Scelidosaurus harrisonii (Owen 1859, 1861) Early Jurassic ~200 mya, ~ 4 m in length was a basal ornithischian derived from a sister to Daemonosaurus and was a sister to Heterodontosaurus.
Distinct from Daemonosaurus, the skull of Scelidosaurus had more robust elements. The teeth were smaller and more suited to plant-eating. The antorbital fenestra was reduced. The mandibular fenestra was nearly sealed. The mandible was deeper.
Postcranially distinct from Pampadromaeus, the cervicals were shorter, the torso was deeper, the neural spines were taller, the tail was more robust. Scutes lined the torso and tail.
The forelimbs were more robust and longer. The ilium was longer. The pubis (unknown in Pampadromaeus, was rotated posteriorly to make room for a larger gut. The femur was shorter relative to the tibia.