Evolutionary convergence in a small cursorial styracosternan ornithopod dinosaur from western Europe

A metatarsal IV from a hitherto unknown endemic small-bodied styracosternan is described uppermost Maastrichtian strata of NE Spain, part the Ibero-Armorican island Late Cretaceous European Archipelago. This element unique among fourth metatarsals all other ornithopods in combining greatly elongated proportions basally branching members clade with prominent medial flange seen styracosternans. specimen becomes holotype new genus and species. Histological data indicate that this individual was late subadult at time death, but not far reaching somatic maturity. By analogy elongate lightly built, cursorial ornithopods, it likely animal also capable rapid locomotion. consistent differential distribution intense bone remodeling IV, resulting biomechanical stress produced during hindlimb propelling. Notably, represents an exception to mediportality large body size characterize clade. The elongation inferred cursoriality, small constitute case evolutionary convergence distantly related non-iguanodontian dryosaurid elasmarian iguanodontians. Unlike regions world where, latest stages Cretaceous, herbivore ecological niche represented by non-iguanodontians non-hadrosauriforms, occupied styracosternan.