=38890667|doi-access=free |bibcode=2017CBio...27...68Y }} Other taxa that may have dispersed by the same route (if not by flying or oceanic dispersal) are parrots, chelid turtles, and the extinct meiolaniid turtles.

Marsupials remaining in South America included didelphimorphs (opossums), paucituberculatans (shrew opossums) and microbiotheres (monitos del monte). Larger predatory relatives of these also existed, such as the borhyaenids and the saber-toothed Thylacosmilus; these were sparassodont metatherians, which are no longer considered to be true marsupials.{{cite web |last=Naish |first=Darren |author-link=Darren Naish |title=Invasion of the marsupial weasels, dogs, cats and bears... or is it? |work=scienceblogs.com |date=29 June 2008 |url=http://scienceblogs.com/tetrapodzoology/2008/06/29/borhyaenoids-intro/ |access-date=2008-12-07}} As the large carnivorous metatherians declined, and before the arrival of most types of carnivorans, predatory opossums such as Thylophorops temporarily attained larger size (about 7 kg).

Metatherians and a few xenarthran armadillos, such as Macroeuphractus, were the only South American mammals to specialize as carnivores; their relative inefficiency created openings for nonmammalian predators to play more prominent roles than usual (similar to the situation in Australia). Sparassodonts and giant opossums shared the ecological niches for large predators with fearsome flightless "terror birds" (phorusrhacids), whose closest living relatives are the seriemas.{{cite web |last=Naish |first=Darren |author-link=Darren Naish |title=Terror birds |work=darrennaish.blogspot.com |date=2006-10-27 |url=http://darrennaish.blogspot.com/2006/10/terror-birds.html |access-date=2008-03-29}}{{cite journal |last=Alvarenga |first=H. M. F. |author2=Höfling, E. |title=Systematic Revision of the Phorusrhacidae (Aves: Ralliformes) |journal=Papéis Avulsos de Zoologia |volume=43 |issue=4 |pages=55–91 |year=2003 |doi=10.1590/S0031-10492003000400001|doi-access=free }} North America also had large terrestrial predatory birds during the early Cenozoic (the related bathornithids), but they died out before the GABI in the Early Miocene, about 20 million years ago. Through the skies over late Miocene South America (6 Ma ago) soared one of the largest flying birds known, Argentavis, a teratorn that had a wing span of 6 m or more, and which may have subsisted in part on the leftovers of Thylacosmilus kills.{{cite journal |last1=Palmqvist |first1=Paul |last2=Vizcaíno |first2=Sergio F. |title=Ecological and reproductive constraints of body size in the gigantic Argentavis magnificens (Aves, Theratornithidae) from the Miocene of Argentina |journal=Ameghiniana |volume=40 |issue=3 |pages=379–385 |date=2003-09-30 |url=http://webpersonal.uma.es/de/ppb/Argentavis.pdf |access-date=2008-12-11}} Terrestrial sebecid (metasuchian) crocodyliforms with ziphodont teeth{{refn|group=n|Ziphodont (lateromedially compressed, recurved and serrated) teeth tend to arise in terrestrial crocodilians because, unlike their aquatic cousins, they are unable to dispatch their prey by simply holding them underwater and drowning them; they thus need cutting teeth with which to slice open their victims.}} were also present at least through the middle Miocene{{cite journal |last1=Paolillo |first1=A. |last2=Linares |first2=O. J. |title=Nuevos Cocodrilos Sebecosuchia del Cenozoico Suramericano (Mesosuchia: Crocodylia) |journal=Paleobiologia Neotropical |volume=3 |pages=1–25 |date=2007-06-05 |url=http://www.paleobio.labb.usb.ve/Paleobio03.pdf |access-date=2008-09-28 |archive-date=2009-03-03 |archive-url=https://web.archive.org/web/20090303221605/http://www.paleobio.labb.usb.ve/Paleobio03.pdf |url-status=dead }}{{cite journal

|last=Busbey |first=Arthur B. III

|title=New Material of Sebecus cf. huilensis (Crocodilia: Sebecosuchidae) from the Miocene La Venta Formation of Colombia

|journal=Journal of Vertebrate Paleontology |volume=6 |issue=1 |pages=20–27

|date=1986-03-07

|doi=10.1080/02724634.1986.10011595 |jstor=4523070|bibcode=1986JVPal...6...20B

}}{{cite book

|first=R. |last=Salas-Gismondi |editor-last=Díaz-Martínez |editor-first=E. |editor2-last=Rábano |editor2-first=I.

|contribution=Middle Miocene Crocodiles From the Fitzcarrald Arch, Amazonian Peru

|contribution-url=http://www.igme.es/4empsla/libro/62.pdf

|title=4th European Meeting on the Palaeontology and Stratigraphy of Latin America

|year=2007 |pages=355–360 |place=Madrid

|publisher=Instituto Geológico y Minero de España

|isbn=978-84-7840-707-1

|display-authors=etal}}{{cite journal

|last=Gasparini |first=Zulma

|title=New Tertiary Sebecosuchia (Crocodylia: Mesosuchia) from Argentina

|journal=Journal of Vertebrate Paleontology |volume=4 |issue=1

|pages=85–95 |date=September 1984 |doi=10.1080/02724634.1984.10011988

|jstor=4522967|bibcode=1984JVPal...4...85G

}} and maybe to the Miocene-Pliocene boundary.{{cite journal |last1=Liccardo |first1=A. |last2=Weinschütz |first2=L. C. |title=Registro inédito de fósseis de vertebrados na Bacia Sedimentar de Curitiba (PR) |journal=Revista Brasileira de Geociências |volume=40 |issue=3 |pages=330–338 |date=September 2010 |language=pt |url=http://www.ppegeo.igc.usp.br/index.php/rbg/article/view/7760 |access-date=2017-10-23 |doi=10.25249/0375-7536.2010403330338|doi-broken-date=1 November 2024 |doi-access=free |url-access=subscription }} Some of South America's aquatic crocodilians, such as Gryposuchus, Mourasuchus and Purussaurus, reached monstrous sizes, with lengths up to 12 m (comparable to the largest Mesozoic crocodyliforms). They shared their habitat with one of the largest turtles of all time, the 3.3 m (11 ft) Stupendemys.

File:NationalZooAnteater.JPG, Myrmecophaga tridactyla, the largest living descendant of South America's early Cenozoic mammalian fauna]]

Xenarthrans are a curious group of mammals that developed morphological adaptations for specialized diets very early in their history.{{cite journal

|last1=Möller-Krull |first1=Maren

|last2=Delsuc |first2=Frédéric |last3=Churakov |first3=Gennady |last4=Marker |first4=Claudia |last5=Superina |first5=Mariella |last6=Brosius |first6=Jürgen |last7=Douzery |first7=Emmanuel J. P. |last8=Schmitz |first8=Jürgen

|title=Retroposed Elements and Their Flanking Regions Resolve the Evolutionary History of Xenarthran Mammals (Armadillos, Anteaters, and Sloths)

|journal=Molecular Biology and Evolution |volume=24 |issue=11 |pages=2573–2582

|date=2007-09-17

|doi=10.1093/molbev/msm201

|pmid=17884827

|doi-access=free }} In addition to those extant today (armadillos, anteaters, and tree sloths), a great diversity of larger types was present, including pampatheres, the ankylosaur-like glyptodonts, predatory euphractines, various ground sloths, some of which reached the size of elephants (e.g. Megatherium), and even semiaquatic to aquatic marine sloths.{{cite journal |last1=Muizon |first1=C. de |last2=McDonald |first2=H. G. |last3=Salas |first3=R. |last4=Urbina |first4=M. |title=The evolution of feeding adaptations of the aquatic sloth Thalassocnus |journal=Journal of Vertebrate Paleontology |volume=24 |issue=2 |pages=398–410 |date=June 2004 |doi=10.1671/2429b |jstor=4524727 |bibcode=2004JVPal..24..398D |s2cid=83859607}}{{cite journal |last1=Amson |first1=E. |last2=Muizon |first2=C. de |last3=Laurin |first3=M. |last4=Argot |first4=C. |last5=de Buffrénil |first5=V. |title=Gradual adaptation of bone structure to aquatic lifestyle in extinct sloths from Peru |journal=Proceedings of the Royal Society B: Biological Sciences |volume=281 |issue=1782 |pages=20140192 |date=2014 |doi=10.1098/rspb.2014.0192 |pmid=24621950 |pmc=3973278}}

File:Macrauchenia_patachonica_Life_Reconstruction.pngMacrauchenia, an ungulate belonging to the extinct South American native ungulate order Litopterna]]

The notoungulates and litopterns had many strange forms, such as Macrauchenia, a camel-like litoptern with a small proboscis. They also produced a number of familiar-looking body types that represent examples of parallel or convergent evolution: one-toed Thoatherium had legs like those of a horse, Pachyrukhos resembled a rabbit, Homalodotherium was a semibipedal, clawed browser like a chalicothere, and horned Trigodon looked like a rhinoceros. Both groups started evolving in the Lower Paleocene, possibly from condylarth stock, diversified, dwindled before the great interchange, and went extinct at the end of the Pleistocene. The pyrotheres and astrapotheres were also strange, but were less diverse and disappeared earlier, well before the interchange.

The North American fauna was a typical boreoeutherian one, supplemented with Afrotherian proboscids.

{{See also|Oceanic dispersal}}

File:Capibara 2 edit.jpg, Hydrochoerus hydrochaeris]]

File:Tamarin portrait edit.jpg, Saguinus imperator]]

The invasions of South America started about 40 Ma ago (middle Eocene), when caviomorph rodents arrived in South America.{{cite journal |last1=Poux |first1=C. |last2=Chevret |first2=P. |last3=Huchon |first3=D. |last4=De Jong |first4=W. W. |last5=Douzery |first5=E. J. P. |title=Arrival and Diversification of Caviomorph Rodents and Platyrrhine Primates in South America |journal=Systematic Biology |volume=55 |issue=2 |pages=228–244 |year=2006 |url=http://www.tau.ac.il/%7Ehuchond/SB2006.pdf |doi=10.1080/10635150500481390 |access-date=2011-10-25 |pmid=16551580 |archive-date=2016-06-02 |archive-url=https://web.archive.org/web/20160602151725/http://www.tau.ac.il/~huchond/SB2006.pdf |url-status=dead }}{{cite web |last=Mangels |first=J. |title=Case Western Reserve University expert uses fossil teeth to recast history of rodent |publisher=Cleveland Live, Inc. |date=2011-10-15 |url=http://www.cleveland.com/science/index.ssf/2011/10/fossil_teeth_tell_of_rodents_f.html |access-date=2011-10-25}}{{cite journal |last1=Antoine |first1=P.-O. |last2=Marivaux |first2=L. |last3=Croft |first3=D. A. |last4=Billet |first4=G. |last5=Ganerod |first5=M. |last6=Jaramillo |first6=C. |last7=Martin |first7=T. |last8=Orliac |first8=M. J. |last9=Tejada |first9=J. |last10=Altamirano |first10=A. J. |last11=Duranthon |first11=F. |last12=Fanjat |first12=G. |last13=Rousse |first13=S. |last14=Gismondi |first14=R. S. |title=Middle Eocene rodents from Peruvian Amazonia reveal the pattern and timing of caviomorph origins and biogeography |journal=Proceedings of the Royal Society B: Biological Sciences |volume=279 |issue=1732 |year=2011 |pages=1319–1326 |doi=10.1098/rspb.2011.1732 |display-authors=8 |pmid=21993503 |pmc=3282368}} Their subsequent vigorous diversification displaced some of South America's small marsupials and gave rise to – among others – capybaras, chinchillas, viscachas, and New World porcupines. The independent development of spines by New and Old World porcupines is another example of parallel evolution. This invasion most likely came from Africa.{{cite journal |title=Recent advances in South American mammalian paleontology |last1=Flynn |first1=J. J. |last2=Wyss |first2=A. R. |journal=Trends in Ecology and Evolution |volume=13 |issue=11 |pages=449–454 |year=1998 |doi=10.1016/S0169-5347(98)01457-8 |pmid=21238387|bibcode=1998TEcoE..13..449F }}{{cite journal |title=South America's Missing Mammals |last1=Flynn |first1=John J. |last2=Wyss |first2=André R. |last3=Charrier |first3=Reynaldo |author-link3=Reynaldo Charrier |journal=Scientific American |issue=May |volume=296 |pages=68–75 |year=2007 |doi=10.1038/scientificamerican0507-68 |pmid=17500416 |bibcode=2007SciAm.296e..68F}} The crossing from West Africa to the northeast corner of Brazil was much shorter then, due to continental drift, and may have been aided by island hopping (e.g. via St. Paul's Rocks, if they were an inhabitable island at the time) and westward oceanic currents.{{cite journal |title=Low-Latitude Circulation and Mass Transport Pathways in a Model of the Tropical Atlantic Ocean |last1=Fratantoni |first1=D. M. |last2=Johns |first2=W. E. |last3=Townsend |first3=T. L. |last4=Hurlburt |first4=H. E. |journal=Journal of Physical Oceanography |volume=30 |issue=8 |pages=1944–1966 |date=August 2000 |doi=10.1175/1520-0485(2000)030<1944:LLCAMT>2.0.CO;2 |bibcode=2000JPO....30.1944F|s2cid=54534830 |doi-access=free }} Crossings of the ocean were accomplished when at least one fertilised female (more commonly a group of animals) accidentally floated over on driftwood or mangrove rafts. Hutias (Capromyidae) would subsequently colonize the West Indies as far as the Bahamas, reaching the Greater Antilles by the early Oligocene.{{cite journal |last1=Vélez-Juarbe |first1=J. |last2=Martin |first2=T. |last3=Macphee |first3=R. D. E. |last4=Ortega-Ariza |first4=D. |title=The earliest Caribbean rodents: Oligocene caviomorphs from Puerto Rico |journal=Journal of Vertebrate Paleontology |volume=34 |issue=1 |date=January 2014 |pages=157–163 |doi=10.1080/02724634.2013.789039 |bibcode=2014JVPal..34..157V |s2cid=140178414}} Over time, some caviomorph rodents evolved into larger forms that competed with some of the native South American ungulates, which may have contributed to the gradual loss of diversity suffered by the latter after the early Oligocene. By the Pliocene, some caviomorphs (e.g., Josephoartigasia monesi) attained sizes on the order of {{convert|500|kg|lb|abbr=on}} or larger.{{cite journal |last=Millien |first=Virginie |date=May 2008 |title=The largest among the smallest: the body mass of the giant rodent Josephoartigasia monesi |journal=Proceedings of the Royal Society B |volume=275 |issue=1646 |pages=1953–5; discussion 1957–8 |doi=10.1098/rspb.2008.0087 |pmid=18495621 |pmc=2596365}}

• {{cite news |date=20 May 2008 |title=Biggest rodent 'shrinks in size' |work=BBC News |url=http://news.bbc.co.uk/2/hi/science/nature/7408743.stm}}

Later (by 36 Ma ago),{{cite journal |doi=10.1038/nature14120 |title=Eocene primates of South America and the African origins of New World monkeys |journal=Nature |volume=520 |issue=7548 |pages=538–541 |date=2015-02-04 |last1=Bond |first1=M. |last2=Tejedor |first2=M. F. |last3=Campbell |first3=K. E. |last4=Chornogubsky |first4=L. |last5=Novo |first5=N. |last6=Goin |first6=F. |bibcode=2015Natur.520..538B |pmid=25652825 |hdl=11336/79088 |s2cid=4456556|hdl-access=free }} primates followed, again from Africa in a fashion similar to that of the rodents. Primates capable of migrating had to be small. Like caviomorph rodents, South American monkeys are believed to be a clade (i.e., monophyletic). However, although they would have had little effective competition, all extant New World monkeys appear to derive from a radiation that occurred long afterwards, in the Early Miocene about 18 Ma ago. Subsequent to this, monkeys apparently most closely related to titis island-hopped to Cuba, Hispaniola, and Jamaica. Additionally, a find of seven 21-Ma-old apparent cebid teeth in Panama suggests that South American monkeys had dispersed across the seaway separating Central and South America by that early date. However, all extant Central American monkeys are believed to be descended from much later migrants, and there is as yet no evidence that these early Central American cebids established an extensive or long-lasting population, perhaps due to a shortage of suitable rainforest habitat at the time.{{cite journal |last1=Wade |first1=L. |title=Monkey ancestors rafted across the sea to North America |journal=Science |date=2016-04-20 |doi=10.1126/science.aaf4154}}{{cite journal |last1=Bloch |first1=J. I. |last2=Woodruff |first2=E. D. |last3=Wood |first3=A. R. |last4=Rincon |first4=A. F. |last5=Harrington |first5=A. R. |last6=Morgan |first6=G. S. |last7=Foster |first7=D. A. |last8=Montes |first8=C. |last9=Jaramillo |first9=C. A. |last10=Jud |first10=N. A. |last11=Jones |first11=D. S. |last12=MacFadden |first12=B. J. |title=First North American fossil monkey and early Miocene tropical biotic interchange |journal=Nature |date=2016-04-20 |doi=10.1038/nature17415 |volume=533 |issue=7602 |pages=243–246 |pmid=27096364 |bibcode=2016Natur.533..243B |s2cid=4445687}}

Fossil evidence presented in 2020 indicates a second lineage of African monkeys also rafted to and at least briefly colonized South America. Ucayalipithecus remains dating from the Early Oligocene of Amazonian Peru are, by morphological analysis, deeply nested within the family Parapithecidae of the Afro-Arabian radiation of parapithecoid simians, with dental features markedly different from those of platyrrhines. The Old World members of this group are thought to have become extinct by the Late Oligocene. Qatrania wingi of lower Oligocene Fayum deposits is considered the closest known relative of Ucayalipithecus.{{cite journal |last1=Seiffert |first1=E.R. |last2=Tejedor |first2=M.F. |last3=Fleagle |first3=J.G. |last4=Novo |first4=N.M. |last5=Cornejo |first5=F.M. |last6=Bond |first6=M. |last7=de Vries |first7=D. |last8=Campbell |first8=K.E. |title=A parapithecid stem anthropoid of African origin in the Paleogene of South America |journal=Science |volume=368 |issue=6487 |year=2020 |pages=194–197 |doi=10.1126/science.aba1135 |pmid=32273470 |bibcode=2020Sci...368..194S |s2cid=215550773}}{{cite journal |last1=Godinot |first1=M. |title=Rafting on a wide and wild ocean |journal=Science |volume=368 |issue=6487 |year=2020 |pages=136–137 |doi=10.1126/science.abb4107 |pmid=32273458 |bibcode=2020Sci...368..136G |s2cid=215551148}}

