New Titanosaur Bones Discovered In China Proves That Sauropods Lived Through The Cretaceous Period
The discovery of the fossil remains of a plant-eating sauropod called Yongjinglong datangi by a team of University of Pennsylvania paleontologists in northwestern China may revise the current view that sauropods were predominant in the Jurassic age but were nearly extinct by the onset of the Cretaceous.
The Yongjinglong datangi, according to a new study published in the online journal PLOS ONE, roamed the earth through to the Early Cretaceous period, more than 100 million years ago. "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," said Dr. Peter Dodson of the University of Pennsylvania, in a press release.
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The site of this discovery was the southeastern Lanzhou-Minhe Basin in Ganshu province in China, an hour's distance from Lanzhou, the province's capital. Two other Titanosaurs have been discovered barely a km away from the site of Yongjinglong fossils within the last decade. "As recently as 1997 only a handful of dinosaurs were known from Gansu," Dodson said. "Now it's one of the leading areas of China. This dinosaur is one more of the treasures of Gansu."
This newly-discovered medium-sized juvenile sauropod is among the largest living creatures ever on earth: it belongs to the group of dinos known as Titanosauria, and likely measured about 50 to 60 feet long. The adults could have been longer.
UPenn grad student Gansu Lingo Li studied the remains - consisting of three teeth, eight vertebrae, the left shoulder blade, and the right radius and ulna - while on a trip to Gansu. Li noticed a similarity between these bones and another Titanosaur, named Euhelopus zdanskyi, that paleontologists had discovered way back in 1929, based on the anatomical features of the bone. In addition, the team identified several unique characteristics.
"The shoulder blade was very long, nearly 2 meters, with sides that were nearly parallel, unlike many other Titanosaurs whose scapulae bow outward," Li said. When the long scapula didn't appear to fit into the animal's body cavity Li and team suggested that the bone fitted best at an angle of 50 degrees horizontally. The researchers concluded that the bones were of a juvenile from the unfused portion of the shoulder blade. "The scapula and coracoid aren't fused here," Li said. "It is open, leaving potential for growth." Apart from the well-preserved ulna and radius, the researchers could also identify grooves and ridges for muscle attachments in the dinosaur's leg.
The longest tooth the researchers found was 15 centimeters long while a short tooth was characterized by two bony ridges inside or "buttresses." Only one buttress was found in the teeth of Euhelopus. The researchers compared the sauropod they found with other specimens from the U.S, South America, Africa, China and other places to position it on the family tree of sauropods.
The evidence from its remains showed it to be closely similar to the species from South America, while it was found more advanced than Euhelopus. The discovery makes it clear than Titanosaurs constituted a diverse group of dinosaurs and also that they were dominant during the early Cretaceous.
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