Dinosaurs A to Z
Ceratopsia

Psittacosaurus mongoliensis sih-TAK-oh-SOR-us

"Parrot lizard"

Psittacosaurus silhouette
You 1.8 m (5.9 ft) tall
Psittacosaurus 2 m (6.6 ft) long
as long as 2 people standing fingertip to fingertip
silhouette · Matthew Dempsey (CC-BY) via PhyloPic
Length
2 m (6.6 ft) — About 2 m long, ~20 kg — bipedal, parrot-beaked, with bristles on its tail.
Period
Early Cretaceous (125–100 Mya)
Place
Asia · China · Mongolia · Russia
Food
Herbivore — Tough plants and seeds, cracked by the parrot-like beak — likely the most abundant herbivore of its time.
Clade
Ceratopsia Dinosauria Ornithischia Cerapoda Marginocephalia Beaked, frilled herbivores. Most famous: Triceratops.

A parrot-beaked plant-eater so common it gave its name to a slice of Cretaceous Asia.

Psittacosaurus reconstruction by Nobu Tamura (http://spinops.blogspot.com)
Reconstruction · Nobu Tamura (http://spinops.blogspot.com) (CC-BY)

Psittacosaurus is one of the best-known dinosaurs because so many specimens have been found — over 400, ranging from hatchlings to adults. One spectacular Chinese specimen preserves the skin, gut contents, and even bristles on the tail. Color analysis of the skin shows the underside was lighter than the back — counter-shading like a modern deer.

More about Psittacosaurus

Discovery

Named by Henry Fairfield Osborn · 1924 · the Oshih (Khukhtek) Formation in the Artsa Bogdo Basin of Mongolia

During the American Museum of Natural History's Third Asiatic Expedition in 1922, the Mongolian chauffeur, Wong, found a nearly complete skull, jaws, and skeleton nicknamed the "Red Mesa skeleton." Osborn described the specimen in 1924 as Psittacosaurus mongoliensis.

The name means "parrot lizard," a reference to its short, deep skull and robust, parrot-like beak.

Henry Fairfield Osborn. An American paleontologist who took part in the AMNH Third Asiatic Expedition to Mongolia and who also named the family Psittacosauridae in 1923; he coined the name on the suggestion of fellow paleontologist William King Gregory.

Did Psittacosaurus have feather-like structures?
One individual was found preserved with long filaments on the tail, similar to those of Tianyulong. This single specimen hints at a bristle-like integumentThe body covering — skin, scales, feathers, or quills., though the text does not say how widespread such filaments were across the genus.
How smart and active was this little dinosaur?
Based on the proportions and relative size of its brain, Psittacosaurus probably had complex behaviours. It may have been active for short periods during both day and night, and appears to have had well-developed senses of smell and vision.

What we know

  • Over 400 specimens known — one of the best-sampled dinosaurs.
  • Bristles on the tail are clearly preserved on at least one specimen.
  • Skin color reconstructed: dark on top, light underneath (countershading).
  • Early ceratopsian — walked on two legs, unlike its later cousins.

What we guess

  • Function of the tail bristles — display, threat signaling, or both.
  • How young Psittacosaurus interacted with adults — some bonebeds suggest creches.
  • Why ceratopsians later went from bipedal (Psittacosaurus) to quadrupedal (Triceratops).