For years, paleontologists have wondered if Late Jurassic East Asia was cut off from other parts of the supercontinent. A fresh discovery in southwestern China might change that story.
In late 2025, while digging in the Tongnan District of Chongqing, a construction crew stumbled upon the bones of a massive dinosaur. This wasn’t just any find; paleontologists soon identified it as a new species called Tongnanlong zhimingi.
At an estimated length of up to 28 meters (92 feet), this dinosaur is one of the largest land animals we’ve ever known. Its sheer size is fascinating, but what it implies about Jurassic ecosystems and evolutionary trends is even more important.
The research team, led by Xuefang Wei from the Chengdu Center of China Geological Survey, published their findings in Scientific Reports. The fossils were dated to about 147 million years ago and were found in the Suining Formation of the Sichuan Basin.
The fossils include several vertebrae and limb bones. By comparing these with related species, scientists estimated Tongnanlong‘s impressive length. Its unique features, like air-filled vertebrae and strong neural spines, suggest it belongs to the Mamenchisauridae family, known for long necks and lightweight builds.
The fossils were found in fine-grained mudstone, hinting at a rich lakeside environment filled with life. Fossils of turtles and bivalves found in the same area suggest it was a wetland teeming with creatures. Such a habitat could support large herbivores, indicating that this part of East Asia was likely a bustling ecosystem.
The discovery of Tongnanlong zhimingi also challenges the notion that East Asia’s dinosaurs evolved in isolation. Past theories suggested geographical barriers kept species separated. However, this new find, along with other international discoveries, hints that these dinosaurs might have shared a broader habitat than once thought. For instance, fossils like Wamweracaudia keranjei found in Tanzania suggest that related species lived far beyond East Asia.
Xuefang Wei and the team noted, “This new specimen enriches the diversity of Mamenchisauridae and sheds light on the evolution of eusauropod dinosaurs.” They point to additional fossils nearby that indicate these large dinosaurs might have coexisted.
While Tongnanlong is significant, it’s only partially represented in the fossil record. Key pieces, like the skull, remain missing. These elements could reveal much about how this dinosaur lived and fed. No follow-up dig plans have been disclosed yet, but there’s potential for more remains in the area where the bones were initially found.
Tongnanlong zhimingi is currently stored under the watch of the China Geological Survey, awaiting further study.
This discovery not only adds a new giant to our understanding of dinosaur evolution but also opens up exciting questions about the interconnectedness of ancient ecosystems. As more digs happen, the story of dinosaurs like Tongnanlong will likely become even clearer, helping us understand the vast world of the Jurassic period.
