By Tom Metcalfe

NAKHON RATCHASIMA – Fossil bones found by farmers digging a new pond in northeast Thailand have been identified as a new species of dinosaur – the ninth dinosaur species found in this part of Thailand and the sixth found nowhere else on earth. The fossils were uncovered in 2005 on the outskirts of the city by farmers digging a small reservoir to water their crops.

The recently named Sirindhorna khoratensis was a plant-eating iguanodontid, about 6 metres long, which lived around 120 million years ago.

A composite skull reconstruction of Sirindhorna khoratensis. Credit:

A composite skull reconstruction of Sirindhorna khoratensis. Credit: PLOS-One/© 2015 Shibata et al.

The new dinosaur takes it genus name from the daughter of Thailand’s King Bhumibol, Princess Sirindhorn, a patron of dinosaur research. Its species name comes from Khorat, the informal name for the city of Nakhon Ratchasima about 400 kilometres northeast of Bangkok.

The farmers who uncovered the fossils reported the find to scientists at Nakhon Ratchasima Rajabhat University (NRRU), but due to the location dig teams could only collect the fossils when there were no crops in the ground, for a few months each year between 2006 and 2012.

Although the fossils are fragmented, most of the skull and jawbone are complete and Sirindhorna is now one of the best-known iguanodon species in Asia, say researchers from Japan’s Fukui Prefectural University and NRRU.

Iguanodon-like dinosaurs lived in the early Cretaceous Period between 145 million and 100 million years ago, when most of Southeast Asia was covered by jungles, swamps and shallow seas. They may have traveled in herds for protection against predators, like wild elephants today.

Masateru Shibata, a paleontologist at Fukui Prefectural University and the lead author of the research, told Kyodo News that iguanodons are thought to have migrated to Asia from North America and Europe, and that the latest find in northeast Thailand helped researchers establish their range. Iguanodons from the early Cretaceous Period had also been found in Japan, he said, and the discovery of the species from Thailand is “valuable as it shows iguanodons lived in a wide area of Asia.”

The research has been published in the online science journal PLOS-One, and a replica of the full skeleton of the new dinosaur will go on display at the Fukui Prefectural Dinosaur Museum in central Japan on January 30.

Sirindhorna is the ninth new species of dinosaur identified from fossils found in Thailand, all of which were found in the northeast region of Isaan – in the farmland, mountains, and forests that extend from Khorat to Thailand’s Mekong River border with Laos and Cambodia.

Sirindhorna khoratensis replica at Fukui Prefectural University. Photo credit: Fukui Prefectural Dinosaur Museum / Kyodo News

Sirindhorna khoratensis replica at Fukui Prefectural University. Photo credit: Fukui Prefectural Dinosaur Museum / Kyodo News

It is the second Thai dinosaur named after Princess Sirindhorn — Phuwiangosaurus sirindhornae, a 20-metre long suaropod, was named in her honour in 1994.

Northeast Thailand has emerged as a rich source of dinosaur fossils and other archaeological discoveries since the 1970s, when the first fossilized bones were found by prospectors looking for uranium in the broken scarps of Phu Wiang district, 85 kilometres west of the city of Khon Kaen and now a national park.

In 1994, the lucky find of a dinosaur bone by a monk in Kalasin province led to the discovery of a “dinosaur’s graveyard” and the identification of five new species. The discovery site has been developed into a renowned dinosaur museum and paleontology institute. Footprints from tyrannosaurs and other species have been found at several sites in the area.

Archaeologists have also discovered important remains of human occupation in the Middle Mekong Basin, including elaborate pottery and metalwork from grave sites at Ban Chiang and Ban Non Wat in northeast Thailand  — relics of Bronze-Age peoples who lived in the region between 3000 and 4000 years ago.

But experts have warned that the region’s archaeological heritage is threatened by real estate development and looting that takes place before scientists can learn what is there.

Dr. Joyce White, an American archaeologist who has studied the Ban Chiang discoveries since 1976 at the University of Pennsylvania Museum, said at a public lecture in Bangkok last year that the destruction of archaeological sites across the region would have a lasting impact on future prospects for tourism, education, and the rural societies involved.

Dr. White is an expert witness for the US Justice Department in their investigation of a major smuggling case involving antiquities from Ban Chiang and other prehistoric sites in Thailand. As a result of the case, one of the US museums that had accepted donations of smuggled artifacts from Ban Chiang and other Thai archaeological sites returned the artifacts to Thailand in 2014. Resolution of charges against other targets in the case is still ongoing.