Scientists Name a New 92-Foot Sauropod Dinosaur Discovered During Construction Work in China

A team led by Xuefang Wei of the Chengdu Center of China Geological Survey has formally described a colossal new dinosaur species from the Sichuan Basin — a long-necked sauropod estimated to have stretched between 75 and 92 feet in length. The species, named Tongnanlong zhimingi, belongs to Mamenchisauridae, a family of giants whose hollow, air-filled bones helped support bodies of extreme size. The findings were published in the peer-reviewed journal Scientific Reports.

The Details

The discovery began not in a prepared excavation but during construction activity in Chongqing's Tongnan District, according to Earth.com coverage of the paper. Workers exposed fossil material during the construction work before scientists were called in to conduct a formal excavation and analysis. That transition from accidental exposure to systematic study is reflected in the final specimen record now held at Tongnan Museum.

The holotype specimen — the physical reference used to formally define the new species — is catalogued as TNM 0254 and is housed at Tongnan Museum, according to Scientific Reports. The preserved material includes three dorsal vertebrae, six caudal vertebrae, a left shoulder girdle, and hindlimb elements. Although the skeleton is incomplete, those bones were sufficient for the research team to estimate the animal's full body length by comparing them against related sauropods in existing collections.

Researchers put the length estimate at roughly 75 to 92 feet, according to Futura-Sciences. The comparison was based on the proportions of the preserved scapula and fibula relative to known measurements for other members of the mamenchisaurid family. The resulting range suggests Tongnanlong zhimingi sat near the upper end of body sizes recorded for its group.

Mamenchisauridae, the family to which Tongnanlong belongs, is characterized by exceptionally elongated necks and internal bone structures filled with air pockets. According to Scientific Reports, those air-filled structures — a feature technically described as pneumatized bone — helped these dinosaurs manage the structural demands of extreme body mass. The family has been a focal point for researchers studying how terrestrial animals reached and sustained the largest sizes in the fossil record.

The dinosaur lived during the Late Jurassic period and was recovered from the Suining Formation in the Sichuan Basin. The formation is associated with lakeshore or wetland environments, based on the presence of mudstones, sandstones, and freshwater fossils at the site, according to Futura-Sciences. That depositional context places Tongnanlong in a lowland, waterway-adjacent habitat consistent with the ecological conditions documented for other large sauropods of the same era.

Lead researcher Xuefang Wei described the specimen's significance for the broader scientific record. "The new specimen enriches the diversity of Mamenchisauridae and provides additional information for understanding the evolution and diversity of eusauropod dinosaurs," Wei was quoted as saying in Earth.com coverage summarizing the paper.

Context

The Sichuan Basin has produced a number of significant sauropod finds, and the Suining Formation continues to yield specimens that expand the known record of Late Jurassic dinosaur fauna in Asia. The formal description of Tongnanlong adds to that record by identifying a previously unnamed species and anchoring it within the evolutionary context of Mamenchisauridae.

The Scientific Reports paper frames the Tongnanlong discovery as relevant to two broader questions in paleontology: how sauropod dinosaurs reached and sustained the largest body sizes in terrestrial animal history, and how the Late Jurassic dinosaur fauna of Asia relates to assemblages found elsewhere in the world. Both questions remain active areas of research, according to the paper.

Accidental fossil exposure during infrastructure and construction projects is a recurring pathway for new paleontological finds in China. The Tongnan District discovery follows that pattern, with formal excavation and scientific analysis proceeding only after construction workers first uncovered the material, according to Earth.com.

What's Next

The holotype specimen TNM 0254 is now publicly accessible at Tongnan Museum, where it joins the physical collections available to researchers studying Mamenchisauridae and Late Jurassic biogeography in the Sichuan Basin. The Scientific Reports paper, published in full at Nature.com, establishes the formal taxonomic foundation for future comparative analysis of the species.

The research team indicated that the specimen provides new data relevant to the study of eusauropod evolution and diversity, according to Scientific Reports. The paper positions Tongnanlong as contributing evidence for ongoing work on the mechanisms and limits of sauropod gigantism across the Late Jurassic.