A revision of the non-avian dinosaurs ‘Eucercosaurus tanyspondylus’ and ‘Syngonosaurus macrocercus’ from the Cambridge Greensand, UK

The Cambridge Greensand Member (lower Cenomanian: Upper Cretaceous) has yielded a diverse fauna of terrestrial and marine tetrapods, whose remains are largely reworked from the underlying Gault Formation (upper Albian: Lower Cretaceous). Here, we re-describe two non-avian dinosaur taxa named this unit, ‘Eucercosaurus tanyspondylus’ Seeley, 1879 ‘Syngonosaurus macrocercus’ 1879, both which have been referred to as either ankylosaurs or ornithopods but validity not rigorously assessed for over century. Both interpreted iguanodontian dinosaurs possess no clear diagnostic features. Nevertheless, although ‘Eucercosaurus’ ‘Syngonosaurus’ nomina dubia they do indicate that iguanodontians were common components tetrapod and, alongside ‘Trachodon cantabrigiensis’ Lydekker, 1888, represent an important datum understanding distributions during mid-Cretaceous.