Evidence of hominid-like precision grip capability in the hand of the Miocene ape Oreopithecus
- *Institut de Paleontologia M. Crusafont, c/Escola Industrial, 23, 08201 Sabadell, Barcelona, Spain; and ‡Dipartimento di Scienze della Terra and Museo di Geologia e Paleontologia, Universita di Firenze, Via G. La Pira 4, 50121 Firenze, Italy
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Communicated by David Pilbeam, Harvard University, Cambridge, MA (received for review June 25, 1998)
Abstract
Functional and allometric analyses of the hand of the late Miocene ape Oreopithecus bambolii (Tuscany, Italy) reveal a series of features that reflect an improved grasping capability including firm pad-to-pad precision gripping that apes are unable to perform. Related features such as hand length, relative thumb length, a deep and large insertion area for the tendon of the long thumb flexor, and the form of the metacarpal 2/capitate articulation are not present in extant or fossil apes. In these features, the Oreopithecus hand closely matches the pattern of early hominids, presumably as a response to similar functional demands.
Footnotes
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↵ † To whom reprint requests should be addressed.
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↵ § In this study, we use the term “human-like precision grip,” based on the classic definition proposed by Napier (1) and the recently expanded definition of Cristel (3) as far as it is applicable to our material. Thus, in this study the term “precision grip” refers to every type of grip that involves thumb and one or more fingers for fine manipulations, but without applying force. The term “human-like precision grip” refers to the pad-to-pad grip that apes are not able to perform. This capability is determined by morphology and the size relationships of the components of the thumb. “Power grip” is the firm pinching of large objects by using the full or partial volar surface of the hand. This grip depends on the stability and probably on the robusticity of the hand as a whole (21) and is not a subject of this study.
- Copyright © 1999, The National Academy of Sciences
