Callovosaurus

Callovosaurus was a nimble, bipedal herbivorous dinosaur that lived in what is now England during the Middle Jurassic period. It is primarily known from a well-preserved partial left femur discovered in the marine mudstones of the Oxford Clay Formation near Peterborough. Although originally attributed to the genus Camptosaurus by Richard Lydekker, re-examination by Peter Galton in 1980 established it as a distinct genus, and subsequent analyses identified it as the earliest known representative of the family Dryosauridae. Measuring an estimated two and a half to three and a half metres in length, Callovosaurus was slender and built for swift bipedal sprinting. Its presence in marine strata indicates that its carcass was washed out to sea from a nearby forested landmass, where it grazed on ferns, cycads, and other low-growing Jurassic flora.

It is widely recognised as the oldest known member of the dryosaurid ornithopod family.

Where and when

Callovosaurus lived in the Middle Jurassic, from 166 to 163.5 million years ago (Callovian age). Its remains come from United Kingdom, in the Oxford Clay Formation.

The numbers

Length 3 m (estimates run from 2.5 to 3.5 m). Mass about 77 kg. Hip height about 1 m. That is 1.8 human-lengths, or 0.27 of a double-decker bus. These are estimates from fragmentary remains; fields marked estimated by the site are length, mass, hip height.

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