Psittacosaurus

Psittacosaurus (meaning “parrot lizard”) is a genus of small, early ceratopsian dinosaurs that lived during the Early Cretaceous period, roughly 126 to 100 million years ago. Fossils are primarily found in Asia, including China and Mongolia. It is one of the best-known early ceratopsians and provides important insights into the origin and early evolution of the group. The type species is Psittacosaurus mongoliensis, and multiple additional species have been described from Asia, though taxonomic opinions vary.

Psittacosaurus was relatively small, with adult lengths around about 1 meter (some individuals larger) and a body weight likely in the tens of kilograms. It had a beak-like, parrot-shaped rostrum and robust cheek teeth adapted for processing vegetation. The limbs suggest a predominantly bipedal gait in younger individuals, with some adults capable of quadrupedal locomotion while feeding. The tail was long, and the animal lacked the large horns and ornate frill seen in later ceratopsians.

The genus is notable for its well-preserved fossils, including juveniles, which allow study of growth and development. Some specimens preserve skin impressions, including bristle-like integument along the tail, implying that Psittacosaurus may have possessed primitive feather-like structures. As a basal ceratopsian, Psittacosaurus helps illuminate the early evolutionary steps that led to the later ceratopsians, including changes in locomotion, dentition, and display features.