The Xenarthrans: Armadillos, Glyptodonts, Anteaters, and Sloths

  • Thomas Defler
Part of the Topics in Geobiology book series (TGBI, volume 42)


From the time that the first xenarthrans appeared as early armadillos in the Early Paleocene Itaborai, the group diversified into strange and wonderful forms. Besides the Dasypodidae, a group called the Glyptodontidae arose and diversified; some were the size (and shape) of a Volkswagen bug and were harmless grazers. They were very common on the grassy savannas of South America. Also, the sloth lineage appeared with the last species reaching the greatest size of any southern mammal. Megatherium americanum became one of the largest mammals known in South America, equivalent in size to an elephant. Finally a short history of the little-known anteaters is presented. A discussion of the possible but unconfirmed origins of the xenarthra is suggested, and the group is presented as one of the most ancient lineages of modern mammals and native South Americans.


  1. Aguilar DH, Laurito CA (2009) El armadillo gigante (Mammalia, Xenarthra, Pampatheriidae) del Río Tomayate, Blancano Tardío-Irvingtoniano temprano, El Salvador,América Central. Revista Geológico de América Central 41:25–36Google Scholar
  2. Amson E, de Muizon C, Laurin M, Argot C, de Burfénil V (2014) Gradual adaptation of bone structure to aquatic lifestyle in extinct sloths from Peru. Proc R Soc B 281.
  3. Antoine PO, Marivaux L, Croft DA, Billet G et al (2011) Middle Eocene rodents from Peruvian Amazonia reveal the pattern and timing of caviomorph origins and biogeography. Proc R Soc B 279:1319–1326CrossRefGoogle Scholar
  4. Bargo MS (2001) The ground sloth Megatherium americanum: skull shape, bite forces, and diet. Acta Palaeontol Pol 46(2):173–192Google Scholar
  5. Bargo MS, Vizcaíno SF (2008) Paleobiology of Pleistocene ground sloths (Xenarthra, Tardigrada): biomechanics, morphogeometry and ecomorphology applied to the masticatory apparatus. Ameghiniana (Rev Asoc Paleontol Argent) 45(1):175–196Google Scholar
  6. Bargo MS, Toledo N, Vizcaíno SF (2012) Paleobiology of the Santa Crucian sloths and anteaters (Xenarthra, Pilosa). In: Vizcaino SF, Kay M, Bargo MS (eds) Early Miocene paleobiology in Patagonia: high-latitude paleocommunities of the Santa Cruz Formation. Cambridge University Press, Cambridge, pp 216–242CrossRefGoogle Scholar
  7. Bergqvist LP, Abrantes EAL, Avilla LS (2004) The Xenarthra (Mammalia) of Sao José de Itaboraí Basin (upper Palaeocene, Itaboraian) Rio de Janeiro, Brazil. Geodiversitas 26(2):323–337Google Scholar
  8. Campbell KE Jr, Frailey DC, Romero-Pittman L (2000) The late Miocene gomphothere Amahuacatherium peruvium (Proboscidea: Gomphotheriidae) from Amazonian Peru: implications for the great American faunal interchange. Boletin-Instituto Beologico Minero y Metalúrgico. Serie D: Estudios Regionales 23:1–152Google Scholar
  9. Campbell KE Jr, Frailey DC, Romero-Pittman L (2009) In defense of Amahuacatherium (Proboscidea: Gomphotheriidae). Neues Jahrb Geol P-A 252:113–128Google Scholar
  10. Campbell KE Jr, Prothero DR, Romero-Pittman L, Hertel F, Rivera N (2010) Amazonian magnetostratigraphy: dating the first pulse of the great American faunal interchange. J S Am Earth Sci 26:619–626CrossRefGoogle Scholar
  11. Campbell KE Jr, Heizler M, Frailey CD, Romero-Pittman L, Prothero DR (2001) Upper Cenozoic chronostratigraphy of the southwestern Amazon basin. Geology 29(7):595–598CrossRefGoogle Scholar
  12. Canto J, Salas-Gismondi R, Cozzuol M, Yáñez J (2008) The aquatic sloth Thalassocnus (Mammalia, Xenarthra) from the late Miocene of North-Central Chile: biogeographic and ecological implications. J Vertebr Paleontol 28(3):918–922.[918:TASTMX]2.0.CO;2CrossRefGoogle Scholar
