The Great American Interchange is an important end-to-end Cenozoicum paleozoogeography event in which soil and freshwater fauna migrate from North America through Central America to South America and vice versa, when malignant Panama lands up from the seabed and bridge the continents, continents that were previously separated. Migration peaks dramatically around three million years (Ma) then during the age of Piacenzian. It produces the Neotropic joins (roughly South America) and the Nearctic (roughly North America) ecozones are definitive to form America. This exchange is evident from both biostratigraphy and natural observations (neonology). The most dramatic effect is on the mammalian zoogeography but also provides an opportunity for reptiles, amphibians, arthropods, birds flying weak or flying, and even freshwater fish to migrate.
The exchange was first discussed in 1876 by the "father of biogeography", Alfred Russel Wallace. Wallace had spent 1848-1852 to explore and collect specimens in the Amazon basin. Others who made significant contributions to the understanding of events in the century that followed included Florentino Ameghino, W. D. Matthew, W. B. Scott, Bryan Patterson, George Gaylord Simpson and S. David Webb. Pliocene's timing of relationship between North and South America was discussed in 1910 by Henry Fairfield Osborn.
Analogue exchange occurred earlier in the Kenozoic, when previously isolated lands from India and Africa made contact with Eurasia c. 50 and 30 Ma ago, respectively.
Video Great American Interchange
fauna endemik di Amerika Selatan
After the outbreak of the Mesozoic Gondwana, South America spent most of the Kenozoic era as a "beautifully isolated" island continent allowing the fauna to evolve into forms not found elsewhere on Earth, most of which are now extinct. Endemic mammals initially consist mainly of metatherians (marsupials and sparassodonts), xenarthrans, and diverse groups of original ungulates: notoungulates ("southern ungulates"), litopterns, astrapotheres, pyrotes and xenungulates. Some non-therian mammals - monotremes, gondwanatheres, dryolestids and possibly multituberculates cimolodont - are also present in Paleocene; while none were significantly diversified and most of the lineages did not last long, forms like Necrolestes and Patagonia remained as recently as Miocene.
Marsupial seems to have traveled through Gondwanan's land connections from South America through Antarctica to Australia at the end of Cretaceous or early Tertiary. A live South American marsupial, monito del monte, has proven to be more closely related to Australian marsupials than any other South American marsupial; however, this is the most basic australidelphian, which means that this superorder appeared in South America and then colonized Australia after the monito del monte parted ways. Monotreme fossils such as the 61-Ma-old platypus of Patagonia may represent an Australian immigrant. Paleognath birds (ratites and tinamous South America) may migrate with this route around the same time, more likely in the direction of South America to Australia/New Zealand. Other taxis that may have been dispersed by the same route (if not by flying or floating across the ocean) are parrots, chelid turtles, and meiolaniid turtles (extinct).
Marsupials present in South America include didelphimorphs (opossum) and several other small groups; larger predatory relatives of this also exist, such as borhyaenids and sabertooth Thylacosmilus (sparassodont meteologists who are no longer regarded as true marsupials). After the extinction of sparassodonts, and prior to the arrival of carnivorans, giant opossums such as Thylophorops represent true marsupial macropreditor.
Metatherians (and some armadillos xenarthran such as
Xenarthrans is a curious group of mammals that developed a morphological adaptation to a special diet early in their history. In addition to those still present (armadillos, pangolins, and tree sloths), there is a great diversity of larger types, including pamphlets, glyptodonts like ankylosaurus, euphractines predators, various ground sloths, some of which reach elephant size (eg > Megatherium ), and even semiotics to sea water sloth.
The notoungulates and litopterns have many strange shapes, such as Macrauchenia , litoptern like-camels with small trunks. They also produce a number of familiar-looking body types that represent examples of parallel or convergent evolution: one-toed Thoatherium has a horse-like leg, Pachyrukhos resembling a rabbit, Homalodotherium i> is a semi-bipedal clawed browser like chalicothere, and horned Trigodon looks like a rhinoceros. The two groups began to evolve in Lower Paleocene, possibly from condylar stock, diversified, diminished before a major exchange, and became extinct at the end of the Pleistocene. The pyrotes and astrapotheres are also strange but less diverse and disappear earlier, long before the exchange.
North American Fauna is a typical boreoeutherian type, equipped with proboscid Afrotheria.
