New species of giant dinosaur identified from remains found in Thailand

The discovery of some bones at the edge of a pond in Thailand a decade ago has led to the identification of a new type of dinosaur, with a massive size, long neck and tail, and a plant diet.

Named “Nagatitan chaiyaphumensis” by researchers in Thailand and London, the reptile is the largest dinosaur ever to be discovered in Southeast Asia.

Weighing in at an estimated 27 metric tons — or almost 60,000 pounds — it was approximately 27 meters long, or almost 89 feet, according to the study published in the journal Scientific Reports on Thursday. For context, a large Tyrannosaurus rex would have weighed between 9,000 and 15,000 pounds and been more than 12 meters long (about 39 feet).

Nagatitan chaiyaphumensis belonged to a group of dinosaurs known as sauropods, which were the largest animals ever to walk on land. Among these plant-eating, long-necked, thick-legged dinosaurs, with a torso containing a huge gut, were the Diplodocus and Brontosaurus.

The newly discovered dinosaur’s humerus, or front leg bone, measured 1.78 meters (almost six feet) in length, according to a statement.

“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 on Friday.

“When I first laid eyes on the humerus, it was taller than me, and that was quite surprising,” he continued, adding that the dinosaur is about double the size of another known sauropod species in Thailand.

Childhood dream fulfilled

The leg bone was among several fossils discovered by a local resident on the side of a communal pond in northeastern Thailand in 2016, during the dry season when the water levels were lower.

Skeletal remains were found during fieldwork there between 2016 and 2019, and further excavation work took place in 2024.

The researchers — from UCL and Thailand’s Department of Mineral Resources, Mahasarakham University and Suranaree University of Technology — took 3D scans of the remains, which came from the dinosaur’s leg bones, spine, ribs and pelvis, before analyses revealed the animal was a previously unknown species.

The “naga” in Nagatitan chaiyaphumensis’ name refers to the name of a mythological serpent from South and Southeast Asian folklore. “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.

“Titan” relates to giants from Greek mythology and refers to the animal’s size, and “chaiyaphumensis” refers to the Thai province in which the dinosaur was discovered.

“It fulfills a kind of childhood promise,” said Sethapanichsakul, whose home country is Thailand. “That, yeah, I’m going to name a dinosaur one day. And I want it to be from Thailand.”

Nagatitan probably lived during the late Early Cretaceous period, around 120 million to 100 million years ago, according to the study. It would have lived alongside smaller, medium-sized plant-eating dinosaurs, similar to Iguanodons, as well as “a kind of very early form of what we would call Ceratopsians, cousins of Triceratops,” Sethapanichsakul said.

The environment at that time was “very dry and warm,” he said, adding that the site where the dinosaur was found represents a sort of meandering river system that would have had “freshwater fish, freshwater sharks, crocodiles, turtles.”

Sethapanichsakul said he thinks Thailand has “some of the highest diversity” of dinosaur fossils in Asia, partly due to having a very thick layer of sedimentary rocks from the Mesozoic Era, approximately 252 million to 66 million years ago.

“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 set up at the site of the discovery, said Sethapanichsakul, who continues to work on sauropods from Southeast Asia.

A life-sized reconstruction of the Nagatitan chaiyaphumensis is on display at the Thainosaur Museum in Bangkok.

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