Thailand’s largest dinosaur found, a 27-metre sauropod named Nagatitan

Thailand has a new prehistoric giant to anchor its fossil record: Nagatitan chaiyaphumensis, a sauropod estimated at about 27 metres long and 25 to 28 tonnes, making it the largest dinosaur yet found in Southeast Asia. The animal lived about 113 million years ago, in the late Early Cretaceous, and its discovery gives researchers their clearest look yet at a colossal plant-eater that roamed what is now northeastern Thailand.

The bones were first noticed in 2016 by a local villager, Thanom Luangnan, at the edge of a pond in Chaiyaphum province, who alerted Thailand’s Department of Mineral Resources. Scientists later recovered spine, rib, pelvis and leg bones, including a front leg bone, or humerus, measuring 1.78 metres. That more complete skeleton matters because Thailand’s biggest dinosaurs have often been known from scattered fragments, leaving paleontologists to guess at their size, anatomy and place on the evolutionary tree. Nagatitan is now the 14th dinosaur named in Thailand.

The species came from the Khok Kruat Formation, the youngest fossil-bearing Mesozoic rock unit in Thailand, and the first diagnostic sauropod specimen known from that layer. Researchers led by Thitiwoot Sethapanichsakul, with colleagues at University College London, Mahasarakham University, Suranaree University of Technology and the Sirindhorn Museum, placed it among the somphospondylan titanosauriforms, likely within Euhelopodidae. That classification helps map how giant sauropods spread and diversified across Asia, where the fossil record has lagged far behind better-known regions such as South America and East Asia.

The setting was just as revealing as the size of the animal. Nagatitan lived in an arid to semi-arid landscape crossed by rivers, alongside fish, freshwater sharks and crocodiles. The same ecosystem likely supported smaller plant-eating dinosaurs, large meat-eaters such as carcharodontosaurians and spinosaurids, and fish-eating pterosaurs. The study suggests the animal may reflect a broader mid-Cretaceous trend toward larger titanosaurs in Asia, even as lead author Thitiwoot Sethapanichsakul noted it was still smaller than South American giants such as Patagotitan and Ruyangosaurus.

For Southeast Asia, the find does more than add a record-breaking dinosaur. It strengthens a regionally important fossil map that has long been thin, especially for large-bodied sauropods, and it shows that Thailand’s younger Cretaceous rocks still hold major clues about how dinosaur communities evolved, adapted and disappeared across the continent.