Wikipedia

Toxodon

Toxodon (meaning "bow tooth" in reference to the curvature of the teeth) is an extinct genus of large ungulate native to South America from the Pliocene to the end of the Late Pleistocene.[1][2] 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.[3] Toxodon is a member of the family Toxodontidae, which includes medium to large sized herbivores.[4] 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).

Toxodon
Temporal range: Pliocene–Holocene
Skeleton of Toxodon in Buenos Aires
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: †Notoungulata
Family: †Toxodontidae
Subfamily: †Toxodontinae
Genus: †Toxodon
Owen, 1837
Type species
†Toxodon platensis
Owen, 1837
Other species
  • †T. burmeisteri Giebel, 1866
  • †T. chapalmalensis Ameghino, 1908
  • †T. ensenadensis Ameghino, 1887
  • †T. expansidens Cope, 1886
  • †T. gracilis Gervais and Ameghino, 1880
Synonyms

Genus-level

  • Dilobodon Ameghino, 1886
  • Chapalmalodon Pascual, 1957
  • Chapadmalodon Tonni et al., 1992 (lapsus calami)

T. platensis

  • T. angustidens Owen, 1846
  • T. owenii Burmeister, 1866
  • T. gervaisii Gervais & Ameghino, 1880
  • T. aguirrei Ameghino, 1917
  • T. gezi Ameghino, 1917

T. burmeisteri

  • T. paradoxus Ameghino, 1882
  • T. protoburmeisteri Ameghino, 1887
  • T. bilobidens Ameghino, 1887

T. chapalmalensis

  • Chapalmalodon chapalmalensis Pascual, 1957
  • T. chapadmalensis Cione & Tonni, 1995 (lapsus calami)
  • T. chapalmalalensis Oliva & Cerdeno, 2007 (lapsus calami)

T. ensenadensis

  • T. giganteus Moreno, 1888
  • T. elongatus Roth, 1898

T. gracilis

  • T. voghti Moreno, 1888

Remains of Toxodon were first collected by Charles Darwin during the voyage of the Beagle in 1832-33, and later scientifically named by Richard Owen in 1837. Both Darwin and Owen were puzzled by Toxodon's unusual anatomical features, including its long, ever-growing cheek teeth.

Toxodon has been found across much of South America, excluding southern Patagonia, the Andes and northeastern-most region of the continent.[5] Evidence suggests that Toxodon was ecologically plastic and able to adapt its diet to local conditions.[6]

Toxodon became extinct as part of the end-Pleistocene extinctions around 12,000 years ago, along with most large mammals across the Americas. The extinctions followed the arrival of humans to South America, who may have been a contributory factor in the extinctions.[3] Several sites have been found suggesting human interaction with Toxodon.

Taxonomy and evolution

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Historical restoration of Toxodon platensis from 1913

Charles Darwin, who was in South America as part of the second voyaging expedition of the HMS Beagle, was one of the first to collect Toxodon fossils.[7] In September-October 1832 and October 1833, Darwin collected several isolated teeth as well as a mandible from various localities in northern Argentina.[7] On November 26, 1833, Darwin paid 18 pence (equivalent to £6.40 in 2018[8]) for a T. platensis skull from a farmer in Uruguay.[9][10] In his book covering the expedition, The Voyage of the Beagle. Darwin wrote, "November 26th – I set out on my return in a direct line for Montevideo. Having heard of some giant's bones at a neighbouring farm-house on the Sarandis, a small stream entering the Rio Negro, I rode there accompanied by my host, and purchased for the value of eighteen pence the head of the Toxodon." The skull had been propped up against a fence and been used as target practice for throwing stones by local children, who had knocked out its teeth.[11][8] Since Darwin discovered that the fossils of similar mammals of South America were different from those in Europe, he invoked many debates about the evolution and natural selection of animals.

In his own words, Darwin wrote down in his journal,

Lastly, the Toxodon, perhaps one of the strangest animals ever discovered: In size it equaled an elephant or megatherium, but the structure of its teeth, as Mr. Owen states, proves indisputably that it was intimately related to the Gnawers, the order which, at the present day, includes most of the smallest quadrupeds: In many details it is allied to the Pachydermata: Judging from the position of its eyes, ears, and nostrils, it was probably aquatic, like the Dugong and Manatee, to which it is also allied. How wonderfully are the different Orders, at the present time so well separated, blended together in different points of the structure of the Toxodon!