Remarkably, the descendants of those few bedraggled "waifs" that crawled ashore from their rafts of African flotsam in the Eocene now constitute more than twice as many of South America's species as the descendants of all the flightless mammals previously resident on the continent (372 caviomorph and monkey species versus 136 marsupial and xenarthran species).{{refn|group=n|It is also notable that both simians (ancestral to monkeys) and hystricognath rodents (ancestral to caviomorphs) are believed to have arrived in Africa by rafting from Eurasia about 40 Ma ago.{{cite journal |last1=Chaimanee |first1=Y. |last2=Chavasseau |first2=O. |last3=Beard |first3=K. C. |last4=Kyaw |first4=A. A. |last5=Soe |first5=A. N. |last6=Sein |first6=C. |last7=Lazzari |first7=V. |last8=Marivaux |first8=L. |last9=Marandat |first9=B. |last10=Swe |first10=M. |last11=Rugbumrung |first11=M. |last12=Lwin |first12=T. |last13=Valentin |first13=X. |last14=Zin-Maung-Maung-Thein |last15=Jaeger |first15=J. -J. |title=Late Middle Eocene primate from Myanmar and the initial anthropoid colonization of Africa |doi=10.1073/pnas.1200644109 |journal=Proceedings of the National Academy of Sciences |volume=109 |issue=26 |pages=10293–10297 |year=2012 |pmid=22665790 |pmc=3387043 |bibcode=2012PNAS..10910293C|doi-access=free }}}}

Many of South America's bats may have arrived from Africa during roughly the same period, possibly with the aid of intervening islands, although by flying rather than floating. Noctilionoid bats ancestral to those in the neotropical families Furipteridae, Mormoopidae, Noctilionidae, Phyllostomidae, and Thyropteridae are thought to have reached South America from Africa in the Eocene, possibly via Antarctica. Similarly, free-tailed bats (Molossidae) may have reached South America from Africa in as many as five dispersals, starting in the Eocene. Emballonurids may have also reached South America from Africa about 30 Ma ago, based on molecular evidence.{{cite journal |last=Lim |first=B. K. |title=Review of the Origins and Biogeography of Bats in South America |journal=Chiroptera Neotropical |volume=15 |issue=1 |pages=391–410 |publisher=Departamento de Zoologia – Universidade de Brasília |date=July 2009 |url=http://revistas.bvs-vet.org.br/chiroptera/article/view/11994 |access-date=2018-01-24}}{{cite journal |last1=Teeling |first1=E. C. |last2=Springer |first2=M. |last3=Madsen |first3=O. |last4=Bates |first4=P. |last5=O'Brien |first5=S. |last6=Murphy |first6=W. |title=A Molecular Phylogeny for Bats Illuminates Biogeography and the Fossil Record |doi=10.1126/science.1105113 |journal=Science |volume=307 |issue=5709 |pages=580–584 |date=2005-01-28 |pmid=15681385 |bibcode=2005Sci...307..580T |s2cid=25912333}} Vespertilionids may have arrived in five dispersals from North America and one from Africa. Natalids are thought to have arrived during the Pliocene from North America via the Caribbean.

File:Geochelone carbonaria 1.jpg, Chelonoidis carbonaria]]

Tortoises also arrived in South America in the Oligocene. They were long thought to have come from North America, but a recent comparative genetic analysis concludes that the South American genus Chelonoidis (formerly part of Geochelone) is actually most closely related to African hingeback tortoises.{{refn|group=n|North American gopher tortoises are most closely related to the Asian genus Manouria.}}{{cite journal |last1=Le |first1=M. |last2=Raxworthy |first2=C. J. |last3=McCord |first3=W. P. |last4=Mertz |first4=L. |title=A molecular phylogeny of tortoises (Testudines: Testudinidae) based on mitochondrial and nuclear genes |journal=Molecular Phylogenetics and Evolution |volume=40 |issue=2 |pages=517–531 |date=2006-05-05 |url=http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Le_etal_2006.pdf |doi=10.1016/j.ympev.2006.03.003 |access-date=2012-04-12 |pmid=16678445 |bibcode=2006MolPE..40..517L |archive-url=https://web.archive.org/web/20120316211953/http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Le_etal_2006.pdf |archive-date=2012-03-16 |url-status=dead}} Tortoises are aided in oceanic dispersal by their ability to float with their heads up, and to survive up to six months without food or water. South American tortoises then went on to colonize the West Indies{{cite journal |last1=Williams |first1=E. E. |last2=Anthony |first2=H. E. |last3=Goodwin |first3=G. G. |title=A new fossil tortoise from Mona Island, West Indies, and a tentative arrangement of the tortoises of the world |journal=Bulletin of the American Museum of Natural History |volume=99 |issue=9 |pages=541–560 |publisher=American Museum of Natural History |date=1952 |hdl=2246/418}} and Galápagos Islands (the Galápagos tortoise). A number of clades of American geckos seem to have rafted over from Africa during both the Paleogene and Neogene.{{cite journal |doi=10.1111/j.1420-9101.2010.02184.x |title=Coming to America: Multiple origins of New World geckos |journal=Journal of Evolutionary Biology |volume=24 |issue=2 |pages=231–244 |date=2010-12-03 |last1=Gamble |first1=T. |last2=Bauer |first2=A. M. |last3=Colli |first3=G. R. |last4=Greenbaum |first4=E. |last5=Jackman |first5=T. R. |last6=Vitt |first6=L. J. |last7=Simons |first7=A. M. |url=http://www.tc.umn.edu/~gambl007/publications/Gamble_etal_2011_jeb.pdf |pmid=21126276 |pmc=3075428}} Skinks of the related genera Mabuya and Trachylepis apparently dispersed across the Atlantic from Africa to South America and Fernando de Noronha, respectively, during the last 9 Ma.{{cite journal |last1=Carranza |first1=S. |last2=Arnold |first2=N. E. |title=Investigating the origin of transoceanic distributions: mtDNA shows Mabuya lizards (Reptilia, Scincidae) crossed the Atlantic twice |journal=Systematics and Biodiversity |volume=1 |issue=2 |pages=275–282 |date=2003-08-05 |doi=10.1017/S1477200003001099 |bibcode=2003SyBio...1..275C |s2cid=55799145}} Surprisingly, South America's burrowing amphisbaenians{{cite journal |last1=Vidal |first1=N. |last2=Azvolinsky |first2=A. |last3=Cruaud |first3=C. |last4=Hedges |first4=S. B. |title=Origin of tropical American burrowing reptiles by transatlantic rafting |doi=10.1098/rsbl.2007.0531 |journal=Biology Letters |volume=4 |issue=1 |pages=115–118 |date=2007-12-11 |pmid=18077239 |pmc=2412945}} and blind snakes{{cite journal |doi=10.1098/rsbl.2010.0220 |title=Blindsnake evolutionary tree reveals long history on Gondwana |journal=Biology Letters |volume=6 |issue=4 |pages=558–561 |date=2010-03-31 |last1=Vidal |first1=N. |last2=Marin |first2=J. |last3=Morini |first3=M. |last4=Donnellan |first4=S. |author-link4=Steve Donnellan (scientist) |last5=Branch |first5=W. R. |author-link5=:fr:William Roy Branch |last6=Thomas |first6=R. |author-link6=:fr:Richard Thomas (zoologiste) |last7=Vences |first7=M. |author-link7=Miguel Vences |last8=Wynn |first8=A. |last9=Cruaud |first9=C. |last10=Hedges |first10=S. B. |author-link10=Stephen Blair Hedges |pmid=20356885 |pmc=2936224}} also appear to have rafted from Africa, as does the hoatzin, a weak-flying bird of South American rainforests.{{cite journal |doi=10.1007/s00114-011-0849-1 |title=Out of Africa: Fossils shed light on the origin of the hoatzin, an iconic Neotropic bird |journal=Naturwissenschaften |volume=98 |issue=11 |pages=961–966 |date=2011-10-01 |last1=Mayr |first1=G. |last2=Alvarenga |first2=H. |last3=Mourer-Chauviré |first3=C. C. |pmid=21964974 |bibcode=2011NW.....98..961M |s2cid=24210185}}

File:Megalonyx wheatleyi skeleton & restoration.jpg]]

The earliest traditionally recognized mammalian arrival from North America was a procyonid that island-hopped from Central America before the Isthmus of Panama land bridge formed, around 7.3 Ma ago.{{cite journal |last1=Woodburne |first1=M. O. |title=The Great American Biotic Interchange: Dispersals, Tectonics, Climate, Sea Level and Holding Pens |journal=Journal of Mammalian Evolution |volume=17 |issue=4 |date=2010-07-14 |pages=245–264 |doi=10.1007/s10914-010-9144-8 |pmid=21125025 |pmc=2987556}} This was South America's first eutherian carnivore. South American procyonids then diversified into forms now extinct (e.g. the "dog-coati" Cyonasua, which evolved into the bear-like Chapalmalania). However, all extant procyonid genera appear to have originated in North America.{{cite journal

|title=Phylogeny of the Procyonidae (Mammalia: Carnivora): Molecules, morphology and the Great American Interchange

|last1=Koepfli |first1=K.-P.

|last2=Gompper |first2=M. E. |last3=Eizirik |first3=E. |last4=Ho |first4=C.-C. |last5=Linden |first5=L. |last6=Maldonado |first6=J. |last7=Wayne |first7=E. R. K.

|journal=Molecular Phylogenetics and Evolution |volume=43 |issue=3 |pages=1076–1095 |year=2007

|doi=10.1016/j.ympev.2006.10.003 |pmid=17174109 |bibcode=2007MolPE..43.1076K |citeseerx=10.1.1.495.2618}} The first South American procyonids may have contributed to the extinction of sebecid crocodilians by eating their eggs, but this view has not been universally viewed as plausible.{{refn|group=n|An alternative explanation blames climatic and physiographic changes associated with the uplift of the Andes.}} The procyonids were followed to South America by rafting or island-hopping hog-nosed skunks{{cite journal

|last=Webb |first=S. D.

|title=Mammalian Faunal Dynamics of the Great American Interchange

|journal=Paleobiology |volume=2 |issue=3 |pages=220–234

|year=1976 |jstor=2400220 |doi=10.1017/S0094837300004802

|bibcode=1976Pbio....2..220W

|s2cid=251050063

}} and sigmodontine rodents.{{cite journal

|last1=Marshall |first1=L. G. |last2=Butler |first2=R. F. |last3=Drake |first3=R. E. |last4=Curtis |first4=G. H. |last5=Tedford |first5=R. H.

|title=Calibration of the Great American Interchange

|journal=Science |volume=204 |issue=4390 |pages=272–279 |date=1979-04-20

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|last1=Engel |first1=S. R. |last2=Hogan |first2=K. M. |last3=Taylor |first3=J. F. |last4=Davis |first4=S. K.

|title=Molecular Systematics and Paleobiogeography of the South American Sigmodontine Rodents

|journal=Molecular Biology and Evolution |volume=15 |issue=1 |pages=35–49

|year=1998 |doi =10.1093/oxfordjournals.molbev.a025845 |pmid=9491603}}{{cite journal

|last1=Smith |first1=M. F. |last2=Patton |first2=J. L.

|title=Phylogenetic Relationships and the Radiation of Sigmodontine Rodents in South America: Evidence from Cytochrome b

|journal=Journal of Mammalian Evolution |volume=6 |issue=2 |pages=89–128 |year=1999 |doi=10.1023/A:1020668004578 |s2cid=22355532}}{{cite journal |last1=Parada |first1=A. |last2=Pardiñas |first2=U. F. J. |last3=Salazar-Bravo |first3=J. |last4=D'Elía |first4=G. |last5=Palma |first5=R. E. |title=Dating an impressive Neotropical radiation: Molecular time estimates for the Sigmodontinae (Rodentia) provide insights into its historical biogeography |journal=Molecular Phylogenetics and Evolution |volume=66 |issue=3 |date=March 2013 |pages=960–968 |doi=10.1016/j.ympev.2012.12.001 |pmid=23257216|bibcode=2013MolPE..66..960P |hdl=11336/5595 |hdl-access=free }} The oryzomyine tribe of sigmodontine rodents went on to colonize the Lesser Antilles to Anguilla.

One group has proposed that a number of large Neartic herbivores actually reached South America as early as 9–10 Ma ago, in the late Miocene, via an early incomplete land bridge. These claims, based on fossils recovered from rivers in southwestern Peru, have been viewed with caution by other investigators, due to the lack of corroborating finds from other sites and the fact that almost all of the specimens in question have been collected as float in rivers without little to no stratigraphic control.{{cite book |last1=Defler |first1=T. |chapter=The Great American Biotic (Faunal) Interchange |title=History of Terrestrial Mammals in South America |series=Topics in Geobiology |volume=42 |year=2019 |pages=259–287 |doi=10.1007/978-3-319-98449-0_13 |isbn=978-3-319-98448-3|s2cid=134089273 }} These taxa are a gomphothere (Amahuacatherium),{{cite journal |last1=Campbell |first1=K. E. |last2=Frailey |first2=C. D. |last3=Romero-Pittman |first3=L. |url=http://en.calameo.com/read/000820129151a8ebd0a91 |title=The Late Miocene Gomphothere Amahuacatherium peruvium (Proboscidea: Gomphotheriidae) from Amazonian Peru: Implications for the Great American Faunal Interchange-[Boletín D 23]. |journal=Ingemmet |year=2000}}{{cite journal |doi=10.1127/0077-7749/2009/0252-0113 |title=In defense of Amahuacatherium (Proboscidea: Gomphotheriidae) |journal=Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen |volume=252 |issue=1 |pages=113–128 |date=April 2009 |last1=Campbell |first1=K. E. |last2=Frailey |first2=C. D. |last3=Romero-Pittman |first3=L.}} peccaries (Sylvochoerus and Waldochoerus),{{cite journal |doi=10.1666/12-012.1 |title=Two New Genera of Peccaries (Mammalia, Artiodactyla, Tayassuidae) from Upper Miocene Deposits of the Amazon Basin |journal=Journal of Paleontology |volume=86 |issue=5 |pages=852–877 |date=September 2012 |last1=Frailey |first1=C. D. |last2=Campbell |first2=K. E. |bibcode=2012JPal...86..852F |s2cid=85961848}} tapirs and Surameryx, a palaeomerycid (from a family probably ancestral to cervids).{{cite journal |doi=10.1666/13-022 |title=New late Miocene dromomerycine artiodactyl from the Amazon Basin: Implications for interchange dynamics |journal=Journal of Paleontology |volume=88 |issue=3 |pages=434–443 |date=May 2014 |last1=Prothero |first1=D. R. |last2=Campbell |first2=K. E. |last3=Beatty |first3=B. L. |last4=Frailey |first4=C. D. |s2cid=55245294}} The identification of Amahuacatherium and the dating of its site is controversial; it is regarded by a number of investigators as a misinterpreted fossil of a different gomphothere, Notiomastodon, and biostratigraphy dates the site to the Pleistocene.{{cite journal |last1=Prado |first1=J. L. |last2=Alberdi |first2=M. T. |last3=Azanza |first3=B. |last4=Sánchez |first4=B. |last5=Frassinetti |first5=D. |year=2005 |title=The Pleistocene Gomphotheriidae (Proboscidea) from South America |journal=Quaternary International |volume=126–128 |pages=21–30 |doi=10.1016/j.quaint.2004.04.012 |bibcode=2005QuInt.126...21P}}{{cite journal |last1=Lucas |first1=S.G. |title=The palaeobiogeography of South American gomphotheres |journal=Journal of Palaeogeography |volume=2 |issue=1 |pages=19–40 |date=January 2013 |doi=10.3724/SP.J.1261.2013.00015 |url=https://www.sciencedirect.com/science/article/pii/S2095383615301292 |access-date=2020-01-23 |doi-broken-date=1 November 2024|bibcode=2013JPalG...2...19L }} The early date proposed for Surameryx has also been met with skepticism.{{cite journal |last1=Antoine |first1=P.-O. |last2=Salas-Gismondi |first2=R. |last3=Pujos |first3=F. |last4=Ganerød |first4=M. |last5=Marivaux |first5=L. |title=Western Amazonia as a Hotspot of Mammalian Biodiversity Throughout the Cenozoic |journal=Journal of Mammalian Evolution |volume=24 |issue=1 |year=2016 |pages=5–17 |doi=10.1007/s10914-016-9333-1 |s2cid=43163341|hdl=11336/63465 |hdl-access=free }}

Megalonychid and mylodontid ground sloths island-hopped to North America by 9 Ma ago. A basal group of sloths{{cite journal |last1=Presslee |first1=S. |last2=Slater |first2=G. J. |last3=Pujos |first3=F. |last4=Forasiepi |first4=A. M. |last5=Fischer |first5=R. |last6=Molloy |first6=K. |last7=Mackie |first7=M. |last8=Olsen |first8=J. V. |last9=Kramarz |first9=A. |last10=Taglioretti |first10=M. |last11=Scaglia |first11=F. |last12=Lezcano |first12=M. |last13=Lanata |first13=J. L. |last14=Southon |first14=J. |last15=Feranec |first15=R. |last16=Bloch |first16=J. |last17=Hajduk |first17=A. |last18=Martin |first18=F. M. |last19=Gismondi |first19=R. S. |last20=Reguero |first20 =M. |last21=de Muizon |first21=C. |last22=Greenwood |first22=A. |last23=Chait |first23=B. T. |last24=Penkman |first24=K. |author24-link=Kirsty Penkman |last25=Collins |first25=M. |last26=MacPhee |first26=R.D.E. |title=Palaeoproteomics resolves sloth relationships |journal=Nature Ecology & Evolution |volume=3 |issue=7 |pages=1121–1130 |year=2019 |doi=10.1038/s41559-019-0909-z |pmid=31171860 |bibcode=2019NatEE...3.1121P |s2cid=174813630 |url=http://eprints.whiterose.ac.uk/147061/1/5426_3_merged_1554730549.pdf}} had colonized the Antilles previously, by the early Miocene.{{citation

|last=Morgan |first=Gary S. |editor-last=Emry |editor-first=Robert J.

