A new genus and species of non-hadrosaurid hadrosauroid dinosaur, named Qianjiangsaurus changshengi, has been identified from a specimen found in 2022 in southwest China.
Qianjiangsaurus changshengi. Image credit: Hai Xing / Sci.News.
Qianjiangsaurus changshengi lived in China during the Late Cretaceous epoch, around 70 million years ago.
The 8-m- (26-foot) long herbivore belongs to Hadrosauroidea, a superfamily of ornithischian dinosaurs that includes the so-called duck-billed dinosaurs and their close relatives.
“Hadrosauroidea is a diverse, highly specialized clade of ornithischian dinosaurs, remains of which have been found in the Late Early and Late Cretaceous deposits of Asia, Europe, the Americas, Africa and Antarctica,” said Dr. Hai Xing, a paleontologist at the National Natural History Museum of China, the Canadian Museum of Nature and the Nanjing Institute of Geology and Palaeontology, and colleagues.
“It is phylogenetically defined as the most inclusive taxon containing Parasaurolophus but not Iguanodon, and is famous for the duck-billed rostrum and complex tooth batteries of the skull.”
“Since the beginning of the 20th century, Hadrosauroidea has been regarded as an important component of the terrestrial vertebrate faunas of the entire Cretaceous.”
“The fossil record of the group includes bonebed assemblages yielding copious disarticulated elements, dozens of largely articulated skeletons, eggs and embryonic material, soft-tissue impressions and footprints.”
“Within Hadrosauroidea, non-hadrosaurid species together form a paraphyletic group that reveals the transitional morphology from early-branching iguanodontians to hadrosaurids.”
“The majority of the non-hadrosaurid hadrosauroids are known from the Cretaceous of Asia, notably north and central China, where the Early Cretaceous Equijubus, Xuwulong and Probactrosaurus, as well as the Late Cretaceous Tanius, Gilmoreosaurus and Zhanghenglong, were recovered.”
“However, comparable material from the Cretaceous of southwest China is extremely scarce and fragmentary.”
An incomplete, partially articulated skeleton of Qianjiangsaurus changshengi was collected in 2022 from the top of the Zhengyang Formation, Chongqing municipality, southwest China.
“Qianjiangsaurus changshengi is a second formally named hadrosauroid dinosaur from south China, in addition to Nanningosaurus dashiensis,” the paleontologists said.
The specimen displays a transitional morphology between hadrosauroid and non-hadrosaurid hadrosaurid dinosaurs, and improves the understanding of the diversity and evolution of non-hadrosaurid hadrosauroids.
“Given that the age assemblage of the eight hadrosauroids closely related to Qianjiangsaurus changshengi in phylogeny spans the Santonian-early Maastrichtian time interval, the top of the Zhengyang Formation, from which Qianjiangsaurus changshengi is recovered, is possibly restricted to the late Late Cretaceous in age,” the authors said.
“Hierarchical clustering of twelve hadrosauroid-bearing dinosaur assemblages from the Late Cretaceous deposits of Asia shows a strong correlation between the Zhengyang Formation and the Djadokhta and Baruungoyot formations in Mongolia that supports coeval interchange of dinosaur faunas across East Asia.”
The team’s paper was published August 27, 2024 in the journal Cretaceous Research.
_____
Hui Dai et al. A new late-diverging non-hadrosaurid hadrosauroid (Dinosauria: Ornithopoda) from southwest China: support for interchange of dinosaur faunas across East Asia during the Late Cretaceous. Cretaceous Research, published online August 27, 2024; doi: 10.1016/j.cretres.2024.105995