Skip to main content

Advertisement

SpringerLink
Log in

Thoracic member (pectoral girdle and forelimb) bones of Mylodon darwinii Owen (Xenarthra, Mylodontidae) from the Late Pleistocene of Central Argentina and their phylogenetic implications

  • Research Paper
  • Published:
PalZ Aims and scope Submit manuscript

Abstract

A nearly complete skeleton, including most of the thoracic member bones of the sloth Mylodon darwinii, have been found in Upper Pleistocene strata from Anisacate River, Argentina. The thoracic member bones resemble their homologues in Glossotherium robustum, Paramylodon harlani, and Mylodonopsis ibseni in the following traits: (1) the olecranon is mediolaterally compressed; (2) the radius has an acute styloid process; (3) the radial diaphysis medial border is straight for two thirds of its length; (4) the radial shaft medial border forms an angle with the medial border of the styloid process. The radius presents a distinctive, mostly proximally facing articular circumference. The unfused epiphyses and feeble muscle attachment ridges indicate a sub-adult ontogenetic stage. Deviation of the olecranon and weak M. teres major origin and insertion, suggest a low fossorial specialization. The structure of the thoracic limb bones does not support climbing habits, because pronation-related features are reduced and the humeral head is not prominent. The structure of the radius suggests graviportal adaptations: the proximal head is mediolaterally expanded and the diaphysis straight. A phylogenetic analysis adding thoracic member characters recovers M. darwinii as part of a clade that includes Glossotherium robustum and Paramylodon harlani, but excludes Lestodon armatus. This contrasts with the results of previous analyses focusing on the head skeleton, highlighting the relevance of sampling postcranial characters in phylogenetic analyses of mylodontine sloths.

Kurzfassung

Ein nahezu komplettes Skelett des Faultiers Mylodon darwinii, inklusive der meisten Brust-Extremitätenknochen, wurde in oberpleistozänen Schichten des Anisacate-Flusses in Argentinien gefunden. Es erlaubt erstmals eine detaillierte Beschreibung der Schultergliedmaßen und Unterarmknochen. Diese spiegeln die Homologien in Glossotherium robustum, Paramylodon harlani und Mylodonopsis ibseni mit den folgenden Eigenschaften wider: (1) der Ellenbogen ist mediolateral zusammengedrückt; (2) der Radius hat einen spitzen Styloid-Fortsatz; (3) der radiale Diaphysen-Medialrand ist auf 2/3 der Länge gerade; (4) der radiale Schaft-Medialrand bildet einen Winkel mit dem Medialrand des Styloid-Fortsatzes. Der Radius zeigt einen deutlichen hauptsächlich proximal gerichteten Gelenkumfang. Die unverschmolzenen Epiphysen und schwachen Muskelansatzrücken deuten auf ein sub-adultes ontogenetisches Stadium hin. Grazile Unterarmknochen und die Ausbildung eines schwachen großen Rundmuskels weisen auf eine weniger grabende Spezialisierung hin. Die Struktur der Brust-Extremitätenknochen unterstützt keine Kletterhabitate, da pronations-ähnliche Merkmale reduziert sind und der Humeruskopf nicht markant ist. Die Struktur des Radius deutet auf graviportale Anpassungen hin: der proximale Kopf ist mediolateral ausgeweitet und die Diaphyse ist gerade. Eine phylogenetische Analyse mit Merkmalen der Brust-Extremitätenknochen zeigt, dass M. darwinii näher mit Glossotherium robustum und Paramylodon harlani verwandt ist, als die Lestodontini. Dies steht im Gegensatz zu Resultaten früherer Analysen, welche auf den Schädel fokussiert waren und verdeutlicht damit die Relevanz postcranialer Merkmale in phylogenetischen Analysen von mylodontinen Faultieren.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4

Similar content being viewed by others

References

  • Allen, G.M. 1913. A new Mylodon. Memoirs of the Museum of Comparative Zoology at Harvard College 40: 319–346 + Pl. 1–4.

  • Ameghino, F. 1881. La Antigüedad del Hombre en el Plata. Parte Segunda, 1–309. Paris and Buenos Aires: Masson-Igon Hermanos.

  • Ameghino, F. 1887. Enumeración sistemática de las especies de mamíferos fósiles coleccionadas por Carlos Ameghino en los terrenos eocenos de la Patagonia austral y depositadas en el Museo La Plata. Boletín del Museo de La Plata 1: 1–26.

    Google Scholar 

  • Ameghino, F. 1891. Mamíferos y aves fósiles argentinas. Especies nuevas, adiciones y correcciones. Revista Argentina de Ciencias Naturales 1: 240–259.

    Google Scholar 

  • Ameghino, F. 1894. Sur les oiseaux fossiles de Patagonie; et la faune mammalogique des couches à Pyrotherium. Boletín del Instituto Geográfico Argentino 15: 501–660.

    Google Scholar 

  • Aramayo, S.A. 1988. Nuevos restos de Proscelidodon sp. (Edentata, Mylodontidae) del yacimiento de Monte Hermoso (Plioceno inferior a medio) provincial de Buenos Aires, Argentina. Estudio morfológico funcional. In Actas. Segundas Jornadas Geológicas Bonaerenses, Bahía Blanca, 99–107. La Plata: Comisión de Investigaciones Científicas, Provincia de Buenos Aires.

