Acinonyx pleistocaenicus
Acinonyx pleistocaenicus is an extinct felid species belonging to the genus Acinonyx, native to Eurasia from the Early Pleistocene to Middle Pleistocene, from 1.3 to 0.6 million years ago. This species was larger than Acinonyx pardinensis.
Taxonomy
Classification
Originally described as Cynailurus pleistocaenicus, several studies have since considered Acinonyx pleistocaenicus as a subspecies of Acinonyx pardinensis. However, Jiangzuo et al. suggested that its cranial and dental anatomy have more distinguishing features and resemble modern cheetahs based on new specimens, classifying A. pleistocaenicus and A. pardinensis as separate species.
Evolution
Acinonyx pleistocaenicus may have evolved from A. pardinensis in Eurasia during the Early Pleistocene. During the Middle Pleistocene, A. pleistocaenicus was replaced by Acinonyx intermedius. In spite of its similarity to A. intermedius and modern cheetah, A. pleistocaenicus is probably not a direct ancestor to either species.
Description
Acinonyx pleistocaenicus was the largest known species within the Acinonyx genus. Within Untermassfeld, males and females weighing and respectively, based on postcranial bones. Individuals within Zhoukoudian were even larger and were the largest members of the species, with males and females respectively weighing and. Considering the specimens found in Zhoukoudian were youngest record for the species, this may suggest A. pleistocaenicus increased in size over time, at least during the early Middle Pleistocene in East Asia. Despite its larger size, postcranial bones suggests its body was similar to modern cheetahs.
Paleobiology and Paleoecology
Within the upper deposits of Jinyuan Cave, Acinonyx pleistocaenius coexisted with predators such as Xenocyon ''lycaonoides, Ursus, Pachycrocuta brevirostris sinensis, Megantereon, and Panthera gombaszogensis jinpuensis. In Zhoukoudian, carnivorans present were Ursus arctos, Pachycrocuta brevirostris sinensis, Homotherium latidens, and tigers. It was one of the largest carnivores within its fauna and unlike modern cheetahs, would’ve been able to defend their kills due to its large body size and robust canines. Ideal prey for this species would’ve weighed, such as Cervus, Sinomegaceros, and Equus''. The ectotympanic chamber wasn’t enlarge as modern cheetahs, suggesting it wasn’t as adapted for open environments.