Great American Interchange

Source: Wikipedia, the free encyclopedia.
Examples of migrant species in both Americas. Olive green silhouettes denote North American species with South American ancestors; blue silhouettes denote South American species with North American ancestors.

The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late

Ma) ago during the Piacenzian age.[1] It resulted in the joining of the Neotropic (roughly South American) and Nearctic (roughly North American) biogeographic realms definitively to form the Americas. The interchange is visible from observation of both biostratigraphy and nature (neontology). Its most dramatic effect is on the zoogeography of mammals, but it also gave an opportunity for reptiles, amphibians, arthropods, weak-flying or flightless birds, and even freshwater fish to migrate. Coastal and marine biota, however, were affected in the opposite manner; the formation of the Central American Isthmus caused what has been termed the Great American Schism, with significant diversification and extinction occurring as a result of the isolation of the Caribbean from the Pacific.[2]

The occurrence of the interchange was first discussed in 1876 by the "father of biogeography", Alfred Russel Wallace.[3][4] Wallace had spent five years exploring and collecting specimens in the Amazon basin. Others who made significant contributions to understanding the event in the century that followed include Florentino Ameghino, W. D. Matthew, W. B. Scott, Bryan Patterson, George Gaylord Simpson and S. David Webb.[5] The Pliocene timing of the formation of the connection between North and South America was discussed in 1910 by Henry Fairfield Osborn.[6]

Analogous interchanges occurred earlier in the Cenozoic, when the formerly isolated land masses of India and Africa made contact with Eurasia about 56 and 30 Ma ago, respectively.[7][8][9][10][11][12][13][14][15][16][17][excessive citations]

Before the interchange

Isolation of South America

Thylacosmilus, a sparassodont

After the late

Patagonia remained as recently as the Miocene.[25]

The monito del monte, Dromiciops gliroides, South America's only australidelphian marsupial
Astrapotherium magnum

Marsupials appear to have traveled via Gondwanan land connections from South America through Antarctica to Australia in the late

meiolaniid
turtles.

Marsupials remaining in South America included didelphimorphs (

borhyaenids and the saber-toothed Thylacosmilus; these were sparassodont metatherians, which are no longer considered to be true marsupials.[31] 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

crocodyliforms with ziphodont teeth[n 5] were also present at least through the middle Miocene[35][36][37][38] and maybe to the Miocene-Pliocene boundary.[39] 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
.

The giant anteater, 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.

euphractines, various ground sloths, some of which reached the size of elephants (e.g. Megatherium), and even semiaquatic to aquatic marine sloths.[41][42]

The litoptern Macrauchenia

The notoungulates and litopterns had many strange forms, such as

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

proboscids
.

Pre-interchange oceanic dispersals

Capybara, Hydrochoerus hydrochaeris
Emperor tamarin, Saguinus imperator

The invasions of South America started about 40 Ma ago (middle

Josephoartigasia monesi) attained sizes on the order of 500 kg (1,100 lb) or larger.[52]

Later (by 36 Ma ago),

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.[54][55]

Fossil evidence presented in 2020 indicates a second lineage of African monkeys also rafted to and at least briefly colonized South America.

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.[56][57]

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).[n 6]

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

Thyropteridae are thought to have reached South America from Africa in the Eocene,[59] possibly via Antarctica.[60] Similarly, free-tailed bats (Molossidae) may have reached South America from Africa in as many as five dispersals, starting in the Eocene.[59] Emballonurids may have also reached South America from Africa about 30 Ma ago, based on molecular evidence.[59][61] Vespertilionids may have arrived in five dispersals from North America and one from Africa.[59] Natalids are thought to have arrived during the Pliocene from North America via the Caribbean.[59]

Red-footed tortoise, 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

blind snakes[67] also appear to have rafted from Africa, as does the hoatzin, a weak-flying bird of South American rainforests.[68]

Megalonyx wheatleyi

The earliest traditionally recognized mammalian arrival from North America was a

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.

palaeomerycid (from a family probably ancestral to cervids).[80] 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.[81][82][83] The early date proposed for Surameryx has also been met with skepticism.[84]

Megalonychid and mylodontid ground sloths island-hopped to North America by 9 Ma ago.[72] A basal group of sloths[85] had colonized the Antilles previously, by the early Miocene.[86] In contrast, megatheriid and nothrotheriid ground sloths did not migrate north until the formation of the isthmus. Terror birds may have also island-hopped to North America as early as 5 Ma ago.[87]

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.[49][50] Except in the case of Jamaica, oryzomyine rodents of North American origin were able to enter the region only after invading South America.

