Cranial morphology in sabretooth mammals: allometry, function, and phylogeny

TURAZZINI, G. F.; PREVOSTI, F. J.; CHEMISQUY, M. A.

San Rafael, Mendoza, Argentina

Jornada; XXIV Jornadas Argentinas de Paleontología de Vertebrados; 2009

Asociación Paleontológica Argentina

Cranial morphology of felids and sabre-toothed mammals has been studied using differentapproaches and methodologies. Recent studies used geometric morphometric analyses of the lateral view of the mandible and skull, and showed that “derived” sabretooth cats are separated from recent felids by having a set of characters (e.g. small coronoid process, large mental flanges and mastoid process) associated with the presence of hypertrophied upper canines. In this work, we used geometric morphometric to analyse the shape of the skull (dorsal and ventral views) and mandible (lateral view) in a large sample of recent felids (Felinae), extinct sabretooth felids (Machaerodontinae), Nimravidae, Creodonta and the marsupial sabretooth cat Thylacosmilus Riggs. The results were similar to the obtained by other authors that studied the lateral view of the skull: “primitive” sabretooth were placed with recent felids, but “derived” ones fell outside the range of the Felinae, because they possessed larger mastoid process, larger and more procumbent upper incisors, smaller temporal fossa, among other characters. Besides that, most sabretooth shared some features with large Felinae (e.g. Panthera Oken), suggesting that they could also hunt large mammals. The pattern of cranial variability of these groups is explained by ecological factors but also by phylogenetic constraints. The shape of the skull was correlated with the size and length of the upper canines, two features that present a clear correlation along the phylogeny of the group.