DEDUCING THE BODY POSTURE OF EXTINCT LARGE VERTEBRATES FROM THE SHAPEOF THE VERTEBRAL COLUMN

Simple measurements were taken from the vertebral column of several ex tinct and extant terrestrial vertebrates in order to estimate the bend ing moments in a sagittal plane that could be sustained along the long itudinal body axis. According to theoretical expectations, the estimat ed patterns of sustainable bending moments prove to differ between bip eds and quadrupeds of different body proportions. In an analysis of th e vertebral column of the dinosaurs Plateosaurus and Iguanodon, the fo rmer appears as a habitual quadruped, while the latter must have assum ed a bipedal posture more frequently or carried most weight on the hin dlimbs during quadrupedal locomotion. A separate analysis of the cross sectional areas of the vertebral centra and the lever arms of the epa xial muscles gives further information on the use of the vertebral col umn during locomotion and reveals aspects of the ecology of the animal s under study.