|chapter=Late Rancholabrean Mammals from Southernmost Florida, and the Neotropical Influence in Florida Pleistocene Faunas

|title=Cenozoic Mammals of Land and Sea: Tributes to the Career of Clayton E. Ray

|year=2002 |series=Smithsonian Contributions to Paleobiology

|location=Washington, D.C. |volume=93 |pages=15–38

|chapter-url=http://www.sil.si.edu/smithsoniancontributions/Paleobiology/sc_RecordSingle.cfm?filename=SCtP-0093

}} In contrast, megatheriid and nothrotheriid ground sloths did not migrate north until the formation of the isthmus. Sloths first appear in Florida after a major sea level lowstand at the terminus of the Miocene.{{Cite journal |last=Killingsworth |first=Stephanie R. |last2=Moran |first2=Sean M. |last3=MacFadden |first3=Bruce J. |last4=Perez |first4=Victor J. |last5=Pirlo |first5=Jeanette |last6=Ziegler |first6=Michael J. |date=1 March 2025 |title=Marine strontium isotopes preserved in fossil shark teeth calibrate Neogene land mammal evolution |url=https://www.sciencedirect.com/science/article/pii/S0031018224006874 |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |language=en |volume=661 |pages=112698 |doi=10.1016/j.palaeo.2024.112698 |access-date=1 February 2025 |via=Elsevier Science Direct|doi-access=free }} Terror birds may have also island-hopped to North America as early as 5 Ma ago.{{cite journal |last1=McFadden |first1=B. |last2=Labs-Hochstein |first2=J. |last3=Hulbert |first3=R.C. Jr.|last4=Baskin |first4=J.A. |year=2007 |title=Revised age of the late Neogene terror bird (Titanis) in North America during the Great American Interchange |journal=Geology |volume=35 |issue=2 |pages=123–126 |doi=10.1130/G23186A.1 |bibcode=2007Geo....35..123M}}

The Caribbean Islands were populated primarily by species from South America, due to the prevailing direction of oceanic currents, rather than to a competition between North and South American forms.{{cite journal |last1=Hedges |first1=S. Blair |title=Historical biogeography of West Indian vertebrates |journal=Annual Review of Ecology and Systematics |volume=27 |issue=1 |date=November 1996 |pages=163–196 |doi=10.1146/annurev.ecolsys.27.1.163}}{{cite journal |last=Hedges |first=S. Blair |title=Paleogrography of the Antilles and Origin of West Indian Terrestrial Vertebrates |journal=Annals of the Missouri Botanical Garden |volume=93 |issue=2 |pages=231–244 |date=2006-08-23 |doi=10.3417/0026-6493(2006)93[231:POTAAO]2.0.CO;2|s2cid=198149958 |url=https://www.biodiversitylibrary.org/part/390680 }} Except in the case of Jamaica, oryzomyine rodents of North American origin were able to enter the region only after invading South America.

The formation of the Isthmus of Panama led to the last and most conspicuous wave, the Great American Biotic Interchange (GABI), starting around 2.7 Ma ago. This included the immigration into South America of North American ungulates (including camelids, tapirs, deer and horses), proboscids (gomphotheres), carnivorans (including felids such as cougars, jaguars and saber-toothed cats, canids, mustelids, procyonids and bears) and a number of types of rodents.{{refn|group=n|Of the 6 families of North American rodents that did not originate in South America, only beavers and mountain beavers failed to migrate to South America. (However, human-introduced beavers have become serious pests in Tierra del Fuego.)}} The larger members of the reverse migration were ground sloths, terror birds, glyptodonts, pampatheres, capybaras, and the notoungulate Mixotoxodon (the only South American ungulate known to have invaded Central America).

File:Skeleton of Titanis at the Florida Museum of Natural History.jpg, the only known North American terror bird]]

In general, the initial net migration was symmetrical. Later on, however, the Neotropic species proved far less successful than the Nearctic. This difference in fortunes was manifested in several ways. Northwardly migrating animals often were not able to compete for resources as well as the North American species already occupying the same ecological niches; those that did become established were not able to diversify much, and in some cases did not survive for long. Southwardly migrating Nearctic species established themselves in larger numbers and diversified considerably more, and are thought to have caused the extinction of a large proportion of the South American fauna.{{cite journal |last1=Marshall |first1=L. G. |last2=Cifelli |first2=R. L. |title=Analysis of changing diversity patterns in Cenozoic land mammal age faunas, South America |journal=Palaeovertebrata |volume=19 |pages=169–210 |date=1990 |url =http://palaeovertebrata.com/Articles/sendFile/284/published_article |access-date=2018-10-08}} (No extinctions in North America are plainly linked to South American immigrants.{{refn|group=n|In this connection, however, chalicotheres, clawed perissodactyl herbivores ecologically similar to ground sloths, died out in North America in the Miocene about 9 Ma ago, while they survived to the early Pleistocene in Asia and Africa.{{cite web |url=https://research.amnh.org/paleontology/perissodactyl/evolution/groups/chalicotheriidae |title=Chalicotheriidae |website=www.amnh.org |publisher=AMNH |access-date=2018-10-08}}}}) Native South American ungulates did poorly, with only a handful of genera withstanding the northern onslaught. (Several of the largest forms, macraucheniids and toxodontids, have long been recognized to have survived to the end of the Pleistocene. Recent fossil finds indicate that one species of the horse-like proterotheriid litopterns did, as well.{{cite journal |last1=Gaudioso |first1=P. J. |last2=Gasparini |first2=G. M. |last3=Herbst |first3=R. |last4=Barquez |first4=R. M. |title=First record of the Neolicaphrium recens Frenguelli, 1921 (Mammalia, Litopterna) in the Pleistocene of Santiago del Estero Province, Argentina |journal=Papéis Avulsos de Zoologia |volume=57 |issue=31 |year=2017 |pages=23–29 |doi=10.11606/0031-1049.2017.57.03|doi-access=free |hdl=11336/56638 |hdl-access=free }} The notoungulate mesotheriids and hegetotheriids also managed to hold on at least part way through the Pleistocene.){{Ref label|A|A|none}} South America's small marsupials, though, survived in large numbers, while the primitive-looking xenarthrans proved to be surprisingly competitive and became the most successful invaders of North America. The African immigrants, the caviomorph rodents and platyrrhine monkeys, were less impacted by the interchange than most of South America's 'old-timers', although the caviomorphs suffered a significant loss of diversity,{{refn|group=n|Simpson, 1950, p. 382}}{{refn|group=n|Marshall, 1988, p. 386}} including the elimination of the largest forms (e.g. the dinomyids). With the exception of the North American porcupine and several extinct porcupines and capybaras, however, they did not migrate past Central America.{{refn|group=n|Of the 11 extant families of South American caviomorph rodents, five are present in Central America; only two of these, Erethizontidae and Caviidae, ever reached North America. (The nutria/coypu has been introduced to a number of North American locales.)}}

Due in large part to the continued success of the xenarthrans, one area of South American ecospace the Nearctic invaders were unable to dominate was the niches for megaherbivores. Before 12,000 years ago, South America was home to about 25 species of herbivores weighing more than {{Cvt|1000|kg}}, consisting of Neotropic ground sloths, glyptodonts, and toxodontids, as well as gomphotheres and camelids of Nearctic origin.{{refn|group=n|P. S. Martin (2005), pp. 30–37, 119. The figure of 25 South American megaherbivore species breaks down as follows: four gomphotheres, two camelids, nine ground sloths, five glyptodonts, and five toxodontids. This can be compared to Africa's present and recent total of six megaherbivores: one giraffe, one hippo, two rhinos, and two elephants (considering the African forest elephant as a separate species).}} Native South American forms made up about 75% of these species. However, none of these megaherbivores has survived.

File:Opossum 1.jpg, Didelphis virginiana, the only marsupial in temperate North America]]

Armadillos, opossums and porcupines are present in North America today because of the Great American Interchange. Opossums and porcupines were among the most successful northward migrants, reaching as far as Canada and Alaska, respectively. Most major groups of xenarthrans were present in North America until the end-Pleistocene Quaternary extinction event (as a result of at least eight successful invasions of temperate North America, and at least six more invasions of Central America only). Among the megafauna, ground sloths were notably successful emigrants; four different lineages invaded North America. A megalonychid representative, Megalonyx, spread as far north as the Yukon{{cite journal |last1=McDonald |first1=H. G. |last2=Harington |first2=C. R. |last3=De Iuliis |first3=G. |title=The Ground Sloth Megalonyx from Pleistocene Deposits of the Old Crow Basin, Yukon, Canada |journal=Arctic |volume=53 |issue=3 |pages=213–220 |date=September 2000 |url=http://pubs.aina.ucalgary.ca/arctic/Arctic53-3-213.pdf |access-date=2008-08-16 |doi=10.14430/arctic852 |archive-date=2020-07-03 |archive-url=https://web.archive.org/web/20200703013709/http://pubs.aina.ucalgary.ca/arctic/Arctic53-3-213.pdf |url-status=dead }} and Alaska,{{cite journal

|last=Stock |first=C.

|title=A ground sloth in Alaska |journal=Science

|volume=95 |issue=2474 |pages=552–553

|date=1942-05-29 |doi=10.1126/science.95.2474.552 |pmid=17790868 |bibcode=1942Sci....95..552S}} and might well have invaded Eurasia had a suitable habitat corridor across Beringia been present.

Generally speaking, however, the dispersal and subsequent explosive adaptive radiation of sigmodontine rodents throughout South America (leading to over 80 currently recognized genera) was vastly more successful (both spatially and by number of species) than any northward migration of South American mammals. Other examples of North American mammal groups that diversified conspicuously in South America include canids and cervids, both of which currently have three or four genera in North America, two or three in Central America, and six in South America.{{refn|name=canidlisting|group=n|The extant canid and cervid genera by continent are as follows:

Canid genera by continent

• North America: 3 genera, 9 species – Canis, Urocyon, Vulpes
• Central America: 3 genera, 4 species – Canis, Speothos, Urocyon
• South America: 6 genera, 11 species – Atelocynus, Cerdocyon, Chrysocyon, Lycalopex, Speothos, Urocyon
• Eurasia: 4 genera, 12 species – Canis, Cuon, Nyctereutes, Vulpes
• Africa: 4 genera, 12 species – Canis, Lycaon, Otocyon, Vulpes

Cervid genera by continent

• North America: 4 genera, 5 species – Alces, Cervus, Odocoileus, Rangifer
• Central America: 2 genera, 4 species – Mazama, Odocoileus
• South America: 6 genera, 16 species – Blastocerus, Hippocamelus, Mazama, Odocoileus, Ozotoceros, Pudu
• Eurasia: 10 genera, 36 species – Alces, Axis, Capreolus, Cervus, Dama, Elaphodus, Elaphurus, Hydropotes, Muntiacus, Rangifer
• Africa: 1 genus, 1 species – Cervus

}}{{refn|group=n|Including extinct genera, South America has hosted nine genera of cervids, eight genera of mustelids, and 10 genera of canids. However, some of this diversity of South American forms apparently arose in North or Central America prior to the interchange. Significant disagreement exists in the literature concerning how much of the diversification of South America's canids occurred prior to the invasions. A number of studies concur that the grouping of endemic South American canids (excluding Urocyon and Canis, although sometimes transferring C. gezi to the South American group) is a clade. However, different authors conclude that members of this clade reached South America in at least two,{{cite journal |last1=Perini |first1=F. A. |last2=Russo |first2=C. A. M. |last3=Schrago |first3=C. G. |title=The evolution of South American endemic canids: a history of rapid diversification and morphological parallelism |journal=Journal of Evolutionary Biology |volume=23 |issue=2 |date=2009-11-26 |pages=311–322 |doi=10.1111/j.1420-9101.2009.01901.x |pmid=20002250 |s2cid=20763999}} three to four,{{cite journal |last1=Prevosti |first1=F. J. |title=Phylogeny of the large extinct South American Canids (Mammalia, Carnivora, Canidae) using a "total evidence" approach |journal=Cladistics |volume=26 |issue=5 |date=2010-09-07 |pages=456–481 |doi=10.1111/j.1096-0031.2009.00298.x |pmid=34875763 |s2cid=86650539|doi-access=free }} or six{{cite journal |last1=Slater |first1=G. J. |last2=Thalmann |first2=O. |last3=Leonard |first3=J. A. |last4=Schweizer |first4=R. M. |last5=Koepfli |first5=K.-P. |last6=Pollinger |first6=J. P. |last7=Rawlence |first7=N. J. |last8=Austin |first8=J. J. |last9=Cooper |first9=A. |last10=Wayne |first10=Robert K. |title=Evolutionary history of the Falklands wolf |journal=Current Biology |volume=19 |issue=20 |date=2009-11-03 |pages=R937–R938 |doi=10.1016/j.cub.2009.09.018 |pmid=19889366 |s2cid=36185744 |display-authors=8|doi-access=free |bibcode=2009CBio...19.R937S |hdl=10261/58562 |hdl-access=free }} invasions from North America.}} Although members of Canis (specifically, coyotes) currently range only as far south as Panama,{{refn|group=n|Canis, e.g. Canis dirus, was present in South America until the end of the Pleistocene.}} South America still has more extant genera of canids than any other continent.{{refn|name=canidlisting|group=n}}

The effect of formation of the isthmus on the marine biota of the area was the inverse of its effect on terrestrial organisms, a development that has been termed the "Great American Schism". The connection between the east Pacific Ocean and the Caribbean (the Central American Seaway) was severed, setting now-separated populations on divergent evolutionary paths.{{cite journal

|last=Lessios |first=H.A.

|title=The Great American Schism: Divergence of Marine Organisms After the Rise of the Central American Isthmus

|journal=Annual Review of Ecology, Evolution, and Systematics

|volume=39 |pages=63–91

|date=December 2008

|doi=10.1146/annurev.ecolsys.38.091206.095815

}} Caribbean species also had to adapt to an environment of lower productivity after the inflow of nutrient-rich water of deep Pacific origin was blocked.{{cite journal

|last1=Jain |first1=S. |last2=Collins |first2=L. S.

|title=Trends in Caribbean Paleoproductivity related to the Neogene closure of the Central American Seaway

|journal=Marine Micropaleontology |volume=63 |issue=1–2 |pages=57–74 |date=2007-04-30 |doi=10.1016/j.marmicro.2006.11.003 |bibcode=2007MarMP..63...57J}} The Pacific coast of South America cooled as the input of warm water from the Caribbean was cut off. This trend is thought to have caused the extinction of the marine sloths of the area.{{cite journal |last1=Amson |first1=E. |last2=Argot |first2=C. |last3=McDonald |first3=H. G. |last4=de Muizon |first4=C. |year=2015 |title=Osteology and functional morphology of the axial postcranium of the marine sloth Thalassocnus (Mammalia, Tardigrada) with paleobiological implications |journal=Journal of Mammalian Evolution |volume=22 |issue=4 |pages=473–518 |doi=10.1007/s10914-014-9280-7 |s2cid=16700349}}

File:Arctotherium.jpg bonariense, a South American short-faced bear]]

During the last 7 Ma, South America's terrestrial predator guild has changed from one composed almost entirely of nonplacental mammals (metatherians), birds, and reptiles to one dominated by immigrant placental carnivorans (with a few small marsupial and avian predators like didelphine opossums and seriemas). It was originally thought that the native South American predator guild, including sparassodonts, carnivorous opossums like Thylophorops and Hyperdidelphys, armadillos such as Macroeuphractus, terror birds, and teratorns, as well as early-arriving immigrant Cyonasua-group procyonids, were driven to extinction during the GABI by competitive exclusion from immigrating placental carnivorans, and that this turnover was abrupt.{{cite book |title=Evolution of the Thylacosmilidae, extinct saber-tooth marsupials of South America |last=Marshall |first=L.G. |date=1976 |publisher=Museum of Paleontology, University of California |oclc=8409501}}{{cite book |last=Marshall |first=L.G. |title=Major Patterns in Vertebrate Evolution |chapter=Evolution of the Carnivorous Adaptive Zone in South America |date=1977 |chapter-url=https://books.google.com/books?id=9ubvBwAAQBAJ&pg=PA709 |doi=10.1007/978-1-4684-8851-7_24 |pages=709–721 |publisher=Springer US |isbn=978-1-4684-8853-1 |access-date=2020-01-24}} However, the turnover of South America's predator guild was more complex, with competition only playing a limited role.

