Morphometric analysis of humerus and femur shape in Morrison sauropods: implications for functional morphology and paleobiology

Abstract

Abstract Morphometric analyses of sauropod limbs have the potential to illuminate functional aspects of sauropod locomotion and paleobiology. However, analyses of sauropod limb dimensions typically show few discernible morphological trends because of large size differences among the individuals in a sample. For sauropods, combined analyses of both limb dimension and shape may be more desirable. Numerous humeri and femora from Apatosaurus, Diplodocus, and Camarasaurus provide an opportunity to explore and compare limb morphology in contemporaneous, sympatric sauropods. Thin-plate splines were used to analyze landmark-based shape differences in combination with traditional morphometrics. The aims of the analysis were (1) to determine if humerus and femur shape were significantly different among the genera; (2) to determine where shape changes occurred; and (3) to infer the basic functional implications of the shape differences using an Extant Phylogenetic Bracket approach. Few differences were detected amon...