Effects and aftermath

The

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.[n 9] 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).

Titanis walleri, 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.

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,[n 11][n 12] 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.[n 13]

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.[94] Before 12,000 years ago, South America was home to about 25 species of herbivores weighing more than 1,000 kg (2,200 lb), consisting of Neotropic ground sloths, glyptodonts, and toxodontids, as well as gomphotheres and camelids of Nearctic origin.[n 14]
Native South American forms made up about 75% of these species. However, none of these megaherbivores has survived.

The Virginia opossum, 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

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[96] and Alaska,[97]
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.[n 15][n 16] Although members of Canis (specifically, coyotes) currently range only as far south as Panama,[n 17] South America still has more extant genera of canids than any other continent.[n 15]

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.[2] 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.[101] 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.[102]

Disappearance of native South American predators

Arctotherium bonariense, a South American short-faced bear

During the last 7 Ma, South America's

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.[103][104] 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.

Thylacosmilids last occur about 3 Ma ago and appear to be rarer at pre-GABI Pliocene sites than Miocene ones.[105]

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.[103][106] 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.[114] 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.[105] Bears, cats, and skunks do not appear in South America until the early Pleistocene (about 1 Ma ago or slightly earlier).[105] 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 600 km (370 mi) from the Isthmus of Panama.[115][114][116][117]

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.[118][119] 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.[119] 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.[120] Terror birds also decline in diversity after about 3 Ma ago.[105] At least one genus of relatively small terror birds, Psilopterus, appears to have survived to as recently as about 96,000 years ago.[121][122]

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.

caiman Purussaurus and giant gharial Gryposuchus, which is thought to be related to the loss of wetlands habitat across northern South America.[127][128]

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.[129] 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.[99]

Reasons for success or failure

Af, 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

. Thus, climate alone cannot fully account for the greater success of species of Nearctic origin during the interchange.

Land areas over which ancestors of Neotropic (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.[n 19] Eurasia was connected in turn to Africa, which contributed further to the species that made their way to North America.[n 20] 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,[n 21][88][130][131] where evolution would have proceeded more rapidly. They tended to be more efficient and brainier,[n 22][n 23] 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.[58]

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).[139][140] Their low metabolic rate may in turn have been advantageous in allowing them to subsist on less abundant[141] 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
.

Late Pleistocene extinctions

The North American porcupine, 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).

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,

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 900 kg (2,000 lb), and the largest surviving Nearctic migrant to South America, Baird's tapir
, can reach 400 kg (880 lb).

Paleo-Indians and †Glyptodon
Baird's tapir, Tapirus bairdii, the largest surviving Nearctic migrant to South America

The near-simultaneity of the megafaunal extinctions with the glacial retreat and the

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.

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.[168][n 25][n 26]

List of North American species of South American origin

Distributions beyond Mexico

Extant or extinct (†) North American taxa whose ancestors migrated out of South America and reached the modern territory of the contiguous United States:[n 27]

Fish

Amphibians

Birds

Mammals

Distributions restricted to Mexico

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:[n 27][n 29]

Invertebrates

Fish

Amphibians

Reptiles

Birds

Mammals

List of South American species of North American origin

Extant or extinct (†) South American taxa whose ancestors migrated out of North America:[n 27]

