Researchers identify Datai yingliangis that roamed China 900m years ago
An artistic rendering of the Gandititan cavocaudatus. (ZHAO CHUANG / FOR CHINA DAILY)
Chinese and Canadian dinosaur researchers jointly published a paper last month in the professional journal Vertebrate Anatomy Morphology Palaeontology, describing two fossils of a new dinosaur species discovered in Huichang county, Jiangxi province, that lived about 900 million years ago.
The discovery of Datai yingliangis, as named by the researchers, is an important addition to the fossil record of the early years of the Late Cretaceous period, providing new evidence for understanding the divergence of ankylosaurid dinosaurs within and outside the ankylosaur subfamily, said Xing Lida, coauthor of the paper and associate professor from China University of Geosciences in Beijing.
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"In the entire Ganzhou area in Jiangxi province, during the Late Cretaceous period, there was likely a very thriving dinosaur fauna," he said, adding that there have been many discoveries, including oviraptorid fossils, lizard fossils, hadrosaurs, tyrannosaurs and sauropods.
"Their living environment was likely lush with vegetation and abundant water sources. The abundant number of dinosaurs is likely why they have been so extensively preserved in the vicinity of rivers and lakes," Xing said.
In 2016, during road excavations along the Gongshui River in Huichang, local villagers noticed some white bone-like objects among scattered reddish-purple rock fragments by the roadside and took photos, posting them on an online forum for identification.
Niu Kecheng, executive curator of the Yingliang Stone Natural History Museum in Fujian province who was the moderator of a fossil forum at the time, suggested that the objects might be dinosaur fossils. Due to the severely fragmented state of the specimen and the lack of cleaning and restoration, it was difficult to determine the specific species.
In 2018, Niu learned that the fossils had been collected and retained by local villagers. His museum contacted the villagers, who donated the fossils to it.
"Through a lengthy process of assembly and restoration, two overlapping ankylosaurid specimens gradually emerged. As the bone sutures on the vertebrae had not completely fused, researchers believed both specimens to be subadult individuals, with a body length of approximately 3.5 to 4 meters," Xing said.
Through phylogenetic analysis, the research team concluded that Datai yingliangis represents a derived clade within the Asian ankylosaurid subfamily and formed a sister group with Pinacosaurus, discovered in Mongolia and northern China, according to Xing.
Ankylosaurs are a well-known group of dinosaurs that lived in the Late Cretaceous of North America and Asia.
Ankylosaurids are characterized by extensive bony armor from head to tail, earning them the nickname "tank dinosaurs".
Members of the ankylosaurid subfamily are larger in size, have wide bodies and possess a well-developed tail club.
Datai yingliangis exhibits a prominent premaxilla, with a cranial ornamentation similar to that of most ankylosaurid subfamily members.
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A unique feature of Datai yingliangis is the presence of a pair of small jugal or postorbital horns on each side of the cheek, extending outward.
The buried position of the overlapping Datai yingliangis specimens also provides additional information on the behavior of ankylosaurids.
Xing mentioned that this burial posture has also been observed in the case of Pinacosaurus found in Mongolia and northern China, where it was interpreted as a rapid burial by in situ windblown sand, indirectly suggesting gregarious behavior in Pinacosaurus. Although the two Datai yingliangis specimens were buried in situ in a river or lake environment, it is highly likely that they are also associated with gregarious behavior in ankylosaurids.
"The benefit of juvenile ankylosaurus living in groups is to better perceive danger, increased success in finding food and water sources and an overall improvement in individual survival rates," Xing said.