Toxodon and its type species, T. platensis, were described in 1837 by Richard Owen based on remains collected by Darwin, in a paper titled "A description of the cranium of the Toxodon platensis, a gigantic extinct mammiferous species, referrible by its dentition to the Rodentia, but with affinities to the Pachydermata and the herbivorous Cetacea", reflecting the many unusual characteristics of its anatomy.[7]

Evolution

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Toxodon is a member of Notoungulata, a group of South American native ungulates that had been part of the fauna of South America since the Paleocene, over 60 million years ago, and had evolved in isolation in South America, prior to the arrival of living ungulates in South America around 2.5 million years ago as part of the Great American Interchange.[3] Notoungulata represents the most diverse group of indigenous South American ungulates, with over 150 described genera in 13 different families.[12] Notoungulates are morphologically diverse, including forms morphologically distant from Toxodon such as rodent and rabbit-like forms.[3]

Analysis of collagen sequences obtained from Toxodon as well as from Macrauchenia, a member of another indigenous South American ungulate order, Litopterna, found that notoungulates and litopterns were closely related to each other, and form a sister group to perissodactyls (which contains equids, rhinoceroses and tapirs) as part of the clade Panperissodactyla, making them true ungulates.[13][14] This finding has been corroborated by an analysis of mitochondrial DNA extracted from a Macrauchenia fossil, which yielded a date of 66 million years ago for the time of the split from perissodactyls.[15]

Toxodon belongs to Toxodontidae, a large bodied group of notoungulates which first appeared in the Late Oligocene (Deseadan), ~28-23 million years ago,[16] and underwent a great radiation during the Miocene epoch (~23-5.3 million years ago), when they reached their apex of diversity.[17] The diversity of toxodontids, along with other notoungulates began to decline from around the Pliocene onwards,[3] possibly as a result of climate change, as well as the arrival of competitors and predators from North America during the Great American Interchange following formation of the Isthmus of Panama.[18] By the Late Pleistocene (Lujanian), the once great diversity of notoungulates had declined to only a few of species of toxodontids, with all other notoungulate families having become extinct.[3]

Cladogram of Toxodontidae, showing the position of Toxodon relative to other toxodontids, after Forasiepi et al., 2014:[19]

   †Notoungulata   

Species

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There has not been a recent taxonomic revision of the genus Toxodon, leaving the number of valid species uncertain.[20]

The species Toxodon chapalmalensis is known from the Pliocene (Montehermosan-Chapadmalalan) of Argentina,[21] while Toxodon platensis, the type species, is known from the Pleistocene. The validity of other potential species like Toxodon darwini Burmeister, 1866, and Toxodon ensenadensis Ameghino, 1887 from the Early Pleistocene of Argentina is uncertain, and the species Toxodon gezi C. Ameghino, 1917 and Toxodon aguirrei Ameghino, 1917 have been considered junior synonyms of Toxodon platensis by recent authors.[22] Some recent authors have argued that Toxodon gracilis Gervais and Ameghino, 1880, should be recognised as a distinct species from the Pleistocene of the Pampas significantly smaller than T. platensis, with these authors suggesting that T. platensis and T. gracilis represent the only valid species of Toxodon in the Pleistocene of the Pampas region.[20] Other authors have argued that all Pleistocene Toxodon species should be considered synonymous with T. platensis.[23]

Description

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The bodyform of Toxodon and other toxodontids have been compared to those of hippopotamuses and rhinoceroses.[24] Toxodon platensis is one of the largest known toxodontids and notoungulates, with an estimated body mass of approximately 1,000–1,200 kilograms (2,200–2,600 lb),[25] and a body length of around 2.7 metres (8 ft 10 in).[26]