In the case of sparassodonts and carnivorans, which has been the most heavily studied, little evidence shows that sparassodonts even encountered their hypothesized placental competitors.{{cite book |url=https://books.google.com/books?id=XCdFDwAAQBAJ |title=Evolution of South American Mammalian Predators During the Cenozoic: Paleobiogeographic and Paleoenvironmental Contingencies |last1=Prevosti |first1=F.J. |last2=Forasiepi |first2=A.M. |date=2018 |publisher=Springer International Publishing |isbn=978-3-319-03700-4 |series=Springer Geology |location=Cham |doi=10.1007/978-3-319-03701-1 |bibcode=2018esam.book.....P |s2cid=134939823}}{{cite journal |last1=Prevosti |first1=F.J. |last2=Forasiepi |first2=A. |last3=Zimicz |first3=N. |date=March 2013 |title=The Evolution of the Cenozoic Terrestrial Mammalian Predator Guild in South America: Competition or Replacement? |journal=Journal of Mammalian Evolution |volume=20 |issue=1 |pages=3–21 |doi=10.1007/s10914-011-9175-9 |s2cid=15751319|hdl=11336/2663 |hdl-access=free }}{{cite journal |last1=López-Aguirre |first1=C. |last2=Archer |first2=M. |last3=Hand |first3=S.J. |last4=Laffan |first4=S.W. |date=January 2017 |editor-last=Smith |editor-first=A. |title=Extinction of South American sparassodontans (Metatheria): environmental fluctuations or complex ecological processes? |journal=Palaeontology |volume=60 |issue=1 |pages=91–115 |doi=10.1111/pala.12272|bibcode=2017Palgy..60...91L |s2cid=132584097 |doi-access=free }} Many supposed Pliocene records of South American carnivorans have turned out to be misidentified or misdated.{{cite journal |last1=Prevosti |first1=F.J. |last2=Pardiñas |first2=U.F.J. |date=September 2009 |title=Comment on "The oldest South American Cricetidae (Rodentia) and Mustelidae (Carnivora): Late Miocene faunal turnover in central Argentina and the Great American Biotic Interchange" by D.H. Verzi and C.I. Montalvo [Palaeogeography, Palaeoclimatology, Palaeoecology 267 (2008) 284–291] |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=280 |issue=3–4 |pages=543–547 |doi=10.1016/j.palaeo.2009.05.021 |bibcode=2009PPP...280..543P|hdl=11336/94480 |hdl-access=free }} Sparassodonts appear to have been declining in diversity since the middle Miocene, with many of the niches once occupied by small sparassodonts being increasingly occupied by carnivorous opossums,{{cite journal |last1=Croft |first1=D.A. |last2=Engelman |first2=R.K. |last3=Dolgushina |first3=T. |last4=Wesley |first4=G. |date=2018-01-10 |title=Diversity and disparity of sparassodonts (Metatheria) reveal non-analogue nature of ancient South American mammalian carnivore guilds |journal=Proceedings of the Royal Society B: Biological Sciences |volume=285 |issue=1870 |pages=20172012 |doi=10.1098/rspb.2017.2012 |pmc=5784193 |pmid=29298933}}{{cite journal |last=Zimicz |first=N. |date=December 2014 |title=Avoiding Competition: the Ecological History of Late Cenozoic Metatherian Carnivores in South America |journal=Journal of Mammalian Evolution |volume=21 |issue=4 |pages=383–393 |doi=10.1007/s10914-014-9255-8 |s2cid=10161199 |issn =1064-7554}}{{cite journal |last1=Engelman |first1=R.K. |last2=Anaya |first2=F. |last3=Croft |first3=D.A. |title=Australogale leptognathus, gen. et sp. nov., a Second Species of Small Sparassodont (Mammalia: Metatheria) from the Middle Miocene Locality of Quebrada Honda, Bolivia |journal=Journal of Mammalian Evolution |volume=27 |pages=37–54 |doi=10.1007/s10914-018-9443-z |issn=1064-7554 |year=2020 |s2cid=49473591}}{{cite journal |last1=Beck |first1=R.M.D. |last2=Taglioretti |first2=M.L. |date=2019 |title=A Nearly Complete Juvenile Skull of the Marsupial Sparassocynus derivatus from the Pliocene of Argentina, the Affinities of "Sparassocynids", and the Diversification of Opossums (Marsupialia; Didelphimorphia; Didelphidae) |journal=Journal of Mammalian Evolution |volume=27 |issue=3 |pages=385–417 |doi=10.1007/s10914-019-09471-y |s2cid=198190603|doi-access=free }}{{cite journal |last1=Engelman |first1=R.K. |last2=Croft |first2=D.A. |date=2014-04-16 |title=A new species of small-bodied sparassodont (Mammalia, Metatheria) from the middle Miocene locality of Quebrada Honda, Bolivia |journal=Journal of Vertebrate Paleontology |volume=34 |issue=3 |pages=672–688 |doi=10.1080/02724634.2013.827118 |bibcode=2014JVPal..34..672E |s2cid=84680371 |issn=0272-4634|url=https://figshare.com/articles/dataset/A_new_species_of_small_bodied_sparassodont_Mammalia_Metatheria_from_the_middle_Miocene_locality_of_Quebrada_Honda_Bolivia/1017004 |doi-access=free }} which reached sizes of up to roughly 8 kg (~17 lbs). Whether sparassodonts competed with carnivorous opossums or whether opossums began occupying sparassodont niches through passive replacement is still debated. Borhyaenids last occur in the late Miocene, about 4 Ma before the first appearance of canids or felids in South America. Thylacosmilids last occur about 3 Ma ago and appear to be rarer at pre-GABI Pliocene sites than Miocene ones.

In general, sparassodonts appear to have been mostly or entirely extinct by the time most nonprocyonid carnivorans arrived, with little overlap between the groups. Purported ecological counterparts between pairs of analogous groups (thylacosmilids and saber-toothed cats, borhyaenids and felids, hathliacynids and weasels) neither overlap in time nor abruptly replace one another in the fossil record. Procyonids dispersed to South America by at least 7 Ma ago, and had achieved a modest endemic radiation by the time other carnivorans arrived (Cyonasua-group procyonids). However, procyonids do not appear to have competed with sparassodonts, the procyonids being large omnivores and sparassodonts being primarily hypercarnivorous.{{cite journal |last1=Engelman |first1=R.K. |last2=Croft |first2=D.A. |date=September 2019 |title=Strangers in a strange land: Ecological dissimilarity to metatherian carnivores may partly explain early colonization of South America by Cyonasua-group procyonids |journal=Paleobiology |volume=45 |issue=4 |pages=598–611 |doi=10.1017/pab.2019.29 |bibcode=2019Pbio...45..598E |s2cid=209308325 |issn=0094-8373|doi-access=free }} Other groups of carnivorans did not arrive in South America until much later. Dogs and weasels appear in South America about 2.9 Ma ago, but do not become abundant or diverse until the early Pleistocene. Bears, cats, and skunks do not appear in South America until the early Pleistocene (about 1 Ma ago or slightly earlier). Otters and other groups of procyonids (i.e., coatis, raccoons) have been suggested to have dispersed to South America in the Miocene based on genetic data, but no remains of these animals have been found even at heavily sampled northern South American fossil sites such as La Venta (Colombia), which is only {{Cvt|600|km}} from the Isthmus of Panama.{{cite journal |last1=Nigenda-Morales |first1=S.F. |last2=Gompper |first2=M.E. |last3=Valenzuela-Galván |first3=D. |last4=Lay |first4=A.R. |last5=Kapheim |first5=K.M. |last6=Hass |first6=C. |last7=Booth-Binczik |first7=S.D. |last8=Binczik |first8=G.A. |last9=Hirsch |first9=B.T. |last10=McColgin |first10=M. |last11=Koprowski |first11=J.L. |date=February 2019 |title=Phylogeographic and diversification patterns of the white-nosed coati (Nasua narica): Evidence for south-to-north colonization of North America |journal=Molecular Phylogenetics and Evolution |volume=131 |pages=149–163 |doi=10.1016/j.ympev.2018.11.011 |pmid=30468940|s2cid=53712751 |doi-access=free |bibcode=2019MolPE.131..149N }}{{cite journal |last1=Koepfli |first1=K.-P. |last2=Gompper |first2=M.E. |last3=Eizirik |first3=E. |last4=Ho |first4=C.-C. |last5=Linden |first5=L. |last6=Maldonado |first6=J.E. |last7=Wayne |first7=R.K. |date=June 2007 |title=Phylogeny of the Procyonidae (Mammalia: Carnivora): Molecules, morphology and the Great American Interchange |journal=Molecular Phylogenetics and Evolution |volume=43 |issue=3 |pages=1076–1095 |doi=10.1016/j.ympev.2006.10.003 |pmid=17174109|bibcode=2007MolPE..43.1076K }}{{cite book |last=Eizirik |first=E. |title=Bones, Clones, and Biomes |chapter=A Molecular View on the Evolutionary History and Biogeography of Neotropical Carnivores (Mammalia, Carnivora) |doi=10.7208/chicago/9780226649214.003.0007 |date=2012 |pages=123–142 |publisher=University of Chicago Press |isbn=978-0-226-64919-1}}

Other groups of native South American predators have not been studied in as much depth. Terror birds have often been suggested to have been driven to extinction by placental carnivorans, though this hypothesis has not been investigated in detail.{{cite journal |last=Marshall |first=L.G. |date=February 1994 |title=The Terror Birds of South America |journal=Scientific American |volume=270 |issue=2 |pages=90–95 |doi=10.1038/scientificamerican0294-90 |bibcode=1994SciAm.270b..90M |issn=0036-8733}}{{cite book |title=Palaeobiology of giant flightless birds |last1=Angst |first1=D. |last2=Buffetaut |first2=É. |publisher=ISTE Press |year=2017 |isbn=978-0-08-101143-0 |location =London |oclc=1012400051}} Titanis dispersed from South America to North America against the main wave of carnivoran migrations, being the only large native South American carnivore to accomplish this. However, it only managed to colonize a small part of North America for a limited time, failing to diversify and going extinct in the early Pleistocene (1.8 Ma ago); the modest scale of its success has been suggested to be due to competition with placental carnivorans.{{cite journal |last1=MacFadden |first1=B.J. |last2=Labs-Hochstein |first2=J. |last3=Hulbert |first3=R.C. |last4=Baskin |first4=J.A. |date=2007 |title=Revised age of the late Neogene terror bird (Titanis) in North America during the Great American Interchange |journal=Geology |volume=35 |issue=2 |pages=123 |doi=10.1130/G23186A.1 |issn=0091-7613 |bibcode=2007Geo....35..123M}} Terror birds also decline in diversity after about 3 Ma ago. At least one genus of relatively small terror birds, Psilopterus, appears to have survived to as recently as about 96,000 years ago.{{cite journal |last1=Alvarenga |first1=H. |last2=Jones |first2=W. |last3=Rinderknecht |first3=A. |date=2010-05-01 |title=The youngest record of phorusrhacid birds (Aves, Phorusrhacidae) from the late Pleistocene of Uruguay |journal=Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen |volume=256 |issue=2 |pages=229–234 |doi=10.1127/0077-7749/2010/0052}}{{cite journal |last1=Jones |first1=W. |last2=Rinderknecht |first2=A. |last3=Alvarenga |first3=H. |last4=Montenegro |first4=F. |last5=Ubilla |first5=M. |date=June 2018 |title=The last terror birds (Aves, Phorusrhacidae): new evidence from the late Pleistocene of Uruguay |journal=PalZ |volume=92 |issue=2 |pages=365–372 |doi=10.1007/s12542-017-0388-y |bibcode=2018PalZ...92..365J |s2cid=134344096}}

The native carnivore guild appears to have collapsed completely roughly 3 Ma ago (including the extinction of the last sparassodonts), not correlated with the arrival of carnivorans in South America, with terrestrial carnivore diversity being low thereafter.{{cite journal |last1=Vizcaíno |first1=S.F. |last2=Fariña |first2=R.A. |last3=Zárate |first3=M.A. |last4=Bargo |first4=M.S. |last5=Schultz |first5=P. |date=October 2004 |title=Palaeoecological implications of the mid-Pliocene faunal turnover in the Pampean Region (Argentina) |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=213 |issue=1–2 |pages=101–113 |doi=10.1016/j.palaeo.2004.07.004 |bibcode=2004PPP...213..101V|hdl=11336/81756 |hdl-access=free }} This has been suggested to have opened up ecological niches and allowed carnivorans to establish themselves in South America due to low competition.{{cite journal |last1=Mitchell |first1=K.J. |last2=Bray |first2=S.C. |last3=Bover |first3 =P. |last4=Soibelzon |first4=L. |last5=Schubert |first5=B.W. |last6=Prevosti |first6=F. |last7=Prieto |first7=A. |last8=Martin |first8=F. |last9=A. |first9=J.J. |last10=Cooper |first10=A. |date=2016-04-30 |title=Ancient mitochondrial DNA reveals convergent evolution of giant short-faced bears (Tremarctinae) in North and South America |journal=Biology Letters |volume=12 |issue=4 |pages=20160062 |doi=10.1098/rsbl.2016.0062 |pmc=4881349 |pmid=27095265}}{{cite journal |last=Van Valkenburgh |first=B. |date=1991 |title=Iterative evolution of hypercarnivory in canids (Mammalia: Carnivora): evolutionary interactions among sympatric predators |journal=Paleobiology |volume=17 |issue=4 |pages=340–362 |doi=10.1017/s0094837300010691 |bibcode=1991Pbio...17..340V |s2cid=251052044 |issn=0094-8373}} A meteor impact 3.3 million years ago in southern South America has been suggested as a possible cause of this turnover, but this is still controversial.{{cite journal |last=Schultz |first=P.H. |date=1998-12-11 |title=A 3.3-Ma Impact in Argentina and Possible Consequences |journal=Science |volume=282 |issue=5396 |pages=2061–2063 |doi=10.1126/science.282.5396.2061 |pmid=9851923 |bibcode=1998Sci...282.2061S}} A similar pattern occurs in the crocodilian fauna, where modern crocodiles (Crocodylus) dispersed to South America during the Pliocene and became the dominant member of crocodilian communities after the late Miocene extinction of the previously dominant large native crocodilians such as the giant caiman Purussaurus and giant gharial Gryposuchus, which is thought to be related to the loss of wetlands habitat across northern South America.{{cite journal |last1=Moreno-Bernal |first1=J.W. |last2=Head |first2=J. |last3=Jaramillo |first3=C.A. |date=2016-05-03 |title=Fossil Crocodilians from the High Guajira Peninsula of Colombia: Neogene faunal change in northernmost South America |journal=Journal of Vertebrate Paleontology |volume=36 |issue=3 |pages=e1110586 |doi=10.1080/02724634.2016.1110586 |bibcode=2016JVPal..36E0586M |s2cid=130332367 |issn=0272-4634}}{{cite journal |last1=Cidade |first1=G. M. |last2=Fortier |first2=D. |last3=Hsiou |first3=A.S. |date=March 2019 |title=The crocodylomorph fauna of the Cenozoic of South America and its evolutionary history: a review |journal=Journal of South American Earth Sciences |volume=90 |pages=392–411 |doi=10.1016/j.jsames.2018.12.026 |bibcode=2019JSAES..90..392C|s2cid=134902094 }}

Whether this revised scenario with a reduced role for competitive exclusion applies to other groups of South American mammals such as notoungulates and litopterns is unclear, though some authors have pointed out a protracted decline in South American native ungulate diversity since the middle Miocene.{{cite journal |last1=Croft |first1=D.A. |last2=Gelfo |first2=J.N. |last3=López |first3=G.M. |date=2020-05-30 |title=Splendid Innovation: The Extinct South American Native Ungulates |journal=Annual Review of Earth and Planetary Sciences |volume=48 |issue=1 |pages=annurev–earth–072619-060126 |doi=10.1146/annurev-earth-072619-060126 |bibcode=2020AREPS..48..259C |s2cid=213737574 |issn=0084-6597}} Regardless of how this turnover happened, it is clear that carnivorans benefitted from it. Several groups of carnivorans such as dogs and cats underwent an adaptive radiation in South America after dispersing there, and the greatest modern diversity of canids in the world is in South America.

File:Americas Köppen Map.png, Am and Aw), cover much of South America and nearly all of Central America, but very little of the rest of North America.]]

The eventual triumph of the Nearctic migrants was ultimately based on geography, which played into the hands of the northern invaders in two crucial respects. The first was a matter of climate. Any species that reached Panama from either direction obviously had to be able to tolerate moist tropical conditions. Those migrating southward would then be able to occupy much of South America without encountering climates that were markedly different. However, northward migrants would have encountered drier or cooler conditions by the time they reached the vicinity of the Trans-Mexican Volcanic Belt. The challenge this climatic asymmetry (see map on right) presented was particularly acute for Neotropic species specialized for tropical rainforest environments, which had little prospect of penetrating beyond Central America. As a result, Central America currently has 41 mammal species of Neotropical origin,{{refn|name=CAlisting|group=n|The Central American species of South American origin (opossums, xenarthrans, caviomorph rodents and platyrrhine monkeys) are as follows:

Central American opossum species

• Derby's woolly opossum (Caluromys derbianus)
• Water opossum (Chironectes minimus)
• Common opossum (Didelphis marsupialis)
• Virginia opossum (Didelphis virginiana)
• Mexican mouse opossum (Marmosa mexicana)
• Robinson's mouse opossum (Marmosa robinsoni)
• Panama slender opossum (Marmosops invictus)
• Brown four-eyed opossum (Metachirus nudicaudatus)
• Alston's mouse opossum (Micoureus alstoni)
• Sepia short-tailed opossum (Monodelphis adusta)
• Gray four-eyed opossum (Philander opossum)
• Grayish mouse opossum (Tlacuatzin canescens)

Central American xenarthran species

• Nine-banded armadillo (Dasypus novemcinctus)
• Northern naked-tailed armadillo (Cabassous centralis)
• Pygmy three-toed sloth (Bradypus pygmaeus)
• Brown-throated sloth (Bradypus variegatus)
• Hoffmann's two-toed sloth (Choloepus hoffmanni)
• Silky anteater (Cyclopes didactylus)
• Giant anteater (Myrmecophaga tridactyla)
• Northern tamandua (Tamandua mexicana)

Central American caviomorph rodent species

• Rothschild's porcupine (Coendou rothschildi)
• Mexican hairy dwarf porcupine (Sphiggurus mexicanus)
• Lesser capybara (Hydrochoerus hydrochaeris)
• Coiban agouti (Dasyprocta coibae)
• Mexican agouti (Dasyprocta mexicana)
• Central American agouti (Dasyprocta punctata)
• Ruatan Island agouti (Dasyprocta ruatanica)
• Lowland paca (Cuniculus paca)
• Rufous soft-furred spiny-rat (Diplomys labilis)
• Armored rat (Hoplomys gymnurus)
• Tome's spiny-rat (Proechimys semispinosus)

Central American platyrrhine monkey species

• Coiba Island howler (Alouatta coibensis) – may be a subspecies of Alouatta palliata
• Mantled howler (Alouatta palliata)
• Guatemalan black howler (Alouatta pigra)
• Panamanian night monkey (Aotus zonalis) – may be a subspecies of gray-bellied night monkey (Aotus lemurinus)
• Black-headed spider monkey (Ateles fusciceps)
• Geoffroy's spider monkey (Ateles geoffroyi)
• White-headed capuchin (Cebus capucinus)
• Geoffroy's tamarin (Saguinus geoffroyi)
• Cottontop tamarin (Saguinus oedipus) – possibly recently extirpated in Central America
• Central American squirrel monkey (Saimiri oerstedii)

}} compared to only three for temperate North America. However, species of South American origin (marsupials, xenarthrans, caviomorph rodents, and monkeys) still comprise only 21% of species from nonflying, nonmarine mammal groups in Central America, while North American invaders constitute 49% of species from such groups in South America. Thus, climate alone cannot fully account for the greater success of species of Nearctic origin during the interchange.

File:Nearctic-Neotropic map.png (green) and Nearctic (red) species could wander via two-way migrations during the latter part of the Cenozoic prior to the interchange: The smaller area available for Neotropic species to evolve in tended to put them at a competitive disadvantage.]]

