Macrauchenia

Last updated

Contents

Macrauchenia
Temporal range: Pliocene–Late Pleistocene
Phenacodus primaevus and Macrauchenia patachonica.jpg
Holotype skeleton of M. patachonica (larger) and Phenacodus primaevus (smaller) at American Museum of Natural History
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order:† Litopterna
Family:† Macraucheniidae
Subfamily:† Macraucheniinae
Genus:† Macrauchenia
Owen, 1838
Type species
†Macrauchenia patachonica
Owen, 1838
Macrauchenia range map.svg
Map showing the distribution of Macrauchenia in red, and Xenorhinotherium in yellow, inferred from fossil finds

Macrauchenia ("long llama", based on the now-invalid llama genus, Auchenia, from Greek "big neck") is an extinct genus of large ungulate native to South America from the late Pliocene to the end of the Pleistocene. [1] It is a member of the extinct order Litopterna, a group of South American native ungulates distinct from the two orders which contain all living ungulates which had been present in South America since the early Cenozoic, over 60 million years ago, prior to the arrival of living ungulates in South America around 2.5 million years ago as part of the Great American Interchange. [2] The bodyform of Macrauchenia has been described as similar to a camel, [3] being one of the largest known litopterns, with an estimated body mass of around 1 tonne. [2] The genus gives its name to its family, Macraucheniidae, which like Macrauchenia typically had long necks and three toed feet, as well a retracted nasal region, [1] which in Macrauchenia manifests as the nasal opening being on the top of the skull behind the eye sockets. [4] This has historically been argued to correspond to the presence of a tapir-like proboscis, but some recent authors suggest a moose-like prehensile lip is more likely. [5]

Only one species is generally considered valid, [6] M. patachonica, which was described by Richard Owen based on remains discovered by Charles Darwin during the voyage of the Beagle. [7] M. patachonica is primarily known from localities in the Pampas, but is known from remains found across the Southern Cone extending as far south as southernmost Patagonia, and as far northeast as Southern Peru. Another genus of macraucheniid Xenorhinotherium was present in northeast Brazil and Venezuela during the Late Pleistocene. [4]

Macrauchenia became extinct as part of the end-Pleistocene extinctions around 12,000 years ago, along with the vast majority of other large mammals native to the Americas. [2]

Taxonomy

Limb bones of M. patachonica Machrauchenia patachonica, liptoptern, Museu de Ciencies Naturals de Valencia.JPG
Limb bones of M. patachonica

Macrauchenia fossils were first collected on 9 February 1834 at Port St Julian in Patagonia (Argentina) by Charles Darwin, when HMS Beagle was surveying the port. [8] As a non-expert he tentatively identified the leg bones and fragments of spine he found as "some large animal, I fancy a Mastodon". In 1837, soon after the Beagle's return, the anatomist Richard Owen identified the bones, including vertebrae from the back and neck, as from a gigantic creature resembling a llama or camel, which Owen named Macrauchenia patachonica. [9] In naming it, Owen noted the original Greek terms µακρος (makros, large or long), and αυχην (auchèn, neck) as used by Illiger as the basis of Auchenia as a generic name for the llama, Vicugna and so on. [10] The find was one of the discoveries leading to the inception of Darwin's theory. Since then, more Macrauchenia fossils have been found, mainly in Patagonia, but also in Bolivia, Chile and Venezuela.

The related genus Cramauchenia was named by Florentino Ameghino as a deliberate anagram of Macrauchenia.