Maps Great American Interchange
Island-hopping 'waif spreader'
The South American invasion began about 40 Ma ago (middle Eocene), when the caviomorph rodents arrived in South America. The next strong diversification displaced several small marsupials in South America and spawned - among others - capybaras, chinchillas, viscachas, and New World hedgehogs. (The independent development of thorns by the hedgehogs of the New World and the Old World is another example of parallel evolution.) This invasion is most likely to come from Africa. The crossing from West Africa to the northeast corner of Brazil was much shorter at the time, due to continental drift, and possibly aided by hopping the island (eg via St. Paul's Rocks, if they were an uninhabited island at the time) and the western ocean currents. Ocean crossings are reached when at least one fertilized woman (more often a group of animals) accidentally hovers on a floating wooden or mangrove raft. (The Kaviomorphs who crave the island will then colonize the West Indies as far as the Bahamas, reaching the Great Antilles at the beginning of the Oligocene.) Over time, some rodent caviomorphs evolved into larger shapes that competed with some of the native ungulates of South America, which may have contributed to the loss of diversity gradually suffered by the latter after the initial Oligocene. During the Pliocene period, some caviomorph (eg, Josephoartigasia ) reach sizes in the order of 500 kg (1,100 pounds) or larger.
Then (by 36 Ma then) the primates followed, once again from Africa in a manner similar to rodents. Primates that are able to migrate must be small. Like rodent caviomorphs, South American monkeys are believed to be clades (ie, monophyletic). However, although they will have little effective competition, all of the remaining New World monkeys emerge from radiation that occurred long after that, at the beginning of Miocene about 18 Ma ago. After this, the monkeys seem most closely associated with the island's titis-jumping to Cuba, Hispaniola and Jamaica. In addition, the discovery of seven decadent 21-Ma-long cebid teeth in Panama showed that South American monkeys had spread in the sea separating Central and South America at an early date. However, all remaining Central American monkeys are believed to have originated from many later immigrants, and there is no evidence that this early Central American cebid formed a large or durable population, possibly due to the lack of appropriate rainforest habitat at the time.
Remarkably, the descendants of some drenched young people who crept ashore from their raft of African flotsam in Eocene are now more than twice as many South American species as the offspring of all nonflying mammals previously domiciled on the continent (372 caviomorphs and monkeys). species versus 136 marsupial and xenarthran species).
Many South American bats may have arrived from Africa for roughly the same period, perhaps with the help of the intervening islands, albeit flying rather than floating. Noctilionoid bats originating from the neotrophic family Furipteridae, Mormoopidae, Noctilionidae, Phyllostomidae, and Thyropteridae are thought to have reached South America from Africa in the Eocene, possibly through Antarctica. Similarly, moloside bats may have reached South America from Africa as many as five deployments, beginning with Eocene. The emballonurid bats may also reach South America from Africa about 30 Ma ago, based on molecular evidence. Vespertilionid bats may have arrived at five deployments from North America and one from Africa. The Natalid bat is thought to have arrived during the Pliocene from North America through the Caribbean.
Turtles also arrived in South America in Oligocene. It has long been thought that they are from North America, but a recent analysis of comparative genetics concludes that the South American genus Chelonoidis (formerly part of Geochelone ) is actually closely related to turtles -kura Africa. Turtles are assisted in the deployment of oceans with their ability to float with their heads, and last up to six months without food or water. South American turtles then proceed to colonize the West Indies and Galapagos Islands. A number of clades of American geckos seem to have been tidied from Africa during both Paleogene and Neogene. Skink of the related genera Mabuya and Trachylepis appears to be spread across the Atlantic from Africa to South America and Fernando de Noronha, respectively, for the last 9 Ma. Surprisingly, ampibibaenians and South American blind snakes also appear to have flown from Africa, as do hoatzins, South American rainforest bird birds that fly weakly.
The earliest traditionally recognized mammal arrival from North America is a prokyon that originated in Central America before the precarious land of Panama's mainland bridge was formed, about 7.3 million years ago. This is the first eutherian carnivore in South America. South American proyonism then diversified into the now extinct form (eg "dog-coati" Cyonasua , which evolved into a bear-like Chapalmalania ). However, all the remaining procyonid genera seem to originate in North America. It has been argued that the first South American proclamides may have contributed to the extinction of crocodiles sebecid by eating their eggs, but this view has not been universally seen as plausible. Prokonyid followed to South America by sword sword and chopsticks and sigmodontine rats. The oryzomyine tribe of sigmodontine mice proceed to colonize the Lesser Antilles into Anguilla.