The second and more important advantage geography gave to the northerners is related to the land area in which their ancestors evolved. During the Cenozoic, North America was periodically connected to Eurasia via Beringia, allowing repeated migrations back and forth to unite the faunas of the two continents.{{refn|group=n|During the Miocene alone, between about 23 and 5 Ma ago, 11 episodes of invasions of North America from Eurasia have been recognized, bringing a total of 81 new genera into North America.{{cite journal

|last=Webb |first=S. David

|title=The Great American Biotic Interchange: Patterns and Processes

|journal=Annals of the Missouri Botanical Garden

|volume=93 |issue=2 |pages=245–257 |date=23 August 2006 |doi=10.3417/0026-6493(2006)93[245:TGABIP]2.0.CO;2

|s2cid=198152030

}}}} Eurasia was connected in turn to Africa, which contributed further to the species that made their way to North America.{{refn|group=n|The combination of Africa, Eurasia and North America was termed the "World Continent" by George Gaylord Simpson.{{cite journal

|last=Simpson |first=George Gaylord |author-link=George Gaylord Simpson

|title=History of the Fauna of Latin America

|journal=American Scientist |volume=38 |issue=3 |pages=361–389 |date=July 1950

|url=http://www.wku.edu/~smithch/biogeog/SIMP1950.htm

|jstor=27826322 |access-date=2013-02-14}}}} South America, though, was connected only to Antarctica and Australia, two much smaller and less hospitable continents, and only in the early Cenozoic. Moreover, this land connection does not seem to have carried much traffic (apparently no mammals other than marsupials and perhaps a few monotremes ever migrated by this route), particularly in the direction of South America. This means that Northern Hemisphere species arose within a land area roughly six times greater than was available to South American species. North American species were thus products of a larger and more competitive arena,{{refn|group=n|Simpson, 1950, p. 368}}{{cite book

|last=Gould |first=Stephen Jay |author-link=Stephen Jay Gould

|title=The Panda's Thumb |publisher=W. W. Norton & Company

|year=1980 |pages=[https://books.google.com/books?id=z0XY7Rg_lOwC 352] (see pp. 294–5)

|isbn=978-0-393-01380-1 |oclc=6331415 |title-link=The Panda's Thumb (book)}}{{cite book

|last=Wilson |first=Edward O. |author-link=E. O. Wilson

|title=The Diversity of Life |publisher=W. W. Norton & Company |year=1999

|pages=432 (see p. 130) |url=https://books.google.com/books?id=FzPaB_6Pw4MC

|isbn=978-0-393-31940-8 |oclc=25508994}} where evolution would have proceeded more rapidly. They tended to be more efficient and brainier,{{refn|group=n|According to data on the EQ (encephalization quotient, a measure of the brain to body size ratio adjusted for the expected effect of differences in body size) of fossil ungulates compiled by H. Jerison,{{cite book

|last=Jerison |first=Harry J.

|title=Evolution of the Brain and Intelligence

|publisher=Academic Press |year=1973 |location=New York and London

|pages=(see pp. 320–339) |url=https://books.google.com/books?id=4-jaAAAAMAAJ

|isbn=978-0-12-385250-2 |oclc=700636}} North American ungulates showed a trend towards greater EQs going from the Paleogene to the Neogene periods (average EQs of 0.43 and 0.64, respectively), while the EQs of South American ungulates were static over the same time interval (average EQ unchanged at 0.48). This analysis was later criticized.{{cite journal

|last=Radinsky |first=L.

|title=Brain Evolution in Extinct South American Ungulates

|journal=Brain, Behavior and Evolution

|volume=18 |issue=4 |pages=169–187 |year=1981

|doi=10.1159/000121785 |pmid=7284752

}} Jerison subsequently presented data suggesting that native South American ungulates also lagged in the relative size of their neocortices (a measurement not subject to the vagaries of body mass estimation).{{cite book

|first=Harry J. |last=Jerison

|editor-last=Kaas |editor-first=J. H.

|contribution=What Fossils Tell Us about the Evolution of the Neocortex

|contribution-url=http://hjerison.bol.ucla.edu/pdf/neocortex.pdf

|title=Evolution of Nervous Systems, Vol. 3

|year=2007 |pages=1–12 |place=New York and Oxford |publisher=Elsevier

|doi=10.1016/B0-12-370878-8/00065-3

|isbn=978-0-12-392560-2

|volume=3}} Interestingly, the late survivor Toxodon had one of the highest EQ values (0.88) among native Neotropic ungulates.

Jerison also found that Neogene xenarthrans had low EQs, similar to those he obtained for South American ungulates.}}{{refn|group=n|The estimated EQ of Thylacosmilus atrox, 0.41 (based on a brain mass of 43.2 g, a body mass of 26.4 kg,{{cite journal

|last1=Wroe |first1=S.

|last2=Myers |first2=T. |last3=Seebacher |first3=F |last4=Kear |first4=B. |last5=Gillespie |first5=A. |last6=Crowther |first6=M. |last7=Salisbury |first7=S.

|title=An alternative method for predicting body mass: the case of the Pleistocene marsupial lion

|journal=Paleobiology |volume=29 |issue=3 |pages=403–411

|year=2003 |doi=10.1666/0094-8373(2003)029<0403:AAMFPB>2.0.CO;2|bibcode=2003Pbio...29..403W

|s2cid=85776991

|url=http://doc.rero.ch/record/15424/files/PAL_E2790.pdf

}} and an EQ of 43.2/[0.12*26400^(2/3)]), is high for a sparassodont,{{cite journal

|last1=Quiroga |first1=J. C. |last2=Dozo |first2=M. T.

|title=The brain of Thylacosmilus atrox. Extinct South American saber-tooth carnivore marsupial

|journal=J. Hirnforschung |volume=29 |issue=5 |pages=573–586

|year=1988 |pmid=3216103}} but is lower than that of modern felids, with a mean value of 0.87.{{cite journal

|last=Radinsky |first=L.

|title=Evolution of the Felid Brain |journal=Brain, Behavior and Evolution

|volume=11 |issue=3–4 |pages=214–254 (see p. 242) |year=1975

|doi=10.1159/000123635 |pmid=1181005

}} Estimates of 0.38{{cite book

|last=Jerison |first=Harry J.

|title=Evolution of the Brain and Intelligence

|publisher=Academic Press |year=1973

|location=New York and London |pages=(see p. 359)

|url=https://books.google.com/books?id=4-jaAAAAMAAJ

|isbn=978-0-12-385250-2 |oclc=700636}} and 0.59 have been given for the EQ of much larger Smilodon fatalis (based on body mass estimates of 330 and 175 kg, respectively).}} generally able to outrun and outwit their South American counterparts, who were products of an evolutionary backwater. In the cases of ungulates and their predators, South American forms were replaced wholesale by the invaders, possibly a result of these advantages.

The greater eventual success of South America's African immigrants compared to its native early Cenozoic mammal fauna is another example of this phenomenon, since the former evolved over a greater land area; their ancestors migrated from Eurasia to Africa, two significantly larger continents, before finding their way to South America.

Against this backdrop, the ability of South America's xenarthrans to compete effectively against the northerners represents a special case. The explanation for the xenarthrans' success lies in part in their idiosyncratic approach to defending against predation, based on possession of body armor or formidable claws. The xenarthrans did not need to be fleet-footed or quick-witted to survive. Such a strategy may have been forced on them by their low metabolic rate (the lowest among the therians).{{cite journal

|last1=Elgar |first1=M. A. |last2=Harvey |first2=P. H.

|title=Basal Metabolic Rates in Mammals: Allometry, Phylogeny and Ecology

|journal=Functional Ecology |volume=1 |issue=1 |pages=25–36

|year=1987 |doi=10.2307/2389354 |jstor=2389354|bibcode=1987FuEco...1...25E }}{{cite journal

|last=Lovegrove |first=B. G.

|title=The Zoogeography of Mammalian Basal Metabolic Rate

|journal=The American Naturalist |volume=156 |issue=2

|pages=201–219; see 214–215 |date=August 2000 |doi=10.1086/303383 |pmid=10856202 |jstor=3079219 |s2cid=4436119

}} Their low metabolic rate may in turn have been advantageous in allowing them to subsist on less abundant{{cite journal

|last=McNab |first=Brian K.

|title=Energetics and the limits to the temperate distribution in armadillos

|journal=Journal of Mammalogy |volume=61 |issue=4 |pages=606–627; see p. 618 |date=November 1980 |doi=10.2307/1380307

|jstor=1380307}} or less nutritious food sources. Unfortunately, the defensive adaptations of the large xenarthrans would have offered little protection against humans armed with spears and other projectiles.

{{Further|Quaternary extinction#Nearctic: North America|Quaternary extinction#Neotropic: South America}}

File:Porcupine NPS11952.jpg, Erethizon dorsatum, the largest surviving Neotropic migrant to temperate North America]]

At the end of the Pleistocene epoch, about 12,000 years ago, three dramatic developments occurred in the Americas at roughly the same time (geologically speaking). Paleoindians invaded and occupied the New World (although humans may have been living in the Americas, including what is now the southern US and Chile, more than 15,000 years ago{{Cite web |last1=Magazine |first1=Smithsonian |last2=Gerszak |first2=Jennie Rothenberg Gritz, Fen Montaigne, Rafal |title=The Story of How Humans Came to the Americas Is Constantly Evolving |url=https://www.smithsonianmag.com/science-nature/how-humans-came-to-americas-180973739/ |access-date=2022-03-12 |website=Smithsonian Magazine |language=en}}), the last glacial period came to an end, and a large fraction of the megafauna of both North and South America went extinct. This wave of extinctions swept off the face of the Earth many of the successful participants of the GABI, as well as other species that had not migrated.

All the pampatheres, glyptodonts, ground sloths, equids, proboscideans,{{cite journal

|last=Agenbroad |first=L. D.

|title=North American Proboscideans: Mammoths: The state of Knowledge, 2003

|journal=Quaternary International

|volume=126–128 |pages=73–92 |date=2004-06-26 |doi=10.1016/j.quaint.2004.04.016 |bibcode=2005QuInt.126...73A}}{{cite book

|first=R. W. |last=Graham

|editor-last=Cavarretta |editor-first=G.

|editor2-last=Gioia |editor2-first=P.

|editor3-last=Mussi |editor3-first=M.

|display-editors=3 |editor4-last=Palombo |editor4-first=M. R.

|contribution=Late Quaternary Biogeography and Extinction of Proboscideans in North America

|contribution-url=http://www.sovraintendenzaroma.it/content/download/4925/63042/file/707_709.pdf

|title=The World of Elephants (La Terra degli Elefanti) – Proceedings of the 1st International Congress (Atti del 1 Congrsso Internazionale), Rome October 16–20, 2001

|year=2001 |pages=707–709 |place=Rome |publisher=Consiglio Nazionale delle Ricerche

|isbn=978-88-8080-025-5}} giant short-faced bears, dire wolves, and machairodont species of both continents disappeared. The last of the South and Central American notoungulates and litopterns died out, as well as North America's giant beavers, lions, dholes, cheetahs, and many of its antilocaprid, bovid, cervid, tapirid and tayassuid ungulates. Some groups disappeared over most or all of their original range, but survived in their adopted homes, e.g. South American tapirs, camelids, and tremarctine bears (cougars and jaguars may have been temporarily reduced to South American refugia also). Others, such as capybaras, survived in their original range, but died out in areas to which they had migrated. Notably, this extinction pulse eliminated all Neotropic migrants to North America larger than about 15 kg (the size of a big porcupine), and all native South American mammals larger than about 65 kg (the size of a big capybara or giant anteater). In contrast, the largest surviving native North American mammal, the wood bison, can exceed {{Cvt|900|kg}}, and the largest surviving Nearctic migrant to South America, Baird's tapir, can reach {{Cvt|400|kg}}.

File:Glyptodon old drawing.jpg and †Glyptodon]]

File:Tapirus bairdii -Franklin Park Zoo, Massachusetts, USA-8a.jpg, Tapirus bairdii, the largest surviving Nearctic migrant to South America]]

The near-simultaneity of the megafaunal extinctions with the glacial retreat and the peopling of the Americas has led to proposals that both climate change and human hunting played a role. Although the subject is contentious,{{cite journal

|last=Martin |first=Paul S. |author-link=Paul Schultz Martin

|title=The Discovery of America: The first Americans may have swept the Western Hemisphere and decimated its fauna within 1000 years

|journal=Science |volume=179 |issue=4077 |pages=969–974 |year=1973

|url=http://www.cnr.berkeley.edu/classes/espm-103/Discovery%20of%20America.pdf

|doi=10.1126/science.179.4077.969 |pmid=17842155 |bibcode=1973Sci...179..969M |s2cid=10395314}}{{cite journal

|last1=Grayson |first1=D. K. |last2=Meltzer |first2=D. J.

|title=A requiem for North American overkill |journal=Journal of Archaeological Science

|volume=30 |issue=5 |pages=585–593 |year=2003

|doi=10.1016/S0305-4403(02)00205-4 |bibcode=2003JArSc..30..585G |url=http://www.unl.edu/rhames/courses/current/requiem-overkill.pdf}}{{cite journal

|last1=Fiedel |first1=S. |last2=Haynes |first2=G.

|title=A premature burial: comments on Grayson and Meltzer's "Requiem for overkill"

|journal=Journal of Archaeological Science |volume=31 |issue=1 |pages=121–131 |date=January 2004 |doi=10.1016/j.jas.2003.06.004|bibcode=2004JArSc..31..121F }}{{cite journal

|last1=Grayson |first1=D. K. |last2=Meltzer |first2=D. J.

|title=North American overkill continued? |journal=Journal of Archaeological Science

|volume=31 |issue=1 |pages=133–136 |year=2004

|url=http://faculty.washington.edu/grayson/jas31contd.pdf

|doi=10.1016/j.jas.2003.09.001 |bibcode=2004JArSc..31..133G |access-date=2009-06-12}}{{cite journal

|last=Haynes |first=G.

|title=A review of some attacks on the overkill hypothesis, with special attention to misrepresentations and doubletalk

|journal=Quaternary International |volume=169–170 |pages=84–94 |date=July 2007 |doi=10.1016/j.quaint.2006.07.002 |bibcode=2007QuInt.169...84H}} a number of considerations suggest that human activities were pivotal.{{cite book

|last=Martin |first=P. S. |author-link=Paul Schultz Martin

|title=Twilight of the Mammoths: Ice Age Extinctions and the Rewilding of America

|publisher=University of California Press |year=2005

|url=https://archive.org/details/twilightofmammot00paul

|url-access=registration |isbn=978-0-520-23141-2 |oclc=58055404}}{{cite journal

|last1=Burney

|first1=D. A.

|last2=Flannery

|first2=T. F.

|author-link2=Tim Flannery

|title=Fifty millennia of catastrophic extinctions after human contact

|journal=Trends in Ecology & Evolution

|volume=20

|issue=7

|pages=395–401

|date=July 2005

|url=http://web.njit.edu/~krussell/Required.pdf

|doi=10.1016/j.tree.2005.04.022

|pmid=16701402

|access-date=2014-11-11

|url-status=dead

|archive-url=https://web.archive.org/web/20140525232116/http://web.njit.edu/~krussell/Required.pdf

|archive-date=2014-05-25

}} The extinctions did not occur selectively in the climatic zones that would have been most affected by the warming trend, and no plausible general climate-based megafauna-killing mechanism could explain the continent-wide extinctions. The climate change took place worldwide, but had little effect on the megafauna in Africa and southern Asia, where megafaunal species had coevolved with humans. Numerous very similar glacial retreats had occurred previously within the ice age of the last several million years without ever producing comparable waves of extinction in the Americas or anywhere else.

