The discovery of fossilized bones near a pond in northeastern Thailand has led scientists to identify a new dinosaur species believed to be the largest ever found in Southeast Asia.
The dinosaur, named Nagatitan chaiyaphumensis, was a massive plant-eating reptile with a long neck and tail. Researchers estimate it weighed around 27 metric tons, nearly 60,000 pounds and measured about 27 meters (89 feet) in length, according to a study published in Scientific Reports.
It belonged to the sauropod group, a family of enormous herbivorous dinosaurs that included well-known genera such as Diplodocus and Brontosaurus. Scientists said the dinosaur’s humerus, or upper front leg bone, measured nearly 1.8 meters (about six feet) long.
“We don’t have a lot of specimens that are of that scale in Thailand,” lead study author and paleontologist Thitiwoot Sethapanichsakul, a PhD student at University College London, told CNN.
“When I first laid eyes on the humerus, it was taller than me, and that was quite surprising,” he said, adding that the dinosaur is roughly twice the size of another known sauropod species found in Thailand.
The fossils were first discovered in 2016 by a local resident during the dry season, when water levels in a communal pond dropped. Excavations from 2016 to 2019 uncovered additional bones, with further fieldwork carried out in 2024.
Researchers from University College London, Thailand’s Department of Mineral Resources, Mahasarakham University, and Suranaree University of Technology used 3D scanning to analyse bones from the legs, spine, ribs, and pelvis, confirming the find as a previously unknown species.
The name combines cultural and mythological references. “Naga” comes from a serpent-like creature in South and Southeast Asian folklore, while “Titan” refers to giants in Greek mythology. The suffix “chaiyaphumensis” refers to Thailand’s Chaiyaphum province, where the fossils were found.
“The Nagas are also often associated with water, and considering the dinosaur was found on the side of a communal pond, it just seemed very apt to have a serpent giant be the name,” Sethapanichsakul said.
“It fulfills a kind of childhood promise,” he added. “That, yeah, I’m going to name a dinosaur one day. And I want it to be from Thailand.”
The dinosaur likely lived during the late Early Cretaceous period, around 120 million to 100 million years ago. It shared its environment with smaller plant-eating dinosaurs similar to Iguanodon and early relatives of Triceratops.
At the time, the region was hot and dry, with river systems supporting freshwater fish, sharks, crocodiles, and turtles.
Sethapanichsakul said Thailand may have “some of the highest diversity” of dinosaur fossils in Asia, thanks to its extensive layers of exposed sedimentary rocks from the Mesozoic Era.
“These rocks are exposed to less rain and vegetation, which could end up eroding or destroying those bones,” he added.
A research center has been established at the discovery site, and a life-sized reconstruction of Nagatitan chaiyaphumensis is on display at the Thainosaur Museum in Bangkok.