One group has proposed that a large number of Neartic herbivores actually reached South America in the early 9-10 Ma ago, at the end of the Miocene, through the "Baudo pathway", an early ground bridge that may be incomplete and require some ponds and islands. -stop to traverse. Limited evidence for these early immigrants probably reflects their existence especially in the Amazon basin, an area where fewer fossils are collected. These taxis are: proboscidean ( Amahuacatherium ), peccaries ( Sylvochoerus and Waldochoerus ), tapir and palaeomerycid (from families who may be ancestors to cervids) Surameryx ; paleomerycids may not succeed in colonizing South America.
Similarly, megalonychid and mylodontid land sloths island-jumped to North America by 9 Ma ago. Megalonychid had colonized Antillen earlier, at the beginning of the Miocene. (Megatheriids and not land laziness did not move north until the formation of the isthmus.) Terror birds may have also visited the island to North America since 5 Ma ago.
The Caribbean islands are inhabited mainly by species from South America. This is due to the prevailing ocean currents, rather than to the competition between North and South America. (Except in the case of Jamaica, North American oryzomyine rodents may enter the territory only after attacking South America.)
Great American Biography Exchange
The Establishment of the Isthmus of Panama led to the last and most conspicuous wave, the great intersection, about 3 Ma ago. These include immigration to South America from North American ungulates (including camelids, tapirs, deer and horses), proboscids (gomphotheres), carnivorans (including felids such as cougars and saber-toothed cats, canids, mustelids, procyonids and bears) and numbers of types rodents. The larger members of the inverse migration, in addition to the soil sloth and the terror birds, are glyptodonts, pampatheres, capybaras and notoungulate Mixotoxodon (the only South American ungulate known to have attacked Central America).
In general, net early migration is symmetrical. But then, Neotropic species proved far less successful than Nearctic. This misfortune happens both ways. Animals migrating north often are unable to compete for resources and also North American species that already occupy the same ecological niche; those who become established can not diversify much. Nearctic species migrating south have established themselves in larger numbers and diversified more, and are thought to have caused the extinction of most South American fauna. (There is no extinction in North America that is clearly linked to South American immigrants.) Though birds of terror can attack parts of North America, their success is only temporary; this lineage disappeared about two million years ago. The great Neotropic meteoric predators fared no better. The South American native ungulat also did poorly, with only a handful of genera holding back the onslaught in the north. (It has long been known that some of the largest forms, macraucheniids and toxodontids, survived to the end of the Pleistocene.) The recent fossil findings suggest that a species of litoptern proterotheriid-like horse also does the same.Anotheriids and unknown hegetotheriids are also successful in maintaining at least part of the way through the Pleistocene.) On the other hand, small marsupials in South America persist in large numbers, while primitive-looking xenarthrans prove to be very competitive and become the most successful invaders in North America. African immigrants, rodent caviomorphs and platyrrhine monkeys, were less influenced by exchanges than most 'parents' in South America, although the caviomorph experienced significant diversity loss, including the elimination of the largest forms (eg, dinomidids). With the exception of North American hedgehogs and some extinct hedgehogs and capybaras, they did not migrate past Central America.
The early waves of southern Nearctic carnivores migrate rapidly into the predator niches of South America, displacing phorusrhacids and sparassodonts, as well as eliminating Chapalmalania. It has been argued that canids may play a major role in the extinction of borhyaenids; they are ecologically and morphologically more similar to them than other carnivores, and are also the most diverse families of modern carnivores on this continent. The lack of initial competition and abundant prey seem to have enabled short-sighted bears to rapidly evolve into the largest known terrestrial known land or terrestrial mammal carnivore species; Arctotherium angustidens is estimated to weigh about 1600 kg. Later species of Arctotherium exhibited a tendency towards smaller size and more omnivorous diets, possibly due to increased competition from later or developing carnivores. In contrast, Smilodon shows a tendency toward increased body size that culminates in the appearance of S. populator , to nearly 500 kg of the most massive known felid.
