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Horny old dinosaur found

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21.03.2002

Liaoceratops was about the size of a large dog.
© Nature

Knee-high relative of Triceratops unearthed.

The fearsome horns and bony neck plates of Triceratops have scared generations of kids. Now fossil finds reveal that its predecessor was a little more huggable: it was a dog-sized creature with a beak.

Triceratops is the most famous member of the late ceratopsians, which were rhinoceros-like dinosaurs with horns. Little is known about the early evolution of this large and varied group of plant-eaters because their fossils are scarce.

Now the oldest ceratopsian ever found has been uncovered in China. Unlike its daunting relative, Liaoceratops was about the size of a large dog. It had a blunt beak and a dainty neck frill¹.

"He’s like a precursor to Triceratops," explains palaeontologist Cathy Forster of the State University of New York. Liaoceratops may also have walked on hind legs, she speculates, whereas later family members lumbered on four.

The creature sorts out some details of ceratopsian evolution. The original group split into two - beaked psittacosaurids and horned neoceratopsians - but it is not clear exactly when. is a neoceratopsian, which dates the split to before his birthday, roughly 120-145 million years ago.

Liaoceratops has a mix of subtle features previously thought to belong to one group or the other. "He fills the gap between the two," says his discoverer, Xing Xu of the Chinese Academy of Sciences in Beijing. The sequence in which such characteristics appeared now has to be re-ordered, a common process when new specimens are found.

Horns and frills

Xu and his team found Liaoceratops skulls and skeletons in the Yixian formation, a rich fossil bed in northeast China.

Liaoceratops was a puny forebear of the feisty Triceratops. Size, horns and spectacular frills came later in ceratopsian evolution. By the time the dinosaurs became extinct at the end of the Cretaceous period around 65 million years ago, Triceratops could take on the mighty Tyrannosoarus.

The flamboyant accoutrements of ceratopsians have led people to wonder about their function. Some think they were for protection, others for show. Those on Liaoceratops seem to have a practical explanation: the small neck frill appears to be for muscle attachment.

References

1. Xu, X. et al. A ceratopsian dinosaur from China and the early evolution of Ceratopsia. Nature, 416, 314 - 317, (2002).