  • Bargo, M.S., and C.M. Deschamps. 1996. El registro de Mylodon Owen, 1840 (Mammalia, Tardigrada) en el Pleistoceno del sur de la Provincia de Buenos Aires. Comentarios sobre la distribución de los “sedimentos pampeanos”. Ameghiniana 33: 343–348.

    Google Scholar 

  • Bargo, M.S., S.F. Vizcaíno, F.M. Archuby, and R.E. Blanco. 2000. Limb bone proportions, strength and digging in some Lujanian (Late Pleistocene-Early Holocene) mylodontid ground sloths (Mammalia, Xenarthra). Journal of Vertebrate Paleontology 20: 601–610.

    Article  Google Scholar 

  • Bocquentin-Villanueva, J. 1984. Un nuevo representante de la subfamilia Prepotheriinae (Mammalia, Edentata) proveniente del Mioceno de Venezuela. III Congreso Latinoamericano de Paleontología, Memorias, 516–523. México: Oaxtepec.

    Google Scholar 

  • Brandoni, D., B.S. Ferrero, and E. Brunetto. 2010. Mylodon darwini Owen (Xenarthra, Mylodontinae) from the Late Pleistocene of Mesopotamia, Argentina, with remarks on individual variability, paleobiology, paleobiogeography, and paleoenvironment. Journal of Vertebrate Paleontology 30: 1547–1558.

    Article  Google Scholar 

  • Burmeister, H. 1881. Bericht über ein Skelet von Scelidotherium leptocephalum. Monatsberichte der Kayserlichen Akademie der Wissenschaften zu Berlin; Sitzungberichte der physicalisch-mathematischen Klasse 46: 374–380 + 1 Pl.

  • Cabrera, A. 1936. Las especies del género Glossotherium. Notas del Museo de La Plata: Paleontología 1: 193–206.

    Google Scholar 

  • Carlini, A.A., and G.J. Scillato-Yané. 2004. The oldest Megalonychidae (Tardigrada, Xenarthra) and the phylogenetic relationships of the family. Neues Jahrbuch für Geologie und Paläontologie 233: 423–443.

    Article  Google Scholar 

  • Carlini, A.A., D. Brandoni, and R. Sánchez. 2006a. First megatheriines (Xenarthra, Phyllophaga, Megatheriidae) from the Urumaco (Late Miocene) and Codore (Pliocene) Formations, Estado Falcón, Venezuela. Journal of Systematic Palaeontology 4: 269–278.

    Article  Google Scholar 

  • Carlini, A.A., G.J. Scillato-Yané, and R. Sánchez. 2006b. New Mylodontoidea (Xenarthra, Phyllophaga) from the middle Miocene-Pliocene of Venezuela. Journal of Systematic Palaeontology 4: 255–267.

    Article  Google Scholar 

  • Carlini, A.A., D. Brandoni, G.J. Scillato-Yané, and F. Pujos. 2002. Una nueva especie de megaterino (Xenarthra, Megatheriidae) del Mioceno Tardío-Plioceno de Catamarca, Argentina. Ameghiniana 39: 367–377.

    Google Scholar 

  • Cartelle, C. 1980. Estudo comparativo do rádio e esqueleto da mão de Glossotherium (Ocnotherium) giganteum Lund, 1842. Anais da Academia Brasileira de Ciências 52: 359–377.

    Google Scholar 

  • Cartelle, C. 1991. Um novo Mylodontinae (Edentata, Xenarthra) do Pleistoceno final da região intertropical brasileira. Anais da Academia Brasileira de Ciências 63: 161–170.

    Google Scholar 

  • Cartelle, C. 1992. Edentata e megamamiferos herbívoros extintos da Toca dos Ossos (Ourolãndia, BA, Brasil). Unpublished PhD thesis, Universidade Federal de Minas Gerais, I–V + 1–301, Belo Horizonte.

  • Cartelle, C., and J.S. Fonseca. 1981. Espécies do gênero Glossotherium no Brasil. In Anais do II Congresso Latino-Americano de Paleontologia. Volume 2, 805–818. Porto Alegre: Universidade Federal do Rio Grande do Sul.

  • Cartelle, C., G. De Iuliis, and R. Lopes-Ferreira. 2009. Systematic revision of tropical Brazilian scelidotheriine sloths (Xenarthra, Mylodontoidea). Journal of Vertebrate Paleontology 29: 555–566.

    Article  Google Scholar 

  • Cattoi, N. 1962. Un nuevo (Xenarthra) del Terciario de Patagonia, Chubutherium ferelloii gen. et sp. nov. (Megalonychoidea, Mylodontidae). Revista del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Zoología 8(11): 123–133.

  • Cattoi, N. 1966. Edentata. In Paleontografía Bonaerense. Fascículo IV. Vertebrata, ed. A.V. Borrello, 59–100 + Pl. XIV–XLVI. La Plata: Gobernación de la Provincia de Buenos Aires.

  • Christiansen, P., and R.A. Fariña. 2003. Mass estimation of two fossil ground sloths (Mammalia, Xenarthra, Mylodontidae). Senckenbergiana lethaea 83 (1): 95–101.

    Google Scholar 

  • Collins, R.L. 1934. Venezuelan Tertiary mammals. Johns Hopkins University Studies in Geology 11: 23–244.

