Proportions and function of the limbs of glyptodonts

Authors

  • SERGIO F. VIZCAÍNO,

    1. Sergio F. Vizcaíno [vizcaino@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, B1900FWA La Plata, Argentina, CONICET; R. Ernesto Blanco [ernesto@fisica.edu.uy], Instituto de Física, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay; Benjamin Bender [jbbender@mendoza-conicet.gov.ar], Museo de Ciencias Naturales José Lorca, Liceo Agrícola y Enológico – Universidad Nacional de Cuyo, Av. San Francisco de Asis s/n, Parque San Martín, Mendoza 5500 Argentina; Nick Milne [milne@anhb.uwa.edu.au], School of Anatomy and Human Biology, University of Western Australia;
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  • R. ERNESTO BLANCO,

    1. Sergio F. Vizcaíno [vizcaino@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, B1900FWA La Plata, Argentina, CONICET; R. Ernesto Blanco [ernesto@fisica.edu.uy], Instituto de Física, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay; Benjamin Bender [jbbender@mendoza-conicet.gov.ar], Museo de Ciencias Naturales José Lorca, Liceo Agrícola y Enológico – Universidad Nacional de Cuyo, Av. San Francisco de Asis s/n, Parque San Martín, Mendoza 5500 Argentina; Nick Milne [milne@anhb.uwa.edu.au], School of Anatomy and Human Biology, University of Western Australia;
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  • J. BENJAMÍN BENDER,

    1. Sergio F. Vizcaíno [vizcaino@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, B1900FWA La Plata, Argentina, CONICET; R. Ernesto Blanco [ernesto@fisica.edu.uy], Instituto de Física, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay; Benjamin Bender [jbbender@mendoza-conicet.gov.ar], Museo de Ciencias Naturales José Lorca, Liceo Agrícola y Enológico – Universidad Nacional de Cuyo, Av. San Francisco de Asis s/n, Parque San Martín, Mendoza 5500 Argentina; Nick Milne [milne@anhb.uwa.edu.au], School of Anatomy and Human Biology, University of Western Australia;
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  • NICK MILNE

    1. Sergio F. Vizcaíno [vizcaino@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Paseo del Bosque s/n, B1900FWA La Plata, Argentina, CONICET; R. Ernesto Blanco [ernesto@fisica.edu.uy], Instituto de Física, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay; Benjamin Bender [jbbender@mendoza-conicet.gov.ar], Museo de Ciencias Naturales José Lorca, Liceo Agrícola y Enológico – Universidad Nacional de Cuyo, Av. San Francisco de Asis s/n, Parque San Martín, Mendoza 5500 Argentina; Nick Milne [milne@anhb.uwa.edu.au], School of Anatomy and Human Biology, University of Western Australia;
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Abstract

Vizcaíno, S.F., Blanco, R.E., Bender, J.B. & Milne, N. 2010: Proportions and function of the limbs of glyptodonts. Lethaia, Vol. 44, pp. 93–101.

This study examines the limb bone proportions and strength of glyptodonts (Xenarthra, Cingulata). Two methods are used to estimate the body mass and location of the centre of gravity of the articulated specimens. These estimates, together with measurements of the femur and humerus, are used to calculate strength indicators (SI). The other long bones of the limbs are used to calculate limb proportion indices that give an indication of digging ability, speed, and limb dominance in armadillos, the glyptodonts’ living closest relatives. The results show that regardless of how the body mass and centre of gravity are calculated, the majority of the glyptodont’s weight is borne by the hindlimbs. The SI calculations show that femora are sturdy enough to bear these loads. The fact that the femora have higher SI than the humerii indicates that sometimes the hindlimbs are required to bear an even greater proportion of the body weight, possibly when rising to a bipedal posture or pivoting on their hindlimbs to deliver a blow with their armoured tail. The analysis of limb proportions indicates that both the hindlimb and the forelimb have proportions that correlate strongly with body mass. This outcome supports the other results, but also shows that forelimbs must be also involved in manoeuvring the glyptodont body. □Glyptodonts, Mammalia, Xenarthra, limbs, strength indicators.

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