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Hominid radius from the middle Pliocene of Lake Turkana, Kenya
Author(s) -
Heinrich R. E.,
Rose M. D.,
Leakey R. E.,
Walker A. C.
Publication year - 1993
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.1330920203
Subject(s) - geology , anatomy , paleontology , crest , lunate , wrist , biology , physics , quantum mechanics
A nearly complete left radius, KNM‐ER 20419, was recovered from middle Pliocene sediments east of Lake Turkana, Kenya in 1988. Ape‐like characteristics of the fossil include an eccentrically positioned articular fovea, relatively long radial neck, wide distal metaphysis, and large brachioradialis crest. The robustness of the radial neck in proportion to the radial head, and the semilunar shape of the distal diaphysis, however, clearly distinguish KNM‐ER 20419 as hominid. The distal articular surface possesses a larger area for radius‐lunate articulation than for radius and scaphoid, a radiocarpal arrangement that is associated with increased wrist adduction among quadrumanous climbers. Since this morphology is also found in hylobatids, Pongo , and other early australopithecines, it is argued to be plesiomorphic for hominoids. This further supports the argument that vertical climbing was an important locomotor behavior among both early hominoids and our more immediate prebipedal ancestors. © 1993 Wiley‐Liss, Inc.