    Google Scholar 

  • Cuenca Anaya, J. 1995. El aparato locomotor de los escelidoterios (Edentata, Mammalia) y su paleobiología. Estudis, Adjuntament de Valencia 6: 1–452.

    Google Scholar 

  • Cuvier, G. 1796. Notice sur le squelette d’une très grande espèce de quadrupède inconnue jusqu’à présent, trouvé au Paraguay, et déposé au cabinet d’Histoire naturelle de Madrid. Magasin Encyclopédique 1: 303–310 + Pl. II.

  • De Iuliis, G., T.J. Gaudin, and M.J. Vicars. 2011. A new genus and species of nothrotheriid sloth (Xenarthra, Tardigrada, Nothrotheriidae) from the late Miocene (Huayquerian) of Peru. Palaeontology 54 (1): 171–205.

    Article  Google Scholar 

  • De Iuliis, G., G.H. Ré, and S.F. Vizcaíno. 2004. The Toro Negro megatheriine (Mammalia, Xenarthra): A new species of Pyramiodontherium and a review of Plesiomegatherium. Journal of Vertebrate Paleontology 24: 214–227.

    Article  Google Scholar 

  • Desmarest, M.A.G. 1822. Mammalogie ou Description des Espèces de Mammifères. Seconde Partie, I–VII + 277–556. Paris: Imprimeur Libraire rue des Poitevins.

  • Esteban, G.I. 1996. Revisión de los Mylodontinae cuaternarios (Edentata-Tardigrada) de Argentina, Bolivia y Uruguay. Sistemática, filogenia, paleobiología, paleozoogeografía y paleoecología. Unpublished PhD thesis, Universidad Nacional de Tucumán, 1–235. San Miguel de Tucumán.

  • Esteban, G.I., F. Abdala, and N. Nasif. 1992. Nuevos restos de Scelidotherium (Edentata) de Rosario de La Frontera, provincia de Salta, Argentina. Consideraciones sistemáticas basadas en aspectos morfológicos del carpo. Boletín de la Real Sociedad Española de Historia Natural (Sección Geología) 87: 24–35.

    Google Scholar 

  • Flower, W.H. 1883. On the arrangement of the orders and families of existing Mammalia. Proceedings of the Zoological Society of London 1883: 178–186.

  • Gaudin, T.J. 2004. Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): the craniodental evidence. Zoological Journal of the Linnean Society 140: 255–305.

    Article  Google Scholar 

  • Gervais, P. 1855. Recherches sur les mammifères fossiles de l’Amérique méridionale. In Expédition dans les parties centrales de l’Amérique du Sud. Septième Partie: Zoologie, ed. F. de Castelnau, 1–63. Paris: P. Bertrand.

  • Gervais, P. 1873. Mémoire sur plusieurs espèces de mammifères fossiles propres a l’Amérique méridionale. Mémoires de la Société Géologique de France (sér. 2) 9: 1–44 + Pl. XXI–XXIX.

  • Gill, T. 1872. Arrangements of the families of mammals, with analytical tables. Smithsonian Miscellaneous Collections 11: 1–98.

    Google Scholar 

  • Goloboff, P.A., J.S. Farris, and K.C. Nixon. 2003. T.N.T.: Tree Analysis Using New Technology. Online at http://www.lillo.org.ar/phylogeny/tnt/. Last Accessed 28 July 2014.

  • Goloboff, P.A., J.S. Farris, and K.C. Nixon. 2008. TNT, a free program for phylogenetic analysis. Cladistics 24: 774–786.

    Article  Google Scholar 

  • Harlan, R. 1843. Description of the bones of a new fossil animal of the order Edentata. American Journal of Science (ser. 1) 44: 69–80 + Pl. I–III.

  • Haro, J.A., A.A. Tauber, and J.M. Krapovickas. 2016. The manus of Mylodon darwinii Owen (Tardigrada, Mylodontidae) and its phylogenetic implications. Journal of Vertebrate Paleontology 36 (5): e1188824.

    Article  Google Scholar 

  • Harris, J.D. 2004. Confusing dinosaurs with mammals: tetrapod phylogenetics and anatomical terminology in the world of homology. The Anatomical Record. Part A, Discoveries in Molecular, Cellular, and Evolutionary Biology 281A: 1240–1246.

    Article  Google Scholar 

  • Hay, O.P. 1919. Descriptions of some mammalian and fish remains from Florida of probably Pleistocene age. Proceedings of the United States National Museum 56: 103–112 + Pl. 26–28.

  • Hildebrand, M. 1974. Analysis of Vertebrate Structure, I–XV + 1–710. New York: Wiley.

    Google Scholar 

  • Hirschfeld, S.E. 1985. Ground sloths from the Friasian La Venta Fauna, with additions to the pre-Friasian Coyaima Fauna of Colombia, South America. University of California Publications, Geological Sciences 128: 1–91.

    Google Scholar 

  • Hoffstetter, R. 1952. Les mammifères pléistocènes de la République de l’Équateur. Mémoires de la Société Géologique de France, Nouvelle Série 66: 1–391 + Pl. I–VIII.

