Guanlong: Prehistoric Animal of the Week

Guanlong wucaii was a meat-eating dinosaur that lived in what is now China during the Late Jurassic Period, 160 million years ago.  It measured about ten feet long from snout to tail and would have sported feathers in life.  The genus name, Guanlong, is Chinese for "crested dragon" in reference to the animal's bony crest and the fact that dinosaurs are commonly referred to as dragons in China.  ("long" is basically the Chinese equivalent of "saurus".)  The species name, wucaii, translates to "five colors" in reference to the multi-colored rock formations where this dinosaur's remains were unearthed.

Life reconstruction of Guanlong wucaii by Christopher DiPiazza.  It appears as if he is looking for something...but what?

Guanlong became very popular when it was first discovered in 2006 because of where scientists believe it is placed on the dinosaur family tree.  At first Guanlong is pretty unique looking.  It was small for a dinosaur, and had long arms with three fingers with curved claws on each hand.  Its head was adorned with a flat oval-shaped crest that ran from its nose to just before its eyes.  The crest was too thin to have been a weapon and was likely a display adaptation within the species.  When scientists examined the teeth of Guanlong, they realized that this dinosaur was actually a kind of tyrannosauroid, and thus the earliest known relative of the famous Tyrannosaurus.  Tyrannosaurid teeth are more curved and D-shaped than those of other theropods.  Guanlong shared more in common with more basal tyrannosauroids that sported longer arms like Dryptosaurus, however.

Part of a Guanlong skull.

Guanlong is known from two well preserved specimens that scientists believed to be of different stages in life.  (An adult and a juvenile most likely.)  They were both found practically on top of each other along with a few other kinds of dinosaurs that would have coexisted with them in life, including the oldest known ceratopid, Yinlong.  160 million years ago, the site of these fossils was a pit of loose mud that would have trapped small animals like Guanlong and Yinlong.  As the they struggled to escape, the poor little guys would have been sucked deeper in the mud and eventually died.  Sad for the individual dinosaurs but great for fossilization!  These pits are a rich source for dinosaur fossils in China and have provided paleontologists with a lot of important information about what animals used to live there and where they fall on the dinosaur family tree.  I personally think it's really cool how the oldest members of the two most famous dinosaurs, Tyrannosaurus and Triceratops, were both found at the same time in the same place over 90 million years prior to the Late Cretaceous.  Those tyrannosauroids and ceratopids just can't seem to get away from each other!  Late Jurassic, China was ground zero for the most well-known evolutionary arms race in dinosaur history!

That is all for this week!  Feel free to comment below or on our facebook page as always!

References

Eberth, D. A., X. Xing, and J. M. Clark. "Dinosaur Death Pits From The Jurassic Of China." Palaios 25.2 (2010): 112-25. Web.

Xu X., Clark, J.M., Forster, C. A., Norell, M.A., Erickson, G.M., Eberth, D.A., Jia, C., and Zhao, Q. (2006). "A basal tyrannosauroid dinosaur from the Late Jurassic of China". Nature 439 (7077): 715–718. doi:10.1038/nature04511. PMID 16467836.