Sinotyrannus Temporal range: Early Cretaceous,
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Skeletal diagram of Sinotyrannus based on Yutyrannus and other proceratosaurids | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | †Proceratosauridae |
Genus: | †Sinotyrannus Ji et al., 2009 |
Type species | |
†Sinotyrannus kazuoensis Ji et al., 2009
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Sinotyrannus (meaning “Chinese tyrant”) was an early, large-bodied genus within the superfamily Tyrannosauroidea.[1] This dinosaur had a single type species, S. kazuoensis, with the only known specimen containing a partial skull, some vertebrae, and a hip,[2] all of which were found in the Early Cretaceous aged Jiufotang Formation of Liaoning, China. While it exhibited greater body size that would put it on par with the later tyrannosaurids such as Tyrannosaurus (a group that Sinotyrannus was initially suspected of being in), Sinotyrannus was probably a member of the basal tyrannosaur family known as the Proceratosauridae. This family originated in the Jurassic, whose members are known from Europe and Asia. Sinotyrannus, alongside another early tyrannosaur, Yutyrannus, appears to have been oddly large when compared to most tyrannosaurs of the Early Cretaceous, such as Dilong. Most of the world during the Early Cretaceous was dominated by more basal tetanurans, such as the megalosaurs and allosaurs, with tyrannosaurids themselves only taking over after both groups started to decline. However, Sinotyrannus and Yutyrannus appear to be exceptions to this. Sinotyrannus was the largest theropod in the Jiufotang Formation, reaching up to 10 meters (32.8 ft) in overall length and having a general mass similar to that of a large rhino.[3]
This animal was quite likely an active predator, as has been speculated for most tyrannosaurs, and may have been covered in a simple feathery coat as was the case with most basal coelurosaurs, including many early tyrannosaurs.[4] Sinotyrannus lived in a rather wet environment with well-watered forests and large lakes. The area experienced great diversity in terms of vertebrate fauna, with many taxa, such as Microraptor, living alongside Sinotyrannus. Despite this, the area was quite prone to high volcanism.[5] S. kazuoensis, was described by Ji et al. in 2009.[2]