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

SEBASTIÁN ECHARRI; FRANCISCO J. PREVOSTI

Jornada; Reunión de Comunicaciones de la Asociación Paleontológica Argentina; 2013

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 thecomparison of their results. We study mandible disparity in mammalian clades that possesscarnivore species (extant and extinct) to test differences between clades (Carnivora, Marsupialia,Sparassodonta) using geometric morphometry, two disparity index, the variance and the mean ofthe procrustes distances. Our results show significant differences in the disparities betweenCarnivora and metatherian carnivore clades in most of the analyses. In some results of the samplesthat include fossils, we did not found significant differences in both disparities, except when weexcluded the saber-tooth morphotype. This can be explained by the extreme morphology of thismorphotype, which increases the variance and reduce the effect of the disparity of the other speciesin the analyses. However, using Procrustes we found significant differences between Carnivora andMetatheria disparities distances in most of the analyses. The mandibular disparity in Carnivora isgreater than carnivore metatherian mammals in most cases, and this can be related with differencesin the evolutionary history and constraints of both groups. The pattern found in the mandible issimilar to that found in the rostrum of the skull but not observed in the braincase, something that itis congruent with the functions that each part of the skull have.