  • International Committee on Veterinary Gross Anatomical Nomenclature. 2005. Nomina Anatomica Veterinaria. Fifth Edition, I–XVII + 1–166. Hannover, Columbia, Ghent, Sapporo: I.C.V.G.A.N. Editorial Comitee.

  • Jacob, C. 1899. Exámen microscópico de la pieza cutánea del mamífero misterioso de la Patagonia, Grypotherium domesticum. Revista del Museo de La Plata 10: 61–62 + 1 Pl.

  • Kraglievich, L. 1928. « Mylodon Darwin » Owen es la especie genotipo de « Mylodon » Ow. Rectificación de la nomenclatura genérica de los milodontes. Physis 9: 169–185 + Pl. I–II.

  • Kraglievich, L. 1934. Contribución al conocimiento de « Mylodon Darwini » Owen y especies afines. Revista del Museo de La Plata 34: 255–292 + Pl. I–VII.

  • Latham, J., and H. Davies. 1795. Faunula indica. Appendix to J.R. Forster, Zoologia Indica, Editorial Secunda, I–III + 1–36. Halle an der Saale: Gebauer.

  • Lehmann-Nitsche, R. 1902. La pretendida existencia actual del Grypotherium; supersticiones araucanas referentes a la lutra y al tigre. Anales del Museo de La Plata 10: 268–281.

    Google Scholar 

  • Leidy, J. 1855. A memoir on the extinct sloth tribe of North America. Smithsonian Contributions to Knowledge 7: 1–68 + Pl. I–XVI.

  • Linares, O. 2004. Nuevos restos del género Lestodon Gervais, 1855 (Xenarthra, Tardigrada, Mylodontidae), del Mioceno Tardío y Plioceno Temprano de Urumaco (Venezuela), con descripción de dos nuevas especies. Paleobiología Neotropical 2: 1–14.

    Google Scholar 

  • Linnaeus, C. 1758. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata, I–III + 1–824. Stockholm: Laurentii Salvius.

  • Lull, R.S. 1915. A Pleistocene ground sloth, Mylodon harlani, from Rock Creek, Texas. American Journal of Science (series 4) 39: 327–385.

  • Lund, P.W. 1839. Blik paa Brasiliens Dyreverden för Sidste Jordomvaeltning. Anden Afhandling: Patterdyrene. Det Kongelige Danske Videnskabernes Selskabs Skrifter. Naturvidenskabelige og Mathematiske Afhandlinger 8: 61–144 + Pl. I–XIII.

  • Martín, F.M. 2008. Bone crunching felids at the end of the Pleistocene in Fuego-Patagonia, Chile. Journal of Taphonomy 6: 337–372.

    Google Scholar 

  • McAfee, R.K. 2009. Reassessment of the cranial characters of Glossotherium and Paramylodon (Mammalia: Xenarthra: Mylodontidae). Zoological Journal of the Linnean Society 155: 885–903.

    Article  Google Scholar 

  • McAfee, R.K. 2016. Description of new postcranial elements of Mylodon darwinii Owen 1839 (Mammalia: Pilosa: Mylodontinae), and functional morphology of the forelimb. Ameghiniana 53: 418–443.

    Article  Google Scholar 

  • McDonald, H.G. 1977. Description of the osteology of the extinct gravigrade edentate Megalonyx with observations on its ontogeny, phylogeny, and functional anatomy. Unpublished Master’s thesis, University of Florida, I–XIV + 1–326. Gainesville.

  • McDonald, H.G. 1987. A systematic review of the Plio-Pleistocene scelidotherinae ground sloths (Mammalia: Xenarthra: Mylodontidae). Unpublished PhD thesis, University of Toronto, I–VIII + 1–478. Toronto.

  • McDonald, H.G. 1997. Xenarthrans: Pilosans. In Vertebrate paleontology in the neotropics: the Miocene Fauna of La Venta, Colombia, ed. R.F. Kay, R.H. Madden, R.L. Cifelli, and J.J. Flynn, 233–245. Washington, DC: Smithsonian Institution Press.

    Google Scholar 

  • Miño-Boilini, A.R. 2012. Sistemática y evolución de los Scelidotheriinae (Xenarthra, Mylodontidae) cuaternarios de la Argentina. Importancia bioestratigráfica, paleobiogeográfica y paleoambiental. Unpublished PhD thesis, Universidad Nacional de La Plata, I–XIV + 1–301. La Plata.

  • Miño-Boilini, A.R., A.A. Carlini, and G.J. Scillato-Yané. 2014. Revisión sistemática y taxonómica del género Scelidotherium Owen, 1839 (Xenarthra, Phyllophaga, Mylodontidae). Revista Brasileira de Paleontologia 17: 43–58.

    Article  Google Scholar 

  • Montellano-Ballesteros, M., and O. Carranza-Castañeda. 1986. Descripción de un milodóntido del Blancano Temprano de la mesa central de México. Revista del Instituto de Geología de la Universidad Nacional Autónoma de México 6: 193–203.

    Google Scholar 

  • Moreno, F.P., and A.S. Woodward. 1899. On a portion of mammalian skin, named Neomylodon listai, from a cavern near Consuelo Cove, Last Hope Inlet, Patagonia. Proceedings of the Zoological Society of London (1899): 144–156 + Pl. XIII–XV.

