Who ate OH80 (Olduvai Gorge, Tanzania)? A geometric-morphometric analysis of surface bone modifications of a Paranthropus boisei skeleton

Olduvai Gorge (Tanzania) is one of the key areas for the study of human origins, given the sheer abundance of archaeological and paleontological sites discovered. Several of these archaeological sites have yielded numerous hominin fossils and traces of their activities, thus offering invaluable insights into the nature and origins of human behavior. Nevertheless, certain taphonomic discussions that have been of great importance for the study of the South African cave sites have remained unnoticed in East Africa. One of these issues revolves around the interpretation of Paranthropus as a common prey of predators. In this paper, we analyze the postcranial remains of OH80, a partial skeleton of a Paranthropus boisei discovered at the BK site (Bell Korongo, Bed II of Olduvai Gorge, Tanzania) in 2010. Some of the specimens of this skeleton have been reported to show surface modifications tentatively associated to the action of carnivores. Here, several pits observed on OH80-12, the Paranthropus boisei femur, were digitally reconstructed and analyzed through geometric morphometrics to determine the nature of the marks. The OH80-12 marks are compared with a modern sample of percussion marks and several carnivore tooth pits, since the action of both agents has previously been identified at the site and can sometimes result in equifinality problems. Alongside already published geometric morphometric tests, here we present a very newly developed approach based on the combination of geometric morphometric data and the training of machine learning algorithms. Both methodologies highlight that OH80 was consumed by carnivores, being a felid the most likely modifying agent.