| Diet | Herbivore |
| Height | 1.5m |
| Length | 4m |
| Weight | 1.5 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Early Cretaceous |
| Type | Other |
| Location | England |
Regnosaurus was a herbivorous dinosaur that lived during the Early Cretaceous period, approximately 137 million years ago. This mysterious creature is known from a single partial jaw bone discovered in the Wealden Formation of Sussex, England, making it one of the more enigmatic dinosaurs from British fossil deposits.
Originally classified as a stegosaur and thought to be related to the Chinese Huayangosaurus, Regnosaurus has since become the subject of considerable scientific debate. Modern research suggests it was likely an armoured thyreophoran dinosaur, though its exact relationships remain unclear due to the limited fossil evidence. The creature would have been a quadrupedal plant-eater, estimated to measure around 4 metres in length and standing approximately 1.5 metres tall at the hip.
Living in the lush, subtropical environment of Early Cretaceous England, Regnosaurus shared its habitat with other dinosaurs including Iguanodon and various smaller theropods. As a herbivore, it would have fed on the abundant ferns, cycads, and early flowering plants that dominated the landscape. The partial jaw bone suggests it had teeth adapted for processing tough plant material, typical of armoured dinosaurs of this period.
Despite being one of the earliest dinosaurs discovered in Britain, Regnosaurus remains poorly understood, highlighting how much we still have to learn about dinosaur diversity during the Cretaceous period in Europe.
Regnosaurus is distinguished primarily by its partial jaw bone, which shows characteristics suggesting it was an armoured thyreophoran dinosaur. The jaw structure indicates adaptations for herbivorous feeding, with teeth designed for processing plant material.
Based on its classification as a thyreophoran, Regnosaurus likely moved slowly on four legs, using its presumed armoured body as defence against predators. It would have spent much of its time feeding on low-growing vegetation, using its specialised teeth to process tough plant fibres.
Regnosaurus was first described by Gideon Mantell in 1848. The original fossils were discovered at Wealden Formation, Sussex, England.