  13. Carlini AA, Scillato-Yané GJ, Vizcaíno SF, Dozo MT (1992) Un singular Myrmecophagidae (Xenarthra, Vermilingua) de Edad Colhuehuapense (Oligoceno Tardio-Miocene Temprano) de Patagonia, Argentina. Ameghiniana 29:176Google Scholar
  14. Cartelle C, De Luliis G (1995) Eremotherium laurillardi: the Panamerican late Pleistocene megatheriid sloth. J Vertebr Paleontol 15(4):830–841CrossRefGoogle Scholar
  15. Cartelle C, De Luliis G (2006) Eremotherium laurillardi (Lund) (Xenarthra, Megatheriidae), the Panamerican giant ground sloth: taxonomic aspects of the ontogeny of skull and dentition. J Syst Palaeontol 4(2):199–209CrossRefGoogle Scholar
  16. Ciancio MR, Carlini AA, Campbell KE, Scillato-Yané GJ (2013) New Paleogene cingulates (Mammalia, Xenarthra) from Santa Rosa, Perú and their importance in the context of South American faunas. J Syst Palaeontol 11(6):727–741CrossRefGoogle Scholar
  17. Cope ED (1889) The Edentata of North America. Am Nat 23(272):657–664CrossRefGoogle Scholar
  18. Croft DA (2016) Horned armadillos and rafting monkeys. Indiana University Press, BloomingtonGoogle Scholar
  19. Croft DA, Flynn JJ, Wyss AR (2007) A new basal glyptodontid and other Xenarthra of the early Miocene Chucal Fauna, Northern Chile. J Vertebr Paleontol 27(4):781–797CrossRefGoogle Scholar
  20. Cuvier G (1796) Notice sur le squelette d’une très grande espèce de quadrupede inconnue jusqu’à présent, trouvé au Paraguay, et déposé au cabinet d’histoire naturelle de Madrid. Mag encyclop, ou J des Sci, de Lettres et del Art 1:303–310; 2:227–228Google Scholar
  21. Dantas MAT, Dutra RP, Cherkinsky A, Costa Fortier D, Yoshino Kamino LH, Cozzuol MA, Ribeiro S, Silva Vieira FS (2012) Paleoecology and radiocarbon dating of the Pleistocene megafauna of the Brazilian intertropical region. Quat Res 79:61. Scholar
  22. De Muizon C, McDonald HG (1995) An aquatic sloth from the Pliocene of Peru. Nature 375:224–227CrossRefGoogle Scholar
  23. De Muizon C, McDonald HG, Salas R, Urbina M (2003) A new early species of the aquatic sloth Thalassocnus (Mammalia, Xenarthra) from the late Miocene of Peru. J Vertebr Paleontol 23(4):886–894CrossRefGoogle Scholar
  24. De Muizon C, McDonald HG, Salas R, Urbina M (2004a) The youngest species of the aquatic sloth Thalassocnus and a reassessment of the relationships of the Nothrothere sloths (Mammalia: Xenarthra). J Vertebr Paleontol 24(2):387–397CrossRefGoogle Scholar
  25. De Muizon C, McDonald HG, Salas R, Urbina M (2004b) The evolution of feeding adaptations of the aquatic sloth Thalassocnus. J Vertebr Paleontol 24(2):398–410CrossRefGoogle Scholar
  26. Delsuc F, Ctzeflis FM, Stanhope MJ, Douzery EJP (2001) The evolution of armadillos, anteaters and sloths depicted by nuclear and mitochondrial phylogenies: implications for the status of the enigmatic fossil Eurotamandua. Proc R Soc Lond B 268(1476):1605–1615CrossRefGoogle Scholar
  27. Delsuc F, Scally M, Madsen O, Stanhope MJ, de Jong WW, Catzeflis FM, Springer MS, Douzery EJP (2002) Molecular phylogeny of living xenarthrans and the impact of character and taxon sampling on the placental tree rooting. Mol Biol Evol 19:1656–1671CrossRefGoogle Scholar
  28. Delsuc F, Stanhope MJ, Douzery EJP (2003) Molecular systematics of armadillos (Xenarthra, Dasypodidae): contribution of maximum likelihood and Bayesian analyses of mitochondrial and nuclear genes. Mol Phylogenet Evol 28(2):261–275CrossRefGoogle Scholar
  29. Delsuc F, Vizcaíno SF, Souzery EJP (2004) Influence of Tertiary paleoenvironmental changes on the diversification of South American mammals: a relaxed molecular clock study within xenarthrans. BMC Evol Biol 4:1–13CrossRefGoogle Scholar
  30. Englemann G (1985) The phylogeny of the Xenarthra. In: Montgomery GG (ed) The ecology and evolution of armadillos, sloths, and vermilinguas. Smithsonian Institution Press, Washington, DC, pp 51–64Google Scholar
