Post-weaning cranial ontogeny in two bandicoots (Mammalia, Peramelomorphia, Peramelidae) and comparison with carnivorous marsupials

DAVID A. FLORES; FERNANDO ABDALA; NORBERTO P. GIANNINI

ZOOLOGY

ELSEVIER GMBH

Año: 2013

0944-2006

The ontogeny of skull has been quantitatively studied in several marsupial groups such as didelphids, microbiotheriids, and dasyurids. Here, we describe and compare postweaning ontogeny of the skull in two species of bandicoots: Echymipera kalubu and Isoodon macrourus. Growth patterns were analyzed both qualitative and quantitatively, the latter including bivariate and multivariate analyses of allometry. We identified morphological changes between juvenile and adult stages in both species, many related with the development of the trophic apparatus. In E. kalubu changes involve principally the lengthening of the snout, including the appearance of a series of diastemata in adults, which are far less evident in I. macrourus. The tympanic bullae of I. macrourus are comparatively larger in juveniles and the fusion of basioccipital and exoccipital seems to take place earlier with respect to E. kalubu. Allometric trends of I. macrourus and E. kalubu are dominated by the growth of the snout, although this seems to be more marked in the later. Notable differences were detected in the patterns of growth, suggesting some divergences in ontogenetic changes between both species. Both bivariate and multivariate allometry indicate that positive allometries in E. kalubu affected longitudinal dimensions, whereas in I. macrourus, positive allometries were restricted to vertical dimensions of the skull. The orbit was isometric in E. kalubu negative in I. macrourus. Integration of allometric results in two representative of the Peramelomorphia clade with previously studied taxa reveals growth trends that appear highly conservative through the array of marsupial species studied to date.