This dinosaur which spent most of its time standing on its two hind legs is thought to have been near the ancestry of the horned dinosaurs (neoceratopsians), which include such well known forms as Triceratops .
The generic name for this dinosaur, Psittacosaurus , means the 'parrot-like lizard' in reference to its prominent parrot-like beak. This feature was one of the principal advances of this form from the generalised bipedal fabrosaurids and hypsilophodontids that gave rise to it.
Psittacosaurus was the first step on the path towards the four-footed, horned descendants that were to appear more than twenty millions years later. It had a special bone called the rostral, found in the horned dinosaurs, even though in many ways, such as in the construction of its teeth, it is still very similar to hypsilophodonts in a way.
Psittacosaurus is a missing link between two large groups of dinosaurs!
Psittacosaurus was one of the most common dinosaurs in the Early Cretaceous collections from Mongolia sometimes making up over 90% of all the dinosaur bones found, most frequently in lake and stream deposits.
Psittacosaurus was a plant eater with leaf-shaped teeth that sliced past one another like the blades of scissors. It must have grabbed plants with its parrot-like beak, chopped them up, and then smashed them up with gizzard stones, which have been found inside the body cavity of some skeletons of this little dinosaur.