  • Nordenskiöld, E. 1900. Iakttagelser och fynd grottor vid Ultima Esperanza i sydvestra Patagonien. Konglinga Svenska Vedenskapsakademien Handlingar, Stockholm 33(3): 1–24 + Pl. I–VII.

  • Owen, R. 1839. Part I. Fossil Mammalia. In The Zoology of the Voyage of H.M.S. Beagle, ed. C. Darwin, 13–111 + Pl. I–XXXII. London: Smith, Elder and Co.

  • Owen, R. 1842. Description of the skeleton of an extinct gigantic sloth, Mylodon robustus, Owen, with observations on the osteology, natural affinities, and probable habits of the megatherioid quadrupeds in general, 1–176. London: R. and J.E. Taylor.

    Google Scholar 

  • Owen, R. 1858. On the Megatherium (Megatherium americanum, Cuvier and Blumenbach). Part IV. Bones of the anterior extremities. Philosophical Transactions of the Royal Society of London 148: 261–278.

    Article  Google Scholar 

  • Philippi, R.A. 1900. Contribución a la osteolojía del Grypotherium domesticum Roth i un nuevo delfin, 1–12 + 4 Pls. Santiago de Chile: Imprenta Cervantes.

    Google Scholar 

  • Philippi, R.A. 1901. Beiträge zur Kenntniss der Knochen des Grypotherium domesticum Roth. Archiv für Naturgeschichte 67(1): 271–275 + Pl. XV.

  • Pitana, V.G. 2011. Estudo do gênero Glossotherium Owen, 1840 (Xenarthra, Tardigrada, Mylodontidae), Pleistoceno do Estado do Rio Grande do Sul, Brasil. Unpublished Master’s thesis, Universidade Federal do Rio Grande do Sul, 1–183. Porto Alegre.

  • Pujos, F., G. De Iuliis, C. Argot, and L. Werdelin. 2007. A peculiar climbing Megalonychidae from the Pleistocene of Peru and its implication for sloth history. Zoological Journal of the Linnean Society 149: 179–235.

    Article  Google Scholar 

  • Rautenberg, M. 1906. Über Pseudolestodon hexaspondylus. Palaeontographica 53: 1–50 + Pl. I–VI.

  • Reinhardt, J. 1875. Bidrag til Kundskab om Kjæmpedovendyret Lestodon armatus. Dei Kongelige Danske Videnskavernes Selskabs Schrifter, 5 Raekke, Naturvidens og Mathematisk Afdeling 11: 1–38 + Pl. I–III.

  • Reinhardt, J. 1879. Beskrivelse of Hovedskallen of et Kaempedovendyret Grypotherium Darwini, fra La Plata-Landenes plejstocene Dannelser. Dei Kongelige Danske Videnskavernes Selskabs Schrifter, 5 Raekke, Naturvidens og Mathematisk Afdeling 12: 353–380 + Pl. I–II.

  • Rincón, A.D., H.G. McDonald, A. Solórzano, M. Núñez Flores, and D. Ruiz-Ramoni. 2015. A new enigmatic Late Miocene mylodontoid sloth from northern South America. Royal Society Open Science. doi:10.1098/rsos.140256.

    Google Scholar 

  • Ridewood, W. 1901. On the structure of the hairs of Mylodon Listai and other South American Edentata. Quarterly Journal of Microscopical Science 2: 393–411 + Pl. 26.

  • Robertson, J.S. 1976. Latest Pleistocene mammals from Haile XV A, Alachua County, Florida. Bulletin of the Florida State Museum 20: 111–186.

    Google Scholar 

  • Roth, S. 1899. Descripción de los restos encontrados en la caverna de Última Esperanza. Revista del Museo de La Plata 9: 421–453 + Pl. II–V.

  • Roth, S. 1902. Nuevos restos de mamíferos de la Caverna Eberhardt en Última Esperanza. Revista del Museo de La Plata 11: 39–53 + Pl. I–III.

  • Rovereto, C. 1914. Los estratos araucanos y sus fósiles. Anales del Museo Nacional de Historia Natural de Buenos Aires 25: 1–250 + Pl. I–XXXI.

  • Saint-André, P.-A., F. Pujos, C. Cartelle, G. De Iuliis, T.J. Gaudin, H.G. McDonald, and B. Mamani Quispe. 2010. Nouveaux paresseux terrestres (Mammalia, Xenarthra, Mylodontidae) du Néogène de l’Altiplano bolivien. Geodiversitas 32: 255–306.

    Article  Google Scholar 

  • Scott, W.B. 1904. Mammalia of the Santa Cruz beds, part 1. Edentata. Report of the Princeton University Expedition to Patagonia, 1896–1899 5: 161–364.

  • Spillmann, F. 1931. Die Säugetiere Ecuadors im Wandel der Zeit, 1–112. Quito: Universidad Central.

    Google Scholar 

  • Stock, C. 1925. Cenozoic gravigrade edentates of western North America with special reference to the Pleistocene Megalonychinae and Mylodontidae of Rancho La Brea. Carnegie Institute of Washington Publication 331: 1–206 + Pl. 1–47.

  • Studer, T. 1905. Ueber neue Funde von Grypotherium listai Amegh., in der Eberhardshöhle von Ultima Esperanza. Neue Denkschriften der allgemeinen schweizerischen Gesellschaft für die gesammten Naturwissenschaften 40: 1–18 + Pl. I–III.

