Cranial ontogeny in canids and felids: a comparison with carnivorous marsupials

SEGURA, VALENTINA; FLORES, DAVID; PREVOSTI, FRANCISCO

Mendoza, Argentina

Congreso; 10 th International Mammalogical Congress (IMC 10); 2009

International Federation of Mammalogists (IFM)

The postnatal ontogenies of some carnivorous marsupials were recently studied in a bivariate and multivariate frame. In a comparative context, we analyzed the ontogenetic trajectory (RMA and multivariate allometry) of the skull in three species of eutherian carnivorous: Puma concolor (n=71), P. yagouaroundi (n=41) (Felidae) and Lycalopex culpaeus (n=100) (Canidae). As in marsupials, we detect a close interaction between neurocranium and splachnocranium, which results in a modified adult skull, functionally adapted to a more carnivore feeding habits. The trends observed includes some common patterns as the negative allometry of the braincase, shared in all groups (can be interpreted as present in the theria ancestor), the negative allometry of the orbit is a common feature observed in almost all groups, although it is isometric in P. yagouaroundi (as in the australidelphian Dromiciops gliroides). The positive allometry of the zygomatic breadth detected in the larger placental carnivorous analyzed (P. concolor and L. culpaeus) combined with the breadth of the braincase determine the space for the temporal musculature. This pattern is shared with the higly carnivorous australasian marsupial Dasyurus albopunctatus. Seemingly, the heigth of the mandibular ascendent ramus in placental predators, implied in the insertion of masseteric muscle, is related with the mechanical resistance, as in the small sized P. yagouaroundi it is isometric, whereas in the larger P. concolor and L. culpaeus it is positively allometric. Indeed, in marsupials this variable is positively allometric only in the larger D. albopunctatus and Didelphis albiventris. The trends observed in this study suggest that some patterns are strongly influenced by functional demands more than by phylogenetic constraints.