Siamraptor suwati: New Giant Carnivorous Dinosaur Unveiled

Friday, October 11, 2019

Siamraptor suwati. Credit: Marcio L. Castro

Paleontologists have announced the discovery of a new genus and species of carcharodontosaurian dinosaur, based on the fossilized remains found in Thailand.

Dubbed Siamraptor suwati by its discoverers, the newly-discovered dinosaur lived approximately 120 million years ago (Cretaceous period).

The ancient creature was a member of Carcharodontosauria, a group of large carnivorous dinosaurs from the Jurassic and Cretaceous periods.

In fact, Siamraptor suwati is the oldest carcharodontosaurian dinosaur known and is the first of its kind from Southeast Asia.

Skeletal reconstruction of Siamraptor suwati. Scale bar – 1 m. Image credit: Chokchaloemwong et al, doi: 10.1371/journal.pone.0222489.

The fossilized remains of at least four Siamraptor suwati individuals — skull, backbone, limbs, and hips — were recovered from the Khok Kruat Formation in Nakhon Ratchasima province, Thailand.

The fossils were analyzed by Dr. Duangsuda Chokchaloemwong of Nakhon Ratchasima Rajabhat University and her colleagues from Thailand and Japan.

“The phylogenetic analyses revealed that Siamraptor suwati is a basal species of Carcharodontosauria, involving a new sight of the paleobiogeographical context of this group,” the paleontologists said.

Siamraptor suwati is the best preserved carcharodontosaurian theropod in Southeast Asia, and it sheds new light on the early evolutionary history of Carcharodontosauria.”

Locality map of new theropod material and stratigraphy of Khorat Group: A – map of Nakhon Ratchasima Province, Thailand; B – distribution map of the Khok Kruat Formation in Nakhon Ratchasima Province; C – enlarged locality map of Suranaree and Khok Kruat subdistricts with the subdistrict boundaries; D – a photograph of the excavation site; E – stratigraphic column of the Khorat Group. A red-colored star indicates the new theropod locality, the dotted lines indicate the subdistrict boundaries, and the gray-colored lines indicate the roads in C, respectively. Image credit: Chokchaloemwong et al, doi: 10.1371/journal.pone.0222489.

The team’s paper was published online October 9, 2019 in the journal PLoS ONE.


D. Chokchaloemwong et al. 2019. A new carcharodontosaurian theropod (Dinosauria: Saurischia) from the Lower Cretaceous of Thailand. PLoS ONE 14 (10): e0222489; doi: 10.1371/journal.pone.0222489