DIFFERENCES OF MANDIBULAR DISPARITY BETWEEN EXTANT AND EXTINCT METATHERIAN AND PLACENTAL CARNIVORES CLADES (DIDELPHIMORPHIA, SPARASSODONTA, AUSTRALIDELPHIA AND CARNIVORA)

SEBASTIÁN ECHARRI; FRANCISCO J. PREVOSTI

Congreso; Reunión Anual de Comunicaciones de la Asociación Paleontológica Argentina; 2013

Asociación Paleontológica Argentina

The differences between morphological disparity in carnivore clades (placental and metatherian) was discussed in some works which use skull or jaw, but the use of different sampling strategies (fossil inclusion, inclusion only of carnivore mammals or species with other diet habits) difficult the comparison of their results. We study mandible disparity in mammalian clades that possess carnivore species (extant and extinct) to test differences between clades (Carnivora, Marsupialia, Sparassodonta) using geometric morphometry, two disparity index, the variance and the mean of the procrustes distances. Our results show si gnificant differences in the disparities between Carnivora and metatherian carnivore clades in most of the analyses. In some results of the samples that include fossils, we did not found significant differences in both disparities, except when we excluded the saber-tooth morphotype. This can be explained by the extreme morphology of this morphotype, which increases the variance and reduce the effect of the disparity of the other species in the analyses. However, using Procrustes we found significant differences between Carnivora and Metatheria disparities distances in most of the analyses. The mandibular disparity in Carnivora is greater than carnivore metatherian mammals in most cases, and this can be related with differences in the evolutionary history and constraints of both groups. The pattern found in the mandible is similar to that found in the rostrum of the skull but not observed in the braincase, something that it is congruent with the functions that each part of the skull have.