  31. Fariña RA (1996) Trophic relationships among Lujanian mammals. Evol Theory 11:125–134Google Scholar
  32. Fariña RA, Blanco RE (1996) Megatherium, the stabber. Proc R Soc Lond 263:1725–1729CrossRefGoogle Scholar
  33. Fariña RA, Vizcaíno SF (2001) Carved teeth and strange jaws: how glyptodonts masticated. Acta Palaeontol Pol 46(2):219–234Google Scholar
  34. Fariña RA, Vizcaíno SF, Bargo MS (1998) Body mass estimations in Lujanian (Late Pleistocene-Early Holocene of South America) mammal megafauna. Mastozool Neotrop 5(2):87–108Google Scholar
  35. Fernicola JC (2005) Análisis filogenético de la familia Glyptodontidae Gray 1869. PhD dissertation, Universidad de la República, MontevideoGoogle Scholar
  36. Fernicola JC (2008) Nuevos aportes para la sistemática de los Glyptodontia Ameghino 1889 (Mammalia, Xenarthra, Cingulata): Ameghiniana 45(3):553–574Google Scholar
  37. Fernicola JC, Vizcaíno SF, Fariña RA (2008) The evolution of armored xenarthrans and a phylogeny of the glyptodonts. In: Vizcaíno SF, Loughry WJ (eds) The biology of the Xenarthra. University Press of Florida, Gainesville, pp 79–85Google Scholar
  38. França LM, Trindade DAntas MA, Bocchiglieri A, Cherckinsky A, Souza Ribeiro A, Bocherens H (2014) Chronology and ancient feeding ecology of two upper Pleistocene megamammals from the Brazilian intertropical region. Quat Sci Rev 99:78–83CrossRefGoogle Scholar
  39. Gardner AL (2005a) Order Cingulata. In: Wilson DE, Reeder DAM (eds) Mammal species of the world: a taxonomic and geographic reference, vol I. The Johns Hopkins University Press, Baltimore, pp 94–99Google Scholar
  40. Gardner AL (2005b) Order Pilosa. In: Wilson DE, Reeder DAM (eds) Mammal species of the world: a taxonomic and geographic reference, vol I. The Johns Hopkins University Press, Baltimore, pp 100–103Google Scholar
  41. Gardner AL (2007) Cohort Placentalia Owen, 1837, Magnorder Xenarthra Cope, 1889. In: Gardner AL (ed) Mammals of South America. Vol. 1. marsupials, xenarthrans, shrews, and bats. University of Chicago Press, ChicagoGoogle Scholar
  42. Gaudin TJ (2004) Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): the creniodental evidence. Zool J Linn Soc Lond 140:255–305CrossRefGoogle Scholar
  43. Gaudin TJ, Branham DG (1998) The phylogeny of the Myrmecophagidae (Mammalia, Xenarthra, Vermilingua) and the relationship of Eurotamandua to the Vermilingua. J Mamm Evol 5(3):237–265Google Scholar
  44. Gaudin TJ, Wible JR (2006) Chapter 6: The phylogeny of living and extinct armadillos (Mammalia, Xenarthra, Cingulata): a craniodental analysis. In: Carrano MT (ed) Amniote paleobiology: perspectives on the evolution of mammals, birds and reptiles. University of Chicago Press, Chicago, pp 153–198Google Scholar
  45. Góis F, Scillato-Yané GJ, Carlini AA (2012) Una nueva especie de Holmesina (Xenarthra, Cingulata, Pampatheriidae) del Pleistoceno de Rondộnia, sudoste de la Amazonia, Brasil. Rev Bras Paleontol 15(2):211–227CrossRefGoogle Scholar
  46. Goís F, Scillato-Yané GJ, Carlini AA, Guilherme E (2013) A new species of Scirrotherium Edmund & Theodor, 1977 (Xenarthra, Cinculata, Pampatheriidae) from the late Miocene of South America. Alcheringa 37:175–186CrossRefGoogle Scholar
  47. González LR (2010) Los Cingulata (Mammalia, Xenarthra) del Mioceno temprano y medio de Patagonia (Edades Santacrucense y “Friasense”). Revisión sistemática y concentraciones bioestratigráficas. Mastozool Neotrop 17(2):397–398Google Scholar
  48. González-Ruiz LR, Góis F, Ciancio MR, Scillato-Yané GJ (2013) Los Peltephilidae (Mammalia, Xenarthra) de la formación Collón Curá (Colloncurense, Miocéno medio), Argentina. Rev Bras Paleontol 16(2):319–330CrossRefGoogle Scholar
