Southeast Asia's largest dinosaur weighing 27 tonnes dug up in Thailand

A pile of giant bones found at the edge of a pond a decade ago has turned out to be the largest dinosaur ever discovered in Southeast Asia, and it could also be the last to be found in Thailand.

In Short

• Fossil hunters found giant bones in Chaiyaphum, Thailand, 10 years ago
• 14th dinosaur species in region, possibly last large sauropod in Thailand
• Estimated weight 27 tonnes, length 27 metres, similar to nine elephants

Ten years ago, a group of fossil hunters in north-eastern Thailand stumbled upon a collection of enormous bones at the edge of a pond in Chaiyaphum province.

The bones were large enough to raise eyebrows, but it has taken years of research by scientists from University College London, Mahasarakham University, Suranaree University of Technology, and Thailand's Sirindhorn Museum to confirm what they had really discovered.

A newly published study has announced the fossil they discovered as a brand-new species, Nagatitan chaiyaphumensis, which is also the largest dinosaur ever found in Southeast Asia.

The creature weighed an estimated 27 tonnes, or roughly the same as nine adult Asian elephants, and stretched approximately 27 metres from head to tail, comparable in length to a blue whale.

GIANT AMONG GIANTS

The newly discovered species belongs to the sauropods, the group of long-necked, plant-eating dinosaurs that produced some of the largest land animals in Earth's history, including the famous Diplodocus and Brontosaurus.

Amongst the bones recovered were several vertebrae, ribs, parts of the pelvis, and two leg bones, with one measuring over 5.8 feet alone.

"Our dinosaur is big by most people's standards — it likely weighed at least 10 tonnes more than 'Dippy the Diplodocus'," said lead author Thitiwoot Sethapanichsakul, a Thai PhD student at UCL's Earth Sciences department. "However, it is still dwarfed by sauropods like Patagotitan that weighed 60 tonnes, or Ruyangosaurus of 50 tonnes."

The dinosaur lived during the Early Cretaceous period, roughly 120 to 100 million years ago, in a landscape not entirely unlike north-eastern Thailand today, containing semi-arid plateaus cut through by rivers. The fossil site also yielded remains of fish, freshwater sharks, and crocodiles, painting a vivid picture of the ancient ecosystem it once inhabited.

ANOTHER THAI DINOSAUR

Chaiyaphum province has been a rich hunting ground for palaeontologists since 1986, when the first Thai dinosaur species was formally identified. Nagatitan is now the 14th unique dinosaur species found in the region, and it may well be the last large sauropod ever discovered in Thailand.

"We refer to Nagatitan* as 'the last titan' of Thailand," said Sethapanichsakul. "That is because it was discovered in Thailand's youngest dinosaur-bearing rock formation. Younger rocks laid down towards the end of the time of the dinosaurs are unlikely to contain dinosaur remains because the region by then had become a shallow sea. So this may be the last or most recent large sauropod we will find in Southeast Asia."

The discovery belongs to a subgroup of sauropods called Euhelopodidae, found exclusively in Asia, whose close relatives, the titanosaurs, have been unearthed on every continent including Antarctica.

For Sethapanichsakul, the find is both a scientific milestone and a personal mission.

"My dream is to continue pushing to get Southeast Asian dinosaurs recognised internationally," he said. "More international collaborations can further our understanding of the region's palaeobiology and apply it to a global context."

- Ends