Due largely to the success of xenarthrans, one area of ​​South American ecosses, Nearctic invaders can not dominate is a niche for megaherbivores. Before 12,000 years ago, South America was home to about 25 species of herbivores weighing more than 1000 kg, consisting of Neotropic ground sloths, glyptodonts and toxodontids, as well as gomphotheres and camelids of Nearctic origin. The original form of South America comprises about 75% of this species. However, none of these megaherbivores survive.
Armadillos, opossums, and porcupines are present in North America today due to the Great American Exchange. Squirrels and hedgehogs are among the most successful northern migrants, reaching as far as Canada and Alaska, respectively. Most xenarthrans groups were present in North America until the end of the Pleistocene Quarter destruction period (as a result of at least eight successful invasions in temperate North America, and at least six Central American invasions alone). Among megafauna, the ground sloth is a successful emigrant; Megalonyx spreads as far north as the Yukon and Alaska, and may eventually reach Eurasia if the extinction event does not intervene.
In general, however, subsequent explosive dissemination and subsequent adaptive radiation of sigmodontine mice throughout South America (leading to more than 80 currently recognized genera) is much more successful (spatially or by species number) than in the migration of South American mammals to the north. Other examples of North American mammal groups that diversify prominently in South America include canida and cervida, which currently have 3 or 4 genera in North America, 2 or 3 in Central America, and 6 in South America. Although members of the Canis (specifically, coyotes) currently only range as far south as Panama, South America still has a wider genera than other continents.
The effect of isthmus formation on the marine biota of the area is the opposite of its effect on terrestrial organisms, a development which has been called the "Great American Schism". The relationship between the eastern Pacific Ocean and the Caribbean (Central American Seaway) was cut off, setting the present separate population on different evolutionary paths. Caribbean species also have to adapt to the environment with lower productivity after the entry of water rich in deep-seated Pacific nutrients.
Reasons for success or failure
The ultimate victory of Nearctic migrants is ultimately based on geography, which is played into the hands of the northern invaders in two important respects. The first is the climate problem. Any species that reaches Panama from both directions clearly should be able to tolerate the humid tropical conditions. Those who migrate south will then be able to occupy much of South America without facing a very different climate. However, migrants to the north will face more dry and/or cooler conditions by the time they reach the Trans-Mexican Volcanic Belt. This challenge of climate asymmetry (see map on the right) is presented very acutely to Neotropic species specific to tropical rain forest environments, which have little prospect of penetrating beyond Central America. As a result, Central America currently has 41 mammalian species of Neotropic origin, compared with only 3 for temperate North Americans. However, South American species (marsupials, xenarthrans, caviomorph rodents and monkeys) still comprise only 21% of species from non-marine mammal groups, nonmarine in Central America, while North American colonists account for 49% of species from such groups it's in South America. Thus, the climate alone can not fully account for the greater success of near-origin species during the exchange.
The second and more important geographic advantage given to northerners is related to the area of ​​land available to their ancestors to evolve. During the Kenozoic, North America was periodically connected to Eurasia via Beringia, allowing repeated migration back and forth to unite the fauna of two continents. Eurasia is connected in turn to Africa, which contributes further to the species that makes their way to North America. South America, on the other hand, is only connected to Antarctica and Australia, two continents much smaller and less friendly, and only at the beginning of the Kenozoic. Moreover, this land relationship does not seem to carry much traffic (apparently no mammals other than marsupials and possibly some monotrema that have ever migrated with this route), particularly towards South America. This means that the Northern Hemisphere species appears on an area of ​​approximately six times larger than that available to South American species. The North American species is thus a product of a larger and more competitive arena, where evolution will run faster. They tend to be more efficient and smarter, generally able to outrun and outwit their South American counterparts, which are the product of reverse evolution. This advantage can be seen clearly in cases of ungulates and predators, in which the form of South America was replaced wholesale by the invaders.
The greater final success of South African immigrants compared to the original early Cenozoic mammal fauna is another example of this phenomenon, since the former evolved over a wider field; their ancestors migrated from Eurasia to Africa, two much larger continents, before finding their way to South America.
