Psittacosaurus facts for kids

Quick facts for kids Psittacosaurus Temporal range: Lower Cretaceous
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Superorder:	Dinosauria
Order:	Ornithischia
Suborder:	Cerapoda
Infraorder:	Ceratopsia
Family:	Psittacosauridae
Genus:	Psittacosaurus Osborn, 1923
Species
P. mongoliensis (type)      Osborn, 1923 P. sinensis      Young, 1958 P. meileyingensis      Sereno et al., 1988 P. xinjiangensis      Sereno & Zhao, 1988  ?P. sattayaraki      Buffetaut & Suteethorn, 1992 P. neimongoliensis      Russell & Zhao, 1996 P. ordosensis      Russell & Zhao, 1996 P. mazongshanensis      Xu, 1997  ?P. sibiricus      Voronkevich, 1998 P. lujiatunensis      Zhou et al., 2006
Synonyms
Protiguanodon  Osborn, 1923

Psittacosaurus was a small ceratopsian dinosaur from the Lower Cretaceous of what is now Asia, about 130 to 100 million years ago. It was notably more basal than other members of the Ceratopsia: it was bipedal, and had no horns or frill on its head. What made it a ceratopsian was its beak.

It is notable for being the most species-rich dinosaur genus. Nine to eleven species are recognized from fossils found in different regions of China, Mongolia and Russia, with a possible additional species from Thailand.

All species of Psittacosaurus were gazelle-sized bipedal herbivores with a high, powerful beak on the upper jaw. At least one species had long, quill-like structures on its tail and lower back, possibly with a display function. Psittacosaurs were extremely early ceratopsians and, while they developed many novel adaptations of their own, they also shared many features with later ceratopsians, such as Protoceratops and the elephant-sized Triceratops.

Description

Size comparison of P. mongoliensis to a human.

The species of Psittacosaurus vary in size and specific features of the skull and skeleton, but share the same overall body shape. The best-known—P. mongoliensis—can reach 2 metres (6.5 ft) in length. The maximum adult body weight was most likely over 20 kilogrammes (44 lb) in P. mongoliensis. Several species approach P. mongoliensis in size (P. lujiatunensis, P. neimongoliensis, P. xinjiangensis), while others are somewhat smaller (P. sinensis, P. meileyingensis). The smallest known species, P. ordosensis, is 30% smaller than P. mongoliensis. The largest are P. lujiatunensis and P. sibiricus, although neither is significantly larger than P. mongoliensis. Psittacosaurus postcranial skeletons are more typical of a 'generic' bipedal ornithischian. There are only four digits on the manus ('hand'), as opposed to the five found in most other ornithischians (including all other ceratopsians), while the four-toed hindfoot is very similar to many other small ornithischians.

Skeletal restoration of the P. mongoliensis holotype

The skull of Psittacosaurus is highly modified compared to other ornithischian dinosaurs of its time. Extremely tall in height and short in length, the skull has an almost round profile in some species. The portion in front of the orbit (eye socket) is only 40% of total skull length, shorter than any other known ornithischian. The lower jaws of psittacosaurs are characterised by a bulbous vertical ridge down the centre of each tooth. Both upper and lower jaws sport a pronounced beak, formed from the rostral and predentary bones, respectively. The bony core of the beak may have been sheathed in keratin to provide a sharp cutting surface for cropping plant material. As the generic name suggests, the short skull and beak superficially resemble those of modern parrots. Psittacosaurus skulls share several adaptations with more derived ceratopsians, such as the unique rostral bone at the tip of the upper jaw, and the flared jugal (cheek) bones. There is still no sign of the bony neck frill or prominent facial horns which would develop in later ceratopsians. Bony horns protrude from the skull of P. sibiricus, but these are thought to be an example of convergent evolution.

Images for kids

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  Holotype of P. mongoliensis (specimen AMNH 6254), American Museum of Natural History

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  Type skull of P. mongoliensis from Osborn, 1923

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  Restoration of P. sibiricus

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  P. meileyingensis fossil, Copenhagen Zoological Museum

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  Juveniles formerly described as Hongshanosaurus, Hong Kong Science Museum

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  Skeletal restoration of Psittacosaurus sp. SMF R 4970

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  Model based on SMF R 4970

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  Restored heads of eight species, to scale

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  Reconstructed skeletons of an adult with juveniles

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  P. sibiricus skull in front view

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  Mounted P. mongoliensis skeleton, Dinosaurium

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  P. lujiatunensis skull LHPV 1 from the left and above

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  Restoration of P. mongoliensis

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  P. mongoliensis specimen AMNH 6254 with gastroliths in its stomach region (arrow)

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  Mounted P. mongoliensis skeleton casts in upright and crouching poses

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  Skull of a hatchling P. mongoliensis, AMNH

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  Group of six juveniles that died together – specimen IVPP V14341

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  Cast of a six-year-old specimen associated with juveniles

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  Fossil of Repenomamus robustus, juvenile Psittacosaurus remains preserved in its stomach

See also

In Spanish: Psittacosaurus para niños