Scelidosaurus

Scelidosaurus (; with the intended meaning of "limb lizard", from Greek skelis/σκελίς meaning 'rib of beef' and sauros/σαυρος meaning 'lizard') is a genus of herbivorous armoured ornithischian dinosaur from the Jurassic of England. Scelidosaurus lived during the Early Jurassic epoch, during the Sinemurian to Pliensbachian ages around 191 million years ago, at the time when Europe formed an island archipelago. Its fossils have been found in the Charmouth Mudstone Formation near Charmouth in Dorset, England, and these fossils are known for their excellent preservation. Scelidosaurus has been claimed as one of the earliest complete dinosaurs, and is among the most completely known dinosaur of the British Isles. Despite this, a modern description only materialised in 2020. After initial finds in the 1850s, comparative anatomist Richard Owen named and described Scelidosaurus in 1859. Only one species, Scelidosaurus harrisonii named by Owen in 1861, is considered valid today, although one other species was proposed in 1996. Scelidosaurus was about 4 metres (13 ft) long. It was a largely quadrupedal animal, feeding on low scrubby plants, the parts of which were bitten off by the small, elongated head to be processed in the large gut. Scelidosaurus was lightly armoured, protected by long horizontal rows of keeled oval scutes that stretched along the neck, back and tail. One of the oldest known and most "primitive" of the thyreophorans, the exact placement of Scelidosaurus within this group has been the subject of debate for nearly 150 years. This was not helped by the limited additional knowledge about the early evolution of armoured dinosaurs. Today most evidence suggests that Scelidosaurus is the most derived of the known basal thyreophorans, either closely related to Ankylosauria or Stegosauria+Ankylosauria.