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Humble Origins

5-2_skrepnick_einiosaurus_p.jpg

© Michael W. Skrepnick

Einiosaurus.

Its skull doesn't have any horns, but Psittacosaurus is also a member of the same group as Triceratops and other horned dinosaurs. The very first ceratopsians did not have horns or frills and probably looked much like Psittacosaurus.

The elaborate skulls we associate with the horned dinosaurs were the products of millions of years of evolution. Over time, ceratopsians diversified into numerous species, each with a distinctive appearance: The three horns on Triceratops, the massive frill and dramatic spikes on Styracosaurus and the hooked nose horn on Einiosaurus.

Psittacosaur Beaks

Psittacosaurs don't have dramatic horns and frills like their larger close relatives. So for many years, scientists didn't realize these animals were part of the horned-dinosaur family. But only ceratopsians have a rostral bone, which formed the tip of the upper beak. Psittacosaurs have this unique feature and are therefore part of the ceratopsian family. These dinosaurs likely used their beaks to break off leaves and branches as they browsed for food.

A Diverse Family

Like species of African antelope, species of horned dinosaurs were closely related to each other yet looked very different. Such differences may have been important to mating rituals and could have been used by the animals to identify members of their own species.

Fast Facts: Psittacosaurus
  • Species: Psittacosaurus mongoliensis
  • Pronunciation: "sih-TACK-oh-sore-us mon-go-lee-EN-sis"
  • LENGTH: 130 centimeters (4 feet)
  • HEIGHT: 60 centimeters (2 feet)
  • Food: plants
  • When it lived: 100 million years ago
  • Fun fact: This dinosaur was named for its beak: Psittacosaurus means "parrot reptile."

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