Wednesday, February 08, 2006

Meet the "crowned dragon"

Abstract: The tyrannosauroid fossil record is mainly restricted to Cretaceous sediments of Laurasia, although some very fragmentary Jurassic specimens have been referred to this group. Here we report a new basal tyrannosauroid, Guanlong wucaii gen. et sp. nov., from the lower Upper Jurassic of the Junggar Basin, northwestern China. G. wucaii is the oldest known tyrannosauroid and shows several unexpectedly primitive pelvic features.

Nevertheless, the limbs of G. wucaii share several features with derived coelurosaurs, and it possesses features shared by other coelurosaurian clades. This unusual combination of character states provides an insight into the poorly known early radiation of the Coelurosauria.

Notably, the presumed predatory Guanlong has a large, fragile and highly pneumatic cranial crest that is among the most elaborate known in any non-avian dinosaur and could be comparable to some classical exaggerated ornamental traits among vertebrates.

Theropoda Marsh, 1881
Coelurosauria von Huene, 1914
Tyrannosauroidea Osborn, 1905
Guanlong wucaii gen. et sp. nov.

Etymology. The generic name is derived from the Chinese Guan (crown) and long (dragon); the specific name is from the Chinese wucai (five colours), which refers to the rich colours of rocks that produced the specimens.

Holotype. IVPP (Institute of Vertebrate Paleontology and Paleoanthropology, Beijing) V14531 is a partly articulated skeleton preserving most of the elements.

Referred material. IVPP V14532 is much smaller than the holotype and is a fully articulated, nearly complete skeleton.

Locality and horizon. Wucaiwan area, Junggar Basin, Xinjiang; Oxfordian upper part of the Shishugou Formation.

Xing Xu, James M. Clark, Catherine A. Forster, Mark A. Norell, Gregory M. Erickson, David A. Eberth, Chengkai Jia and Qi Zhao. (2006). A basal tyrannosauroid dinosaur from the Late Jurassic of China. Nature 439: 715-718

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