The picture above shows a Chinese alligator, closely related to the newly discovered one Alligator munensis from Thailand. This groundbreaking research reveals unique skull characteristics and offers a deeper dive into the evolutionary lineage of Asian alligators.
A study recently published in Scientific reports describes the discovery of a previously unidentified ancient alligator species found in Thailand, which shares close evolutionary ties with the Chinese alligator (Alligator sinensis).
Researchers Gustavo Darlim, Márton Rabi, Kantapon Suraprasit, Pannipa Tian and their team identified the new species by examining a nearly complete fossilized skull – which they date to younger than 230,000 years old – from Ban Si Liam, Thailand. They have named the species Alligator munensis referring to the nearby Mun River.
The authors examined the remains and examined the evolutionary relationships between A. munensis and other species by comparing its remains with those from 19 specimens from four extinct alligator species, as well as the living American alligator (Alligator mississippiensis), Chinese alligator and spectacled caiman (Caiman crocodile) species. They also reviewed previously published research on skeletal characteristics and evolutionary relationships among alligator species.
The authors identified several skull features that are unique to A. munensis, including a wide and short muzzle, a high skull, reduced number of dental cavities and nostrils that are located far from the tip of the snout. In addition, they note similarities between the skulls of A. munensis and the Chinese alligator, such as the presence of a small opening in the roof of the mouth, a ridge on top of the skull and a raised ridge behind the nostrils.
They suggest 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 increases in the elevation of the southeastern Tibetan Plateau between 23 and five million years ago may have led to the separation of different populations and the development of two separate species.
The authors noted that A. munensis has large tooth cavities towards the back of the mouth, indicating that it may have had large teeth that could have been able to crush shells. As a result of this, they suggest that A. munensis may have eaten hard-shelled prey, such as snails, in addition to other animals.
The findings provide further insight into the evolution of Asian alligators.
Reference: “An extinct alligator species from Quaternary Thailand and comments on the evolution of crushing dentition in alligatorids” by Gustavo Darlim, Kantapon Suraprasit, Yaowalak Chaimanee, Pannipa Tian, Chotima Yamee, Mana Rugbumrung and Adulrwit Máweerrung. , 13 July 2023, Scientific reports.
DOI: 10.1038/s41598-023-36559-6
