Gigantoraptor!
10:36 pm
The second dinosaur to be named today is an absolutely stupendous oviraptorid from the Late Cretaceous of China.
The aptly named Gigantoraptor erlianensis (“Gigantic raptor from the Erlian basin”) was named for a partial skeleton of an enormous bird-like dinosaur that was approximately 8 meters (25 feet) long and weighed an estimated 1400 kilograms (1.5 tons)! This makes it one of the largest known animals from the Iren Dabasu fauna, larger than the contemporary tyrannosaur Alectrosaurus and only slightly smaller than the resident sauropod Sonidosaurus.
A skeletal reconstruction showing the size of Gigantoraptor is winding its way around the paleo-minded web; one of the larger reproductions is here.
And the only known specimen may not have been as large as Gigantoraptor got. Studies of the holotype’s bone histology suggest that it was a young adult, probably about 11 years old when it died. The growth pattern of the animal’s bone indicates that it grew up quickly, putting on between 150–200lbs. a year for the first seven years of its life. The authors of the study suspect that a full-grown Gigantoraptor would have been even more massive.
Further reading:
Xu, X., Tan, Q., Wang, J., Zhao, X., and Tan, L. 2007. A gigantic bird-like dinosaur from the Late Cretaceous of China. Nature 447: 844–877.
Nature also has a good (and freely accessible) news story, and the figures from the paper are available here.
Wired Science has some of the best images.
Living the Scientific Life and Laelaps have excellent summaries, as well.
Update 6/14: Over at Tetrapod Zoology, Darren Naish has a great post on the latest round of dinosaur news, including Gigantoraptor, Eocursor, a baby diplodocid sauropod, and hints at stories to come. Highly recommended.
Thanks for the link! You certainly have a more complete understanding of dinosaurs from this area than I do, but I’m hoping to write up another post about this new dino today (since I finally got to read the Nature paper and Supplementary Materials).
One wonders what implications the arms of Gigantoraptor have for Therizinosaurus and Deinocheirus.
Thanks Laelaps (and excellent followup post as well). I particularly like the way you’ve analyzed how this story has been reported in various outlets. I can’t claim any familiarity with the Iren Dabasu fauna–everything I’ve written comes right out of the paper and its supplemental materials.
Zach raises a very interesting question, I think. In the Late Cretaceous of Asia you find members of different theropod groups reach gigantic size, with long arms and claws that would make Freddy Krueger feel inadequate. Was there some common selective pressure that allowed Gigantoraptor, Therizinosaurus, and Deinocheirus to converge upon the ultimate “Big Bird” bauplan? Exploitation of a similar food supply, defense against a common predator-type, symbiosis with some undiscovered proto-Snuffleupagus?
Or did they independently achieve heavyweight status based on factors unique to each species’ time, habitat, and/or evolutionary history?