Evolution

Illustration of the skull of Macrauchenia Anales del Museo Publico de Buenos Aires (1864) (17980766940).jpg
Illustration of the skull of Macrauchenia

It is likely that Macrauchenia evolved from earlier litopterns Theosodon , Cramauchenia or Promacrauchenia , or a similar species. Litopterna was one of the five (four in some classifications) ancient orders of endemic South American mammals collectively called meridiungulates. Their relationships with other mammal groups outside South America have been poorly understood, as their early evolutionary history would have been in Western Gondwana, and outside of South America this area is now Antarctica. When South America separated from Antarctica in the Eocene, [11] meridungulate orders survived in South America in isolation. Most flourished in the Paleogene and then diminished. Formerly, North American paleontologists considered them inferior to Northern Hemisphere taxa and to have been outcompeted to extinction in the Great American Biotic Interchange after the establishment of the Central American land bridge. However, more recent evidence shows that three of the meridungulate orders declined long before, just as happened to early mammal groups elsewhere. [12] Litopterns and notoungulates continued, evolving into a variety of more derived forms. While toxodontid notoungulates expanded into North America during the GABI, litopterns remained confined to South America. Macrauchenia was among the last surviving meridungulates, along with litopterns such as Macraucheniopsis , Neolicaphrium , and Xenorhinotherium and the large notoungulates Piauhytherium , Trigodonops , Toxodon, and Mixotoxodon. These last endemic South American hoofed animals died out at the end of the Lujanian (10,000-20,000 years ago). [13]

Sequencing of mitochondrial DNA extracted from an M. patachonica fossil from a cave in southern Chile indicates that Macrauchenia (and by inference, Litopterna) is the sister group to Perissodactyla, with an estimated divergence date of sixty-six million years ago. [14] [15] Analysis of collagen sequences obtained from Macrauchenia and Toxodon reached a similar conclusion and extended membership in the sister group clade to notoungulates. [16] [17]

Description

Size of M. patachonica compared to a human Macrauchenia wiki.png
Size of M. patachonica compared to a human
Skeletal reconstruction of M. patachonica Macrauchenia patachonica Skeletal.png
Skeletal reconstruction of M. patachonica

Macrauchenia had a somewhat camel-like body, with sturdy legs, a long neck and a relatively small head. Its feet, however, more closely resembled those of a modern rhinoceros, with one central toe and two side toes on each foot. It was a large animal, with a body length of around 3 metres (9.8 ft) and a weight up to 909–1,042.8 kg (2,004–2,299 lb), about the size of a black rhinoceros. [18] [19] [20]

One striking characteristic of Macrauchenia is the openings for the nostrils on top of the head, above and between the eyes. Increasingly retracted nostrils are an evolutionary trend in later litopterns. Because mammals with trunks show the nostrils in a similar position, a popular hypothesis is that Macrauchenia had a trunk similar to a tapir or an inflated snout like that of the saiga antelope, perhaps to keep dust out of the nostrils. [18] However, a 2018 study comparing the skulls of tapirs and various other herbivorous extant and extinct mammal species instead saw similarities with the skulls of moose, suggesting that Macrauchenia and other macraucheniids, such as Huayqueriana did not possess trunks. [21] However, pictographs depicting various extinct megafauna dated to around 12,600 to 11,800 years ago from the Serranía de La Lindosa rock formation of Guaviare, Colombia showed what appears to be a possible trunked macraucheniid, presumably Xenorhinotherium . [22] [23]

The snout of Macrauchenia is completely enclosed by bone, and the animal has an elongated neck that allowed it to reach upward; no living mammal with a proboscis has these features. An alternative hypothesis is that these litopterns were high browsers on tough and thorny vegetation, and retracted nostrils allowed them to reach leaves without being impaled in the nose. Sauropod dinosaurs (reconstructed as high browsers on conifer needles and cycads) have similar snouts, and living giraffes and gerenuks, high browsers on thorny vegetation, have more retracted nostrils than related taxa with other feeding habits. [12]

One insight into Macrauchenia's habits is that its ankle joints and shin bones may indicate that it was adapted to have unusually good mobility, being able to rapidly change direction when it ran at high speed. [24]

Macrauchenia is known, like its relative Theosodon , to have had a full set of 44 teeth.[ citation needed ]

Paleobiology

A 1913 restoration by Robert Bruce Horsfall depicting M. patachonica with an elephantine trunk Macrauchenia.jpg
A 1913 restoration by Robert Bruce Horsfall depicting M. patachonica with an elephantine trunk
Restoration with a moose-like nose Macrauchenia (reconstruction).jpg
Restoration with a moose-like nose

