Dinosaurs / Cretaceous / Hypsilophodon
Hypsilophodon
Cretaceous hip-sih-LOFF-oh-don, “high-ridged tooth”
Hypsilophodon was a small, agile herbivorous dinosaur from the Early Cretaceous of southern England. Measuring around two metres from snout to tail and weighing only twenty kilograms, it was roughly the size of a modern sheep. Historically, early twentieth-century researchers envisioned it as an arboreal creature living in trees, but modern anatomical work confirmed it was an exceptional ground runner with long shins, slender toes, and a tail stiffened by ossified tendons to provide balance during sharp turns. Hypsilophodon fed on low-growing vegetation such as ferns and shoots, slicing plant matter with its delicate beak and self-sharpening cheek teeth. Its fossils are remarkably abundant in the Wessex Formation on the Isle of Wight, where dozens of complete or near-complete skeletons have been collected from a specific geological horizon known as the Hypsilophodon Bed.
Early palaeontologists mistakenly thought its long toes enabled it to climb trees like a tree kangaroo.
Where and when
Hypsilophodon lived in the Early Cretaceous, from 130 to 125 million years ago (Barremian age). Its remains come from United Kingdom, in the Wessex Formation.
The numbers
Length 1.8 m (estimates run from 1.5 to 2 m). Mass about 19 kg. Hip height about 0.6 m. That is 1.1 human-lengths, or 0.16 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.