Amphibians

Reptiles

Birds

Mammals

Image gallery

See also

Notes

  1. ^ During the Eocene, astrapotheres[19] and litopterns[20][21] were also present in Antarctica.
  2. perissodactyls.[22][23] Mitochondrial DNA obtained from Macrauchenia corroborates this and gives an estimated divergence date of 66 Ma ago.[24]
  3. ^ 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.
  4. ^ It is the sister group to a clade containing all other extant australidelphians (roughly 238 species).
  5. ^ 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.
  6. ^ 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.[58]
  7. ^ North American gopher tortoises are most closely related to the Asian genus Manouria.
  8. ^ An alternative explanation blames climatic and physiographic changes associated with the uplift of the Andes.[38]
  9. ^ 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.)
  10. 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.[91]
  11. ^ Simpson, 1950, p. 382[93]
  12. ^ Marshall, 1988, p. 386[5]
  13. nutria/coypu
    has been introduced to a number of North American locales.)
  14. African forest elephant
    as a separate species).
  15. ^
    cervid
    genera by continent are as follows: Canid genera by continent Cervid genera by continent
  16. ^ 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.[88] 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[98]) is a clade.[98][99][100] However, different authors conclude that members of this clade reached South America in at least two,[99] three to four,[98] or six[100] invasions from North America.
  17. Canis dirus
    , was present in South America until the end of the Pleistocene.
  18. ^
    platyrrhine monkeys
    ) are as follows: Central American opossum species Central American xenarthran species Central American caviomorph rodent species Central American platyrrhine monkey species
  19. ^ 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.[88]
  20. ^ The combination of Africa, Eurasia and North America was termed the "World Continent" by George Gaylord Simpson.[93]
  21. ^ Simpson, 1950, p. 368[93]
  22. 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,[132] 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).[18] This analysis was later criticized.[133] 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).[134] Interestingly, the late survivor Toxodon had one of the highest EQ values (0.88) among native Neotropic ungulates.[133]

    Jerison also found that Neogene xenarthrans had low EQs, similar to those he obtained for South American ungulates.
    [132]
  23. ^ The estimated EQ of Thylacosmilus atrox, 0.41 (based on a brain mass of 43.2 g, a body mass of 26.4 kg,[135] and an EQ of 43.2/[0.12*26400^(2/3)][134]), is high for a sparassodont,[136] but is lower than that of modern felids, with a mean value of 0.87.[137] Estimates of 0.38[138] and 0.59[137] have been given for the EQ of much larger Smilodon fatalis (based on body mass estimates of 330 and 175 kg, respectively).
  24. giant tortoises of Asia and Africa[161] died out much earlier in the Quaternary than those of South America, Madagascar and Australia, while those of North America[162]
    died out around the same time.
  25. ^ P. S. Martin (2005), p. 175.[95]
  26. shrub-ox
    , were less fortunate).
  27. ^
    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.
  28. ^ Mixotoxodon remains have been collected in Central America and Mexico as far north as Veracruz and Michoacán, with a possible find in Tamaulipas;[176] additionally, one fossil tooth has been identified in eastern Texas, United States.[177]
  29. Geoffroy's spider monkey
    .
  30. giant anteater have been found as far north as northwestern Sonora, Mexico.[186]
  31. 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.[187]
  32. Pangea, perhaps not long before it separated to become Laurasia,[179] 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.
  33. ^ 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.[202] Condor-like forms in North America date back to the Barstovian stage (middle Miocene, 11.8 – 15.5 Ma ago).[201]
  34. ^ This is based on the definition of Sigmodontinae that excludes Neotominae and Tylomyinae.
  35. Ma ago, has traditionally been thought to have evolved from pliohippines.[203][204] 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.[203][204] 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.[204] 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".[204]
  36. American mastodon (Mammut americanum), a proboscid from a different family whose remains have been found no further south than Honduras.[205]
  37. ^ Not to be confused with the South American gray fox.