Macrauchenia was a herbivore, likely living on leaves from trees or grasses. Carbon isotope analysis of M. patachonica's tooth enamel, as well as analysis of its hypsodonty index (low in this case; i.e., it was brachydont), body size and relative muzzle width suggests that it was a mixed feeder, combining browsing on C3 foliage with grazing on C4 grasses. [25] A dental microwear, occusal enamel, and carbon isotope analysis of Macrauchenia and Xenorhinotherium found that both were grazers on C3 grasses. [4]

The genus was widespread, found in environments that ranged from dry to humid, from southern Chile to northeastern Brazil and the coast of Venezuela. Fossils of M. ullomensis have been found in Bolivia at altitudes up to 4000 meters. Habits and diet may have varied depending on the environment, but in plant feeders an elongated neck is usually an adaptation to allow high browsing on trees and shrubs. As the genus was not confined to forest, it was probably able to exploit more marginal environments by mixing high browsing with low browsing and grazing. A site in northern Chile preserved the remains of five subadults associated together, which suggests Macrauchenia may have lived in large herds or family groups. [12]

Restoration of M. patachonica without a trunk Macrauchenia (trunkless).jpg
Restoration of M. patachonica without a trunk

When Macrauchenia first arose, it could have been preyed upon by the largest of native South American mammal predators, the sabertoothed sparassodont Thylacosmilus . The largest phorusrhacid birds may also have been able to prey on juveniles. After the GABI, the primary predator on adults would have been the very large sabertoothed cat Smilodon populator [26] and giant short-faced bears. Dire wolves and jaguars may also have hunted Macrauchenia, particularly juveniles.

It is presumed that Macrauchenia dealt with its predators primarily by outrunning them, or, failing that, kicking them with its long, powerful legs. The large size of adults would have limited their vulnerability to most predators. Its potential ability to twist and turn at high speed could have enabled it to evade pursuers; both Thylacosmilus and S. populator were ambush hunters likely unable to run down prey over distance if the prey evaded the first attack.

Distribution

Fossils of Macrauchenia have been found in: [27]

Miocene
Pliocene
Pleistocene

Related Research Articles

<span class="mw-page-title-main">Litopterna</span> Extinct order of hoofed mammals

Litopterna is an extinct order of South American native ungulates that lived from the Paleocene to the end of the Pleistocene-early Holocene around 63 million-12,000 years ago, and were also present in Antarctica during the Eocene. They represent the second most diverse group of South American ungulates after Notoungulata. It is divided into nine families, with Proterotheriidae and Macraucheniidae being the most diverse and last surviving families.

<i>Toxodon</i> Extinct genus of notoungulates

Toxodon is an extinct genus of large ungulate native to South America from the Late Miocene to early Holocene epochs. Toxodon is a member of Notoungulata, an order of extinct South American native ungulates distinct from the two living ungulate orders that had been indigenous to the continent for over 60 million years since the early Cenozoic, prior to the arrival of living ungulates into South America around 2.5 million years ago during the Great American Interchange. Toxodon is a member of the family Toxodontidae, which includes medium to large sized herbivores. Toxodon was one of the largest members of Toxodontidae and Notoungulata, with Toxodon platensis having an estimated body mass of 1,000–1,200 kilograms (2,200–2,600 lb).

<span class="mw-page-title-main">Notoungulata</span> Extinct order of hoofed mammals

Notoungulata is an extinct order of ungulates that inhabited South America from the early Paleocene to the end of the Pleistocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resembling animals as disparate as rabbits and rhinoceroses. Notoungulata are the largest group of South American native ungulates, with over 150 genera in 14 families having been described, divided into two major subgroupings, Typotheria and Toxodontia. Notoungulates first diversified during the Eocene. Their diversity declined from the late Neogene onwards, with only the large toxodontids persisting until the end of the Pleistocene, perishing as part of the Late Pleistocene extinctions among with most other large mammals in the Americas. Collagen sequence analysis suggests that notoungulates are closely related to litopterns, another group of South American ungulates, and their closest living relatives being perissodactyls, including rhinoceroses, tapirs and equines as part of the clade Panperissodactyla. However their relationships to other South American ungulates are uncertain. Several groups of notoungulates separately evolved ever-growing cheek teeth.