  49. Gutiérrez MA, Martínez G (2008) Trends in the faunal human exploitation during the late Pleistocene and early Holocene in the Pampean region (Argentina). Quat Int 191:53–68CrossRefGoogle Scholar
  50. Gutiérrez MA, Martínez GA, Bargo MS, Vizcaíno SF (2010) Supervivencia diferencial de mamíferos de gran tamaño en la Región Pampeana en el Holoceno temprano y su relación con aspectos paleobiológicos. In: Gutierrez M, De Nigris M, Fernández P, Giardina M, Gil A, Izeta A, Neme G, Yacobaccio H (eds) Zooarqueología a principios del siglo XXI. Aportes teóricos, metodológicos y casos de estudio. Ediciones El Espinillo, Buenos Aires, pp 231–242Google Scholar
  51. Hallström BM, Kullberg M, Nilsson MA, Janke A (2007) Phylogenomic data analyses provide evidence that Xenarthra and Afrotheria are sister groups. Mol Biol Evol 24(9):2059–2068CrossRefGoogle Scholar
  52. Hirschfeld SE (1976) A new fossil anteater (Edentata, Mammalia) from Colombia, S. A. and evolution of the Vermilingua. J Paleontol 50(3):419–432Google Scholar
  53. Iuliis GD, Bargo MS, Vizcaíno SF (2000) Variation in skull morphology and mastication in the fossil giant armadillos Pampatherium spp. and allied genera (Mammalia: Xenarthra: Pampatheriidae), with comments on their systematics and distribution. J Vertebr Paleontol 20(4):743–754CrossRefGoogle Scholar
  54. Krmpotic CM, Ciancio MR, Barbeito C, Mario RC, Carlini AA (2009) Osteoderm morphology in recent and fossil euphractine xenarthrans. Acta Zool 90:339–351CrossRefGoogle Scholar
  55. Liu F-GR, Miyamoto MM, Freire NP, Ong PQ, Tennant MR, Young TS, Gugel KF (2001) Molecular and morphological supertrees for eutherian (placental) mammals. Science 291:1786–1789CrossRefGoogle Scholar
  56. Madsen O, Scally M, Douady CJ, Kao DF, DeBry RW, Adkins R, Amrine HM, Stanhope MJ, de Jong WW, Springer MS (2001) Parallel adaptive radiations in two major clades of placental mammals. Nature 409:610–614CrossRefGoogle Scholar
  57. McKenna MC, Bell SK (1997) Classification of mammals above the species level. Columbia University Press, New YorkGoogle Scholar
  58. McKenna MC, Wyss AR, Flynn JJ (2006) Paleogene pseudoglyptodont xenarthran from Central Chile and Argentinean Patagonia. Am Mus Novit 3536:1–18CrossRefGoogle Scholar
  59. Mead JI, Swift SL, White RS, McDonald HG, Baez A (2007) Late Pleistocene (Rancholabrean) glypotodont and pampathere (Xenarthra, Cingulata) from Sonora, Mexico. Rev Mex Cienc Geol 24(3):439–449Google Scholar
  60. Osborn HF (1904) An armadillo from the middle Eocene (Bridger) of North America. Bull Am Mus Nat Hist 20:163–165Google Scholar
  61. Patterson B, Pascual R (1972) The fossil mammal fauna of South America. In: Keast A, Erk FC, Glass B (eds) Evolution, mammals and southern continents. State University of New York Press, Albany, pp 247–309Google Scholar
  62. Patterson B, Segall W, Turnbull WD (1989) The ear region in Xenarthrans (=Edentata, Mammalia). Part 1. Cingulata. Fieldiana Geol New Ser 18:1–46Google Scholar
  63. Piñero JML (1988) Juan Bautista Bru (1740–1799) and the description of the genus Megatherium. J Hist Biol 21(1):147–163. Scholar
  64. Politis GG, Gutiérrez MA (1998) Gliptodontes y cazadores-recolectores de la región pampeana (Argentina). Lat Am Antiq 9(2):111–134CrossRefGoogle Scholar
  65. Pujos F, de Iuliis G (2007) Late Oligocene Megatheriidae fauna (Mammalia: Xenathra) from Salla-Luribay (Bolivia): New data on basal sloth radiation and cingulata-Tardigrada Split. J Vertebr Paleontol 27(1):132–144CrossRefGoogle Scholar
  66. Pujos F, Gaudin TJ, De Iuliis G, Cartelle C (2012) Recent advances on variability, morpho-functional adaptations, dental terminology, and evolution of sloths. J Mammal Evol 19:159–169CrossRefGoogle Scholar
  67. Rose KD (1999) Eurotamandua and Palaeanodonta: convergent or related? Palaeontol Z 73(3–4):395–401CrossRefGoogle Scholar