References

  1. .
  2. ^ .
  3. .
  4. .
  5. ^ (PDF) from the original on 2013-03-02. Retrieved 2014-04-22.
  6. ^ Osborn, H. (1910). The Age Of Mammals In Europe, Asia, And North America. New York, EEUU: The Macmillan Company. pp. 80–81.
  7. ^ Karanth, K. Praveen (2006-03-25). "Out-of-India Gondwanan origin of some tropical Asian biota" (PDF). Current Science. 90 (6): 789–792. Retrieved 2008-12-29.
  8. . Retrieved 28 August 2022.
  9. .
  10. . Retrieved 28 August 2022.
  11. .
  12. . Retrieved 28 August 2022.
  13. . Retrieved 28 August 2022.
  14. . Retrieved 28 August 2022.
  15. ^ Kapur, Vivesh V.; Carolin, N.; Bajpai, S. (2022). "Early Paleogene mammal faunas of India: a review of recent advances with implications for the timing of initial India-Asia contact". Himalayan Geology. 47 (1B): 337–356. Retrieved 28 August 2022.
  16. PMID 11136239
    .
  17. . Retrieved 28 August 2022.
  18. ^ .
  19. .
  20. S2CID 140546667. {{cite book}}: |journal= ignored (help
    )
  21. .
  22. .
  23. .
  24. .
  25. .
  26. ^ .
  27. .
  28. ^ Pascual, R.; Goin, F. J.; Balarino, L.; Sauthier, D. E. U. (2002). "New data on the Paleocene monotreme Monotrematum sudamericanum, and the convergent evolution of triangulate molars" (PDF). Acta Palaeontologica Polonica. 47 (3): 487–492. Retrieved 2020-01-21.
  29. PMID 12857645
    .
  30. .
  31. ^ Naish, Darren (29 June 2008). "Invasion of the marsupial weasels, dogs, cats and bears... or is it?". scienceblogs.com. Retrieved 2008-12-07.
  32. ^ Naish, Darren (2006-10-27). "Terror birds". darrennaish.blogspot.com. Retrieved 2008-03-29.
  33. .
  34. ^ Palmqvist, Paul; Vizcaíno, Sergio F. (2003-09-30). "Ecological and reproductive constraints of body size in the gigantic Argentavis magnificens (Aves, Theratornithidae) from the Miocene of Argentina" (PDF). Ameghiniana. 40 (3): 379–385. Retrieved 2008-12-11.
  35. ^ Paolillo, A.; Linares, O. J. (2007-06-05). "Nuevos Cocodrilos Sebecosuchia del Cenozoico Suramericano (Mesosuchia: Crocodylia)" (PDF). Paleobiologia Neotropical. 3: 1–25. Archived from the original (PDF) on 2009-03-03. Retrieved 2008-09-28.
  36. JSTOR 4523070
    .
  37. .
  38. ^ .
  39. doi:10.25249/0375-7536.2010403330338 (inactive 2024-02-01). Retrieved 2017-10-23.{{cite journal}}: CS1 maint: DOI inactive as of February 2024 (link
    )
  40. .
  41. .
  42. .
  43. ^
    PMID 16551580. Archived from the original
    (PDF) on 2016-06-02. Retrieved 2011-10-25.
  44. ^ Mangels, J. (2011-10-15). "Case Western Reserve University expert uses fossil teeth to recast history of rodent". Cleveland Live, Inc. Retrieved 2011-10-25.
  45. PMID 21993503
    .
  46. .
  47. .
  48. .
  49. ^ .
  50. ^ .
  51. .
  52. .
  53. S2CID 4456556
    .
  54. .
  55. .
  56. .
  57. .
  58. ^ .
  59. ^
    Universidade de Brasília
    : 391–410. Retrieved 2018-01-24.
  60. ^ .
  61. ^ .
  62. ^
    PMID 16678445. Archived from the original
    (PDF) on 2012-03-16. Retrieved 2012-04-12.
  63. .
  64. .
  65. .
  66. .
  67. .
  68. .
  69. .
  70. .
  71. ^ .
  72. ^ .
  73. .
  74. .
  75. .
  76. .
  77. ^ Campbell, K. E.; Frailey, C. D.; Romero-Pittman, L. (2000). "The Late Miocene Gomphothere Amahuacatherium peruvium (Proboscidea: Gomphotheriidae) from Amazonian Peru: Implications for the Great American Faunal Interchange-[Boletín D 23]". Ingemmet.
  78. .
  79. ^ .
  80. ^ .
  81. .
  82. doi:10.3724/SP.J.1261.2013.00015 (inactive 31 January 2024). Retrieved 2020-01-23.{{cite journal}}: CS1 maint: DOI inactive as of January 2024 (link
    )
  83. ^ .
  84. .
  85. .