  • Tauber, A.A., and J. Di Ronco. 2003. Un esqueleto articulado de Mylodon sp. (Tardigrada, Mylodontidae) del Pleistoceno Tardío de Córdoba, Argentina. Ameghiniana 40(4, Supplement): 108R.

  • Tauber, A.A., J.M. Krapovickas, J. Di Ronco, F. Álvarez, V. Cortassa, A. Lapiana, L. Yedro, M. Petit. 2011. Aptitud fosorial de Mylodon darwini Owen 1840 (Xenarthra, Tardigrada, Mylodontidae). Ameghiniana 48(4, Supplement): R214.

  • Villarroel, A.C. 2000. Un nuevo Mylodontinae (Xenarthra, Tardigrada) en la fauna de La Venta, Mioceno de Colombia: el estado actual de la familia Orophodontidae. Revista de la Academia Colombiana de Ciencias 24 (90): 117–127.

    Google Scholar 

  • Vizcaíno, S.F., R.A. Fariña, and G. Mazzetta. 1999. Ulnar dimensions and fossoriality in armadillos. Acta Theriologica 44: 309–320.

    Article  Google Scholar 

  • Webb, S.D. 1989. Osteology and relationships of Thinobadistes segnis, the first mylodont sloth in North America. In Advances in Neotropical Mammalogy, ed. K.H. Redford, and J.F. Eisenberg, 469–532. Gainesville: Sandhill Crane Press.

    Google Scholar 

  • White, J.L. 1993. Indicators of locomotor habits in xenarthrans: Evidence for locomotor heterogeneity among fossil sloths. Journal of Vertebrate Paleontology 13: 230–242.

    Article  Google Scholar 

  • Wilkinson, M. 1995. Coping with abundant missing entries in phylogenetic inference using parsimony. Systematic Biology 44: 501–514.

    Article  Google Scholar 

  • Winge, H. 1915. Jordfundne og nulevende Gumlere (Edentata) fra Lagoa Santa, Minas Gerais, Brasilien. Med udsigt over gumlernes indbyrdes slaegtskab. E Museo Lundii 3: 1–321.

  • Woodward, A.S. 1900. On some remains of Grypotherium (Neomylodon) listai and associated mammals from a cavern near Consuelo Cove, Last Hope Inlet, Patagonia. Proceedings of the Zoological Society of London 1900: 64–79 + Pl. V–IX.

Download references

Acknowledgements

We thank J. Di Ronco for helping A.A.T. with the field work; M. Sosa and A. Montes for preparing the fossil bones; C. Yonahara for photographing the bones; H. G. McDonald, Á. Miño-Boilini, C. Cartelle, D. Brandoni, R. Hulbert, K. MacKenzie, J. Bar, M. Dantas, R. Juárez, and N. Gardner, for supplying us with relevant literature; D. Peters for editing the English style; H. G. McDonald, R. K. McAfee, and F. Pujos for their useful reviews; the Willi Hennig Society for the free availability of the phylogenetic inference software TNT; CONICET for the postdoctoral fellowships to J.A.H. and J.M.K.; and SeCyT-Universidad Nacional de Córdoba for funding this research (Grant 05/I780).

Author information

Authors and Affiliations

  1. Museo de Paleontología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Vélez Sarsfield 249, X5000JJC, Córdoba, Argentina

    José A. Haro, Adan A. Tauber & Jerónimo M. Krapovickas

  2. Cátedra de Paleontología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Vélez Sarsfield 1611, X5016GCA, Córdoba, Argentina

    José A. Haro, Adan A. Tauber & Jerónimo M. Krapovickas

  3. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina

    José A. Haro & Jerónimo M. Krapovickas

  4. Museo Provincial de Ciencias Naturales “Dr. Arturo Umberto Illía”, Poeta Lugones 395, X5000HZD, Córdoba, Argentina

    Adan A. Tauber

Authors
  1. José A. Haro
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Adan A. Tauber
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Jerónimo M. Krapovickas
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to José A. Haro.

Additional information

Handling Editor: Irina Ruf.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Online Resource 1 Data matrix ready for use in TNT (provided as a.tnt file). (TNT 33 kb)

Appendices

Appendix 1: Sources of comparative data in the literature

Mylodon darwinii Owen, 1839

Lehmann-Nitsche (1902), Roth (1899), Nordenskjöld (1900), Studer (1905), Kraglievich (1934), Bargo and Deschamps (1996), Pitana (2011), Saint-André et al. (2010), McAfee (2016)

Glossotherium robustum (Owen, 1842)

Owen (1842), Rautenberg (1906), Reinhardt (1875), Allen (1913), Lull (1915), Stock (1925), Kraglievich (1934), Hoffstetter (1952), Cartelle (1980), McDonald (1987), Saint-André et al. (2010), Pitana (2011), McAfee (2016)

Glossotherium wegneri (Spillmann, 1931)

Hoffstetter (1952), Cartelle (1992)

Paramylodon harlani (Owen, 1839)

Harlan (1843), Leidy (1855), Allen (1913), Lull (1915), Stock (1925), Kraglievich (1934), Hoffstetter (1952), Hirschfeld (1985), McDonald (1987), Cartelle (1992), Saint-André et al. (2010)

