The Neurocranium of Ekweeconfractus amorui gen. et sp. nov. (Hyaenodonta, Mammalia) and the Evolution of the Brain in Some Hyaenodontan Carnivores

We report on a nearly complete cranium of Ekweeconfractus amorui gen. et sp. nov. (Hyaenodonta, Teratodontinae), from the early Miocene of Moruorot, Kenya. The cranium is dorsoventrally compressed, but sufficiently intact to allow for digital reconstruction of the neurocranium, resulting in a digital endocast that gives us a first glimpse into teratodontine brain morphology. The virtual endocast is one of the most well preserved of any hyaenodont known to date, with many of the cranial nerves and blood vessels identifiable. Endocasts are known from only a handful of hyaenodont species and little work has been done on hyaenodont brains in recent decades. To better understand the evolution of the brain in these animals, we place the endocast of E. amorui gen. et sp. nov., as well as several other previously described endocasts, in the latest phylogenetic framework. This analysis suggests that the expansion of the neocortex occurred convergently in several clades of Hyaenodonta. Our study provides a basis for future research on brain evolution in Hyaenodonta.