Similar megafaunal extinctions have occurred on other recently populated land masses (e.g. Australia,{{cite journal

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|last2=Flannery |first2=T. F. |last3=Ayliffe |first3=L. K. |last4=Yoshida |first4=H. |last5=Olley |first5=J. M. |last6=Prideaux |first6=G. J. |last7=Laslett |first7=G. M. |last8=Baynes |first8=A. |last9=Smith |first9=M. A. |last10=Jones |first10=R. |last11=Smith |first11=B. L.

|author-link2=Tim Flannery

|title=New Ages for the Last Australian Megafauna: Continent-Wide Extinction About 46,000 Years Ago

|journal=Science |volume=292 |issue=5523 |pages=1888–1892

|date=2001-06-08 |url=http://www.uow.edu.au/content/groups/public/@web/@sci/@eesc/documents/doc/uow014698.pdf

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}}{{cite journal

|last1=Johnson |first1=C. N. |last2=Alroy |first2=J. |last3=Beeton |first3=N. J. |last4=Bird |first4=M. I. |last5=Brook |first5=B. W. |last6=Cooper |first6=A. |last7=Gillespie |first7=R. |last8=Herrando-Pérez |first8=S. |last9=Jacobs |first9=Z. |last10=Miller |first10=G. H. |last11=Prideaux |first11=G. J. |last12=Roberts |first12=R. G. |last13=Rodríguez-Rey |first13=M. |last14=Saltré |first14=F. |last15=Turney |first15=C. S. M. |last16=Bradshaw |first16=C. J. A.

|title=What caused extinction of the Pleistocene megafauna of Sahul?

|journal=Proceedings of the Royal Society B: Biological Sciences |volume=283 |issue=1824 |pages=20152399

|date=10 February 2016 |doi=10.1098/rspb.2015.2399 |pmid=26865301 |pmc=4760161}} Japan,{{cite journal

|last1=Norton |first1=C. J. |last2=Kondo |first2=Y. |last3=Ono |first3=A. |last4=Zhang |first4=Y. |last5=Diab |first5=M. C.

|title=The nature of megafaunal extinctions during the MIS 3–2 transition in Japan

|journal=Quaternary International |volume=211 |issue=1–2 |pages=113–122

|date=2009-05-23

|doi=10.1016/j.quaint.2009.05.002

|bibcode=2010QuInt.211..113N}} Madagascar,{{cite journal

|last1=Burney |first1=D. A.

|last2=Burney |first2=L. P. |last3=Godfrey |first3=L. R. |last4=Jungers |first4=W. L. |last5=Goodman |first5=S. M. |last6=Wright |first6=H. T. |last7=Jull |first7=A. J. T.

|title=A chronology for late prehistoric Madagascar

|journal=Journal of Human Evolution |volume=47 |issue=1–2 |pages=25–63

|date=July 2004

|doi=10.1016/j.jhevol.2004.05.005

|pmid=15288523|bibcode=2004JHumE..47...25B

}} New Zealand,{{cite journal

|last1=Holdaway |first1=R. N. |last2=Jacomb |first2=C.

|date=2000-03-24 |title=Rapid Extinction of the Moas (Aves: Dinornithiformes): Model, Test, and Implications

|journal=Science |volume=287 |issue=5461 |pages=2250–2254

|doi=10.1126/science.287.5461.2250

|pmid=10731144 |bibcode=2000Sci...287.2250H}} and many smaller islands around the world, such as Cyprus,{{cite book

|last=Simmons |first=A. H.

|title=Faunal extinction in an island society: pygmy hippopotamus hunters of Cyprus |publisher=Kluwer Academic/Plenum Publishers

|series=Interdisciplinary Contributions to Archaeology

|year=1999 |pages=229–230 |url=https://books.google.com/books?id=hCwYwyEBXEAC

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|oclc=41712246}} Crete, Tilos and New Caledonia{{cite journal

|last1=Anderson |first1=A. |last2=Sand |first2=C. |last3=Petchey |first3=F. |last4=Worthy |first4=T. H.

|title=Faunal extinction and human habitation in New Caledonia: Initial results and implications of new research at the Pindai Caves

|journal=Journal of Pacific Archaeology |volume=1 |issue=1 |pages=89–109

|year=2010 |hdl=10289/5404}}) at different times that correspond closely to the first arrival of humans at each location. These extinction pulses invariably swept rapidly over the full extent of a contiguous land mass, regardless of whether it was an island or a hemisphere-spanning set of connected continents. This was true despite the fact that all the larger land masses involved (as well as many of the smaller ones) contained multiple climatic zones that would have been affected differently by any climate changes occurring at the time. However, on sizable islands far enough offshore from newly occupied territory to escape immediate human colonization, megafaunal species sometimes survived for many thousands of years after they or related species became extinct on the mainland; examples include giant kangaroos in Tasmania,{{cite journal

|last=Diamond |first=Jared |author-link=Jared Diamond

|title=Palaeontology: The last giant kangaroo

|journal=Nature |volume=454 |issue=7206 |pages=835–836

|date=2008-08-13

|doi=10.1038/454835a

|pmid=18704074

|bibcode=2008Natur.454..835D |s2cid=36583693}}{{cite journal

|last1=Turney |first1=C. S. M.

|last2=Flannery |first2=T. F. |last3=Roberts |first3=R. G.

|author-link2=Tim Flannery

|title=Late-surviving megafauna in Tasmania, Australia, implicate human involvement in their extinction

|journal=Proceedings of the National Academy of Sciences |volume=105 |issue=34 |pages=12150–12153 |date=2008-08-21

|doi=10.1073/pnas.0801360105

|pmid=18719103

|pmc=2527880

|bibcode=2008PNAS..10512150T|doi-access=free

}} giant Chelonoidis tortoises of the Galápagos Islands (formerly also of South America{{cite journal

|last1=Cione

|first1=A. L.

|last2=Tonni

|first2=E. P.

|last3=Soibelzon

|first3=L.

|title=The Broken Zig-Zag: Late Cenozoic large mammal and tortoise extinction in South America

|journal=Rev. Mus. Argentino Cienc. Nat. |series=N.S.

|volume=5

|issue=1

|pages=1–19

|year=2003

|url=http://www.ege.fcen.uba.ar/materias/general/Broken_ZigZagMACN_5_1_19_.pdf

|access-date=2011-02-06

|url-status=dead

|archive-url=https://web.archive.org/web/20110706084815/http://www.ege.fcen.uba.ar/materias/general/Broken_ZigZagMACN_5_1_19_.pdf

|archive-date=2011-07-06

|doi=10.22179/REVMACN.5.26

}}), giant Dipsochelys tortoises of the Seychelles (formerly also of Madagascar), giant meiolaniid turtles on Lord Howe Island, New Caledonia and Vanuatu (previously also of Australia),{{cite journal

|last1=White |first1=A. W. |last2=Worthy |first2=T. H. |last3=Hawkins |first3=S. |last4=Bedford |first4=S. |last5=Spriggs |first5=M.

|title=Megafaunal meiolaniid horned turtles survived until early human settlement in Vanuatu, Southwest Pacific

|journal=Proc. Natl. Acad. Sci. USA

|volume=107 |issue=35 |pages=15512–15516

|date=2010-08-16 |doi=10.1073/pnas.1005780107

|pmid=20713711

|pmc=2932593

|bibcode=2010PNAS..10715512W|doi-access=free }}{{refn|group=n|The giant tortoises of Asia and Africa{{cite book

|last=Harrison |first=T.

|title=Paleontology and Geology of Laetoli: Human Evolution in Context

|publisher=Springer Science+Business Media

|series=Vertebrate Paleobiology and Paleoanthropology

|year=2011

|chapter=Tortoises (Chelonii, Testudinidae)

|pages=479–503

|doi=10.1007/978-90-481-9962-4_17

|isbn=978-90-481-9961-7}} died out much earlier in the Quaternary than those of South America, Madagascar and Australia, while those of North America{{cite journal

|last1=Hansen |first1=D. M. |last2=Donlan |first2=C. J. |last3=Griffiths |first3=C. J. |last4=Campbell |first4=K. J.

|title=Ecological history and latent conservation potential: large and giant tortoises as a model for taxon substitutions

|journal=Ecography |volume=33 |issue=2 |pages=272–284

|date=April 2010

|doi=10.1111/j.1600-0587.2010.06305.x

|doi-access=free |bibcode=2010Ecogr..33..272H }} died out around the same time.}} ground sloths on the Antilles,{{cite journal

|last1=Steadman |first1=D. W. |author-link1=David Steadman

|author-link2=Paul Schultz Martin |last2=Martin |first2=P. S. |last3=MacPhee |first3=R. D. E. |last4=Jull |first4=A. J. T. |last5=McDonald |first5=H. G. |last6=Woods |first6=C. A. |last7=Iturralde-Vinent |first7=M. |last8=Hodgins |first8=G. W. L.

|title=Asynchronous extinction of late Quaternary sloths on continents and islands

|journal=Proceedings of the National Academy of Sciences

|volume=102 |issue=33 |pages=11763–11768

|date=2005-08-16

|doi=10.1073/pnas.0502777102

|pmid=16085711

|pmc=1187974 |bibcode=2005PNAS..10211763S|doi-access=free }}{{cite journal |last1=Cooke |first1=S. B. |last2=Dávalos |first2=L. M. |last3=Mychajliw |first3=A. M. |last4=Turvey |first4=S. T. |last5=Upham |first5=N. S. |title=Anthropogenic Extinction Dominates Holocene Declines of West Indian Mammals |journal=Annual Review of Ecology, Evolution, and Systematics |volume=48 |issue=1 |year=2017 |pages=301–327 |doi=10.1146/annurev-ecolsys-110316-022754|s2cid=90558542 }} Steller's sea cows off the Commander Islands{{cite journal

|last=Anderson |first=Paul K.

|title=Competition, Predation, and the Evolution and Extinction of Steller's Sea Cow, Hydrodamalis gigas

|journal=Marine Mammal Science

|volume=11 |issue=3 |pages=391–394 |year=1995

|doi=10.1111/j.1748-7692.1995.tb00294.x

|bibcode=1995MMamS..11..391A

}} and woolly mammoths on Wrangel Island{{cite journal |last1=Vartanyan |first1=S. L. |last2=Garutt |first2=V. E. |last3=Sher |first3=A. V. |year=1993 |title=Holocene dwarf mammoths from Wrangel Island in the Siberian Arctic |journal=Nature |volume=362 |issue=6418 |pages=337–349 |doi=10.1038/362337a0 |bibcode=1993Natur.362..337V |pmid=29633990 |s2cid=4249191}} and Saint Paul Island.{{cite journal |last=Guthrie |first=R. Dale |year=2004 |title=Radiocarbon evidence of mid-Holocene mammoths stranded on an Alaskan Bering Sea island |journal=Nature |volume=429 |issue=6993 |pages=746–749 |doi=10.1038/nature02612 |pmid=15201907 |bibcode=2004Natur.429..746D |s2cid=186242235}}

The glacial retreat may have played a primarily indirect role in the extinctions in the Americas by simply facilitating the movement of humans southeastward from Beringia to North America. The reason that a number of groups went extinct in North America but lived on in South America (while no examples of the opposite pattern are known) appears to be that the dense rainforest of the Amazon basin and the high peaks of the Andes provided environments that afforded a degree of protection from human predation.{{cite book

|last1=Martin |first1=P. S. |author-link=Paul Schultz Martin

|last2=Steadman |first2=D. W. |author2-link=David Steadman

|editor-last=MacPhee |editor-first=R. D. E

|title=Extinctions in near time: causes, contexts and consequences

|place=New York |publisher=Kluwer/Plenum

|series=Advances in Vertebrate Paleobiology |volume=2 |date=1999-06-30

|chapter=Prehistoric extinctions on islands and continents

|chapter-url=https://books.google.com/books?id=UZLuF1YXYTcC&pg=PA38

|pages=17–56; see p. 38 |url=https://books.google.com/books?id=UZLuF1YXYTcC

|isbn=978-0-306-46092-0

|oclc=41368299 |access-date=2015-11-07

}}{{refn|group=n|P. S. Martin (2005), p. 175.}}{{refn|group=n|A number of recently extinct North American (and in some cases also South American) taxa such as tapirs, equids, camelids, saiga antelope, proboscids, dholes, and lions survived in the Old World, probably mostly for different reasons – tapirs being a likely exception, since their Old World representative survived only in the rainforests of Southeast Asia. (Cheetahs in the broadest sense could be added to this list, although the New and Old World forms are in different genera.) Old World herbivores may in many cases have been able to learn to be vigilant about the presence of humans during a more gradual appearance (by development or migration) of advanced human hunters in their ranges. In the cases of predators, the Old World representatives in at least some locations would thus have suffered less from extinctions of their prey species. In contrast, the musk ox represents a rare example of a megafaunal taxon that recently became extinct in Asia, but survived in remote areas of arctic North America (its more southerly-distributed relatives, such as the woodland muskox and shrub-ox, were less fortunate).}}

Extant or extinct (†) North American taxa whose ancestors migrated out of South America and reached the modern territory of the contiguous United States:{{refn|name=qualifier|group=n|This listing currently has fairly complete coverage of mammals, but only spotty coverage of other groups. Crossings by nonflying mammals and birds occurred during the last 10 Ma. Crossings by fish, arthropods, rafting amphibians and reptiles, and flying bats and birds were made before 10 Ma ago in many cases. Taxa listed as invasive did not necessarily cross the isthmus themselves; they may have evolved in the adopted land mass from ancestral taxa that made the crossing.}}

Fish

• Cichlids (Cichlidae: e.g. Texas cichlid) – freshwater fish that often tolerate brackish conditions

Amphibians

• Bufonid toads (Bufo){{cite book |first1=P. E. |last1=Vanzolini |first2=W. R. |last2=Heyer |editor-last=Stehli |editor-first=F. G. |editor2-last=Webb |editor2-first=S. D. |contribution=The American Herpetofauna and the Interchange |contribution-url=http://vertebrates.si.edu/herps/herps_pdfs/heyer_pdfs/1980s/Vanzolini_Heyer_1985_475-487.PDF |title=The Great American Biotic Interchange |series=Topics in Geobiology, vol. 4 |year=1985 |pages=475–487 |publisher=Plenum Press |url=https://books.google.com/books?id=VMUTAQAAIAAJ |isbn=978-0-306-42021-4}}{{cite journal |last1=Pauly |first1=G. B |last2=Hillis |first2=D. M. |last3=Cannatella |first3=D. C. |title=The history of a Nearctic colonization: Molecular phylogenetics and biogeography of the Nearctic toads (Bufo) |journal=Evolution |volume=58 |issue=11 |pages=2517–2535 |date=November 2004 |doi=10.1111/j.0014-3820.2004.tb00881.x |pmid=15612295 |s2cid=10281132|doi-access=free }}
• Hylid frogs{{cite journal |last1=Faivovich |first1=J. |last2=Haddad |first2=C. F. B. |last3=Garcia |first3=P. C. A. |last4=Frost |first4=D. R. |last5=Campbell |first5=J. A. |last6=Wheeler |first6=W. C. |title=Systematic review of the frog family Hylidae, with special reference to Hylinae: phylogenetic analysis and taxonomic revision |journal=Bulletin of the American Museum of Natural History |volume=294 |pages=240 pages; see pp. 125–128 |date=2005-06-24 |url=http://www.cnah.org/pdf_files/248.pdf |access-date=2010-03-07 |doi=10.1206/0003-0090(2005)294[0001:srotff]2.0.co;2 |url-status=dead |archive-url=https://web.archive.org/web/20110726155057/http://www.cnah.org/pdf_files/248.pdf |archive-date=2011-07-26 |citeseerx=10.1.1.470.2967|s2cid=83925199 }}
• Leptodactylid frogs{{cite journal |last1=Heinicke |first1=M. P. |last2=Duellman |first2=W. E. |last3=Hedges |first3=S. B. |title=Major Caribbean and Central American frog faunas originated by ancient oceanic dispersal |journal=Proc. Natl. Acad. Sci. |date=2007-06-04 |volume=104 |issue=24 |pages=10092–10097 |doi=10.1073/pnas.0611051104 |pmid=17548823 |pmc=1891260 |bibcode=2007PNAS..10410092H|doi-access=free }} – as far north as Texas
• Microhylid frogs

Birds

• Parrots (Neotropical parrots: thick-billed parrot, †Carolina parakeet)
• †Terror birds (Phorusrhacidae: Titanis walleri)
• Tanagers (Thraupidae){{cite journal |title=Splendid isolation: historical ecology of the South American passerine fauna |last1=Ricklefs |first1=R. E. |journal=Journal of Avian Biology |volume=33 |issue=3 |pages=207–211 |year=2002 |doi=10.1034/j.1600-048X.2002.330301.x |author-link=Robert Ricklefs|doi-access=free }}
• Hummingbirds (Trochilidae)
• Suboscine birds (Tyranni):
• Tityras and allies (Tityridae): rose-throated becard
• Tyrant flycatchers (Tyrannidae)

Mammals

• Virginia opossum (Didelphis virginiana)
• Xenarthrans (Xenarthra)
• Armadillos (nine-banded armadillo Dasypus novemcinctus, †D. bellus)
• †Pachyarmatherium leiseyi, an enigmatic armored armadillo relative
• †Pampatheres (Plaina, Holmesina) – large armadillo-like animals
• †Glyptodonts (Glyptotherium)
• †Megalonychid ground sloths (Pliometanastes, Megalonyx)
• †Megatheriid ground sloths (Eremotherium)
• †Mylodontid ground sloths (Thinobadistes, Glossotherium,{{cite journal |last1=Castaneda |first1=O. C. |last2=Miller |first2=W. |title=Late Tertiary Terrestrial Mammals from Central Mexico and Their Relationship to South American Immigrants |journal=Revista Brasileira de Paleontologia |volume=7 |issue=2 |pages=249–261 |date=July 2004 |url=http://www.sbpbrasil.org/revista/edicoes/7_2/miller.pdf |doi=10.4072/rbp.2004.2.19 |access-date=2009-01-29}} Paramylodon)
• †Nothrotheriid ground sloths (Nothrotheriops, Nothrotherium)
• Rodents (Rodentia)
• New World porcupines (Erethizon dorsatum, †Erethizon poyeri, †E. kleini)
• Capybaras (†Neochoerus pinckneyi, †N. aesopi, †Hydrochoerus hesperotiganites)
• †Mixotoxodon – a rhino-sized toxodontid notoungulate{{refn|group=n|Mixotoxodon remains have been collected in Central America and Mexico as far north as Veracruz and Michoacán, with a possible find in Tamaulipas;{{cite journal |last1=Arroyo-Cabrales |first1=Joaquín |last2=Polaco |first2=Oscar J. |last3=Johnson |first3=Eileen |last4=Ferrusquía-Villafranca |first4=Ismael |title=A perspective on mammal biodiversity and zoogeography in the Late Pleistocene of México |journal=Quaternary International |volume=212 |issue=2 |pages=187–197 |date=2010-02-01 |doi=10.1016/j.quaint.2009.05.012 |bibcode=2010QuInt.212..187A}} additionally, one fossil tooth has been identified in eastern Texas, United States.{{cite journal |last1=Lundelius |first1=E. L. |last2=Bryant |first2=V. M. |last3=Mandel |first3=R. |last4=Thies |first4=K. J. |last5=Thoms |first5=A. |title=The first occurrence of a toxodont (Mammalia, Notoungulata) in the United States |journal=Journal of Vertebrate Paleontology |volume=33 |issue=1 |date=January 2013 |pages=229–232 |issn=0272-4634 |doi=10.1080/02724634.2012.711405 |bibcode=2013JVPal..33..229L |hdl=1808/13587 |s2cid=53601518 |url=https://kuscholarworks.ku.edu/bitstream/1808/13587/1/Lundelius_et_al_2013.pdf}}}}
• Cougar (Puma concolor) – returning from a South American refugium after North American cougars were extirpated in the Pleistocene extinctions{{cite journal |title=Genomic Ancestry of the American Puma (Puma concolor) |last1=Culver |first1=M. |last2=Johnson |first2=W. E. |last3=Pecon-Slattery |first3=J. |last4=O'Brien |first4=S. J. |journal=Journal of Heredity |volume=91 |issue=3 |pages=186–197 |year=2000 |doi=10.1093/jhered/91.3.186 |url=http://www.fws.gov/filedownloads/ftp_verobeach/Habitat%20Conservation%20Planning/2010%20Orig/2/20091019_release_FWS%20to%20CSWFL/Culver%20et%20al%202000.PDF |pmid=10833043 }}{{Dead link|date=March 2022 |bot=InternetArchiveBot |fix-attempted=yes }}
• Bats (Chiroptera)
• Molossid bats
• Mormoopid bats (Mormoops megalophylla)
• Vampire bats (†Desmodus stocki, †D. archaeodaptes)

File:Green-Treefrog-North-American-Gray-Species-5.JPG|Gray tree frog, Hyla versicolor

