Psittacosaurus

Psittacosaurus was a small, extraordinarily common basal ceratopsian that flourished across East Asia during the Early Cretaceous. Typically measuring between one and two metres in length, it was an agile biped with a parrot-like beak, flaring cheek horns, and powerful jaws capable of shearing tough seeds and stems. Over a thousand fossil specimens have been found, documenting every growth phase from newly hatched juveniles to fully grown adults. Exceptional discoveries from the Jehol Biota show soft-tissue details including countershaded camouflage colouring and a row of stiff, tubular quills lining the upper surface of its tail. As a primitive cousin of later horned giants like Triceratops, Psittacosaurus gives palaeontologists an unmatched glimpse into the early anatomy, ecology, and developmental biology of the horned dinosaur family tree.

One exquisitely preserved specimen possesses long bristly quills along the top of its tail.

Where and when

Psittacosaurus lived in the Early Cretaceous, from 126 to 101 million years ago (Barremian-Albian age). Its remains come from China and Mongolia and Russia, in the Yixian Formation.

The numbers

Length 1.8 m (estimates run from 1.5 to 2 m). Mass about 21 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.

Compare Psittacosaurus with a bus Place on the timeline