Paleontologists working in northwest China have discovered a new species of titanosaur, the group of sauropod dinosaurs that are believed to be the largest creatures to have ever walked the Earth.
The new Early Cretaceous-era species, which has been named Yongjinglong datangi, was between 50-60 feet long, a medium size for a titanosaur.
The fossil remains are few, including just three teeth, eight vertebrae, the creature's left shoulder blade and the radius and ulna from its right leg. However, the ancient bones provided enough evidence for paleontologists, led by a University of Pennsylvania team, to conclude they were dealing with a new species.
Gansu Province, where the fossils were found, is proving to be a hotspot for dinosaur remains. Within the last decade, two other titanosaur species were discovered in Gansu's southeastern Lanzhou-Minhe Basin region within a kilometer of where the latest specimen was discovered.
"As recently as 1997 only a handful of dinosaurs were known from Gansu," said Peter Dodson, one of the leaders of the research. "Now it's one of the leading areas of China. This dinosaur is one more of the treasures of Gansu."
Writing in the journal PLOS One, Dodson and his colleagues describe the new species as one of the most evolutionarily advanced of all the titanosaurs discovered in Asia.
"The shoulder blade was very long, nearly 2 meters, with sides that were nearly parallel, unlike many other titanosaurs whose scapulae bow outward," said Daqing Li of the Gansu Geological Museum in Lanzhou.
Y. datangi's shoulder blade was so long that it did not fit into its body in a conventional way, but was oriented at an angle of 50 degrees from the horizontal, the scientists said.
An unfused section of the shoulder blade is still under investigation to determine whether the specimen was a juvenile or an adult when it died.
"The scapula and coracoid aren't fused here," Li said. "It is open, leaving potential for growth." If the specimen was a juvenile, then a fully grown Y. datangi may have well exceeded 60 feet in length.
The discovery of Y. datangi adds to a growing list of sauropod dinosaurs discovered in China and is further solidifying the theory that sauropods were the dominant dinosaur group in the Early Cretaceous period, a notion that is not supported by US specimens alone, where dinosaur diversity is considered the highest.
"Based on US fossils, it was once thought that sauropods dominated herbivorous dinosaur fauna during the Jurassic but became almost extinct during the Cretaceous," Dodson said. "We now realize that, in other parts of the world, particularly in South America and Asia, sauropod dinosaurs continued to flourish in the Cretaceous, so the thought that they were minor components is no longer a tenable view."