The morphology of Oreopithecus bambolii pollical distal phalanx

Authors

  • Sergio Almécija,

    Corresponding author
    1. Department of Anatomical Sciences, Stony Brook University School of Medicine, Stony Brook, NY
    2. Department of Vertebrate Paleontology, American Museum of Natural History and NYCEP, New York, NY
    3. Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Barcelona, Spain
    • Correspondence to: Sergio Almécija, Department of Anatomical Sciences, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA. E-mail: sergio.almecija@stonybrook.edu

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  • Marvin Shrewsbury,

    1. Wailuku, HI
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  • Lorenzo Rook,

    1. Dipartimento di Scienze della Terra, Università di Firenze, Firenze, Italy
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  • Salvador Moyà-Solà

    1. ICREA at Institut Català de Paleontologia Miquel Crusafont and Unitat d'Antropologia Biològica (Dept. BABVE), Universitat Autònoma de Barcelona, Barcelona, Spain
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ABSTRACT

Oreopithecus bambolii is a Late Miocene ape from Italy, first described in the late 19th century. Its interpretation is still highly controversial, especially in reference to its hand proportions and thumb morphology. In this study, the authors provide detailed descriptions of the available Oreopithecus pollical distal phalanx (PDP) specimens, as well as bivariate and multivariate morphometric analyses in comparison with humans, extant apes, selected anthropoid monkeys, and available Miocene PDP specimens. The multivariate results reveal two opposite poles on the hominoid PDP shape spectrum: on one side, a mediolaterally broad and dorsopalmarly short human PDP, and on the other side, the narrow and “conical” PDP of chimpanzees and orangutans. The authors contend that Oreopithecus exhibits intermediate PDP proportions that are largely primitive for hominoids because it shares morphological similarities with Proconsul. Furthermore, Oreopithecus displays a mediolaterally wide tuft for a hominoid, as well as a palmarly elevated attachment for a long tendon of a flexor muscle that is associated at its proximal edge with a proximal fossa and at its distal edge with an ungual fossa. These nonmetrical traits have been associated in humans with their capability to oppose and contact the proximal pads of the thumb and fingers, that is, pad-to-pad precision grasping. These traits reinforce previous studies that indicate a human-like thumb-to-hand length ratio compatible with pad-to-pad precision grasping in Oreopithecus. Although specific hand use is still unresolved in Oreopithecus, the results suggest enhanced manipulative skills (unrelated to stone tool-making) in this taxon relative to other (extant or fossil) hominoids. Am J Phys Anthropol 153:582–597, 2014. © 2014 Wiley Periodicals, Inc.

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