New extinct species of Asian alligator identified

July 13 () –

A new species of ancient alligator from Thailand that is closely related to the Chinese alligator (‘Alligator sinensis’) has been described in the journal Scientific Reports.

Gustavo Darlim and Márton Rabi, from the University of Tübingen (Germany) and Kantapon Suraprasit and Pannipa Tian, ​​from the University of Bangkok (Thailand), together with their colleagues, identified the new species by examining an almost complete fossilized skull –dating to less than 230,000 years old– from Ban Si Liam, Thailand. They have named the species ‘Alligator munensis’ after the nearby Mun River.

The authors examined the remains and investigated the evolutionary relationships between ‘A. munensis’ and other species by comparing their remains with those of 19 specimens of four extinct alligator species, as well as living species of American alligator (‘Alligator mississippiensis’), Chinese alligator, and spectacled alligator (‘Caiman crocodilus’).

They also reviewed previously published research on skeletal features and evolutionary relationships among alligator species. The findings provide further insight into the evolution of Asian alligators.

The authors identified several unique cranial features of ‘A. munensis’, as a broad, short snout, a high skull, a reduced number of dental cavities, and nostrils set back from the tip of the snout. In addition, they observe similarities between the skulls of ‘A. munensis’ and the Chinese alligator, such as the presence of a small opening in the palate, a crest on top of the skull and a raised crest behind the nostrils.

They propose that the two species are closely related and may have shared a common ancestor in the lowlands of the Yangtze-Xi and Mekong-Chao Phraya river systems. They speculate that the elevation of the southeastern Tibetan Plateau increased between 23 and 5 million years ago. it may have caused the separation of different populations and the evolution of two different species.

The authors observed that ‘A. munensis’ has large dental cavities towards the back of the mouth, indicating that it may have possessed large teeth capable of crushing shells. Therefore, they suggest that ‘A. munensis’ it might have eaten hard-shelled prey, such as snails, in addition to other animals.