  68. Rose KD (2009) The beginning of the age of mammals. The Johns Hopkins University Press, BaltimoreGoogle Scholar
  69. Rose KD, Emory RJ (1993) Relationships of Xenarthra, Pholidota, and fossil “edentates”: the morphological evidence. In: Szalay FS, Novacek MJ, McKenna MC (eds) Mammal phylogeny of placentals. Springer, New York, pp 81–102CrossRefGoogle Scholar
  70. Saint-André PA, de Iuliis G (2001) The smallest and most ancient representative of the genus Megatherium Cuvier, 1796 (Xenarthra, Tardigrada, Megatheriidae), from the Pliocene of the Bolivian Altiplano. Geodiversitas 23(4):625–645Google Scholar
  71. Scillato-Yane GJ (1975) Presencia de Macroeuphractus retusus (Xenarthra, Dasypodidae) en el Plioceno del área mesopotámia (Argentina): Su importancia bioestratigrafica y paleobiogeografica. Ameghiniana 12(4):322–328Google Scholar
  72. Scillato-Yané GJ, Carlini AA, Tonni EP, Noriega JI (2005) Paleobiogeography of the late Pleistocene pampatheres of South America. J S Am Earth Sci 20:131–138CrossRefGoogle Scholar
  73. Shockey BJ, Anaya F (2010) Grazing in a new late Oligocene mylodontid sloth and a mylodontid radiation as a component of the Eocene-Oligocene faunal turnover and the early spread of grasslands/savannas on South America. J Mammal Evol 18:101. Scholar
  74. Simpson GG (1931) Metacheiromys and the Edentata. Bull Am Mus Nat Hist 59:295–381Google Scholar
  75. Simpson GG (1980) Splendid isolation: the curious history of south American mammals. Yale University Press, New HavenGoogle Scholar
  76. Soibelzon LH, Aamorano M, Scillato-Yané GJ, Piazza D, Rodríguez S, Soibelzon E, Tonni EP, Cristóbal JS, Beilinson E (2012) Un Glyptodontidae de gran tamaño en el Holoceno temprano de la región pampeana, Argentina. Rev Bras Paleontol 15(1):105–112CrossRefGoogle Scholar
  77. Tauber AA (1997) Paleoecología de la formación Santa Cruz (Mioceno inferior) en el extremo sudeste de la Patagonia. Ameghiniana 34(4):517–529Google Scholar
  78. Tito G (2008) New remains of Eremotherium laurillardi (Lund, 1842) (Megatheriidae, Xenarthra) from the coastal región of Ecuador. J S Am Earth Sci 26:424–434CrossRefGoogle Scholar
  79. Vizcaíno SF, De Iuliis G (2003) Evidence for advanced carnivory in fossil armadillos (Mammalia: Xenarthra: Dasypodidae). Paleobiology 29(1):123–138CrossRefGoogle Scholar
  80. Vizcaíno SF, Fariña RA (1997) Diet and locomotion of the armadillo Peltephilus: a new view. Lethaia 30(79–86):79–86Google Scholar
  81. Vizcaíno SF, Scillato-Yané GJ (1995) Short note: an Eocene tardigrade (Mammalia, Xenarthra) from Seymour island, West Antarctica. Antarct Sci 7(4):407–408Google Scholar
  82. Vizcaíno SF, Bargo MS, Kay RF, Milne N (2006) The armadillos (Mammalia, Xenarthra, Dasypodidae) of the Santa Cruz Formation (early-middle Miocene): an approach to their paleobiology. Palaeogeogr Palaeoclimatol Palaeoecol 237:255–269CrossRefGoogle Scholar
  83. Vizcaíno SF, Blanco RE, Bender B, Milne N (2011) Proportions and function of the limbs of glyptodonts. Lethaia 44:93–101CrossRefGoogle Scholar
  84. Vizcaíno SF, Fernicola JC, Bargo MS (2012) Paleoecology of the Santacrucian glypdodonts and armadillos (Xenarthra, Cingulata). In: Vizcaino SF, Kay M, Bargo MS (eds) Early Miocene paleobiology in Patagonia: high-latitude paleocommunities of the Santa Cruz formation. Cambridge University Press, Cambridge, pp 194–215CrossRefGoogle Scholar
  85. Wetzel RM, Gardner AL, Redford KH, Eisenberg JF (2007) Order Cingulata Illiger, 1811. In: Gardner AL (ed) Mammals of South America. Marsupials, xenarthrans, shrews, and bats. University of Chicago Press, Chicago, pp 128–157Google Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Thomas Defler
    • 1
  1. 1.Department of BiologyNational University of Colombia, BogotaBogotaColombia

Personalised recommendations