<span class="mw-page-title-main">South American native ungulates</span> Extinct clade of mammals

South American native ungulates, commonly abbreviated as SANUs, are extinct ungulate-like mammals of controversial affinities that were indigenous to South America prior to the Great American Biotic Interchange. They comprise five major groups conventionally ranked as orders—Astrapotheria, Litopterna, Notoungulata, Pyrotheria, and Xenungulata—as well as the primitive "condylarth" groups Didolodontidae and Kollpaniinae. It has been proposed that some or all of the members of this group form a clade, named Meridiungulata, though the relationships of South American ungulates remain largely unresolved. The two largest groups of South American ungulates, the notoungulates and the litopterns, were the only groups to persist beyond the mid Miocene. Only a few of the largest species of notoungulates and litopterns survived until the end-Pleistocene extinction event around 12,000 years ago where they became extinct with most other large mammals in the Americas, shortly after the first arrival of humans into the region.

<span class="mw-page-title-main">Macraucheniidae</span> Family in the extinct South American ungulate order Litopterna, that resembled various camelids

Macraucheniidae is a family in the extinct South American ungulate order Litopterna, that resembled various camelids. The reduced nasal bones of their skulls was originally suggested to have housed a small proboscis, similar to that of the saiga antelope. However, one study suggested that they were openings for large moose-like nostrils. Conversely, prehistoric pictographs by indigenous people seems to depict animals interpreted as macraucheniids with trunks. Their hooves were similar to those of rhinoceroses today, with a simple ankle joint and three digits on each foot. Thus, they may have been capable of rapid directional change when running away from predators, such as large phorusrhacid terror birds, sparassodont metatherians, giant short-faced bears (Arctotherium) and saber-toothed cats (Smilodon). Macraucheniids probably lived in large herds to gain protection against these predators, as well as to facilitate finding mates for reproduction.

<i>Theosodon</i> Extinct genus of litopterns

Theosodon is an extinct genus of litoptern mammal from the Early to Middle Miocene of South America.

<i>Xenorhinotherium</i> Extinct genus of litopterns

Xenorhinotherium is an extinct genus of macraucheniine macraucheniids, closely related to Macrauchenia of Patagonia. The type species is X. bahiense.

<i>Cramauchenia</i> Extinct genus of litoptern South American ungulate

Cramauchenia is an extinct genus of litoptern South American ungulate. Cramauchenia was named by Florentino Ameghino. The name has no literal translation. Instead, it is an anagram of the name of a related genus Macrauchenia. This genus was initially discovered in the Sarmiento Formation in the Chubut Province, in Argentina, and later it was found in the Chichinales Formation in the Río Negro Province and the Cerro Bandera Formation in Neuquén, also in Argentina, in sediments assigned to the SALMA Colhuehuapian, as well as the Agua de la Piedra Formation in Mendoza, in sediments dated to the Deseadan. In 1981 Soria made C. insolita a junior synonym of C. normalis. A specimen of C. normalis was described in 2010 from Cabeza Blanca in the Sarmiento Formation, in sediments assigned to the Deseadan SALMA.

Victorlemoinea is an extinct litoptern genus of the family Sparnotheriodontidae, that lived from the Early to Middle Eocene. Fossils of Victorlemoinea have been found in the Las Flores, Sarmiento and Koluel Kaike Formations of Argentina, the Itaboraí Formation of Brazil and La Meseta Formation, Antarctica.

<i>Scalabrinitherium</i> Extinct genus of litopterns

Scalabrinitherium is an extinct genus of mammals of the family Macraucheniidae. Fossils of this animal were found among the fossils of prehistoric xenarthrans in the Ituzaingó Formation of Argentina.

<span class="mw-page-title-main">Astrapotheria</span> Extinct order of mammals

Astrapotheria is an extinct order of South American and Antarctic hoofed mammals that existed from the late Paleocene to the Middle Miocene, 59 to 11.8 million years ago. Astrapotheres were large, rhinoceros-like animals and have been called one of the most bizarre orders of mammals with an enigmatic evolutionary history.

