Callovosaurus

Type Species: Callovosaurus leedsi

Classification: Dinosauria – Ornithischia – Ornithopoda – Iguanodontia – Dryosauridae 

Time Period: Middle Jurassic

Location: Europe (England)

Diet: Herbivore 

The left thigh bone of the herbivorous ornithopod Callovosaurus was discovered in the Oxford Clay Formation in England. This formation represents the shallow sea that cut among the wooded islands of prehistoric England. This specimen was washed out to sea, where it was likely scavenged by marine reptiles, oceangoing crocodylomorphs, and sharks. Its bones were disarticulated, and its heavy left thigh bone was covered in sediment and became fossilized. Callovosaurus lived among the many islands of England, and as a small herbivore reaching only about eight feet in length, it would’ve browsed on low growing plants. It shared its ecosystem with the sauropod Cetiosauriscus, the stegosaur Lexovisaurus, and the early ankylosaurs Sarcolestes. It would’ve kept a wary eye out for the ten-foot-long theropod Proceratosaurus. Callovosaurus is considered one of the earliest iguanodontian dinosaurs, and many consider a basal iguanodontid. The clade Iguanodontia was an early classification in the dinosaur family tree, including such heavy-hitting ornithopods as Camptosaurus, Iguanodon, and Tenontosaurus, along with the ‘duck-billed’ dinosaurs. It was one of the most diverse and widespread dinosaur groups of the Cretaceous Period, but it got its start halfway through the Jurassic. Though Iguanodontia is considered an informal clade nowadays, as cladistics has advanced and morphed as it is wont to do, it is nevertheless used in regular parlance to refer to ornithopod dinosaurs of certain stripes.