File:Nine-banded Armadillo.jpg|Nine-banded armadillo, Dasypus novemcinctus

File:Gyptodon Cosmo Caixa.JPG|The pampathere †Holmesina septentrionalis

File:Glyptotheriumm.jpg|The glyptodont †Glyptotherium

File:Eremotherium laurillardi2.jpg|The megatheriid ground sloth †Eremotherium

File:Mixotoxodon.jpg|The toxodontid †Mixotoxodon

Extant or extinct (†) North American taxa whose ancestors migrated out of South America, but failed to reach the contiguous United States and were confined to Mexico and Central America:{{refn|name=qualifier|group=n}}{{refn|group=n|Central America is usually defined physiographically as ending at the Isthmus of Tehuantepec or less commonly, at the Trans-Mexican Volcanic Belt. Most of the taxa that proceeded farther but failed to reach the present Mexican border are or were confined to tropical or subtropical climates similar to those of Central America. Examples include the giant anteater, the grayish mouse opossum, the lowland paca, and Geoffroy's spider monkey.}}

Invertebrates

• Gonyleptid harvestmen (Opiliones: Gonyleptidae)

Fish

• Electric knifefishes (Gymnotiformes)
• Hoplosternum punctatum – an armored catfish (Siluriformes: Callichthyidae)
• Several species of loricariid catfish (Siluriformes: Loricariidae)

Amphibians

• Caeciliid caecilians (Caecilia, Oscaecilia) – snake-like amphibians, Panama and Costa Rica only{{cite journal |title=Molecular Evidence for the Early History of Living Amphibians |last1=Feller |first1=A. E. |last2=Hedges |first2=S. B. |journal=Molecular Phylogenetics and Evolution |volume=9 |issue=3 |pages=509–516 |date=June 1998 |doi=10.1006/mpev.1998.0500 |pmid=9667999|bibcode=1998MolPE...9..509F }}
• Poison dart frogs (Dendrobatidae){{cite journal |last1=Santos |first1=J. C. |last2=Coloma |first2=L. A. |last3=Summers |first3=K. |last4=Caldwell |first4=J. P. |last5=Ree |first5=R. |last6=Cannatella |first6=D. C. |title=Amazonian Amphibian Diversity is Primarily Derived from Late Miocene Andean Lineages |journal=PLOS Biology |volume=7 |issue=3 |pages=448–461 (see pp. 452, 454–455) |date=March 2009 |doi=10.1371/journal.pbio.1000056 |pmid=19278298 |pmc=2653552 |doi-access=free }}

Reptiles

• Boine boas (Boidae: Boinae)
• Spectacled caiman (Caiman crocodilus){{cite journal |last1=Taplin |first1=L. E. |last2=Grigg |first2=G. C. |title=Historical Zoogeography of the Eusuchian Crocodilians: A Physiological Perspective |journal=American Zoologist |volume=29 |issue=3 |pages=885–901 |year=1989 |doi=10.1093/icb/29.3.885|doi-access=free }}
• †Purussaurus{{cite journal |last1=Hastings |first1=Alexander K. |last2=Bloch |first2=Jonathan I. |last3=Jaramillo |first3=Carlos A. |last4=Rincon |first4=Aldo F. |last5=Macfadden |first5=Bruce J. |title=Systematics and biogeography of crocodylians from the Miocene of Panama |journal=Journal of Vertebrate Paleontology |date=5 March 2013 |volume=33 |issue=2 |pages=239–263 |doi=10.1080/02724634.2012.713814 |bibcode=2013JVPal..33..239H |s2cid=83972694|doi-access=free }} – giant caimans

Birds

• Great curassow (Crax rubra){{cite journal |last1=Pereira |first1=S. L. |last2=Baker |first2=A. J. |title=Vicariant Speciation of Curassows (Aves, Cracidae): A Hypothesis Based On Mitochondrial DNA Phylogeny |journal=The Auk |volume=121 |issue=3 |year=2004 |pages=682–694 |doi=10.1642/0004-8038(2004)121[0682:VSOCAC]2.0.CO;2|s2cid=86320083 |doi-access=free }}
• Toucans (Ramphastidae)
• Tinamous (Tinamidae)
• Additional suboscine birds (Tyranni):
• Gnateaters (Conopophagidae)
• Cotingas (Cotingidae)
• Ground antbirds (Formicariidae)
• Ovenbirds and woodcreepers (Furnariidae){{cite journal |last1=Irestedt |first1=Martin |last2=Fjeldså |first2=Jon |last3=Johansson |first3=Ulf S. |last4=Ericson |first4=Per G.P. |year=2002 |title=Systematic relationships and biogeography of the tracheophone suboscines (Aves: Passeriformes) |journal=Molecular Phylogenetics and Evolution |volume=23 |issue=3 |pages=499–512 |doi=10.1016/S1055-7903(02)00034-9 |pmid=12099801|bibcode=2002MolPE..23..499I }}
• Antpittas (Grallariidae)
• Manakins (Pipridae)
• Tapaculos (Rhinocryptidae){{cite journal |last1=Weir |first1=J. T. |last2=Bermingham |first2=E. |last3=Schluter |first3=D. |title=The Great American Biotic Interchange in birds |journal=Proceedings of the National Academy of Sciences |volume=106 |issue=51 |date=2009-12-22 |pages=21737–21742 |issn=0027-8424 |doi=10.1073/pnas.0903811106 |pmid=19996168 |pmc=2799814 |bibcode=2009PNAS..10621737W|doi-access=free }}
• Antbirds (Thamnophilidae)
• Other Neotropical parrots (Arinae)

Mammals

• Other opossums (Didelphidae) – 11 additional extant species{{refn|name=CAlisting|group=n}}
• Xenarthrans (Xenarthra)
• Northern naked-tailed armadillo (Cabassous centralis)
• Three-toed sloths (Bradypodidae: Bradypus variegatus, B. pygmaeus)
• Hoffmann's two-toed sloth (Choloepodidae: Choloepus hoffmanni)
• †Scelidotheriid ground sloths (Scelidotherium, found in Panama{{cite web |title=Scelidotherium in the Paleobiology Database |work=Fossilworks |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=43646 |access-date=17 December 2021 |archive-date=18 June 2022 |archive-url=https://web.archive.org/web/20220618111255/http://www.fossilworks.org/cgi-bin/bridge.pl?action=taxonInfo&taxon_no=43646 |url-status=live }})
• Silky anteater (Cyclopedidae: Cyclopes dorsalis)
• Other anteaters (Myrmecophagidae: Myrmecophaga tridactyla,{{refn|group=n|Fossils of the giant anteater have been found as far north as northwestern Sonora, Mexico.{{cite journal |last1=Shaw |first1=C. A. |last2=McDonald |first2=H. G. |title=First Record of Giant Anteater (Xenarthra, Myrmecophagidae) in North America |journal=Science |volume=236 |issue=4798 |pages=186–188 |date=1987-04-10 |pmid=17789783 |doi=10.1126/science.236.4798.186 |jstor=1698387 |bibcode=1987Sci...236..186S |s2cid=27112941}}}} Tamandua mexicana)
• Rodents (Rodentia)
• Rothschild's and Mexican hairy dwarf porcupines (Coendou rothschildi, Sphiggurus mexicanus)
• Other caviomorph rodents (Caviomorpha) – 9 additional extant species{{refn|name=CAlisting|group=n}}
• Platyrrhine monkeys (Platyrrhini) – at least 8 extant species{{refn|name=CAlisting|group=n}}{{refn|group=n|It has been proposed that monkeys invaded Central America in at least three and probably four waves, as follows: (1) an initial invasion by A. pigra and S. oerstedii ~ 3 Ma ago; (2) an invasion by A. palliata (giving rise to A. coibensis), A. geoffroyi and C. capucinus ~ 2 Ma ago; an invasion by A. zonalis and S. geoffroyi ~ 1 Ma ago; a most recent invasion by A. fusciceps. The species of the first wave have apparently been out-competed by those of the second, and now have much more restricted distributions.{{cite book |last1=Ford |first1=S. |editor-last1=Estrada |editor-first1=A. |editor-last2=Garber |editor-first2=P.A. |editor-last3=Pavelka |editor-first3=M.S.M. |editor-last4=Luecke |editor-first4=L. |chapter=The Biogeographic History of Mesoamerican Primates |title=New Perspectives in the Study of Mesoamerican Primates |url=https://archive.org/details/newperspectivess00estr |url-access=limited |pages=[https://archive.org/details/newperspectivess00estr/page/n92 81]–114 |isbn=978-0-387-25854-6 |year=2006 |publisher=Springer |location=New York |doi=10.1007/0-387-25872-8_4 |series=Developments in Primatology: Progress and Prospects}}}}
• Carnivorans (Carnivora)
• Olingos (Bassaricyon) – thought to have arisen in the Andes of northwest South America after their procyonid ancestors invaded from the north, before diversifying and migrating back to Central America{{cite journal |title=Taxonomic revision of the olingos (Bassaricyon), with description of a new species, the Olinguito |last1=Helgen |first1=K. M. |last2=Pinto |first2=M. |last3=Kays |first3=R. |last4=Helgen |first4=L. |last5=Tsuchiya |first5=M. |last6=Quinn |first6=A. |last7=Wilson |first7=D. |last8=Maldonado |first8=J. |journal=ZooKeys |issue=324 |date=2013-08-15 |pages=1–83 |doi=10.3897/zookeys.324.5827 |pmid=24003317 |pmc=3760134|doi-access=free |bibcode=2013ZooK..324....1H }}
• South American short-faced bears (Tremarctinae: †Arctotherium wingei) – thought to have invaded to as far as the Yucatán after arising in South America from North American ancestors{{cite journal |last1=Schubert |first1=B. W. |last2=Chatters |first2=J. C. |last3=Arroyo-Cabrales |first3=J. |last4=Samuels |first4=J. X. |last5=Soibelzon |first5=L. H. |last6=Prevosti |first6=F. J. |last7=Widga |first7=C. |last8=Nava |first8=A. |last9=Rissolo |first9=D. |last10=Erreguerena |first10=P. L. |title=Yucatán carnivorans shed light on the Great American Biotic Interchange |journal=Biology Letters |volume=15 |issue=5 |year=2019 |pages=20190148 |id=20190148 |doi=10.1098/rsbl.2019.0148 |pmid=31039726 |pmc=6548739}}
• South American canids (Caninae: †Protocyon troglodytes) – thought to have invaded to as far as the Yucatán after arising in South America from North American ancestors
• Bats (Chiroptera)
• Emballonurid bats
• Furipterid bats (Furipterus horrens)
• Other mormoopid bats
• Noctilionid bats{{cite journal |last1=Gunnell |first1=G. F. |last2=Simmons |first2=N. B. |last3=Seiffert |first3=E. R. |date=2014-02-04 |title=New Myzopodidae (Chiroptera) from the Late Paleogene of Egypt: Emended Family Diagnosis and Biogeographic Origins of Noctilionoidea |journal=PLoS ONE |volume=9 |issue=2 |pages=e86712 |doi=10.1371/journal.pone.0086712 |pmid=24504061 |pmc=3913578 |bibcode=2014PLoSO...986712G|doi-access=free }} (Noctilio albiventris, Noctilio leporinus)
• Other phyllostomid bats, including all 3 extant vampire bat species (Desmodontinae)
• Thyropterid bats (Thyroptera discifera, Thyroptera tricolor)

File:Oophaga pumilio (Strawberry poision frog) (2532163201).jpg|Strawberry poison-dart frog, Oophaga pumilio

File:Caiman crocodilus llanos.JPG|Spectacled caiman, Caiman crocodilus

File:Choloepus hoffmanni (Puerto Viejo, CR) crop.jpg|The two-toed sloth Choloepus hoffmanni

File:Dasyprocta punctata (8973160761).jpg|Central American agouti, Dasyprocta punctata

File:Capuchin Costa Rica.jpg|White-headed capuchin, Cebus capucinus

File:Great Tinamou.jpg|Great tinamou, Tinamus major

Extant or extinct (†) South American taxa whose ancestors migrated out of North America:{{refn|name=qualifier|group=n}}

Amphibians

• Dermophiid caecilians (Dermophis glandulosus) – only present in northwestern Colombia{{cite journal |last1=Savage |first1=J. M. |last2=Wake |first2=M. H. |last3=Price |first3=A. |title=Reevaluation of the Status of Taxa of Central American Caecilians (Amphibia: Gymnophiona), with Comments on Their Origin and Evolution |journal=Copeia |volume=2001 |issue=1 |year=2001 |pages=52–64 |doi=10.1643/0045-8511(2001)001[0052:ROTSOT]2.0.CO;2|s2cid=86086706 }}
• Lungless salamanders{{refn|group=n|Salamanders apparently dispersed to South America by the Early Miocene, about 23 Ma ago. Nevertheless, the salamander fauna of South America, which is restricted to the tropical region, consists of only 2 clades, and has fewer species and is far less diverse than that of much smaller Central America. Salamanders are believed to have originated in northern Pangea, perhaps not long before it separated to become Laurasia, and are not present anywhere else in the Southern Hemisphere (see the world salamander distribution map). In contrast, caecilians have a mostly Gondwanan distribution. Apart from a small region of overlap in southern China and northern Southeast Asia, Central America and northern South America are the only places in the world where both salamanders and caecilians are present.}} (Bolitoglossa,{{cite journal |last1=Elmer |first1=K. R. |last2=Bonett |first2=R. M. |last3=Wake |first3=D. B. |last4=Lougheed |first4=S. C. |title=Early Miocene origin and cryptic diversification of South American salamanders |journal=BMC Evolutionary Biology |volume=13 |issue=1 |date=2013-03-04 |page=59 |doi=10.1186/1471-2148-13-59 |pmc=3602097 |pmid=23497060 |doi-access=free |bibcode=2013BMCEE..13...59E }}{{cite journal |title=Molecular diversification of salamanders of the tropical American genus Bolitoglossa (Caudata: Plethodontidae) and its evolutionary and biogeographical implications |last1=Parra-Olea |first1=G. |last2=Garcia-Paris |first2=M. |author-link3=David B. Wake |last3=Wake |first3=D. B. |journal=Biological Journal of the Linnean Society |volume=81 |issue=3 |pages=325–346 |year=2004 |url=http://repositories.cdlib.org/postprints/159/ |access-date=2008-01-11 |doi=10.1111/j.1095-8312.2003.00303.x|doi-access=free }} Oedipina) – only present in northern South America
• Ranid frogs – only present in northern South America

Reptiles

• Turtles (Testudines)
• Chelydrid (snapping) turtles (Chelydra acutirostris) – only present in northwestern South America
• Emydid (pond) turtles (Trachemys)
• Geoemydid (wood) turtles (Rhinoclemmys){{cite journal |last1=Le |first1=Minh |last2=McCord |first2=William P. |title=Phylogenetic relationships and biogeographical history of the genus Rhinoclemmys Fitzinger, 1835 and the monophyly of the turtle family Geoemydidae (Testudines: Testudinoidea) |journal=Zoological Journal of the Linnean Society |volume=153 |issue=4 |pages=751–767 |date=2008-07-25 |doi=10.1111/j.1096-3642.2008.00413.x|doi-access=free }} – only present in northern South America
• Snakes (Serpentes)
• Coral snakes (Leptomicrurus, Micrurus){{cite journal |title=Phylogenetic Relationships of Elapid Snakes Based on Cytochrome b mtDNA Sequences |last1=Slowinski |first1=J. B. |author1-link=Joseph Bruno Slowinski |last2=Keogh |first2=J. S. |journal=Molecular Phylogenetics and Evolution |volume=15 |issue=1 |pages=157–164 |date=April 2000 |doi=10.1006/mpev.1999.0725 |pmid=10764543|bibcode=2000MolPE..15..157S }}{{cite journal |title=The Phylogenetic Relationships of Asian Coral Snakes (Elapidae: Calliophis and Maticora) Based on Morphological and Molecular Characters |journal=Herpetologica |volume=57 |issue=2 |pages=233–245 |date=June 2001 |jstor=3893186 |last1=Slowinski |first1=J. B. |last2=Boundy |first2=J. |last3=Lawson |first3=R. |author1-link=Joseph Bruno Slowinski}}
• South American rattlesnake (Crotalus durissus){{cite journal |title=A Quantitative Analysis of the Ancestral Area of Rattlesnakes |last1=Place |first1=A. J. |last2=Abramson |first2=C. I. |journal=Journal of Herpetology |volume=38 |issue=1 |pages=152–156 |year=2004 |doi=10.1670/103-03N |s2cid=86252575}}
• Lanceheads (Bothrops)
• Bushmasters (Lachesis)
• Other pit vipers (Bothriechis schlegelii, Bothriopsis, Porthidium){{cite journal |title=Molecular Systematics and Biogeographical History of Pit Vipers as Determined by Mitochondrial Ribosomal DNA Sequences |last=Parkinson |first=C. L. |journal=Copeia |volume=1999 |issue=3 |pages=576–586 |year=1999 |doi=10.2307/1447591 |jstor=1447591}}

Birds

• American sparrows (Emberizidae){{cite journal |last1=Ericson |first1=P. G. P. |last2=Christidis |first2=L. |last3=Cooper |first3=A. |last4=Irestedt |first4=M. |last5=Jackson |first5=J. |last6=Johansson |first6=U. S. |last7=Norman |first7=J. A. |title=A Gondwanan origin of passerine birds supported by DNA sequences of the endemic New Zealand wrens |journal=Proceedings of the Royal Society B: Biological Sciences |volume=269 |issue=1488 |date=2002-02-07 |pages=235–241 |issn=0962-8452 |doi=10.1098/rspb.2001.1877 |pmid=11839192 |pmc=1690883}}
• Trogons (Trogon){{cite journal |last1=Dacosta |first1=J. M. |last2=Klicka |first2=J. |title=The Great American Interchange in birds: a phylogenetic perspective with the genus Trogon |journal=Molecular Ecology |volume=17 |issue=5 |pages=1328–1343 |date=2008-02-21 |doi=10.1111/j.1365-294X.2007.03647.x |pmid=18302692 |bibcode=2008MolEc..17.1328D |s2cid=25090736}}
• Condors (Vultur gryphus, †Dryornis, †Geronogyps, †Wingegyps, †Perugyps){{cite journal |last=Emslie |first=Steven D. |title=The Fossil History and Phylogenetic Relationships of Condors (Ciconiiformes: Vulturidae) in the New World |journal=Journal of Vertebrate Paleontology |volume=8 |issue=2 |pages=212–228 |date=22 June 1988 |doi=10.1080/02724634.1988.10011699 |jstor=4523192|bibcode=1988JVPal...8..212E }}{{cite journal |last=Emslie |first=Steven D. |title=An early condor-like vulture from North America |journal=The Auk |volume=105 |issue=3 |pages=529–535 |date=July 1988 |url=http://sora.unm.edu/sites/default/files/journals/auk/v105n03/p0529-p0535.pdf |doi=10.1093/auk/105.3.529}}{{cite journal |last1=Stucchi |first1=Marcelo |last2=Emslie |first2=Steven D. |title=A New Condor (Ciconiiformes, Vulturidae) From The Late Miocene/Early Pliocene Pisco Formation, Peru |journal=The Condor |volume=107 |issue=1 |pages=107–113 |date=February 2005 |doi=10.1650/7475 |s2cid=85805971}}{{refn|group=n|Condors apparently reached South America by the late Miocene or early Pliocene (4.5 – 6.0 Ma ago), several million years before the formation of the isthmus. Condor-like forms in North America date back to the Barstovian stage (middle Miocene, 11.8 – 15.5 Ma ago).}}

