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'Mud Dragon' Dinosaur Died an Awful Death at Tail-End of Cretaceous

This dinosaur’s bad luck turned out to be a boon for paleontologists.
Concept art of Tongtianlong limosus stuck in the mud. Image: Zhao Chuang

Paleontologists have discovered a new species of birdlike dinosaurin Ganzhou, China, according to new research published Thursday in Scientific Reports.

The new animal has been named Tongtianlong limosus, meaning "muddy dragon on the road to heaven," because the poor thing appears to have died when it became trapped in a mud patch some 66 to 72 million years ago. The 'Mud Dragon,' as it has been nicknamed, was preserved in a unique posture with its limbs splayed to either side, its neck outstretched, and its head raised, painting a vivid picture of its unpleasant final moments in the sludge.


Tongtianlong limosus holotype specimen. Image: Junchang Lu

But the animal's bad luck is a boon to researchers, because it was preserved almost entirely intact thanks to the prime fossilization conditions provided by that fateful muck. In fact, the authors of the new study suggest that the specimen may have been complete before its excavation, which is extremely rare. But because it was blasted into view by explosives at a construction site, there was some damage done, including a visible TNT drill hole near the animal's pelvic girdle.

Study co-author Steve Brusatte, a paleontologist based at the University of Edinburgh, pointed out that development in Ganzhou is a mixed blessing to fossil hunters: while these blasts do sometimes blemish specimens, active construction work there has also helped paleontologists find extinct animals.

"I think the Ganzhou area is one of the most important new places for dinosaur fossils," Brusatte told me via email. "It is a real hotspot. When new buildings and roads are being constructed, the workmen need to blast through the bedrock, which just so happens to be Late Cretaceous rocks full of dinosaur fossils. It's thanks to this building boom, and the keen eyes of the workmen, that we now are learning so much about these important dinosaurs from the end of the Cretaceous."

Image: Junchang Lu

"Unfortunately a lot of this work is done with dynamite—which is a little dangerous for fossils!" he added. Researchers got lucky that this Mud Dragon was far enough away from the blast that it only suffered minor damage. Without the dynamite, he added, "we would never know this dinosaur existed."


That would have been a pity, because Tongtianlong limosus belongs to an exceptionally weird, fascinating family of feathered dinosaurs known as oviraptorosaurs, which appears to have been particularly successful in Cretaceous Ganzhou.

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These two-legged, flightless animals were close relatives of birds; their skulls tapered off into sharp parrot-like beaks with no teeth and many of them sported ornamented cranial crests that paleontologists think could have been used as sexual displays. The fossil record has revealed a spectacular diversity of oviraptorosaur shapes and sizes, ranging from turkey-scale creatures to the intimidating 16-foot-tall Gigantoraptor.

Oviraptorosaur diversity. Image: Jaime A. Headden

The new Mud Dragon is one of many oviraptorosaur species that have been found in recent years, which suggests that these animals may have been on an evolutionary upswing in the final stretch of the Age of Dinosaurs, before they were wiped out alongside all other non-avian dinosaurs by a massive asteroid impact 66 million years ago.

"[T]his hypothesis is based on the huge number of oviraptorosaur fossils, and the large number of species (now six), from this same part of southern China," Brusatte told me. "These small bird-like dinosaurs were clearly still diversifying during those final few million years of the dinosaurs."

"This doesn't jibe at all with the idea that dinosaurs were struggling before the asteroid hit," he said. "Instead, they seem to have been at the top of their game. And it's not only these oviraptorosaurs, but they were living alongside so many other types of dinosaurs: tyrannosaurs, sauropods, duck-bills. This was a vibrant ecosystem."

To reconstruct this lush web of life, paleontologists will have to parse the finer details of oviraptorosaur specimens, as well as the larger ecosystem that they inhabited.

Specimens that have already been discovered need to be meticulously categorized as distinct species, or as male, female, juvenile, adult, and other incarnations of the same family. Clues about diet, behavior, and habitat could also help reveal how so many different kinds of oviraptorosaurs were able to coexist in the same place. The new holotype individual of Tongtianlong limosus, ill-fated though it was, will be an essential part of solving this Cretaceous puzzle.

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