Adaptações morfológicas no esqueleto apendicular de Xenartha do Quaternário da Serra da Bodoquena

Abstract

Mammals of the superorder Xenarthra is subdivided into two orders: Cingulata, which includes armadillos and glyptodonts with carapaces, and Pilosa, which includes extinct and living sloths (suborder Folivora) and anteaters (suborder Vermilingua), which have a dense covering of hair all over their bodies. Therefore, in the present work, slides of long bones (femur and humerus) from fossil and current xenarthran specimens were prepared, analyzing Haversian systems (average diameter, average quantity and density) and comparing them with bone size and estimated body mass. Here the correlation test was used in order to verify whether there is a correlation between bone length and mean diameter of the Haversian systems, bone length x mean density of the Haversian systems, mean density of the Haversian systems x estimated body mass of the specimens for both the femur and the humerus. Correlation tests were carried out using PAST software version 4.0. In addition, the pairwise Mann-Whitney statistical test was performed to verify whether there were significant differences in the number of Haversian systems. The results of this work corroborate previous hypotheses that current cingulates have bones with a lower density of Haversian systems than some pilosos species, while femur and humerus have similar amounts of systems indicating that they have long bones biomechanically adapted to fossorial habits. Different from the extinct pilosos and cingulates animals, which have a greater number of Haversian systems on the femur, which indicates that they needed to support a large amount of body mass on the hind limbs during locomotion and for exercising an upright position both extinct and current pilosos.