Mammalian Biology

, Volume 75, Issue 4, pp 326–333 | Cite as

Evolution of the axial skeleton in armadillos (Mammalia, Dasypodidae)

  • Fernando C. Galliari
  • Alfredo A. Carlini
  • Marcelo R. Sánchez-VillagraEmail author
Original Investigation


Intraspecific and interspecific variation in cervical, thoracic, and lumbar region of the vertebral column of Dasypodidae were examined in a phylogenetic framework. The number of vertebrae for each region were recorded for 86 specimens and metric data for each vertebra (centrum length, high, and width) were recorded for 72 specimens, including eight of the nine living genera. The number of vertebrae and degree of fusion between them were used to define four characters which were plotted on two alternative phylogenies of Dasypodidae. The ratio between centrum height and width is similar across all taxa analyzed except for Chlamyphorus, which exhibits a deviation in the last two lumbars. Tolypeutes matacus is unique among the taxa examined in having a second co-osified bone called postcervical bone, which is a fusion of the seventh cervical and first thoracic vertebrae. The thoraco-lumbar numbers of dasypodids are reduced when compared with other xenarthrans and are more diverse than those of some other mammalian clades of similar geological age and higher ecomorphological diversity. Changes in size are somewhat coupled with changes in the number of body segments. Independent of the phylogenetic framework taken, changes in size are accompanied with small changes in numbers of thoracolumbar vertebrae within each genus. There are functional and phylogenetic correlates for changes in number of thoraco-lumbar vertebrae in dasypodids.


