title: Estimating thumb-index finger precision grip and manipulation potential in extant and fossil primates.
abstract: Primates, and particularly humans, are characterized by superior manual dexterity compared with other mammals. However, drawing the biomechanical link between hand morphology/behaviour and functional capabilities in non-human primates and fossil taxa has been challenging. We present a kinematic model of thumb-index precision grip and manipulative movement based on bony hand morphology in a broad sample of extant primates and fossil hominins. The model reveals that both joint mobility and digit proportions (scaled to hand size) are critical for determining precision grip and manipulation potential, but that having either a long thumb or great joint mobility alone does not necessarily yield high precision manipulation. The results suggest even the oldest available fossil hominins may have shared comparable precision grip manipulation with modern humans. In particular, the predicted human-like precision manipulation of Australopithecus afarensis, approximately one million years before the first stone tools, supports controversial archaeological evidence of tool-use in this taxon.
authors: Department of Mechanical Engineering and Materials Science, Yale University, 9 Hillhouse Avenue, New Haven, CT 06511, USA thomas.feix@yale.edu.
authors: Thomas
authors: T
authors: Feix
authors: Animal Postcranial Evolution Laboratory, School of Anthropology and Conservation, University of Kent, Marlowe Building, Canterbury CT2 7NR, UK Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany.
authors: Tracy L
authors: TL
authors: Kivell
authors: Département d'Ecologie et de Gestion de la Biodiversité, UMR 7179 CNRS/MNHN, 57 rue Cuvier, Case postale 55, 75231 Paris Cedex 5, France.
authors: Emmanuelle
authors: E
authors: Pouydebat
authors: Department of Mechanical Engineering and Materials Science, Yale University, 9 Hillhouse Avenue, New Haven, CT 06511, USA.
authors: Aaron M
authors: AM
authors: Dollar
mesh_terms: D000818:Animals; D003198:Computer Simulation; D005384:Finger Joint / Q000033:anatomy & histology / Q000502:physiology*; D005385:Fingers / Q000033:anatomy & histology / Q000502:physiology*; D005580:Fossils / Q000033:anatomy & histology; D018737:Hand Strength / Q000502:physiology*; D008954:Models, Biological; D009048:Motor Skills / Q000502:physiology*; D011323:Primates / Q000033:anatomy & histology / Q000502:physiology*; D016059:Range of Motion, Articular
keywords: Australopithecus; Neanderthal; grasping; kinematic model; manipulation; primates