Thursday, April 26, 2012

[Paleontology • 2012] Yutyrannus huali 'feathered tyrant' • A gigantic feathered dinosaur from the Lower Cretaceous of China

 Numerous feathered dinosaur specimens have recently been recovered from the Middle–Upper Jurassic and Lower Cretaceous deposits of northeastern China, but most of them represent small animals1. Here we report the discovery of a gigantic new basal tyrannosauroid, Yutyrannus huali gen. et sp. nov., based on three nearly complete skeletons representing two distinct ontogenetic stages from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Y. huali shares some features, particularly of the cranium, with derived tyrannosauroids, but is similar to other basal tyrannosauroids in possessing a three-fingered manus and a typical theropod pes. Morphometric analysis suggests that Y. huali differed from tyrannosaurids in its growth strategy. Most significantly, Y. huali bears long filamentous feathers, thus providing direct evidence for the presence of extensively feathered gigantic dinosaurs and offering new insights into early feather evolution.

An artist's impression of a group of Yutyrannus, the largest known frathered dinosaur, and two smaller Beipiaosaurus, the previous record holder.
Illustration by Brian Choo via Nature

Figure 1: Yutyrannus huali (ZCDM V5000 and ZCDM V5001).

Figure 2: Selected elements of Y. huali (ZCDM V5000, ZCDM V5001 and ELDM V1001).

Figure 3: A simplified cladogram showing the systematic position of Y. huali among the Tyrannosauroidea.

Xu, X., Wang, K., Zhang, K., Ma, Q., Xing, L., Sullivan, C., Hu, D., Cheng, S., and Wang, S. 2012. A gigantic feathered dinosaur from the Lower Cretaceous of China. Nature.