Roughly 150 million years ago, a plant-eating giant as long as a cricket pitch swung its enormous neck through a Late Jurassic forest in what is now northeastern Thailand. Palaeontologists have finally given it a name – Uragasaurus kalasinensis – and in doing so have filled a conspicuous gap on the map of the dinosaur world.
The find, published in the journal Scientific Reports and announced on 8 July, comes from the Phu Noi site in Kalasin province, one of the richest fossil beds in Southeast Asia. The location was first flagged back in 2008, when a local resident stumbled on fragments that resembled serpent scales. Since then the site has yielded a trove of Late Jurassic remains, the overwhelming majority of them dinosaur bones.
What makes the discovery striking is how little it rests on. The species is known from a single, exceptionally well-preserved vertebra from the animal's upper back. A CT scan revealed a distinctive Y-shaped arrangement of bony ridges, or laminae, that the team led by Dr Apirut Nilpanapan of Mahasarakham University describes as unlike anything seen in related dinosaurs. That lone bone was enough to place the animal within Mamenchisauridae, a family of sauropods celebrated for necks of almost improbable length.
Those necks are the whole point. Researchers estimate Uragasaurus reached 18 to 20 metres from nose to tail, with the neck alone making up roughly half of that length and holding between 17 and 19 vertebrae – where most sauropods make do with 13 to 15. Raised to full height, the animal could have peered over a three-storey building.
Why it matters
Until now, mamenchisaurids were almost a Chinese signature, their fossils concentrated in the Sichuan Basin and only rarely found elsewhere. Uragasaurus is the first member of the family to be formally named in Thailand – and in Southeast Asia as a whole – and becomes the country's fifteenth named dinosaur. Its name blends the Sanskrit uraga, for serpent, with the Greek sauros, for lizard, a nod to that unlikely neck; kalasinensis honours the province where it was found. For scientists, the discovery redraws the range of these long-necked giants, suggesting that mainland Southeast Asia was part of their world all along – and hinting that Phu Noi still has more to give.