The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)

Cercopithecine forelimb locomotor adaptations: 3D geometric morphometric analysis of modern and fossil monkeys from the Hadar and Middle Ledi sites, Afar Region, Ethiopia


Anthropology Department, Virginia Commonwealth University

March 26, 2015 1:00, Grand Ballroom C Add to calendar

Understanding how fossil mammals used their environments is key to reconstructing paleohabitats. Since most large mammal fossils are recovered as isolated postcranial elements, methods of reconstructing behaviors using ecomorphological indicators are often necessary. For hominin-bearing fossil localities, these types of analyses are especially important for reconstructing the ecological parameters of the paleocommunity within which hominins adapted and evolved through time. Cercopithecinae are of particular interest when reconstructing hominin paleoenvironments because they represent the majority of non-hominin primates recovered from many east African localities.

The current study applies 3D geometric morphometric analyses to the distal humeri and proximal ulnae of a sample of >40 modern cercopithecine species with varying locomotor habits to differentiate morphology associated with locomotor behavior and substrate use. The multivariate analyses quantifying modern variation were then used to retrodict locomotor behaviors of more than 60 isolated fossil monkey elements from the Hadar and Middle Ledi fossil localities with whom Australopithecus afarensis shared environments.

Results of PCA and DFA suggest that morphology of the distal humerus and proximal ulna can be successfully used to distinguish arboreal, terrestrial, and mixed arboreal/terrestrial substrate use in modern cercopithecine primates. Further, the variation in these elements can be applied to categorize likely substrate use of fossil monkeys. The fossil primate communities of Hadar and Middle Ledi are reconstructed as significantly terrestrial. A. afarensis co-existed and evolved within a community of primates approaching similar body size who also spent a significant part of their time moving, and likely foraging, on the ground.