  86. ^ Morgan, Gary S. (2002), "Late Rancholabrean Mammals from Southernmost Florida, and the Neotropical Influence in Florida Pleistocene Faunas", in Emry, Robert J. (ed.), Cenozoic Mammals of Land and Sea: Tributes to the Career of Clayton E. Ray, Smithsonian Contributions to Paleobiology, vol. 93, Washington, D.C., pp. 15–38{{citation}}: CS1 maint: location missing publisher (link)
  87. .
  88. ^ .
  89. ^ Marshall, L. G.; Cifelli, R. L. (1990). "Analysis of changing diversity patterns in Cenozoic land mammal age faunas, South America". Palaeovertebrata. 19: 169–210. Retrieved 2018-10-08.
  90. ^
    S2CID 88305955
    .
  91. AMNH
    . Retrieved 2018-10-08.
  92. .
  93. ^ . Retrieved 2013-02-14.
  94. ^ (PDF) on 2011-07-06. Retrieved 2011-02-06.
  95. ^ .
  96. . Retrieved 2008-08-16.
  97. .
  98. ^ .
  99. ^ .
  100. ^ .
  101. .
  102. .
  103. ^ .
  104. . Retrieved 2020-01-24.
  105. ^ .
  106. ^ .
  107. .
  108. .
  109. .
  110. ^ .
  111. ^ .
  112. ^ .
  113. ^ .
  114. ^ .
  115. .
  116. .
  117. .
  118. .
  119. ^ .
  120. .
  121. .
  122. .
  123. ^ .
  124. .
  125. .
  126. .
  127. .
  128. .
  129. .
  130. .
  131. .
  132. ^ .
  133. ^ .
  134. ^ .
  135. .
  136. .
  137. ^ .
  138. .
  139. .
  140. .
  141. .
  142. ^ Magazine, Smithsonian; Gerszak, Jennie Rothenberg Gritz,Fen Montaigne,Rafal. "The Story of How Humans Came to the Americas Is Constantly Evolving". Smithsonian Magazine. Retrieved 2022-03-12.{{cite web}}: CS1 maint: multiple names: authors list (link)
  143. .
  144. .
  145. .
  146. .
  147. .
  148. . Retrieved 2009-06-12.
  149. .
  150. PMID 16701402. Archived from the original
    (PDF) on 2014-05-25. Retrieved 2014-11-11.
  151. . Retrieved 2011-08-26.
  152. .
  153. .
  154. .
  155. .
  156. .
  157. .
  158. .
  159. .
  160. .
  161. .
  162. .
  163. .
  164. .
  165. .
  166. .
  167. .
  168. . Retrieved 2015-11-07.
  169. ^ .
  170. .
  171. S2CID 83925199. Archived from the original
    (PDF) on 2011-07-26. Retrieved 2010-03-07.
  172. .
  173. ^ .
  174. .
  175. ^ . Retrieved 2009-01-29.
  176. .
  177. .
  178. ]
  179. ^ .
  180. .
  181. .
  182. .
  183. .
  184. .
  185. ^ "Scelidotherium in the Paleobiology Database". Fossilworks. Retrieved 17 December 2021.
  186. S2CID 27112941
    .
  187. .
  188. .
  189. ^ . 20190148.
  190. .
  191. ^ .
  192. . Retrieved 2008-01-11.
  193. .
  194. .
  195. .
  196. .
  197. .
  198. .
  199. .
  200. .
  201. ^ .
  202. ^ .
  203. ^ .
  204. ^ .
  205. .
  206. .
  207. ^ "Canis dirus (dire wolf)". Paleobiology Database. Retrieved 2013-01-27.
  208. S2CID 84760786
    .
  209. . Retrieved 2013-01-28.
  210. ^ "New Clues To Extinct Falklands Wolf Mystery". EurekAlert. Science Daily. 2009-11-03. Retrieved 2011-09-03.
  211. S2CID 205315969
    .
  212. ^ Mones, A.; Rinderknecht, A. (2004). "The First South American Homotheriini (Mammalia: Carnivora: Felidae)" (PDF). Comunicaciones Paleontologicas Museo Nacional de Historia Natural y Anthropologia. 2 (35): 201–212. Retrieved 2013-02-08.
  213. ^ Sanchez, Fabiola (2008-08-21). "Saber-toothed cat fossils discovered". Associated Press. Retrieved 2017-05-07.
  214. ^ Orozco, José (2008-08-22). "Sabertooth Cousin Found in Venezuela Tar Pit – A First". National Geographic News. National Geographic Society. Archived from the original on January 4, 2013. Retrieved 2008-08-30.
  215. ^
    S2CID 129693331
    .
  216. .
  217. .
  218. .
  219. ^ Seymour, K. 2015. Perusing Talara: Overview of the Late Pleistocene fossils from the tar seeps of Peru Archived 2018-10-01 at the Wayback Machine. Natural History Museum of Los Angeles County Science Series, 42: 97-109

Further reading