Chinese construction workers excavating bedrock recently made an explosive discovery when they inadvertently unearthed an unusual new species of feathered dinosaur.
The animal lived about 66 to 72 million years ago, right before a giant impact wiped out large dinosaurs in a catastrophic mass extinction. (Find out what happened on the day the dinosaurs died.)
Scientists named the new species Tongtianlong limosus, or “muddy dragon on the road to heaven”—a prosaic way to describe its final moments before death, mired in mud with its limbs and head outstretched, struggling to escape.
“This new dinosaur is one of the most beautiful, but saddest, fossils I’ve ever seen,” Steve Brusatte, of the University of Edinburgh’s School of Geosciences, says in a press statement.
“But we’re lucky that the mud dragon got stuck in the muck, because its skeleton is one of the best examples of a dinosaur that was flourishing during those final few million years before the asteroid came down and changed the world in an instant.”
Dinosaurs of a Feather
Tongtianlong belongs to a family of feathered dinosaurs called oviraptorosaurs, which had short, toothless heads and sharp beaks. Several species have been discovered in the last few decades in North America and Asia, ranging in size from four feet to over 22 feet long.
The mud dragon, the sixth species to be found in the Ganzhou area of southern China, was about the size of a large sheep or small donkey, the researchers announced this week in Scientific Reports.
In addition to size, one of the key distinguishing features among oviraptorosaurs is their crests, which were ornamental features used to attract mates and intimidate rivals.
“They are similar to horns in some mammals today,” Brusatte tells National Geographic. “Often, different mammals have different types of horns, and that helps define the different species. Same with oviraptorosaurs. Tongtianlong had a domelike crest—a fairly simple, convex, helmet type of crest.”
The existence of so many oviraptorosaurs species crowded together in one region of China has given scientists new insights into the twilight era of the dinosaurs.
“They were diversifying during those few million years before the asteroid hit,” says Brusatte. “They are a sign that dinosaurs were still doing well at this time, still making new species, still dominating ecosystems.” (Also see “What Killed the Dinosaurs? Science Has Had Some Wild Ideas.”)
Southern China back then was a “very dynamic and active environment,” he adds, describing it as a dense jungle forest with lots of rivers and lakes. In addition to the oviraptorosaurs, tyrannosaur species like Qianzhousaurus, big plant-eating sauropods, and duck-billed hadrosaurs roamed the region.
Scientists suspect that the emergence of multiple oviraptorosaurs species in the same region was a case of evolutionary radiation. That’s when organisms rapidly diversify from their ancestral species, developing traits that allow them to adapt and thrive in multiple environmental niches.
For instance, oviraptorosaurs are theropod dinosaurs that evolved from meat-eaters similar to Tyrannosaurus rex and the velociraptor. But the winged creatures lost their teeth, replacing them with beaks, which changed the types of foods they were able to pursue.
“In birds today, we know that beaks can be used in many different ways to eat many different types of food,” says Brusatte. “So oviraptorosaurs probably were omnivorous, with different species targeting different types of food.”
Some had a thick, horny bill paired with powerful jaw muscles, which meant they probably cracked open and ate clams. Others appeared to be herbivores.
The mud dragon’s upper jaw is highly convex at the front of its snout, which implies a specialized diet. But Brusatte says that researchers are still unsure about what kind of food it ate with its uniquely shaped beak.
The scientists are largely thankful that they even have a specimen to observe, given the circumstances of its discovery.
“You can actually see near the fossil where some of the dynamite was placed, and that dynamite did destroy part of the back end of the animal,” says Brusatte. “But without the dynamite, it never would have been exposed. It's a stark example of the fine line between finding a whole new species of dinosaur and never knowing that this species existed.”