Updated

Updated · bbc.co.uk · Jul 10

Thai Palaeontologists Uncover 20m Uragasaurus in Kalasin, Thailand’s First Mamenchisaurid

Updated

Updated · bbc.co.uk · Jul 10

Thai Palaeontologists Uncover 20m Uragasaurus in Kalasin, Thailand’s First Mamenchisaurid

Q: Why was a unique 'snake-necked' dinosaur, long thought exclusive to China, found hundreds of miles south in Thailand?

It was found in Thailand because the group was probably never confined to China; scientists had simply not yet found clear enough evidence elsewhere. The new fossil, *Uragasaurus kalasinensis*, provides the strongest proof so far that mamenchisaurids — the long-necked sauropods often associated with China — also lived in mainland Southeast Asia. The key evidence is anatomical. A CT scan of the Thai vertebra revealed distinctive internal air-cavity patterns and a Y-shaped arrangement of supporting bones that place it within Mamenchisauridae, while also showing features unique enough to define a new species. That makes this not just a similar dinosaur, but the first formally named Thai member of the family. Its age also matters. The animal lived about 150 to 145 million years ago, when parts of what are now China and Thailand were part of connected East Asian land areas. That would have allowed large plant-eating dinosaurs to disperse across the region, making a wider range plausible. The discovery therefore changes the biogeographic picture rather than creating a mystery. Mamenchisaurids were thought to be almost exclusive to China because that is where most fossils had been found. *Uragasaurus* shows the family’s range was broader, and suggests their evolutionary history in Asia was more complex than the fossil record had previously indicated.

3 articles · Updated · bbc.co.uk · Jul 10

Uragasaurus kalasinensis, a 20m plant-eating dinosaur that lived about 150 million years ago, was identified from fossils excavated in Kalasin Province in northeastern Thailand.
A recovered dorsal vertebra led the find: CT scans showed distinctive traits, including a Y-shaped lamina pattern and a unique air-cavity structure that researchers said set the species apart.
The specimen came from Phu Noi, a fossil-rich site first flagged in 2008 after a local man found fragments resembling serpent scales; more than 90% of excavated remains there were dinosaur fragments.
The scans placed the dinosaur in the long-necked Mamenchisauridae family, making it the first such fossil found in Thailand, though most known mamenchisaurids have been discovered in China.
The Nature study adds to a run of major Thai dinosaur finds after scientists in May announced the 27m, 27-tonne nagatitan, the largest dinosaur yet identified in Southeast Asia.