Mylodonopsis ibseni Cartelle, 1991

Cartelle (1980), Cartelle and Fonseca (1981)

Pseudoprepotherium confusum Hirschfeld, 1985

Hirschfeld (1985), Saint-André et al. (2010)

Thinobadistes segnis Hay, 1919

Webb (1989), Saint-André et al. (2010)

Ocnotherium giganteum (Lund, 1839)

Cartelle (1992)

Simomylodon uccasamamensis Saint-André, Pujos, Cartelle, De Iuliis, Gaudin, McDonald, and Mamani Quispe, 2010

Saint-André et al. (2010)

Lestodon armatus Gervais, 1855

Gervais (1873), Reinhardt (1875), Kraglievich (1934), McDonald (1987), Cartelle (1992), Bargo et al. (2000), Saint-André et al. (2010), Pitana (2011)

Brievabradys laventensis Villarroel, 2000

Hirschfeld (1985), McDonald (1997)

Bolivartherium urumaquensis (Linares, 2004)

Carlini et al. (2006b)

Unnamed Intertropical “Glossotherium aff. G. lettsomi” sensu Cartelle (1992)

Cartelle (1992), Pitana (2011)

“Glossotherium aff. G. robustum” specimen LAP-Q 0004 sensu Pitana (2011)

Pitana (2011)

“Glossotherium aff. G. robustum” specimen MCN-PV 9718 sensu Pitana (2011)

Pitana (2011)

Catonyx Ameghino, 1891

Winge (1915), McDonald (1987) Cartelle et al. (2009)

Scelidotherium Owen, 1839

Owen (1839), Burmeister (1881), McDonald (1987), Aramayo (1988), Esteban et al. (1992), Cuenca Anaya (1995), Miño-Boilini (2012), Miño-Boilini et al. (2014), Owen (1842), Cartelle et al. (2009)

Megatherium americanum Cuvier, 1796

Owen (1858)

Megalonyx jeffersoni Desmarest, 1822

Leidy (1855), Stock (1925), McDonald (1977)

Mionothropus cartellei De Iuliis, Gaudin, and Vicars, 2011

De Iuliis et al. (2011)

Hapalops Ameghino, 1887

Scott (1904), Stock (1925)

Appendix 2: Description of characters used in the phylogenetic analysis

These 45 characters were added to our larger matrix formed by combining Gaudin (2004) and Rincón et al. (2015); therefore, their numbering reflects their inclusion in the total character list.

  1. 312

    Supracondylar foramen in humerus: present (0); absent (1) (Owen 1842).

  2. 313

    Calcaneal facets in astragalus: unfused (0); fused (1) (Owen 1842).

  3. 314

    Dermal ossicles: absent (0); present (1) (Ameghino 1881).

  4. 315

    Contact between articular facets for trapezium-metacarpal I and trapezoid in scaphoid: present (0); absent (1) (Hirschfeld 1985).

  5. 316

    Contact between articular facets for trapezoid and magnum in the scaphoid: present (0); absent (1) (Cartelle 1980).

  6. 317

    Articular facet for lunar on scaphoid: subdivided in two parts (0); unique (1) (modified from Hirschfeld 1985).

  7. 318

    Relationship between mediolateral widths of dorsal and palmar borders of radial articular surface in lunar: dorsal border narrower or not much wider (0); dorsal border more than twice palmar border (1) (Hirschfeld 1985).

  8. 319

    Extent of dorsal border of the facet for the unciform relative to extent of border of dorsal surface between facets for radius and magnum in lunar: shorter (0); longer (1) (Cartelle 1980).

  9. 320

    Angle between articular facets for scaphoid and magnum in lunar: lesser to 145° (0); greater to 145° (1) (Hirschfeld 1985).

  10. 321

    Relief of articular surface for ulna in cuneiform in the axis extending from dorsomedial to palmolateral: approximately straight (0); clearly concave (1) (Cartelle 1980).

  11. 322

    Contact between the articular facets for ulna and pisiform in the cuneiform: present (0); absent (1) (Cartelle 1980).

  12. 323

    Distolateral process of cuneiform: poorly developed (0); well developed (1) (Cartelle 1980).

  13. 324

    Relationship of proximodistal length to dorsopalmar depth in cuneiform: lesser (0); greater (1) (modified from Robertson 1976).

  14. 325

    Relationship between proximodistal length and mediolateral width in the cuneiform: lesser than 0.93 (0); larger than 0.93 (1) (modified from Robertson 1976).

  15. 326

    Prominent ridge on proximal region of the dorsal surface of the cuneiform: present (0); absent (1) (Cartelle 1980).

  16. 327

    Proximal facet of trapezium: concave (0); flat (1) (McDonald 1987).

  17. 328

    Contact between trapezium and trapezoid: present (0); absent (1) (McDonald 1987).

  18. 329

    Exposition in dorsal view of articulated manus of contact between metacarpal II and magnum: present (0); absent (1) (Cartelle 1980).

  19. 330

    Proportions of lateral extremity of articular facet for cuneiform in unciform: dorsopalmarly reduced (0); dorsopalmarly expanded (1) (modified from Hirschfeld 1985).

  20. 331

    Mediolateral development of the axial process of trapezium-metacarpal I: low (0); high (1) (Stock 1925).

