Oreopithecus bambolii
• Gervais, 1872
• IGF 4335, Juvenile mandible
• 7 – 6 MYA
• Italy
Showing postcranial morphology that is suggestive of both vertical climbing and bipedalism, Oreopithecus is one of the most uniquely designed apes discovered to date. The mandible and canines are both large and robust as with most apes (Hartwig). Its wide thorax, long and robust clavicle, short and robust lumbar region, and forelimbs longer than hindlimbs propose frequent vertical climbing. The very distinctive foot of Oreopithecus appears to be more for standing than for propulsion. The 2nd – 5th toes are in-line much like hominids but the hallux is quite robust and diverts in towards the midline creating a tripod effect. Due to the absence of predators on Mediterranean islands, Oreopithecus would have been able to develop a pedal design allowing for increased stationary, probably feeding, activities without sacrificing the need for stealthful and deliberate bipedal movements (Kohler and Moya-Sola).Adaptations to the pelvis and the very distinctive feet suggest bipedalism. According to Rook, et al., “In the hips of bipeds, the trabecular bone bundles of the sacropubic and ilioischial areas form high density networks that cover the acetabulum. This construct is in response to the weight of the entire body being transferred from the lumbar-sacral region of the spine to the hip and then to the femur with every step. This characteristic is visible in Oreopithecus, not to the extent seen in humans, but much more than extant apes.” The gracile hands of Oreopithecus reveal a very distinguishing hominid-like trait. As reported by Moya-Sola et al., “Hand grasping tests demonstrate that only humans have the ability to deftly apply pressure between the pads of the index finger and thumb. Proportions of the index finger and thumb of Oreopithecus are comparable to hominids. This ‘precision grip’ is considered a key evolutionary factor in the hominid brain/hand/tool complex.”