Paleontologists have identified a new species of sauropod dinosaur from fossils discovered in northeastern Thailand.
The species, named Nagatitan chaiyaphumensis, is the largest dinosaur known from Southeast Asia. The findings were published in the peer-reviewed journal Scientific Reports on May 14, 2026.
Discovery and Excavation
- Initial Discovery: In 2016, a local resident in Chaiyaphum province, Thailand, noticed large bones along the edge of a pond during the dry season. The resident was identified as Thanom Luangnan by some sources.
- Excavation Timeline: Initial excavations were conducted between 2016 and 2019. Funding was paused in 2020 but resumed in 2023 or 2024 with a grant from the National Geographic Society. The excavation was completed in 2024.
- Recovered Fossils: Approximately a dozen bones were recovered, including spine vertebrae (eight), ribs (five), parts of the pelvis, a femur (upper hind leg bone), and two humeri (upper front leg bones). No skull or teeth were found.
Description and Size
- Classification: Nagatitan chaiyaphumensis is a sauropod, a long-necked, herbivorous dinosaur. It is classified within the subfamily Euhelopodidae.
- Estimated Dimensions: Based on the recovered bones, the dinosaur is estimated to have been approximately 27 meters (88-90 feet) long. Estimated body mass ranges from 25 to 28 tons, with most sources stating approximately 27 tons.
- Key Measurement: A single humerus (upper front leg bone) measured between 1.77 and 1.78 meters (approximately 5.8 to 6 feet) in length.
- Distinguishing Features: Unique features were identified in its spine, pelvis, and legs, justifying its classification as a new species.
Geological and Temporal Context
- Time Period: The dinosaur lived during the late Early Cretaceous period, approximately 100 to 120 million years ago.
- Location: The fossils were found in the Khok Kruat Formation, the youngest dinosaur-bearing rock formation in Thailand. The area now known as the Khorat Plateau later became a shallow sea.
- Regional Significance: Researchers have stated that due to the geological changes that turned the region into a shallow sea, Nagatitan may be the last or most recent large sauropod likely to be discovered in Southeast Asia.
Naming
- The genus name, Nagatitan, combines "Naga" (a mythological serpent-like being in Southeast Asian and Buddhist folklore) and "titan" (referring to giants in Greek mythology).
- The species name, chaiyaphumensis, refers to Chaiyaphum province, where the fossils were found.
Ecosystem and Paleoecology
- Diet: Based on comparison with other sauropods, Nagatitan was likely a bulk browser that consumed large volumes of vegetation, such as conifers and possibly seed ferns, requiring minimal chewing.
- Habitat: The climate at the time was subtropical, featuring forests, savanna, and shrubland habitats.
- Coexisting Species: The dinosaur shared its ecosystem with other dinosaurs, pterosaurs, crocodiles, fish, and freshwater sharks.
- Predation: The largest predator in the ecosystem was a carcharodontosaurid, estimated to be approximately 8 meters (26 feet) long and weighing about 3.5 tons. Researchers have noted that a healthy adult Nagatitan likely faced little threat from predators due to its size. Juvenile sauropods may have grown quickly to reduce predation risk.
Research Team
- The study was co-led by Thitiwoot Sethapanichsakul, a PhD student at University College London, and Sita Manitkoon of Mahasarakham University.
- Paul Upchurch, a paleobiologist at University College London, is a co-author of the study.
- Researchers utilized 3D scanning and printing to study the specimen across institutions in Thailand and University College London.
Public Display
A life-sized reconstruction of Nagatitan chaiyaphumensis is on display as a centerpiece at the Thainosaur Museum in Bangkok.