FUNCTIONAL OSTEOLOGY OF THE PRIMATE CARPUS WITH SPECIAL REFERENCE TO STREPSIRHINI

Preuschoft et al. ([1993] in H. Preuschoft and D. Chivers (eds.): Hand s of Primates. New York: Springer-Verlag, pp. 245-256) used a theoreti cal biomechanical analysis to generate several predictions relating su bordinal differences in primate hand proportions to differences in car pal morphology. This study tests these predictions using quantitative analyses of carpal morphology between extant haplorhine and strepsirhi ne primates. Results show that living strepsirhines have a significant ly larger hamate hamulus than do haplorhines, supporting Preuschoft et al.'s (1993) predictions. Extant strepsirhines also have a significan tly shorter pisiform body than do haplorhines and arboreal nonprimate eutherians and a larger scaphoid tubercle than New and Old World monke ys. These results contrast markedly with those expected under Preuscho ft et al.'s (1993) model. Furthermore, strepsirhines and haplorhines d o not differ significantly in the relative size of their radiocarpal a rticulations. These morphometric observations do not match the predict ed morphological patterns because the kinematic assumptions upon which the biomechanical models are based are incorrect. Living strepsirhine s appear to be derived in having very deep radial and ulnar margins of the carpal tunnel for well-developed extrinsic digital flexors. Moreo ver, tooth-combed prosimians differ from most haplorhines, early Terti ary adapiforms, and arboreal nonprimate eutherians in having a relativ ely short pisiform body, which gives the flexor carpi ulnaris less pow er to flex the wrist from extended (= dorsiflexed) positions. These st ructural observations suggest that powerful manual grasping and an emp hasis on leaping and climbing, rather than palmigrade quadrupedal walk ing and running, are morphotypic for extant Strepsirhini. (C) 1997 Wil ey-Liss, Inc.