<span class="mw-page-title-main">Toxodontidae</span> Extinct family of notoungulate mammals

Toxodontidae is an extinct family of notoungulate mammals, known from the Oligocene to the Holocene of South America, with one genus, Mixotoxodon, also known from the Pleistocene of Central America and southern North America. Member of the family were medium to large-sized, ranging from around 350–400 kilograms (770–880 lb) in Nesodon to 1,000–1,200 kilograms (2,200–2,600 lb) in Toxodon, and had medium to high-crowned dentition, which in derived members of the group evolved into ever-growing cheek teeth. Isotopic analyses have led to the conclusion that Pleistocene members of the family were flexible mixed feeders.

<span class="mw-page-title-main">Proterotheriidae</span> Extinct family of litopterns

Proterotheriidae is an extinct family of litoptern ungulates known from the Eocene-Late Pleistocene of South America. Members of the group were small-medium sized cursorial herbivores with brachydont teeth, with their toes showing progressive reduction, with later members of the group bearing weight on a single large toe similar to living horses.

<i>Neolicaphrium</i> Extinct genus of ungulate mammal

Neolicaphrium is an extinct genus of ungulate mammal belonging to the extinct order Litopterna. This animal lived from the Late Pliocene (Chapadmalalan) to the Late Pleistocene (Lujanian) in southern South America, being the last survivor of the family Proterotheriidae.

Cullinia is an extinct genus of litoptern, an order of South American native ungulates that included horse-like and camel-like animals such as Macrauchenia. It is only known from fragmentary remains. Cullinia levis is known from Chasicoan remains found in the Arroyo Chasicó Formation of Argentina, and remains from the Brazilian state of Acre and the Huayquerian Ituzaingó Formation have been assigned to Cullinia sp..

Promacrauchenia is an extinct genus of macraucheniids that lived during the Late Miocene to Late Pliocene epochs of what is now Argentina and Bolivia. It belongs to the subfamily Macraucheniinae, which also includes Huayqueriana, Macrauchenia, and Xenorhinotherium. Fossils of this genus have been found in the Ituzaingó, Andalhuala, and Cerro Azul Formations of Argentina.

Sparnotheriodontidae is an enigmatic extinct family of litopterns known primarily from teeth. Sparnotheriodontids are one of two South American native ungulate clades known to have reached Antarctica, the other being astrapotheres.

Polymorphis is an extinct genus of litopterns belonging to the family Macraucheniidae. It lived during the Middle Eocene of Argentina.

Uruguayodon is an extinct genus of proterotheriid from the middle Pleistocene of Uruguay. It is known from the type and only species U. alius, named by Corona and colleagues in 2019 for dentaries and a partial postcrania from the Raigón Formation. Uruguayodon represents one of the latest occurrences of Proterotheriidae, with only Neolicaphrium representing other remains from the Pleistocene to possibly Holocene.

<i>Micrauchenia</i> Extinct genus of litopterns

Micrauchenia is an extinct genus of macraucheniine litoptern that lived during the Late Miocene of what is now Chile. Fossils of this genus have been found in the Bahía Inglesa Formation in Chile.

