A small theropod dinosaur from the Lower Jurassic Lias Group of Charmouth, Dorset

Abstract

Terrestrial reptile remains are rare in Early Jurassic deposits from the UK but include important records of early dinosaurs and pterosaurs. Here we report an isolated limb bone from the Charmouth Mudstone Formation (upper Sinemurian) of Charmouth, Dorset that was previously misidentified as a referred specimen of the pterosaur Dimorphodon macronyx. Comparisons with other Early Jurassic tetrapods indicate that this element is the fibula of a neotheropod dinosaur, representing one of only a handful of theropod remains from the Lias Group. Although the material is limited the fibula is distinct from other penecontemporaneous European theropods and might represent a new – though currently undiagnosable – taxon. This, alongside other isolated discoveries, indicates that there might have been a higher diversity of theropod taxa in the Early Jurassic of Europe than is generally appreciated.