The skull of Toxodon is proportionally large,[25] and triangular in shape when viewed from above.[27] All of the teeth in the jaws are high-crowned (hypsodont).[28] Like other toxodontids, the upper and lower first incisors (I1 and i1) are large and protrude, with the second upper incisors (I2) and lower third incisors (i3) being modified into evergrowing tusks.[29] The upper incisors display an arched shape,[30] while the lower incisors project horizontally forwards at the front of the lower jaw.[28][30] The wide front of the lower jaw with the horizontally-arranged incisors has been described as "spade-like".[30] There is a gap (diastema) between the incisors and the cheek teeth.[31] Like other derived toxodontids, Toxodon had long, ever-growing (hypselodont) cheek (premolar and molar) teeth,[32] with the name Toxodon deriving from the curved shape of the upper molars, which are bowed inwards towards the midline of the skull to fit in the upper jaw. Evergrowing cheek teeth are unknown in any living ungulates, but are present in some other mammal groups like wombats and rodents. The surface of the cheek teeth is primarily composed of dentine.[3]

The thoracic vertebrae of Toxodon have elongate neural spines, which likely anchored muscles which supported the large head.[26] The legs of Toxodon are relatively short, with their bones being robust.[33] The hindlimb is considerably longer than the forelimb, resulting in the back being elevated and the shoulder, neck and head being relatively low.[28] The ulna has a strongly backwardly projecting olecranon process similar to that of rhinos, suggesting that the front leg was held extended when standing.[26] The (distal) part of the femur closest to the foot shows a pronounced medial trochlear ridge, which likely served along with the patella (kneecap) to allow the knees to be locked when standing akin to the stay apparatus of living horses as an energy saving mechanism.[34] There are three functional digits on each foot,[33][31] which are tipped with hoof-like phalanges.[35]

  •  
    Mount at Museo de La Plata, Argentina
  •  
    Skull in front-on view
  •  
    Skull in oblique view
  •  
    Skeleton in side-on view
  •  
    Skull in side-on view

Distribution

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Toxodon had a widespread distribution in South America east of the Andes, ranging from northern Argentina and Bolivia to the western Amazon on the Peru-Brazil border, to Northeast Brazil.[36] Although some authors suggest that the distribution of Toxodon extended into Venezuela,[29] other authors suggest that the related Mixotoxodon (which ranged as far north as the southern United States) was the only toxodontid present in the region during the Pleistocene.[37]

Palaeobiology

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Life restoration of Toxodon platensis (background centre-left) in a Pleistocene Brazilian landscape, alongside the giant ground sloth Eremotherium laurillardi (foreground right), the glyptodonts Glyptotherium and Panochthus, the pampathere Holmesina paulacoutoi (midground centre-left) and the armadillo Pachyarmatherium brasiliense (foreground left)

Although some authors have suggested that Toxodon was semiaquatic based on the similarity of some aspects of its anatomy to hippopotamuses, this has been disputed by other authors, and analysis of oxygen isotope ratios (which differ between terrestrial and aquatic animals) suggests a terrestrial lifestyle for Toxodon.[38][6] As such, it has been suggested that Toxodon was probably more ecologically comparable to rhinoceroses.[6]

Toxodon is suggested to have been capable of moving at considerable speed.[30] Toxodon is believed to have been ecologically plastic and have had a wide niche breadth,[6] with its diet varying according to local conditions,[39] with an almost totally C3 browsing diet in the Amazon rainforest, mixed feeding C3 in Bahia and the Pampas to almost completely C4 dominated grazing diet in the Chaco.[36] Within the Brazilian Intertropical Region, local climate had little impact on the diet of T. platensis.[40] Although Toxodon is thought to have inhabited open landscapes like steppe and savannah,[41][42] in some areas like the southwestern Brazilian Amazon, it is suggested to have inhabited woodland.[43][44]

Like living animals of similar size, it has been suggested that Toxodon probably only gave birth to a single offspring at a time.[45]

T. platensis bones have been found displaying signs of disease like osteomyelitis and spondyloarthropathies.[46]

Tracks probably attributable to Toxodon have been reported from eastern Pernambuco in Northeast Brazil.[33]

Isotopic analysis suggests that Toxodon may have been predated upon by the large sabertooth cat Smilodon populator, the apex predator of South American ecosystems during much of the Pleistocene.[47]