  21. 332

    Ratio between length of metacarpal II and dorsopalmar depth of narrowest point in the shaft: more than 0.42 (0); less than 0.42 (1) (modified from Cartelle 1980).

  22. 333

    Relationship between articular facets for metacarpal III and magnum in metacarpal II: contacting (0); separated (1) (Saint-André et al. 2010).

  23. 334

    Articular facet for trapezium in metacarpal II: not concave (0); concave (1) (Saint-André et al. 2010).

  24. 335

    Articular facet for the magnum in metacarpal III: single facet (0); subdivided, with separate dorsoabaxial facet (1) (Hirschfeld 1985).

  25. 336

    Dorsal part of articular facet for metacarpal II in metacarpal III: approximately flat (0); markedly convex (1) (Saint-André et al. 2010).

  26. 337

    Ratio between width of body and bone length in metacarpal III: More than 0.37 (0); 0.37 or less (1) (Haro et al. 2016).

  27. 338

    Expansion of the distal carina upon the dorsal surface of metacarpal III: absent or minimal (0); present, well expanded (1) (Stock 1925).

  28. 339

    Orientation of the distal carina of metacarpal III: dorsopalmar (0) oblique from the middle of the palmar border to the dorsoaxial corner of the distal surface (1) (Stock 1925).

  29. 340

    Proximodistal extension of the articular facet for the metacarpal V in the metacarpal IV: relatively extensive (0); quite narrow (1) (Hirschfeld 1985).

  30. 341

    Relief of palmar region of articular surface for metacarpal III in metacarpal IV: convex (0); concave (1) (Hirschfeld 1985).

  31. 342

    Axial offset in distal articular surface of metacarpal IV: well developed (0); reduced or absent (1) (Hirschfeld 1985).

  32. 343

    Relief of carina on distal articular surface of metacarpal IV in the dorsopalmar direction: flat or concave (0); convex (1) (Rautenberg 1906).

  33. 344

    Palmar extension of articular facet for metacarpal V relative to palmar surface at waist of body in metacarpal IV: does not surpass it (0); surpasses it (1) (Saint-André et al. 2010).

  34. 345

    Ratio between maximal dorsopalmar and axioabaxial extents of proximal phalanx of manual digit II: lesser than 1.27 (0); greater than 1.27 (1) (modified from Stock 1925).

  35. 346

    Dorsopalmar keel in proximal surface of intermediate phalanx in manual digit II: not covered with articular surface (0); mostly covered with articular surface (1) (Cartelle 1980).

  36. 347

    Mediolateral compression in olecranon: absent (0); present (1) (Hirschfeld 1985).

  37. 348

    Distal part of lateral surface of ulna: concave (0); convex (1) (Owen 1842).

  38. 349

    Articular circumference proximal exposition: scarce (0); great (1) (Saint-André et al. 2010).

  39. 350

    Bicipital tubercle location in radius: within proximal third (0); exceeding proximal third (1) (Lull 1915).

  40. 351

    Angle in medial border of radius at pronator crest: well marked (0); not marked (1) (Reinhardt 1875).

  41. 352

    Medial border of radius with convexity expanded along distal half of diaphysis: present (0); absent (1) (Reinhardt 1875).

  42. 353

    Angle in medial border of radius at the distal end: not marked (0); well-marked (1) (Rautenberg 1906).

  43. 354

    Styloid process of radius: not acutely pointed (0); acutely pointed (1) (Rautenberg 1906).

  44. 355

    Separation between articular facets for scaphoid and lunar in the radius: ridge (0); groove (1) (Cartelle 1980).

  45. 356

    Relief of articular surface for scaphoid in radius in mediolateral direction: not concave (0); concave (1) (Rautenberg 1906).

Appendix 3: Data matrix

The following data matrix includes only thoracic member and a few other postcranial skeletal characters. It was analyzed after being fused with those of Gaudin (2004) and Rincón et al. (2015), as explained in the main text. Abbreviations—P, polymorphic, both states 0 and 1 present; X, not applicable.

figure a

Appendix 4: Apomorphic thoracic limb skeleton character states, other than from the manus, of recovered clades

Clade 10::

Character 348: 0 → 1. Distal part of lateral surface of ulna convex.

Clade 11::

Character 349: 0 → 1. Articular circumference in radius with great proximal exposure.

Character 352: 0 → 1. Medial border of radius nearly straight along distal half of diaphysis (convergence in Megatheria).

Character 353: 0 → 1. Angle well marked in medial border of radius at the distal end.

Character 354: 0 → 1. Styloid process of radius acutely pointed.

Clade 12::

Character 356: 1 → 0. Articular surface for scaphoid in radius flat or convex in mediolateral direction.

Clade 12 or 13 (uncertain)::

Character 347: 0 → 1. Olecranon mediolaterally compressed (convergence in Megatherium).

Character 351: 0 → 1. Angle in medial border of radius at pronator crest not marked.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Haro, J.A., Tauber, A.A. & Krapovickas, J.M. Thoracic member (pectoral girdle and forelimb) bones of Mylodon darwinii Owen (Xenarthra, Mylodontidae) from the Late Pleistocene of Central Argentina and their phylogenetic implications. PalZ 91, 439–457 (2017). https://doi.org/10.1007/s12542-017-0350-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12542-017-0350-z

Keywords

Schlüsselwörter

Search

Navigation