Across China: Newly identified dinosaur species in south China sheds light on Jurassic evolution

NANNING, Aug. 25 (Xinhua) -- Scientists have identified a new species of eusauropod dinosaur, a derived clade within sauropod dinosaurs, in south China's Guangxi Zhuang Autonomous Region, marking the earliest known long-necked herbivore in the region and providing fresh insights into sauropod presence during the Jurassic Period.

A team of researchers, led by paleontologist Mo Jinyou from the Natural History Museum of Guangxi, formally named the species Huashanosaurus qini after an iconic local landmark.

According to Mo, the dinosaur can be traced back to the Early to Middle Jurassic, around 180 million years ago, roughly 30 million years earlier than Jingia dongxingensis, the region's oldest known sauropod from the Upper Jurassic.

"These findings offer novel fossil evidence for global Jurassic sauropod evolution and distribution patterns," said Mo. "They also suggest a potentially diverse sauropod community that once roamed south China during this period."

The discovery, detailed in a study published this month in Acta Geologica Sinica (English Edition), stems from the fossils excavated at a quarry near the Mingjiang River in Ningming County.

The scattered bones, first spotted by a local teacher, were later collected during a joint expedition by the Natural History Museum of Guangxi and the local authorities of Ningming County in 2017.

Researchers analyzed the partial skeleton, including fragments of vertebrae, ribs, humerus, ulna, fibula and foot bones, before identifying it as a new species of eusauropod, a group of advanced sauropods known for their massive size and elongated necks.

The defining bone traits that set it apart from other known sauropods include a sharply curved, hook-shaped posterior process on the ulna, which is a first among sauropod dinosaurs, a unique crescent-shaped cross-section in the ulna's shaft due to bone indentation, and a longitudinal groove on the distal end of the fibula's posterior surface.

These characteristics, unseen in other sauropods, suggest specialized adaptations in the dinosaur's limbs, possibly related to locomotion or weight distribution.

"The findings increase the diversity of Jurassic sauropods in China," the researchers noted in their paper.

Based on bone measurements, researchers have estimated that Huashanosaurus qini reached about 12 meters in length, a medium-sized quadrupedal herbivore that likely inhabited forested river and lake shores.

According to Mo, the remains hail from the Wangmen Formation in Guangxi's Shiwandashan Basin, a Mesozoic continental basin with lake and river sediments. Other findings from this area include fish scales, turtle shells, and incomplete sets of plesiosaurian teeth, indicating a humid, ecologically complex environment favorable to sauropod thriving.

"Huashanosaurus qini's discovery fills a gap in Early to Middle Jurassic eusauropod fossils from south China," said Mo. "Its unique features provide new clues to sauropod early differentiation."

Mo expects that further fieldwork at the site and in the Shiwandashan Basin will reveal more about sauropod distribution in south China. ■