Extinction

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Toxodon became extinct at the end of the Late Pleistocene around 12,000 years as part of the end-Pleistocene extinction event alongside almost all other large animals in South America. Previous mid-Holocene dates are now thought to be in error.[48] These extinctions followed the first arrival of humans in the Americas, and it has been suggested human hunting may have been a casual factor in the extinctions.[3] Several sites record apparent interactions between Toxodon and humans. Remains of Toxodon from the Arroyo Seco 2 site in the Pampas are associated with unambiguously butchered megafauna, but it is unclear if the Toxodon itself was actually butchered or the remains were naturally transported to the site.[49] At the Paso Otero 5 site in the Pampas of northeast Argentina, burned bones of Toxodon alongside those of numerous other extinct megafauna species are associated with Fishtail points (a type of knapped stone spear point common across South America at the end of the Pleistocene, suggested to be used to hunt large mammals[50]). The bones of the megafauna were probably deliberately burned as fuel. No cut marks are visible on the vast majority of bones at the site (with only one bone of a llama possibly displaying any butchery marks), which may be due to the burning degrading the bones.[51] Various remains of Toxodon platensis in the collection of the Museum national d'Histoire naturelle collected from the Pampas region in the 19th century including a femur, an iliac fragment, a tibia, as well as a mandible (the latter of which has been radiocarbon dated to around 13,000 years ago), have been found to display cut marks indicative of butchery.[52]

