Scientists Name New 27-Meter Sauropod from 113-Million-Year-Old Thai Fossils

Scientists have identified Southeast Asia’s largest-known dinosaur after unearthing fossils of a 113-million-year-old sauropod in Thailand’s northeastern province of Chaiyaphum. Fossils of Nagatitan chaiyaphumensis were first spotted by a villager. 78 meters) long.

The dinosaur reached almost 90 feet (27 meters) in length. Researchers estimated Nagatitan chaiyaphumensis body mass at 25 to 28 tons based on humerus and femur dimensions. The research was published on May 14, 2026, in the journal Scientific Reports.

Thitiwoot Sethapanichsakul, a University College London doctoral student in palaeontology and lead author of the research, said the dinosaur was probably a bulk browser. “Nagatitan was probably a bulk browser that focused on consuming high volumes of vegetation that required little to no chewing, such as conifers and possibly seed ferns,” Thitiwoot Sethapanichsakul said.

The climate where Nagatitan chaiyaphumensis lived was probably subtropical, with some forests but also savanna-like and shrubland habitats.

Along a meandering river in what is now Thailand, the plant-eating behemoth browsed treetops with little fear of predators due to its size. Nagatitan lived alongside various other dinosaurs as well as flying reptiles called pterosaurs. The rivers were teeming with crocodiles and fish, including freshwater sharks.

5 tons. “At that size, it was dwarfed by Nagatitan. At full size, Nagatitan likely had very little to fear in terms of predation,” Thitiwoot Sethapanichsakul said.

Paul Upchurch, a University College London paleontologist and study co-author, said predators generally avoided healthy adult sauropods. “Predators probably avoided attacking healthy adults of any large sauropod species because of the danger of being squashed. But they may have targeted old or sick adults or vulnerable babies,” Paul Upchurch said.

He added that sauropods grew rapidly after hatching. “Indeed, sauropods are known to have grown very quickly after hatching, and this probably relates to the dangers of predation. The sooner sauropods could become large, the safer they were because they would have been more difficult to tackle,” Paul Upchurch said.

Nagatitan chaiyaphumensis was not on the scale of some South American sauropods such as Argentinosaurus and Patagotitan that topped 100 feet (30 meters) long. In all, there are 14 named dinosaurs known from Thailand. Nagatitan is the largest and the geologically youngest sauropod known from Southeast Asia.

Nagatitan belonged to a subgroup of sauropods that possessed bones with lots of internal air sacs and thin walls. This subgroup originated around 140 million years ago, achieved a global distribution and around 90 million years ago became the only sauropods left worldwide. It thrived until the dinosaur age ended 66 million years ago with an asteroid impact.

Nagatitan provides insight into sauropod diversity in Southeast Asia. Not many sauropods are known from the region. Rappler reported that Nagatitan lived at a time when Earth’s atmospheric carbon dioxide levels were climbing.

“Sauropods seem to have become particularly large at this time, with gigantic forms living in South America, China, probably North Africa, and now with Nagatitan, a fairly large one in Southeast Asia,” Paul Upchurch said. “This possible relationship between large body size and high climatic temperatures is not fully understood, but it’s likely that the high temperatures had an impact on the plant fodder that was important to sauropods, which were very large-bodied herbivores.

Nagatitan gives a glimpse of the period leading up to the eventual peak in body size and temperatures about 10 to 15 million years later,” Paul Upchurch said.