The Cursoriality of Triassic Ornithodirans and Their Implications and Inferences for Early Ornithodiran Evolution

Abstract The phylogenetic placement of many Triassic Ornithodirans is convoluted and in need of more data for the best possible placement. Lagerpeptidae and Silesauridae are both under consideration for placement differing than their traditional setting in Dinosauromorpha. The cursoriality of many of these animals has never been assessed, and it could prove useful for further research. Measurements were taken for seventeen taxa from the literature and three types of cursoriality scores were constructed: tibial, third metatarsal, and lower leg length and then analyzed for significance. The scores add to the growing body of evidence placing Lagerpeptidae into Pterosauromorpha but fall short of any clear evidence regarding Silesauridae.