References

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  1. ^ Baffa O, Brunetti A, Karmann I, Neto CM (May 2000). "ESR dating of a toxodon tooth from a Brazilian karstic cave". Applied Radiation and Isotopes. 52 (5): 1345–9. Bibcode:2000AppRI..52.1345B. doi:10.1016/S0969-8043(00)00093-2. PMID 10836452.
  2. ^ Turvey ST (28 May 2009). Holocene Extinctions. OUP Oxford. ISBN 978-0-19-157998-1.
  3. ^ a b c d e f g h Croft DA, Gelfo JN, López GM (30 May 2020). "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. Retrieved 2 January 2024.
  4. ^ Cassini, Guillermo H.; Flores, David A.; Vizcaíno, Sergio F. (July 2012). "Postnatal ontogenetic scaling of Nesodontine (Notoungulata, Toxodontidae) cranial morphology: Nesodontine cranial allometry". Acta Zoologica. 93 (3): 249–259. doi:10.1111/j.1463-6395.2011.00501.x. hdl:11336/81335.
  5. ^ Cione, Alberto Luis; Gasparini, Germán Mariano; Soibelzon, Esteban; Soibelzon, Leopoldo Héctor; Tonni, Eduardo Pedro (2015), "The GABI in Southern South America", The Great American Biotic Interchange, Dordrecht: Springer Netherlands, pp. 71–96, doi:10.1007/978-94-017-9792-4_3, ISBN 978-94-017-9791-7, S2CID 127856682, retrieved 30 January 2024
  6. ^ a b c d Dantas, Mário André Trindade; Cherkinsky, Alexander; Bocherens, Hervé; Drefahl, Morgana; Bernardes, Camila; França, Lucas de Melo (15 August 2017). "Isotopic paleoecology of the Pleistocene megamammals from the Brazilian Intertropical Region: Feeding ecology (δ13C), niche breadth and overlap". Quaternary Science Reviews. 170: 152–163. doi:10.1016/j.quascirev.2017.06.030. ISSN 0277-3791. Retrieved 2 January 2024 – via Elsevier Science Direct.
  7. ^ a b c 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. ^ a b Kennedy, Maev (6 April 2018). "Darwin's lost fossils – including a sloth the size of a car – to be made public". The Guardian. ISSN 0261-3077. Retrieved 28 November 2024.
  9. ^ Quammen, D. (February 2009). "Darwin's first clues". National Geographic. p. 45.
  10. ^ "Darwin's Fossil Mammals - Toxodon platensis - cranium - Data Portal". data.nhm.ac.uk. Retrieved 28 November 2024.
  11. ^ Darwin, Charles (1997) [1839]. Browne, J.; Neve, M. (eds.). The Voyage of the Beagle. Penguin. ISBN 978-0-14-043268-8. Read, 19th April 1837. A detailed account will appear in the first part of the zoology of Voyage of the Beagle.
  12. ^ Rezende Castro, Luis Otavio; García-López, Daniel A.; Bergqvist, Lilian Paglarelli; De Araújo-Júnior, Hermínio Ismael (30 June 2021). "A New Basal Notoungulate from the Itaboraí Basin (Paleogene) of Brazil". Ameghiniana. 58 (3). doi:10.5710/AMGH.05.02.2021.3387. ISSN 0002-7014. S2CID 234220780.
  13. ^ Welker F, Collins MJ, Thomas JA, Wadsley M, Brace S, Cappellini E, et al. (June 2015). "Ancient proteins resolve the evolutionary history of Darwin's South American ungulates". Nature. 522 (7554): 81–4. Bibcode:2015Natur.522...81W. doi:10.1038/nature14249. hdl:11336/14769. PMID 25799987. S2CID 4467386.
  14. ^ Buckley, M. (7 May 2015). "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.
  15. ^ Westbury M, Baleka S, Barlow A, Hartmann S, Paijmans JL, Kramarz A, et al. (June 2017). "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.
  16. ^ Bonini, Ricardo A.; Schmidt, Gabriela I.; Reguero, Marcelo A.; Cerdeño, Esperanza; Candela, Adriana M.; Solís, Natalia (May 2017). "First record of Toxodontidae (Mammalia, Notoungulata) from the late Miocene–early Pliocene of the southern central Andes, NW Argentina". Journal of Paleontology. 91 (3): 566–576. Bibcode:2017JPal...91..566B. doi:10.1017/jpa.2016.160. hdl:11336/49805. ISSN 0022-3360.
  17. ^ Ferrero, Brenda S.; Schmidt, Gabriela I.; Costamagna, Donato; Miño-Boilini, Ángel R.; Zurita, Alfredo E.; Quiñones, Sofía I.; Cuadrelli, Francisco; Luna, Carlos A.; Solís, Natalia; Candela, Adriana M. (March 2024). "First record of Posnanskytherium (Notoungulata, Toxodontidae) in the late Neogene of eastern Puna, Argentina". Journal of Mammalian Evolution. 31 (1). doi:10.1007/s10914-023-09700-5. ISSN 1064-7554.
