Open AccessEvolution of the biomechanical material properties of the femur
Author(s) -
Erickson Gregory M.,
Catanese Joseph,
Keaveny Tony M.
Publication year - 2002
Publication title -
the anatomical record
Language(s) - English
Resource type - Journals
eISSN - 1097-0185
pISSN - 0003-276X
DOI - 10.1002/ar.10145
Subject(s) - biology , context (archaeology) , clade , evolutionary biology , phylogenetic tree , femur , convergent evolution , vertebrate , phylogenetic comparative methods , character evolution , anatomy , genetics , paleontology , gene
The biomechanical performance of long bones is dictated by four key factors: element size, element shape, loading conditions, and material properties. Our understanding of the latter of these has been mostly limited to eutherian mammals and birds, which show similarity. Whether their possession of comparable material properties reflects common ancestry or independent evolution is uncertain. In the present analysis, we tested the bending strength, modulus, and failure strains of the femur and its pterygiophore homolog in actinpterygian fish. Sixty‐nine specimens representing basal character states in seven major vertebrate crown clades were tested. These data were then coupled with avian and mammalian data from the literature and analyzed in an evolutionary context using phylogenetic character analysis. Mean values of 188 MPa for yield strength, 22.4 GPa for Young's modulus, and 8,437 μ∈ for yield strain were obtained for the long bones. Analysis of variance (ANOVA) revealed comparable values between clades that span a 30,000‐fold range of body mass. We conclude that material properties of the first long bones 475 million years ago were conserved throughout evolution. Major locomotory challenges to femora during vertebrate evolution were almost solely accomplished by modifications of element size and shape. Anat Rec 268:115–124, 2002. © 2002 Wiley‐Liss, Inc.