Against this backdrop, the ability of South American xenarthrans to compete effectively against the north represents a special case. The explanation for the success of xenarthrans lies in the interior of their idiosyncratic approach to defend against predation, based on robust body armor and/or claw possession. Xenarthrans need not be the legs or quick response to survival. Such a strategy may have been imposed on them by their low metabolic rate (the lowest among them). Their low metabolic rate can in turn be beneficial in allowing them to survive with less abundant and/or less nutritious food sources. Unfortunately, a large xenarthrans defensive adaptation will offer little protection against humans armed with spears and other projectiles.
End of Pleistocene extinction
At the end of the Pleistocene age, some 12,000 years ago, three dramatic developments took place in America at about the same time (geologically). Paleoindian invaded and occupied the New World, the last glacial period ended, and most of the North and South American megafauna became extinct. This wave of extinctions swept many of the Earth's faces from successful participants of the American Milky Way, as well as other non-migrating species. All pamphlets, glyptodonts, ground sloths, equids, proboscids, giant short-faced bears, terrible wolves and machairodont species from both continents disappeared. The latter of South America and Central America are united and litopern dies, as well as the North American giant beavers, lions, dholes, cheetahs, and many of the antilocaprid, bovid, cervid, tapirid and tayassuid ungulates. Some groups disappear in most or all of their original ranges but survive in their adoption homes, eg. South American Tapirs, camelids, and tremarctine bears (puma and jaguar may have been temporarily reduced to South American refugees as well). Others, such as capybaras, survive in their hometown but die in the areas where they migrate. In particular, this extinction pulse removes all Neotropic entrants to North America greater than about 15 kg (large hedgehog size), and all South American native mammals are larger than about 65 kg (large capybara size or giant pangolin). By contrast, the largest surviving North American native mammal, wood bison, can exceed 900 kg, and the largest surviving Nearctic migrant to South America, Baird's tapir, can reach 400 kg.
Nearly-simultaneous megafaun extinction with glacial retreats and Americans has led to proposals that both climate change and human hunting play a role. Although the subject is disputed, a number of considerations indicate that human activity is very important. Extinctions do not occur selectively in climatic zones that will be most affected by warming trends, and there is no plausible climate-based megafauna mechanism that could explain the extinction of the entire continent. Climate change occurs worldwide, but has little effect on megafauna in areas such as Africa and southern Asia, where megafaunal species have lived with humans. Many similar glacial cracks have occurred earlier in the ice ages of some of the last Mas without ever producing a wave of extinction comparable in America or elsewhere. Similar megafaunal extinctions have occurred in newly inhabited lands (eg Australia, Japan, Madagascar, New Zealand, and many smaller islands around the world, such as Cyprus, Crete, Tilos and New Caledonia) at different times closely related to the first human arrival at each location. This extinction pulse always sweeps quickly across the entire land adjacent, regardless of whether it is an island or set of connected continental hemispheres. This is true despite the fact that all the larger ground masses involved (as well as many of the smaller ones) contain several climate zones that will be affected differently by the ongoing climate change. However, in large enough islands, offshore from newly occupied territories to avoid immediate human colonization, megafaun species sometimes survive for thousands of years after they or related species become extinct on land; examples include giant kangaroos in Tasmania, giant Chelonoidis tortoises from the GalÃppagos Islands (formerly also from South America), giant Dipsochelys tortoises from the Seychelles (formerly Madagascar ), giant meiolaniid turtles on Lord Howe Island, New Caledonia, and Vanuatu (formerly Australia), slotlands in Antilles, Steller's sea cows from the Command Islands and woolly mammoths on Wrangel Island and Saint Paul Island. The glacial retreat may play an indirect role especially in extinction in America simply by facilitating the movement of humans to the southeast from Beringia to North America. The reason why some groups are extinct in North America but living in South America (while there are no examples of opposite patterns) seems to be the dense rain forest in the Amazon basin and the high Andes peak provides an environment that provides a level of protection from human predation.
