Journal of Mammalian Evolution

, Volume 19, Issue 3, pp 217–224 | Cite as

Life on the Half-Shell: Consequences of a Carapace in the Evolution of Armadillos (Xenarthra: Cingulata)

  • Mariella Superina
  • W. J. Loughry


Without doubt, the possession of an armored carapace represents one of the most conspicuous morphological features of all cingulates. Here, we review some of the many ways in which the carapace may have influenced the evolution of other features of extant armadillos (Xenarthra: Cingulata). Effects range from physiological impacts on respiration and thermoregulation, to mechanical and other constraints on reproduction. Additionally, in mammals, armor has been linked with relatively slow plantigrade locomotion, which in turn may have promoted the low metabolic rate and exploitation of a low quality diet typically observed in armadillos. Finally, this network of relationships may help to explain the lack of any obvious kin-selected altruism in the polyembryonic armadillos, such as the nine-banded armadillo (Dasypus novemcinctus), because of time and energy constraints associated with a short active period devoted almost exclusively to feeding. In mammals, there has been growing interest in describing an ecological “lifestyle” as the particular way in which each species makes its living, and how this lifestyle constrains the evolution of other phenotypic traits. Based on our review, it appears the carapace has been a major determinant of the lifestyle of armadillos and has played a central role in shaping the evolution of many other features of these animals.


Cingulata Hypoxia Kin selection Reproduction Thermoregulation 



The ideas in this paper were first developed and presented during the symposium “Form and function in the Xenarthra” as part of the 9th International Congress of Vertebrate Morphology, held at Punta del Este, Uruguay in 2010. We thank François Pujos and Tim Gaudin for inviting us to participate in the symposium and for encouraging us to write this paper. We also thank them and all the symposium participants for very constructive feedback. This manuscript further benefited from comments provided by Colleen McDonough, Bruce Patterson, and Agustín Abba.


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© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Laboratorio de Endocrinología de la Fauna SilvestreIMBECU, CCT-CONICET MendozaMendozaArgentina
  2. 2.Department of BiologyValdosta State UniversityValdostaUSA

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