References

  1. 1 2 Püschel, Hans P.; Alarcón-Muñoz, Jhonatan; Soto-Acuña, Sergio; Ugalde, Raúl; Shelley, Sarah L.; Brusatte, Stephen L. (June 2023). "Anatomy and phylogeny of a new small macraucheniid (Mammalia: Litopterna) from the Bahía Inglesa Formation (late Miocene), Atacama Region, Northern Chile". Journal of Mammalian Evolution. 30 (2): 415–460. doi: 10.1007/s10914-022-09646-0 . ISSN   1064-7554.
  2. 1 2 3 Croft, Darin A.; Gelfo, Javier N.; López, Guillermo M. (2020-05-30). "Splendid Innovation: The Extinct South American Native Ungulates". Annual Review of Earth and Planetary Sciences. 48 (1): 259–290. Bibcode:2020AREPS..48..259C. doi:10.1146/annurev-earth-072619-060126. ISSN   0084-6597. S2CID   213737574.
  3. ↑ Defler, Thomas (2019), "The Native Ungulates of South America (Condylarthra and Meridiungulata)", History of Terrestrial Mammals in South America, Topics in Geobiology, vol. 42, Cham: Springer International Publishing, pp. 89–115, doi:10.1007/978-3-319-98449-0_5, ISBN   978-3-319-98448-3, S2CID   91879648 , retrieved 2024-01-30
  4. 1 2 3 de Oliveira, Karoliny; Araújo, Thaísa; Rotti, Alline; Mothé, Dimila; Rivals, Florent; Avilla, Leonardo S. (March 2020). "Fantastic beasts and what they ate: Revealing feeding habits and ecological niche of late Quaternary Macraucheniidae from South America". Quaternary Science Reviews. 231: 106178. Bibcode:2020QSRv..23106178D. doi:10.1016/j.quascirev.2020.106178. S2CID   213795563.
  5. ↑ Moyano, Silvana Rocio; Giannini, Norberto Pedro (November 2018). "Cranial characters associated with the proboscis postnatal-development in Tapirus (Perissodactyla: Tapiridae) and comparisons with other extant and fossil hoofed mammals". Zoologischer Anzeiger. 277: 143–147. doi: 10.1016/j.jcz.2018.08.005 .
  6. ↑ Souza Lobo, Leonardo; Lessa, Gisele; Cartelle, Cástor; Romano, Pedro S. R. (September 2017). "Dental eruption sequence and hypsodonty index of a Pleistocene macraucheniid from the Brazilian Intertropical Region". Journal of Paleontology. 91 (5): 1083–1090. Bibcode:2017JPal...91.1083S. doi:10.1017/jpa.2017.54. ISSN   0022-3360.
  7. ↑ Fernicola, J. C., Vizcaino, S. F., & De Iuliis, G. (2009). The fossil mammals collected by Charles Darwin in South America during his travels on board the HMS Beagle. Revista De La Asociación Geológica Argentina, 64(1), 147-159. Retrieved from https://revista.geologica.org.ar/raga/article/view/1339
  8. ↑ Darwin, Charles (2001). Keynes, Richard D. (ed.). Charles Darwin's Beagle diary. Cambridge: Cambridge University Press. p. 214. ISBN   9780521003179 . Retrieved 19 December 2008.
  9. ↑ "Darwin Correspondence Project - Letter 238 — Darwin, C. R. to Henslow, J. S., Mar 1834". Archived from the original on 2009-01-16. Retrieved 2008-12-19.
  10. ↑ Owen 1838 , p. 35
  11. ↑ "Tectonic history: into the deep freeze". Discovering Antarctica. Retrieved 2019-07-10.
  12. 1 2 3 Croft, Darin (2016). Horned Armadillos and Rafting Monkeys; the Fascinating Fossil Mammals of South America. Indiana University Press.
  13. ↑ Alberto L. Cione, Eduardo P. Tonni, Leopoldo Soibelzon: The Broken Zig-Zag: Late Cenozoic large mammal and tortoise extinction in South America. In: Revista del Museo Argentino de Ciencias Naturales. 5, 1, 2003, ISSN   1514-5158, S. 1–19, online Archived 2011-07-06 at the Wayback Machine
