ON THE PHYLOGENY OF THE MACHAIRODONTINAE

Traditionally, the felid subfamily Machairodontinae (saber-toothed cats) is divided into two “tribes” based primarily on the shape of the canines and the overall body form. Generally these felids can be easily classified into the “dirk toothed” Smilodontini (Finely serrated, slender, elongated upper canines, with short limbs and a robust body form), or the “scimitar toothed” Homotherini (coarsely serrated, robust, elongated upper canines, with longer limbs and a more slender body form), with only a few ancestral taxa excluded at the base of the tree. In recent years, the morphological characteristics of this subfamily have been made somewhat less certain with the genus Xenosmilus, which has a mosaic of characters from both tribes. To look more closely at the subfamilial relationships, data was collected from several species both in museums and from literature. A data matrix of eighty characters and fifteen taxa was then created and analyzed.

The current analysis shows that there is still support for the derived Homotherini (Xenosmilus and Homotherium) and Smilodontini (Smilodon and Megantereon) in their own clades, but there now appears to be a third clade that may warrant its own tribe status. The less derived Homotheres seem to cluster into their own group separated from the other Machairodonts by several dental, cranial, and post-cranial characters. This new group is less derived than the two established tribes, but still more derived than the ancestral Machairodonts at the base of the tree.