A massive, long-necked dinosaur that tramped through what is now Southwest China's Chongqing approximately 160 million years ago has been identified as a new species, shedding fresh light on the diversity of giant sauropods in Late Jurassic East Asia.

The dinosaur, formally named Mamenchisaurus sanjiangensis, was described in a study published Thursday in the journal Scientific Reports. Unearthed in 2015 in Chongqing's Hechuan district, the fossil represents a breakthrough for local paleontology. The district sits at the confluence of the Jialing, Fujiang, and Qujiang rivers, which inspired the species' name.

With a reconstructed body length of up to 24 meters, or roughly as long as a blue whale, it ranks among the largest dinosaurs ever discovered in the municipality. Despite being closely related to another local giant, Mamenchisaurus hochuanensis, detailed analysis of its bones confirmed it as a distinct species.

According to the study's lead author, Dai Hui from the Chongqing Institute of Paleontology, this discovery provides insights into the evolution and diversity of sauropods in East Asia during the Jurassic. It also represents a substantial step forward in Chongqing's fossil excavation, research, and scientific interpretation, laying a solid foundation for future studies of regional paleoecology and paleogeography.

The discovery was based on a substantial portion of the skeleton, including a series of vertebrae from the neck, back, and tail, as well as the hips and parts of the left leg. This relative completeness allowed scientists to confidently classify it as a new member of the Mamenchisaurus genus, famed for their extremely long neck.

The fossil was recovered from the Upper Shaximiao Formation, a geologic layer dating to the Late Jurassic period that has yielded many of China's famous dinosaur finds. The research was led by the Chongqing Planning and Natural Resources Bureau.

Mamenchisaurus sanjiangensis is the 11th new dinosaur species to be identified in China in 2024 and brings the total number of dinosaur species confirmed in Chongqing to 15.