  18. ^ Solórzano, Andrés; Núñez-Flores, Mónica; Rodríguez-Serrano, Enrique (November 2024). "The rise and fall of notoungulates: How Andean uplift, available land area, competition, and depredation driven its diversification dynamics". Gondwana Research. 135: 116–132. Bibcode:2024GondR.135..116S. doi:10.1016/j.gr.2024.08.002.
  19. ^ Forasiepi AM, Cerdeno E, Bond M, Schmidt GI, Naipauer M, Straehl FR, et al. (2014). "New toxodontid (Notoungulata) from the Early Miocene of Mendoza, Argentina". Paläontologische Zeitschrift. 89 (3): 611–634. doi:10.1007/s12542-014-0233-5. hdl:11336/20443. S2CID 129293436.
  20. ^ a b Carrillo, Juan D.; Püschel, Hans P. (December 2023). "Pleistocene South American native ungulates (Notoungulata and Litopterna) of the historical Roth collections in Switzerland, from the Pampean Region of Argentina". Swiss Journal of Palaeontology. 142 (1): 28. Bibcode:2023SwJP..142...28C. doi:10.1186/s13358-023-00291-5. ISSN 1664-2376. PMC 10558389. PMID 37810207.
  21. ^ Tomassini, Rodrigo L.; Montalvo, Claudia I.; Deschamps, Cecilia M.; Manera, Teresa (December 2013). "Biostratigraphy and biochronology of the Monte Hermoso Formation (early Pliocene) at its type locality, Buenos Aires Province, Argentina". Journal of South American Earth Sciences. 48: 31–42. Bibcode:2013JSAES..48...31T. doi:10.1016/j.jsames.2013.08.002. hdl:11336/21606. ISSN 0895-9811. Retrieved 2 January 2024 – via Elsevier Science Direct.
  22. ^ Guérin, Claude; Faure, Martine (March 2013). "Un nouveau Toxodontidae (Mammalia, Notoungulata) du Pléistocène supérieur du Nordeste du Brésil". Geodiversitas. 35 (1): 155–205. doi:10.5252/g2013n1a7. ISSN 1280-9659.
  23. ^ Costamagna, Donato; Ferrero, Brenda S.; Giri, Federico; Ribeiro, Ana María (August 2024). "Study of the shape and size in lower molars of Toxodon platensis (Mammalia: Toxodontidae) of the Late Pleistocene of South America". Geobios. doi:10.1016/j.geobios.2024.05.005.
  24. ^ Cassini, Guillermo H.; Cerdeño, Esperanza; Villafañe, Amalia L.; Muñoz, Nahuel A. (11 October 2012), Vizcaíno, Sergio F.; Kay, Richard F.; Bargo, M. Susana (eds.), "Paleobiology of Santacrucian native ungulates (Meridiungulata: Astrapotheria, Litopterna and Notoungulata)", Early Miocene Paleobiology in Patagonia (1 ed.), Cambridge University Press, pp. 243–286, doi:10.1017/cbo9780511667381.015, ISBN 978-0-511-66738-1, retrieved 29 June 2023
  25. ^ a b Nelson, Allison; Engelman, Russell K.; Croft, Darin A. (September 2023). "How to weigh a fossil mammal? South American notoungulates as a case study for estimating body mass in extinct clades". Journal of Mammalian Evolution. 30 (3): 773–809. doi:10.1007/s10914-023-09669-1. ISSN 1064-7554.
  26. ^ a b c Fariña RA, Vizcaíno SF& De Iuliis G. 2012 Megafauna: giant beasts of Pleistocene South America. Bloomington, IN: Indiana University Press. p. 264-265
  27. ^ Ferrero, Brenda S.; Schmidt, Gabriela I.; Pérez-García, María I.; Perea, Daniel; Ribeiro, Ana M. (27 August 2021). "A new Toxodontidae (Mammalia, Notoungulata) from the upper Pliocene–lower Pleistocene of Uruguay". Journal of Vertebrate Paleontology. 41 (5). Bibcode:2021JVPal..41E3167F. doi:10.1080/02724634.2021.2023167. ISSN 0272-4634.
  28. ^ a b c Scott WB. Mammalia of the Santa Cruz Beds. Volume VI, Paleontology. Part II, Toxodontia. In: Scott WB, editor. Reports of the Princeton University Expeditions to Patagonia, 1896–1899. Stuttgart: Princeton University, E. Schweizerbart’sche Verlagshandlung (E. Nägele); 1912. pp. 211-216
  29. ^ a b Braunn, Patrícia; Ferigolo, Jorge; Ribeiro, Ana (2021). "Enamel microstructure of permanent and deciduous teeth of notoungulate Toxodon: development, functional and evolutionary implications". Acta Palaeontologica Polonica. 66. doi:10.4202/app.00772.2020.
  30. ^ a b c d S.F. Vizcaino, R.A. Farina, J.C. Fernicola "Young Darwin and the ecology and extinction of Pleistocene South American fossil mammals" Revista de la Asociacion Geologica Argentina, 64 (2009), pp. 160-169
