Post by Derdadort on Apr 3, 2014 14:35:50 GMT 5
Holotype of Sinotyrannus kazuoensis (by Conty under the Creative Commons Attribution 3.0 Unported license)
Classification
Dinosauria
Saurischia
Theropoda
Coelurosauria
Tyrannosauroidea
Proceratosauridae
Sinotyrannus
S. kazuoensis (Ji, 2009)
Fossilsite: Jiufotang Formation (China)
Age: ca. 125 to 120 mya (lower Cretaceous)
Holotype: KZV-001
Description
Sinotyrannus ("Chinese tyrant") was a genus of large tyrannosauroid dinosaurs from the lower Cretaceous of China (Jehol biota). The holotype and only known specimen of Sinotyrannus kazuoensis was first described by Ji et al. in 2009.
The holotype is very fragmentary, the remains include the anterior parts of the skull and the mandible, three dorsal vertebrae, some rips, a fragmentary illium, parts of the hand and some other incomplete bones.
The complete skull was approximately one metre long. Ji et al. estimate the length of the whole animal with nine to ten metres. However more current studies indicate a length of only six metres. If Ji's estimations are correct S. kazuoensis would be contrary to other proceratosaurids in the size range of the large tyrannosaurids from the upper Cretaceous.
Systematics
In their first description Ji et al. assumed Sinotyrannus could be an early member of Tyrannosauridae, current cladistic analysis put it in Proceratosauridae instead, a family of small to medium sized tyrannosauroids.
Cladogram after Loewe et al. (2013):
Sources:
- Ji Q, Ji S-A, Zhang L.J., "First large tyrannosauroid theropod from the Early Cretaceous Jehol Biota in northeastern China", Geological Bulletin of China, 2009, 28(10):1369-1374: d.yimg.com/kq/groups/1225428/375768469/name/20091001.pdf
- Loewen MA, Irmis RB, Sertich JJW, Currie PJ, Sampson SD: Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans. In: PLoS ONE. 8, Nr. 11, 2013, S. e79420: 10.1371/journal.pone.0079420
- Thomas R. Holtz: HoltzappendixWinter2011.png