Vertebra Modularity Constraint Phylogeny Xenarthra 


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  1. Asher, R.J., Lehmann, T., 2008. Dental eruption in afrotherian mammals. BMC Biol. 6, 14.CrossRefGoogle Scholar
  2. Atkinson, E., 1870. On some points of osteology of the pichiciego (Chlamydophorus truncatus, Harlan). J. Anat. Physiol. 5, 1–17.PubMedPubMedCentralGoogle Scholar
  3. Buchholtz, E.A., Booth, A.C., Webbnik, K.E., 2007. Vertebral anatomy in the florida manatee, Trichechus manatus latirostris: a developmental and evolutionary analysis. The Anatomical Record 290, 624–637.CrossRefGoogle Scholar
  4. Buchholtz, E.A., Stepien, C.C., 2009. Anatomical transformation in mammals: developmental origin of aberrant cervical anatomy in tree sloths. Evol. Dev. 11 (1), 69–79.CrossRefGoogle Scholar
  5. Burke, A.C., Nelson, C.E., Morgan, B.A., Tabin, C., 1995. Hox genes and the evolution of vertebrate morphology. Development 121, 333–346.PubMedGoogle Scholar
  6. Carlini, A.A., Ciancio, M.R., Flynn, J.J., Scillato-Yané, G.J., Wyss, A.R., 2009. The phylogenetic and biostratigraphic significance of new armadillos (Mammalia, Xenarthra, Dasypodidae, Euphractinae) from the Tinguirirican (Early Oligocene) of Chile. J. Syst. Palaeontol. 7, in press.CrossRefGoogle Scholar
  7. Carlini, A.A., Scillato-Yané, G.J., 1995. Chorobates recens (Xenarthra, Dasypodidae) y un análisis de la filogenia de los Euphractini. Rev. Mus. La Plata, Paleontología 59, 225–238.Google Scholar
  8. Delsuc, F., Scally, M., Madsen, O., Stanhope, M.J., de Jong, W.W., Catzeflis, F.M., Springer, M.S., Douzery, E.J.P., 2002. Molecular phylogeny of living xenarthrans and the impact of character and taxon sampling on the placental tree rooting. Mol. Biol. Evol. 19 (10), 1656–1671.CrossRefGoogle Scholar
  9. Flower, W.H., 1885. An introduction to the osteology of the Mammalia. Macmillan and Co., London.CrossRefGoogle Scholar
  10. Galis, F., 1999. Why do almost all mammals have seven cervical vertebrae? Developmental constraints, Hox genes, and cancer. J. Exp. Zool. 285, 19–26.CrossRefGoogle Scholar
  11. Gardner, A.L., 2005. Order Cingulata. In: Wilson, D.E., Reeder, D.M. (Eds.), Mammal Species of the World. A Taxonomic and Geographic Reference, third ed. The Johns Hopkins University Press, Baltimore, pp. 94–103.Google Scholar
  12. Gaudin, T., 1999. The morphology of the xenarthrous vertebrae (Mammalia: Xenarthra). Fieldian. 1505 (41), 1–38.Google Scholar
  13. Gaudin, T.J., Wible, J.R., 2006. The phylogeny of living and extinct armadillos (Mammalia, Xenarthra, Cingulata): a craniodental análisis. In: Carrano, M.T., Gaudin, T.J., Blob, R.W., Wible, J.R. (Eds.), Amniote Paleobiology: Perspectivas on the Evolution of Mammals, Birds, and Reptiles. The University of Chicago Press, Chicago and London pp. 547 ill. 127.Google Scholar
  14. Head, J.J., Polly, P.D., 2007. Dissociation of somatic growth from segmentation drives gigantism in snakes. Biol. Lett. 3 (3), 296–298.CrossRefGoogle Scholar
  15. Jenkins Jr., F.A., 1970. Anatomy and function of expanded ribs in certain edentates and primates. J. Mamm. 51 (2), 288–301.CrossRefGoogle Scholar
  16. Krmpotic, C.M., Ciancio, M.R., Barbeito, C., Mario, R.C., Carlini, A.A., 2009. Osteoderm morphology in recent and fossil euphractinae xeanrthrans. Acta Zool. (Stockh.), 90 (doi:
  17. Maddison, W.P., Maddison, D.R., 2008. Mesquite: a modular system for evolutionary analysis. Version 2.5 <>.
  18. Martin, B.E., 1916. Tooth development in Dasypus novemcinctus. J. Morphol. 27 (3), 647–691.CrossRefGoogle Scholar
  19. Müller, J., Torsten Scheyer, T.M., Barrett, P., Ericsson, P., Head, J., Pol, D., Werneburg, I., Asher, R.J., Sánchez-Villagra, M.R., 2008. Amniote paleontology and development: evolution of vertebral counts and other case studies. Second Meeting of the European Society for Evolutionary Developmental Biology, July 29–August 1, 2008, Ghent, pp. 139–140.Google Scholar
  20. Narita, Y., Kuratani, S., 2005. Evolution of the vertebral formulae in mammals: a perspective on developmental constraint. J. Exp. Zool. 304B, 91–106.CrossRefGoogle Scholar
  21. Nowak, R.M., 1999. Order Xenarthra. In: Nowak, R.M. (Ed.), Walker’s Mammals of the world, vol. I, sixth ed. The Johns Hopkins University Press, Baltimore, pp. 147–168.Google Scholar
  22. Redford, K.H., Eisenberg, J.F., 1992. Order Xenarthra (Edentata). In: Redford, K.H., Eisenberg, J.F. (Eds.), Mammals of the Neotropics. The Southern Cone, vol. 2. The University of Chicago Press, Chicago, pp. 46–68.Google Scholar
  23. Richardson, M.K., Allen, S.P., Wright, G.M., Raynaud, A., Hanken, J., 1998. Somite number and vertebrate evolution. Development 125, 151–160.PubMedGoogle Scholar
  24. Rose, K.D., Emry, R.J., 1993. Chapter 7: relationships of Xenarthra, Pholidota and fossil “Edentates”: The morphological evidence. In: Szalay, F.S., Novacek, M.J., McKenna, M.C. (Eds.), Mammal Phylogeny. Placentals. Springer, New York, pp. 81–102.CrossRefGoogle Scholar
  25. Sánchez-Villagra, M.R., Narita, Y., Kuratani, S., 2007. Thoracolumbar vertebral number: the first skeletal synapomorphy for afrotherian mammals. Syst. Biodivers. 5 (1), 1–7.CrossRefGoogle Scholar
  26. Scillato-Yané, G.J., 1982. Los Dasypodidae (Mammalia, Edentata) del Plioceno y Pleistoceno de Argentina. Tesis Doctoral, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, pp. 159 L. 57.Google Scholar
  27. Scott, W.B., 1903/1905. Part I: Edentata. In: Scott, W.B. (Ed.), Volume V: Mammalia of the Santa Cruz Beds. The University of Stuttgart, Princeton, NJ pp. 364 ill. 63.Google Scholar
  28. Springer, M.S., Murphy, W.J., 2007. Mammalian evolution and biomedicine: new views from phylogeny. Biol. Rev. 82, 375–392.CrossRefGoogle Scholar
  29. Starck, D., 1995. Lehrbuch der Speziellen Zoologie. Wirbeltiere. Teil 5: Saügetiere, vol. 2. Gustav Fischer Verlag, Jena.Google Scholar
  30. Wetzel, R.M., 1980. Revision of the naked-tailed armadillos, genus Cabassous McNurtrie. Ann. Carnegie. Mus. 49, 323–357.Google Scholar
  31. Wiens, J.J., 2000. Coding morphological variation within species and higher taxa for phylogenetic analysis. In: Wiens, J.J. (Ed.), Phylogenetic Analysis of Morphological Data. Smithsonian Institution Press, Washington, pp. 115–145.Google Scholar

Copyright information

© Deutsche Gesellschaft für Säugetierkunde 2009

Authors and Affiliations

  • Fernando C. Galliari
    • 1
  • Alfredo A. Carlini
    • 1
    • 2
  • Marcelo R. Sánchez-Villagra
    • 2
    Email author
  1. 1.Departamento Científico de Paleontología de Vertebrados, Facultad de Ciencias Naturales y MuseoUniversidad Nacional de la PlataLa PlataArgentina
  2. 2.Paläontologisches Institut und MuseumUniversität ZürichZürichSwitzerland

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