Acta Zoologica Cracoviensia, 39(1) 1996

Issue:

VOL 39(1) 1996

Keywords:

Ursidae, Quaternary, biomechanics, femur, cross-sectional morphology

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Femoral morphology of some Quaternary bears

• Günter Karl KUNST

Abstract:

Cross-sectional geometric properties (areas, second moments of area) of ursid femoral diaphyses were calculated using formulae for a hollow ellipse. Inner bone contours were obtained from biplanar radiographs. The species included are Ursus spelaeus, Ursus arctos, Ursus deningeri and Ursus sp. from Deutsch-Altenburg 4B. Midshaft femoral bending rigidity is markedly increased in the mediolateral plane in U. spelaeus, while it is more equally distributed in U. arctos. This relationship is not correlated with size. The Early and Middle Pleistocene species investigated exhibit intermediate properties. Along with other skeletal traits, femoral cross-sectional shape in U. spelaeus is interpreted as being indicative of a limb structure designed primarily for static stability.