Mammals

• Small-eared shrews (Cryptotis) – only present in NW South America: Colombia, Venezuela, Ecuador, Peru
• Rodents (Rodentia)
• Geomyid pocket gophers (Orthogeomys thaeleri) – one species, in Colombia
• Heteromyid mice (Heteromys) – only present in NW South America: Colombia, Venezuela, Ecuador
• Cricetid – primarily sigmodontine – rats and mice (Cricetidae: Sigmodontinae) – the nonsigmodontines consist of two species present only in Colombia and Ecuador{{refn|This is based on the definition of Sigmodontinae that excludes Neotominae and Tylomyinae.|group=n}}
• Tree squirrels (Sciurus, Microsciurus, Sciurillus) – present in northern and central South America
• Cottontail rabbits (Sylvilagus brasiliensis, S. floridanus, ''S. varynaensis) – present in northern and central South America
• Odd-toed ungulates (Perissodactyla)
• Tapirs (Tapirus bairdii, †T. cristatellus, T. pinchaque, †T. rondoniensis, T. terrestris)
• Equids (Equus ferus, †Hippidion){{refn|group=n|Hippidion, a relatively short-legged equid that developed in South America after invading from North America about 2.5 Ma ago, has traditionally been thought to have evolved from pliohippines.{{cite journal |last=Weinstock |first=J. |year=2005 |title=Evolution, systematics, and phylogeography of Pleistocene horses in the New World: a molecular perspective |journal=PLOS Biology |volume=3 |issue=8 |pages=e241 |doi=10.1371/journal.pbio.0030241 |pmid=15974804 |pmc=1159165 |display-authors=etal |doi-access=free }}{{cite journal |last1=Orlando |first1=L. |last2=Male |first2=D. |last3=Alberdi |first3=M. T. |last4=Prado |first4=J. L. |last5=Prieto |first5=A. |last6=Cooper |first6=A. |last7=Hänni |first7=C. |year=2008 |title=Ancient DNA Clarifies the Evolutionary History of American Late Pleistocene Equids |journal=Journal of Molecular Evolution |volume=66 |issue=5 |pages=533–538 |doi=10.1007/s00239-008-9100-x |pmid=18398561 |bibcode=2008JMolE..66..533O |s2cid=19069554}} However, recent studies of the DNA of Hippidion and other New World Pleistocene horses indicate that Hippidion is actually a member of Equus, closely related to the extant horse, E. ferus. Another invasion of South America by Equus occurred about one Ma ago, and this lineage, traditionally viewed as the subgenus Equus (Amerhippus), appears indistinguishable from E. ferus. Both these lineages became extinct at the end of the Pleistocene, but E. ferus was reintroduced from Eurasia by Europeans in the 16th century. Note: the authors of the DNA sequence study of Equus (Amerhippus) use "E. caballus" as an alternative specific name for "E. ferus".}}
• Even-toed ungulates (Artiodactyla)
• Peccaries (†Sylvochoerus, †Waldochoerus, Tayassu pecari, Catagonus wagneri, Dicotyles tajacu)
• †Palaeomerycids (Surameryx)
• Deer (†Antifer, †Morenelaphus, †Agalmaceros, Odocoileus, Blastocerus, Ozotoceros, Mazama, Pudu, Hippocamelus)
• Camelids (Lama guanicoe, Vicugna vicugna, †Eulamaops, †Hemiauchenia, †Palaeolama)
• †Gomphotheres (Cuvieronius hyodon, Notiomastodon{{refn|group=n|Not to be confused with the American mastodon (Mammut americanum), a proboscid from a different family whose remains have been found no further south than Honduras.{{cite book |first1=O. J. |last1=Polaco |first2=J. |last2=Arroyo-Cabrales |first3=E. |last3=Corona-M. |first4=J. G. |last4=López-Oliva |editor-last=Cavarretta |editor-first=G. |editor2-last=Gioia |editor2-first=P. |editor3-last=Mussi |editor3-first=M. |display-editors=3 |editor4-last=Palombo |editor4-first=M. R. |contribution=The American Mastodon Mammut americanum in Mexico |contribution-url=http://www.sovraintendenzaroma.it/content/download/4787/62368/.../237_242.pdf |title=The World of Elephants – Proceedings of the 1st International Congress, Rome October 16–20, 2001 |year=2001 |pages=237–242 |place=Rome |publisher=Consiglio Nazionale delle Ricerche |isbn=978-88-8080-025-5}}}} platensis) – elephant relatives{{cite journal |last1=Mothé |first1=D. |last2=dos Santos Avilla |first2=L. |last3=Asevedo |first3=L. |last4=Borges-Silva |first4=L. |last5=Rosas |first5=M. |last6=Labarca-Encina |first6=R. |last7=Souberlich |first7=R. |last8=Soibelzon |first8=E. |last9=Roman-Carrion |first9=J.L. |last10=Ríos |first10=S.D. |last11=Rincon |first11=A.D. |last12=de Oliveira |first12=G.C. |last13=Lopes |first13=R.P. |title=Sixty years after 'The mastodonts of Brazil': The state of the art of South American proboscideans (Proboscidea, Gomphotheriidae) |journal=Quaternary International |volume=443 |year=2017 |pages=52–64 |doi=10.1016/j.quaint.2016.08.028 |bibcode=2017QuInt.443...52M |url=http://bibdigital.epn.edu.ec/handle/15000/17075|hdl=11336/48585 |hdl-access=free }}
• Carnivorans (Carnivora)
• Otters (Lontra, Pteronura)
• Other mustelids (Mustelinae: Eira, Galictis, Lyncodon, Neogale)
• Hog-nosed skunks (Conepatus chinga, C. humboldtii, C. semistriatus)
• Procyonids (Procyon, Nasua, Nasuella, Potos, Bassaricyon, †Cyonasua, †Chapalmalania)
• Short-faced bears (Tremarctinae: Tremarctos ornatus, †Arctotherium){{cite journal |last1=Soibelzon |first1=L. H. |last2=Tonni |first2=E. P. |last3=Bond |first3=M. |title=The fossil record of South American short-faced bears (Ursidae, Tremarctinae) |journal=Journal of South American Earth Sciences |volume=20 |issue=1–2 |pages=105–113 |date=October 2005 |doi=10.1016/j.jsames.2005.07.005 |bibcode=2005JSAES..20..105S |url=http://sedici.unlp.edu.ar/handle/10915/5366}}
• Wolves (†Canis gezi, †C. nehringi, †A. dirus – the latter known only from as far south as southern Bolivia{{cite web |title=Canis dirus (dire wolf) |work=Paleobiology Database |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=44837 |access-date=2013-01-27 |archive-date=2021-02-15 |archive-url=https://web.archive.org/web/20210215061919/http://fossilworks.org/bridge.pl?taxon_no=44837&action=taxonInfo |url-status=live }}){{cite journal |last1=Hodnett |first1=John-Paul M. |last2=Mead |first2=Jim I. |last3=Baez |first3=A. |title=Dire Wolf, Canis dirus (Mammalia; Carnivora; Canidae), from the Late Pleistocene (Rancholabrean) of East-Central Sonora, Mexico |journal=The Southwestern Naturalist |volume=54 |issue=1 |year=2009 |pages=74–81 |doi=10.1894/CLG-12.1 |s2cid=84760786}}{{cite book |last=Berta |first=A. |title=Quaternary Evolution and Biogeography of the Large South American Canidae (Mammalia: Carnivora) |url=https://books.google.com/books?id=LD5BVM_jG7gC |access-date=2013-01-28 |date=November 1988 |publisher=University of California Press |series=University of California Publications in Geological Sciences |volume=132 |isbn=978-0-520-09960-9}}
• Gray fox{{refn|group=n|Not to be confused with the South American gray fox.}} (Urocyon cinereoargenteus) – only present in NW South America: Colombia, Venezuela
• Other canids (†Dusicyon,{{cite web |url=https://www.sciencedaily.com/releases/2009/11/091102121449.htm |title=New Clues To Extinct Falklands Wolf Mystery |access-date=2011-09-03 |date=2009-11-03 |work=EurekAlert |publisher=Science Daily}}{{cite journal |title=The origins of the enigmatic Falkland Islands wolf |last1=Cooper |first1=A. |last2=Mena |first2=F. |last3=Austin |first3=J. J. |last4=Soubrier |first4=J. |last5=Prevosti |first5=F. |last6=Prates |first6=L. |last7=Trejo |first7=V. |journal=Nature Communications |volume=4 |year=2013 |doi=10.1038/ncomms2570 |page=1552 |pmid=23462995 |bibcode=2013NatCo...4.1552A|s2cid=205315969 |doi-access=free |hdl=2440/74885 |hdl-access=free }} †Theriodictis, †Protocyon, Atelocynus, Cerdocyon, Lycalopex, Chrysocyon, Speothos)
• Small felids (Leopardus) – all 9 extant species (e.g. L. pardalis, L. wiedii)
• Cougar (Puma concolor) and jaguarundi (P. yagouaroundi)
• Jaguar (Panthera onca)
• †Scimitar cats (Xenosmilus, Homotherium) – known so far only from Uruguay{{cite journal |last1=Mones |first1=A. |last2=Rinderknecht |first2=A. |title=The First South American Homotheriini (Mammalia: Carnivora: Felidae) |journal=Comunicaciones Paleontologicas Museo Nacional de Historia Natural y Anthropologia |volume=2 |issue=35 |pages=201–212 |year=2004 |url=http://www.mnhn.gub.uy/innovaportal/file/25910/1/cp35.pdf |access-date=2013-02-08}} and Venezuela{{cite news |last=Sanchez |first=Fabiola |title=Saber-toothed cat fossils discovered |agency=Associated Press |date=2008-08-21 |url=http://www.nbcnews.com/id/26336382/ns/technology_and_science-science/t/saber-toothed-cat-fossils-discovered/ |archive-url=https://web.archive.org/web/20170410052653/http://www.nbcnews.com/id/26336382/ns/technology_and_science-science/t/saber-toothed-cat-fossils-discovered/ |url-status=dead |archive-date=April 10, 2017 |access-date=2017-05-07}}{{cite web |last=Orozco |first=José |title=Sabertooth Cousin Found in Venezuela Tar Pit – A First |work=National Geographic News |publisher=National Geographic Society |date=2008-08-22 |url=http://news.nationalgeographic.com/news/2008/08/080822-scimitar-cat.html |archive-url=https://archive.today/20130104053859/http://news.nationalgeographic.com/news/2008/08/080822-scimitar-cat.html |url-status=dead |archive-date=January 4, 2013 |access-date=2008-08-30}}{{cite journal |last1=Rincón |first1=Ascanio D. |last2=Prevosti |first2=Francisco J. |last3=Parra |first3=Gilberto E. |title=New saber-toothed cat records (Felidae: Machairodontinae) for the Pleistocene of Venezuela, and the Great American Biotic Interchange |journal=Journal of Vertebrate Paleontology |volume=31 |issue=2 |year=2011 |pages=468–478 |doi=10.1080/02724634.2011.550366 |bibcode=2011JVPal..31..468R |s2cid=129693331|hdl=11336/69016 |hdl-access=free }}
• †Saber-toothed cats (Smilodon gracilis, S. fatalis,{{cite journal |doi=10.1016/j.quascirev.2017.11.024 |title=First record of Smilodon fatalis Leidy, 1868 (Felidae, Machairodontinae) in the extra-Andean region of South America (late Pleistocene, Sopas Formation), Uruguay: Taxonomic and paleobiogeographic implications |journal=Quaternary Science Reviews |volume=180 |pages=57–62 |year=2018 |last1=Manzuetti |first1=A. |last2=Perea |first2=D. |last3=Ubilla |first3=M. |last4=Rinderknecht |first4=A. |bibcode=2018QSRv..180...57M }} S. populator)
• †American lion (Panthera leo atrox), reported from Peru{{cite book |last1=Kurtén |first1=B. |last2=Anderson |first2=E. |title=Pleistocene Mammals of North America |url=https://books.google.com/books?id=nBWVngEACAAJ |year=1980 |publisher=Columbia University Press |isbn=978-0231037334 |oclc=759120597}} and Argentina and Chile;{{cite journal |last1=Chimento |first1=N. R. |last2=Agnolin |first2=F. L. |year=2017 |title=The fossil American lion (Panthera atrox) in South America: Palaeobiogeographical implications |journal=Comptes Rendus Palevol |volume=16 |issue=8 |pages=850–864 |doi=10.1016/j.crpv.2017.06.009|bibcode=2017CRPal..16..850C |hdl=11336/65990 |hdl-access=free }} however, the former set of remains has later been identified as belonging to a jaguarSeymour, K. 2015. [http://www.tarpits.org/sites/default/files/pdfs/Scott%20et%20al%202015.%20LACM%20SS%2042.pdf#page=107 Perusing Talara: Overview of the Late Pleistocene fossils from the tar seeps of Peru] {{Webarchive |url=https://web.archive.org/web/20181001080809/http://www.tarpits.org/sites/default/files/pdfs/Scott%20et%20al%202015.%20LACM%20SS%2042.pdf#page=107 |date=2018-10-01}}. Natural History Museum of Los Angeles County Science Series, 42: 97–109 and the latter set of remains were initially identified as being from jaguars
• Bats (Chiroptera)
• Natalid bats (Chilonatalus micropus, Natalus espiritosantensis, N. tumidirostris)
• Vespertilionid bats

Cobra-papagaio - Bothrops bilineatus - Ilhéus - Bahia.jpg|Amazonian palm viper, Bothrops bilineatus

Drymoreomys albimaculatus 002.jpg|Drymoreomys albimaculatus, a sigmodontine rodent

Guanacos, Parque Nacional Torres del Paine, Chile3.jpg|The camelid Lama guanicoe

Cuvieronius.jpg|†Cuvieronius, a gomphothere

Coati roux Amiens 4.jpg|The coati Nasua nasua

Smilodon Populator1.JPG|Saber-toothed †Smilodon populator

• Caribbean Plate § First American land bridge
• Central American Seaway
• Columbian Exchange
• List of mammals of the Caribbean
• List of mammals of Central America
• List of mammals of North America
• List of mammals of South America
• Lists of extinct animals by continent

{{reflist|group=n}}

{{reflist|30em}}

• {{cite book |last1=Cione |first1=A. L. |last2=Gasparini |first2=G. M. |last3=Soibelzon |first3=E. |last4=Soibelzon |first4=L. H. |last5=Tonni |first5=E. P. |title=The Great American Biotic Interchange: A South American Perspective |url=https://books.google.com/books?id=uVCqCAAAQBAJ |date=24 April 2015 |publisher=Springer |isbn=978-94-017-9792-4 |oclc=908103326}}
• {{cite book |last=Croft |first=D. A. |title=Horned Armadillos and Rafting Monkeys: The Fascinating Fossil Mammals of South America |url=https://books.google.com/books?id=NOBpDAAAQBAJ |date=29 August 2016 |publisher=Indiana University Press |isbn=978-0-253-02094-9 |oclc=964782185}}
• {{cite book |author=Defler, T. |title=History of Terrestrial Mammals in South America: How South American Mammalian Fauna Changed from the Mesozoic to Recent Times |url =https://books.google.com/books?id=-HWADwAAQBAJ |date=19 December 2018 |publisher=Springer |isbn=978-3-319-98449-0 |oclc=1125820897}}
• {{cite book |last1=Fariña |first1=R.A. |last2=Vizcaíno |first2=S.F. |last3=De Iuliis |first3=G. |title=Megafauna: Giant Beasts of Pleistocene South America |url=https://books.google.com/books?id=kUAKgNfiAvoC |date=2013 |publisher=Indiana University Press |isbn=978-0-253-00719-3 |jstor=j.ctt16gzd2q |oclc=779244424}}
• {{cite journal

|last=Simpson |first=George Gaylord |author-link=George Gaylord Simpson

|title=History of the Fauna of Latin America

|journal=American Scientist |volume=38 |issue=3 |pages=361–389 |date=July 1950

|url=http://www.wku.edu/~smithch/biogeog/SIMP1950.htm

|jstor=27826322 |access-date=2013-02-14}}

• {{cite book

|editor1-last=Stehli |editor1-first=F. G. |editor2-last=Webb |editor2-first=S. D.

|title=The Great American Biotic Interchange

|volume=4 |series=Topics in Geobiology, vol. 4

|year=2013 |publisher=Springer Science & Business Media

|url=https://books.google.com/books?id=Q7vdBgAAQBAJ

|isbn=978-1-4684-9181-4 |oclc=968646442 |doi=10.1007/978-1-4684-9181-4}}

• {{cite journal |last1=Woodburne |first1=M. O. |title=The Great American Biotic Interchange: Dispersals, Tectonics, Climate, Sea Level and Holding Pens |journal=Journal of Mammalian Evolution |volume=17 |issue=4 |date=2010-07-14 |pages=245–264 |doi=10.1007/s10914-010-9144-8 |pmid=21125025 |pmc=2987556}} The biotic & geologic dynamics of the Great American Biotic Interchange are reviewed and revised.

Category:Biogeography

.Lists

Category:Cenozoic

Category:Fauna of the Americas

Category:Piacenzian