  31. ^ a b E. Anderson Who's who in the Pleistocene: a mammalian bestiary P.S. Martin, R.G. Klein (Eds.), Quaternary Extinctions: a Prehistoric Revolution, The University of Arizona Press, Tucson, AZ (1989), pp. 64
  32. ^ Gomes Rodrigues, Helder; Herrel, Anthony; Billet, Guillaume (31 January 2017). "Ontogenetic and life history trait changes associated with convergent ecological specializations in extinct ungulate mammals". Proceedings of the National Academy of Sciences. 114 (5): 1069–1074. Bibcode:2017PNAS..114.1069G. doi:10.1073/pnas.1614029114. ISSN 0027-8424. PMC 5293108. PMID 28096389.
  33. ^ a b c Oliveira, Édison V.; Bélo, Pétrius S.; Fambrini, Gelson L.; Sial, Alcides N.; Silva, Ana K.B.; Barreto, Alcina M.F. (October 2019). "A new late Pleistocene ichnological site with mammal footprints from Brazil". Journal of South American Earth Sciences. 94: 102216. Bibcode:2019JSAES..9402216O. doi:10.1016/j.jsames.2019.102216.
  34. ^ Shockey BJ. 2001. "Specialized knee joints in some extinct, endemic, South American herbivores" Acta Palaeontologica Polonica 46:277–88
  35. ^ Lorente, Malena; Gelfo, Javier N.; López, Guillermo M. (April 2019). "First skeleton of the notoungulate mammal Notostylops murinus and palaeobiology of Eocene Notostylopidae". Lethaia. 52 (2): 244–259. Bibcode:2019Letha..52..244L. doi:10.1111/let.12310. ISSN 0024-1164.
  36. ^ a b MacFadden BJ (September 2005). "Diet and habitat of toxodont megaherbivores (Mammalia, Notoungulata) from the late Quaternary of South and Central America". Quaternary Research. 64 (2): 113–124. Bibcode:2005QuRes..64..113M. doi:10.1016/j.yqres.2005.05.003. Retrieved 2 January 2024 – via Elsevier Science Direct.
  37. ^ Carrillo-Briceño, Jorge Domingo; Amson, Eli; Zurita, Alfredo; Sánchez-Villagra, Marcelo Ricardo (12 December 2016). "Hermann Karsten (1817–1908): a German naturalist in the Neotropics and the significance of his paleovertebrate collection". Fossil Record. 20 (1): 21–36. Bibcode:2016FossR..20...21C. doi:10.5194/fr-20-21-2016. hdl:11336/81200. ISSN 2193-0074.
  38. ^ Lopes, Renato P.; Ribeiro, Ana Maria; Dillenburg, Sérgio Rebello; Schultz, Cesar Leandro (January 2013). "Late middle to late Pleistocene paleoecology and paleoenvironments in the coastal plain of Rio Grande do Sul State, Southern Brazil, from stable isotopes in fossils of Toxodon and Stegomastodon". Palaeogeography, Palaeoclimatology, Palaeoecology. 369: 385–394. Bibcode:2013PPP...369..385L. doi:10.1016/j.palaeo.2012.10.042.
  39. ^ Pansani TR, Muniz FP, Cherkinsky A, Pacheco ML, Dantas MA (October 2019). "Isotopic paleoecology (δ13C, δ18O) of Late Quaternary megafauna from Mato Grosso do Sul and Bahia States, Brazil". Quaternary Science Reviews. 221: 105864. Bibcode:2019QSRv..22105864P. doi:10.1016/j.quascirev.2019.105864. S2CID 202200336.
  40. ^ Gomes, Verônica Santos; Lessa, Carlos Micael Bonfim; Oliveira, Gustavo Ribeiro de; Bantim, Renan Alfredo Machado; Sayão, Juliana; Bocherens, Hervé; Araújo-Júnior, Hermínio Ismael de; Dantas, Mário André Trindade (January 2023). "Seasonal variations in diet (δ13C) and climate (δ 18O) inferred through toxodonts enamel teeth during the Late Pleistocene in the brazilian intertropical region". Journal of South American Earth Sciences. 121: 104148. doi:10.1016/j.jsames.2022.104148. Retrieved 19 April 2024 – via Elsevier Science Direct.
  41. ^ Dantas, Mário André Trindade; Dutra, Rodrigo Parisi; Cherkinsky, Alexander; Fortier, Daniel Costa; Kamino, Luciana Hiromi Yoshino; Cozzuol, Mario Alberto; Ribeiro, Adauto de Souza; Vieira, Fabiana Silva (January 2013). "Paleoecology and radiocarbon dating of the Pleistocene megafauna of the Brazilian Intertropical Region". Quaternary Research. 79 (1): 61–65. Bibcode:2013QuRes..79...61D. doi:10.1016/j.yqres.2012.09.006. ISSN 0033-5894.
