Sinornithosaurus

Say it like this: “SIEN-or-nith-o-SAWR-us”

Sinornithosaurus millenii

Sinornithosaurus ate meat and walked on two legs. It lived in the Early Cretaceous. Bones have been found in China.

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When: Early Cretaceous (Barremian) · roughly 125.8 to 121.4 million years ago
Named in: 1999 · Xu, X.; Wang, X. L.; Wu, X. C.
Hip height: Not established
Length: 1.2 m · 4 ft
Weight: 3–5 kg · 7–11 lb
Found in: China · Yixian
Food and walking: Carnivore · Two legs
Kind: sharp-clawed runner · Theropod
Family branch: Microraptorinae

The story in short

Sinornithosaurus was formally named in 1999 by X. Xu and colleagues. The name means “chinese bird-lizard.”

Fossils referred to Sinornithosaurus date to the Early Cretaceous (Barremian), roughly 125.8 to 121.4 million years ago. Finds come from China, including the Yixian Formation. It was a carnivore and walked on two legs.

Published estimates put Sinornithosaurus at a length near 1.2 m and a body mass around 3–5 kg.

On the family tree it sits in Microraptorinae, among the theropod dinosaurs.

Close relatives

Changyuraptor

Changyuraptor yangi

Early Cretaceous (Barremian) · roughly 125.8 to 121.4 million years ago

Graciliraptor

Graciliraptor lujiatunensis

Early Cretaceous (Barremian) · roughly 125.8 to 121.4 million years ago

Hesperonychus

Hesperonychus elizabethae

Late Cretaceous (Campanian) · roughly 83.6 to 72.2 million years ago