North American exclusive North American invasion of
North or extinct () North Axons whose ancestors migrated out of South America:
- Cichlids (Cichlidae: for example Texas cichlid) - freshwater fish that often tolerate brackish conditions
- Bufonid frog ( Bufo )
- Hylid frogs
- Leptodactylid frog - as far north as Texas
- Microhylid frog
- Virginia opossum ( Didelphis virginiana )
- Armadillos (nine-band armadillos Dasypus novemcinctus , D. bellus )
- Pachyarmatherium leiseyi , a mysterious armored armadillo
- Pampaster ( Plaina , Holmesina ) - big animals like armadillos
- Glyptodonts ( Glyptotherium )
- Megalonychid ground sloth ( Pliometanastes , Megalonyx )
- Mylodontid Ground Sloth ( Thinobadistes , Glossotherium , Paramylodon )
- Megatheriid Soil Sloth ( Eremotherium )
- Nohrotheriid soil sloth ( Nothrotheriops , Nothrotherium )
- New World hedgehogs ( Erethizon dorsatum , Erethizon poyeri , E. kleini )
- Capybaras ( Neochoerus pinckneyi , N. aesopi )
- Mixotoxodon - an uncomfortable rhinoceros toxodontid
- Cougar ( Puma concolor ) - returned from South American refugium after the North American puma was extinct in the Pleistocene extinction
- Molossid bat
- Mormoopid Bat ( Mormoops megalophylla )
- Vampire bat ( Desmodus stocki , D. archaeodaptes )
- Parrots (Neotropical parrots: thick parrot, Carolina parakeet)
- Terror Bird (Phorusrhacidae: Titanis walleri )
- Tanagers (Thraupidae)
- Hummingbirds (Trochilidae)
- Sub-Mediterans (Tyranni):
- Tityras and allies (Tityridae): becows rose-throated
- Tyrant flycatcher (Tyrannidae)
![Central American Seaway [image] | EurekAlert! Science News](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_vGtoDhyiuxG9WkaOUtnVD8e_aIgtRBh5ajx0h0WbIxsV9FKoKINx-qNk9eguk6oEwP0_tULIFrbeZECODOmrQFenSRs2SHp-_84pdibJd9BY5LYi-F1orkc_-JZFfeRKlc5y0B3s0ygw=s0-d "Central American Seaway [image] | EurekAlert! Science News")
South American invasion expanded only to Central America
Central American taxa or extinct () whose ancestors migrated out of South America:
- Gonyleptid harvest recipient (Opiliones: Gonyleptidae)
- Electric knife blades (Gymnotiformes)
- Hoplosternum punctatum , armored catfish (Siluriformes: Callichthyidae)
- Some species of loricariid catfish (Siluriformes: Loricariidae)
- Caeciliid caecilian ( Caecilia , Oscaecilia ) - snake-like amphibians, Panama and Costa Rica only
- Poison dart frogs (Dendrobatidae)
- Boine boas (Boidae: Boinae)
- Spectacled caiman ( Caiman crocodilus )
- Other Opossums (Didelphidae) - 11 additional species available
- Northern armadillo without a tail ( Cabassous centralis )
- Hoffmann's two-toed sloth (Megalonychidae: Choloepus hoffmanni )
- Three-pointed sloth (Bradypodidae: Bradypus variegatus , B. pygmaeus )
- Silky Pangolin (Cyclopedidae: Cyclopes didactylus )
- Other ant feeders (Myrmecophagidae: Myrmecophaga tridactyla , Tamandua mexicana )
- Rothschild and Mexicans porcupines hairy dwarfs ( Coendou rothschildi , Sphiggurus mexicanus )
- Other caviomorph rodents (Caviomorpha) - 9 other extant species
- Platyrrhine monkeys (Platyrrhini) - at least 8 extant species
- The emballonurid bat
- Furipterid bat ( Furipterus horrens )
- Other mormoopid bats
- Noctilionid bats ( Noctilio albiventris , Noctilio leporinus )
- Other phyllostomid bats, including all 3 remaining species of vampire bats (Desmodontinae)
- Thyropterid bats ( Thyroptera discifera , Thyroptera tricolor )
- Other neotrophic parrots (Arinae)
- Great curassow ( Crax rubra )
- Toucans (Ramphastidae)
- Tinamous (Tinamidae)
- additional sub-plant birds (Tyranni):
- Gnateaters (Conopophagidae)
- Cotingas (Cotingidae)
- Antipeluang on land (Formicariidae)
- Ovenbirds and woodcreepers (Furnariidae)
- Antpittas (Grallariidae)
- Manakins (Pipridae)
- Tapaculos (Rhinocryptidae)
- Antbirds (Thamnophilidae)
North American Invasion to South America
Source of the article : Wikipedia
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