  42. ^ Lopes, Renato Pereira; Scherer, Carolina Saldanha; Pereira, Jamil Corrêa; Dillenburg, Sérgio Rebello (July 2023). "Paleoenvironmental changes in the Brazilian Pampa based on carbon and oxygen stable isotope analysis of Pleistocene camelid tooth enamel". Journal of Quaternary Science. 38 (5): 702–718. Bibcode:2023JQS....38..702L. doi:10.1002/jqs.3502. ISSN 0267-8179.
  43. ^ Asevedo, Lidiane; Ranzi, Alceu; Kalliola, Risto; Pärssinen, Martti; Ruokolainen, Kalle; Cozzuol, Mário Alberto; Nascimento, Ednair Rodrigues do; Negri, Francisco Ricardo; Souza-Filho, Jonas P.; Cherkinsky, Alexander; Trindade Dantas, Mário André (January 2021). "Isotopic paleoecology (δ13C, δ18O) of late Quaternary herbivorous mammal assemblages from southwestern Amazon". Quaternary Science Reviews. 251: 106700. doi:10.1016/j.quascirev.2020.106700.
  44. ^ Chahud, Artur; de Oliveira Costa, Paulo Ricardo; Ferreira Figueiredo, Gisele; Okumura, Mercedes (January 2023). "Quaternary ungulates of the Abismo Ponta de Flecha Cave, Ribeira of Iguape Valley, Southeast Brazil: Zooarchaeological and Paleoenvironmental aspects". Journal of South American Earth Sciences. 121: 104107. Bibcode:2023JSAES.12104107C. doi:10.1016/j.jsames.2022.104107.
  45. ^ Andrea, Elissamburu (July 2016). "Prediction of offspring in extant and extinct mammals to add light on paleoecology and evolution". Palaeogeography, Palaeoclimatology, Palaeoecology. 453: 73–79. Bibcode:2016PPP...453...73A. doi:10.1016/j.palaeo.2016.03.033. hdl:11336/54314.
  46. ^ Luna, Carlos A.; De S. Barbosa, Fernando H.; Gonzalez, Romina; Miño-Boilini, Ángel R.; Repetto, Carolina; Zurita, Alfredo E. (7 February 2024). "Bone diseases in a Pleistocene South American native ungulate species: the case of Toxodon platensis Owen, 1837 (Mammalia, Notoungulata, Toxodontidae)". Journal of Quaternary Science. 39 (8): 1206–1215. doi:10.1002/jqs.3601. ISSN 0267-8179. Retrieved 28 March 2024 – via Wiley Online Library.
  47. ^ Dantas, Mário André Trindade; Cherkinsky, Alexander; Lessa, Carlos Micael Bonfim; Santos, Luciano Vilaboim; Cozzuol, Mario Alberto; Omena, Érica Cavalcante; Silva, Jorge Luiz Lopes; Sial, Alcides Nóbrega; Bocherens, Hervé (14 July 2020). "Isotopic paleoecology (δ13C, δ18O) of a late Pleistocene vertebrate community from the Brazilian Intertropical Region". Revista Brasileira de Paleontologia. 23 (2): 138–152. doi:10.4072/rbp.2020.2.05. ISSN 2236-1715.
  48. ^ Politis GG, Messineo PG, Stafford TW, Lindsey EL (March 2019). "Campo Laborde: A Late Pleistocene giant ground sloth kill and butchering site in the Pampas". Science Advances. 5 (3): eaau4546. Bibcode:2019SciA....5.4546P. doi:10.1126/sciadv.aau4546. PMC 6402857. PMID 30854426.
  49. ^ Politis GG, Gutiérrez MA, Rafuse DJ, Blasi A (28 September 2016). Petraglia MD (ed.). "The Arrival of Homo sapiens into the Southern Cone at 14,000 Years Ago". PLOS ONE. 11 (9): e0162870. Bibcode:2016PLoSO..1162870P. doi:10.1371/journal.pone.0162870. PMC 5040268. PMID 27683248.
  50. ^ Prates, Luciano; Rivero, Diego; Perez, S. Ivan (25 October 2022). "Changes in projectile design and size of prey reveal the central role of Fishtail points in megafauna hunting in South America". Scientific Reports. 12 (1): 16964. Bibcode:2022NatSR..1216964P. doi:10.1038/s41598-022-21287-0. ISSN 2045-2322. PMC 9596454. PMID 36284118.
  51. ^ G. Martínez, M. A. Gutiérrez, Paso Otero 5: A summary of the interdisciplinary lines of evidence for reconstructing early human occupation and paleoenvironment in the Pampean region, Argentina, in Peuplements et Préhistoire de l’Amérique, D. Vialou, Ed. (Muséum National d’ Histoire Naturelle. Departement de Prehistoire, U.M.R, Paris, 2011), pp. 271–284.
  52. ^ Toledo, Marcelo Javier (April 2023). "Anthropic modifications on megafauna bones in the paleontological collections of the Museum national d'Histoire naturelle de Paris: Historical aspects and implications for the Pampean Pleistocene peopling". L'Anthropologie. 127 (2): 103134. doi:10.1016/j.anthro.2023.103134.

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