  14. ↑ Westbury, M.; Baleka, S.; Barlow, A.; Hartmann, S.; Paijmans, J. L. A.; Kramarz, A.; Forasiepi, A. M.; Bond, M.; Gelfo, J. N.; Reguero, M. A.; López-Mendoza, P.; Taglioretti, M.; Scaglia, F.; Rinderknecht, A.; Jones, W.; Mena, F.; Billet, G.; de Muizon, C.; Aguilar, J. L.; MacPhee, R. D. E.; Hofreiter, M. (2017-06-27). "A mitogenomic timetree for Darwin's enigmatic South American mammal Macrauchenia patachonica". Nature Communications. 8: 15951. Bibcode:2017NatCo...815951W. doi:10.1038/ncomms15951. PMC   5490259 . PMID   28654082.
  15. ↑ Strickland, A. (June 27, 2017). "DNA solves ancient animal riddle that Darwin couldn't". CNN. Retrieved June 27, 2017.
  16. ↑ Welker, F.; Collins, M. J.; Thomas, J. A.; Wadsley, M.; Brace, S.; Cappellini, E.; Turvey, S. T.; Reguero, M.; Gelfo, J. N.; Kramarz, A.; Burger, J.; Thomas-Oates, J.; Ashford, D. A.; Ashton, P. D.; Rowsell, K.; Porter, D. M.; Kessler, B.; Fischer, R.; Baessmann, C.; Kaspar, S.; Olsen, J. V.; Kiley, P.; Elliott, J. A.; Kelstrup, C. D.; Mullin, V.; Hofreiter, M.; Willerslev, E.; Hublin, J.-J.; Orlando, L.; Barnes, I.; MacPhee, R. D. E. (2015-03-18). "Ancient proteins resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–84. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. hdl: 11336/14769 . ISSN   0028-0836. PMID   25799987. S2CID   4467386.
  17. ↑ Buckley, M. (2015-04-01). "Ancient collagen reveals evolutionary history of the endemic South American 'ungulates'". Proceedings of the Royal Society B: Biological Sciences. 282 (1806): 20142671. doi:10.1098/rspb.2014.2671. PMC   4426609 . PMID   25833851.
  18. 1 2 Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 248. ISBN   978-1-84028-152-1.
  19. ↑ Fariña RA, Czerwonogora A, di Giacomo M (March 2014). "Splendid oddness: revisiting the curious trophic relationships of South American Pleistocene mammals and their abundance". Anais da Academia Brasileira de Ciências. 86 (1): 311–31. doi: 10.1590/0001-3765201420120010 . PMID   24676170.
  20. ↑ http://sedici.unlp.edu.ar/handle/10915/16838?show=full (in Spanish)
  21. ↑ Moyano, S.R.; Giannini, N.P. (2018-10-10). "Cranial characters associated with the proboscis postnatal-development in Tapirus (Perissodactyla: Tapiridae) and comparisons with other extant and fossil hoofed mammals". Zoologischer Anzeiger. 277 (7554): 143–147. doi: 10.1016/j.jcz.2018.08.005 . ISSN   0044-5231.
  22. ↑ Morcote-Ríos, Gaspar; Aceituno, Francisco Javier; Iriarte, José; Robinson, Mark; Chaparro-Cárdenas, Jeison L. (2020-04-29). "Colonisation and early peopling of the Colombian Amazon during the Late Pleistocene and the Early Holocene: New evidence from La Serranía La Lindosa". Quaternary International. 578: 5–19. doi:10.1016/j.quaint.2020.04.026. ISSN   1040-6182. S2CID   219014558.
  23. ↑ "12,000-Year-Old Rock Drawings of Ice Age Megafauna Discovered in Colombian Amazon | Archaeology | Sci-News.com". Breaking Science News | Sci-News.com. Retrieved 2020-12-04.
  24. ↑ Fariña, Richard A.; Blanco, R. Ernesto; Christiansen, Per (2005). "Swerving as the escape strategy of Macrauchenia patachonica Owen (Mammalia; Litopterna)". Ameghiniana. 42 (4): 752–760.
  25. ↑ MacFadden, B. J.; Shockey, B. J. (Winter 1997). "Ancient feeding ecology and niche differentiation of Pleistocene mammalian herbivores from Tarija, Bolivia: morphological and isotopic evidence". Paleobiology . 23 (1): 77–100. Bibcode:1997Pbio...23...77M. doi:10.1017/S0094837300016651. JSTOR   2401158. S2CID   88948874.
  26. ↑ Anton, Mauricio. "Sabertooth". Indiana University Press. Archived from the original on 2015-06-05. Retrieved 2019-07-10.
  27. ↑ Macrauchenia at Fossilworks.org

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.