Hairy Museum of Natural History

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.

—Matt Celeskey.

File under: Cretaceous, Dinosaurs, Recent Discoveries.

Comments on record: (3)

Scientists have described a new fossil that has the potential to shed light on the origin and evolution of a major branch on the dinosaur family tree.

Eocursor parvus, the “Little Dawn-runner,” lived 210,000,000 years ago in what is now South Africa. It is known from a partial skeleton that preserves parts of its skull, jaw, spinal column, hips, and limbs. A reconstruction of the complete animal suggests that it would have been about a meter long in life and stood about 30cm high at the hips. Its long, slender legs were well-proportioned for running—probably its main defense from larger predators.

What makes Eocursor particularly important is where (and when) it fits on the dinosaur family tree. Eocursor was an early ornithischian, among the first of the great group of beaked, largely plant-eating dinosaurs that would later include armored stegosaurs and ankylosaurs, duck-billed hadrosaurs, horned ceratopsians, and dome-headed pachycephalosaurs. Other Triassic ornithischians are known, but Eocursor is by far the most well-preserved.

Study of this little dinosaur is already providing insight into how ornithischians evolved. Eocursor is similar in shape and (presumably) habits to Jurassic ornithischians like Lesothosaurus and Scutellosaurus, even though it predates them by roughly 10,000,000 years. To the scientists that described Eocursor, this suggests that the later Jurassic radiation of ornithischian dinosaurs was not due to any evolutionary advancement particular to the Ornithischia. Instead, they feel this lends support to the hypothesis that ornithischians expanded into the niches that opened after several groups of non-dinosaurian herbivores went extinct at the end of the Triassic.

Further reading:

Butler, R. J., Smith, R. M. H., and Norman, D. B. 2007. A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithishia [PDF link]. Proceedings of the Royal Society B Published online: doi:10.1098/rspb.2007.0367

Stegosaurus’ little cousin is found, a news article at the (British) Natural History Museum.

And an article from BBC news.

—Matt Celeskey.

File under: Dinosaurs, Recent Discoveries, Triassic.

Comments on record: (1)

Researchers at the Virginia Museum of Natural History have announced the discovery of a 220,000,000 year-old gliding reptile with an uncharacteristically long neck.

Mecistotrachelos apeoros, whose name means “soaring long-neck,” was discovered in Triassic-aged rocks from the Solite Quarry near the Virginia-North Carolina state line.

From the VMNH press release:

“Dr. Nicholas C. Fraser of the Virginia Museum of Natural History, who discovered the fossils, said that while two other reptiles with similar gliding membranes are known from the Triassic Period, they have much shorter necks and therefore conform more to the modern gliding lizard, Draco. Fraser said “one of the really neat things about the new glider is the feet. They are preserved in a hooked posture which is unusual and strongly suggests a grasping habit, further emphasizing a life style in the trees.” It probably fed on insects, scuttling up tree trunks and foraging on the way, before gliding onto neighboring trees.

“The relationships of Mecistotrachelos are unclear, but Fraser considers that it is probably related to the protorosaurs. Protorosaurs are a group of extinct reptiles characterized by a long-necked, including the bizarre Tanystropheus which had a neck longer than the length of the body and tail combined.”

Mecistotrachelos is described in an article in the upcoming issue of the Journal of Vertebrate Paleontology, which I haven’t seen yet but am looking forward to reading. Accompanying the press release is a spiffy life restoration by artist Karen Carr.

Update 6/13: Science Daily has a great photo of a CT-scan showing the skeleton of Mecistotrachelos within its rocky tomb.

—Matt Celeskey.

File under: Reptiles, Triassic.

Comments on record: (1)