In a recent study published in Scientific Reports, a team of researchers, including Gustavo Darlim, Márton Rabi, Kantapon Suraprasit, Pannipa Tian, and their colleagues, have unveiled a new species of ancient alligator discovered in Thailand. This species, named Alligator munensis, is closely related to the Chinese alligator (Alligator sinensis).
The discovery was based on the examination of a well-preserved fossilized skull, believed to be younger than 230,000 years old, found in Ban Si Liam, Thailand. The name “munensis” is derived from the nearby Mun River.
Through careful analysis of the remains, the researchers compared A. munensis with 19 specimens from four extinct alligator species, as well as the living American alligator (Alligator mississippiensis), Chinese alligator, and spectacled caiman (Caiman crocodilus) species. They also reviewed previous research on alligator skeletal characteristics and evolutionary relationships.
Several unique skull features were identified in A. munensis, including a broad and short snout, a tall skull, reduced number of tooth sockets, and nostrils located far from the snout tip. Additionally, similarities were noted between the skulls of A. munensis and the Chinese alligator, such as a small opening in the roof of the mouth, a ridge on the top of the skull, and a raised ridge behind the nostrils.
Based on their findings, the researchers propose that A. munensis and the Chinese alligator are closely related and might have shared a common ancestor in the lowlands of the Yangtze-Xi and Mekong-Chao Phraya river systems. They speculate that geological changes, specifically increases in the elevation of the southeastern Tibetan Plateau between 23 and five million years ago, could have led to the separation of populations and the evolution of two distinct species.
Notably, A. munensis exhibited large tooth sockets at the back of its mouth, suggesting it may have had the ability to crush shells. This leads the researchers to speculate that the species might have consumed hard-shelled prey, such as snails, in addition to other animals.
Overall, this discovery offers valuable insights into the evolution of Asian alligators and their ancient history.