Nagatitan: Giant dinosaur discovered in Thailand

An ancient giant weighing as much as nine elephants has been discovered in Thailand.

Named Nagatitan chaiyaphumensis, the dinosaur lived during the Early Cretaceous, more than 100 million years ago.

Nagatitan's size and name

Like the intermittently recognised Brontosaurus, it was a sauropod, with a long neck, an elongated tail and an enormous appetite for plants. It probably weighed up to 25.4 tonnes and measured around 27 metres in length.

That is truly vast: more than 9.1 tonnes heavier than the enormously famous, and famously enormous, Dippy the Diplodocus. It also makes Nagatitan the largest dinosaur ever found in Southeast Asia.

Even so, Nagatitan would have been relatively modest alongside Patagotitan, a sauropod estimated to have weighed around 63.5 tonnes. It may have been the largest land animal ever to walk the Earth.

Nagatitan also has an intriguing name. “Naga” refers to mythical water serpents commonly found in Asian and Buddhist mythology, while “Titan” comes from the Titans, the elder deities of Greek myth. “Chaiyaphumensis” refers to Thailand's Chaiyaphum province, where the bones were discovered.

Discovering and studying Nagatitan

According to a recent paper by researchers from Thailand and University College London (UCL), the remains were found in 2016 beside a dried-up pond in northeastern Thailand.

The researchers used surface scanning to make three-dimensional models, allowing them to examine fine details and study the bones safely across institutions.

“The material was studied both in Thailand and at UCL – 3D scanning and printing has meant that we can study the specimen and collect data without having to travel,” says Paul Upchurch, a UCL palaeobiologist and one of the study's co-authors.

Compared with many dinosaur fossil finds, the collection was fairly comprehensive. Its bones showed several morphological differences from those of other known sauropods.

The find comprised eight vertebrae, five ribs, parts of the pelvis, a humerus and a femur, as well as some fragments that could not be identified.

Nagatitan's changing environment

The dinosaur appears to have been something of an endling. Researchers have called it “the last titan” because it was found in the Khok Kruat Formation, Thailand's youngest stratigraphic region containing dinosaur fossils.

The formation preserves a varied collection of fossils, from sharks, turtles and pterosaurs to ancestral crocodiles and formidable predatory theropods. These included a shark-toothed predator measuring 8 metres long.

During the Early Cretaceous, the area may have been a landscape of shrublands and savannas crossed by a winding river system. As flying reptiles swooped swiftly to snatch fish from the water, Nagatitan might have lowered its long neck to gulp down vast mouthfuls.

As creatures shaped by their surroundings, sauropods appeared to cope well with rising temperatures despite their size. Their large surface area may have evolved to help them lose heat.

The landscape later changed dramatically, bringing the dinosaurs' reign in Southeast Asia to an end.

“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,” explains Thitiwoot Sethapanichsakul, a UCL palaeontologist and the study's first author.

“So this may be the last or most recent large sauropod we will find in Southeast Asia.”

Nagatitan is not only an important ‘last’; for its discoverers, it is also an exciting first.

“I've always been a dinosaur kid,” says Sethapanichsakul.

“This study doesn't just establish a new species but also fulfils a childhood promise of naming a dinosaur.”

The research was published in Scientific Reports.