Nagatitan chaiyaphumensis could well be the last giant of its kind in Southeast Asia. Discovered in Thailand, this colossal dinosaur went extinct just as the region was transforming into a shallow sea, making any younger fossil highly unlikely.
The bones were unearthed a decade ago near a pond in the northeastern part of the country. Researchers from University College London (UCL) and Thai institutions analyzed vertebrae, ribs, pelvis, and legs. A single front leg bone measured 1.78 meters (about 5 feet 10 inches), roughly the height of a man. The animal reached 27 meters (about 89 feet) in length and weighed 27 metric tons (about 30 short tons), the equivalent of nine Asian elephants.
Artistic illustration of Nagatitan.
Credit: Patchanop Boonsai
As for its name, it blends Thai and Greek mythology: "Naga" evokes a legendary serpent of Southeast Asia, while "Titan" recalls the Greek giants. The species name
chaiyaphumensis honors the province where it was discovered. It is the 14th dinosaur species named in Thailand, belonging to the sauropods, those long-necked herbivores typical of the Early Cretaceous, 100 to 120 million years ago.
At that time, the Thai environment was arid to semi-arid. Sauropods thrived there, possibly regulating their body temperature through their necks and tails. The fossil site also reveals fish-rich rivers, freshwater sharks, and crocodiles. The giant shared its territory with smaller herbivores (iguanodontians, ceratopsians) and predators such as carcharodontosaurs, not to mention fishing pterosaurs.
Skeletal reconstruction with specimens highlighted in yellow.
Credit: Thitiwoot Sethapanichsakul et al
After analysis, scientists classified it among the somphospondyls, a sauropod subgroup, more precisely the Euhelopodidae, exclusive to Asia. Unique features of the spine, pelvis, and legs set it apart. A life-size reconstruction is displayed at the Thainosaur Museum in Bangkok.
The paleogeography of Thailand during the Cretaceous
During the Early Cretaceous, present-day Thailand was part of a continent bordered by shallow seas. The climate was hot and seasonal, with pronounced dry seasons. Deposits from the Khok Kruat Formation, where Nagatitan was found, bear witness to river and lake environments, favorable to fossilization.
Changes in sea level gradually submerged the region, transforming dry land into archipelagos. This marine transgression ended continental sedimentation and thus the preservation of dinosaurs in the most recent layers.
The rivers of that time hosted a diverse fauna: fish, freshwater sharks, crocodiles, and pterosaurs. This paleontological richness makes Thailand one of the most promising countries in Asia for dinosaur research, with about twenty species described in just forty years of intensive study.