The Endocranial Morphology of the Plio-Pleistocene Bone-Cracking Hyena Pliocrocuta perrieri: Behavioral Implications

Abstract

The internal cranial morphology of the bone-cracking hyena Pliocrocuta perrieri (Carnivora, Hyaenidae) is described based on three crania from the late Pliocene and early Pleistocene of the Iberian Peninsula. The shape and size of the inner cranial cavities (with emphasis on encephalization and relative regional brain volumes) are compared with those of extant hyaenids with the aid of computed tomography techniques—which had not been previously used to study the brain morphology of any extinct bone-cracking hyena. Our results indicate that the frontal sinuses of P. perrieri are caudally extended and overlap the brain cavity, as in other extinct and extant bone-cracking hyaenids. In turn, the brain morphology and sulcal pattern of P. perrieri are more similar to those of Hyaena hyaena and Parahyaena brunnea than to those of Crocuta crocuta among extant bone-cracking hyaenids. Our results further indicate that Pliocrocuta is clearly less encephalized than the highly-social Crocuta, and displays an anterior cerebrum relatively smaller than in all extant bone-cracking hyenas (indicating the possession of a poorly-developed frontal cortex). These facts might suggest that P. perrieri possessed less developed cognitive abilities than Crocuta for processing the information associated with complex social behaviors.