In a recent study published in Scientific Reports, a team of researchers led by Gustavo Darlim and Márton Rabi has unveiled a newly discovered species of ancient alligator from Thailand. This remarkable find, closely related to the Chinese alligator (Alligator sinensis), sheds light on the evolutionary history of Asian alligators.
The scientists named the newfound species Alligator munensis, drawing inspiration from the nearby Mun River. To identify the species, the team extensively examined a remarkably well-preserved fossilized skull, estimated to be younger than 230,000 years old, from the Ban Si Liam region in Thailand.
By comparing the remains of A. munensis with those of 19 specimens from four extinct alligator species, as well as the living American alligator (Alligator mississippiensis), Chinese alligator, and spectacled caiman (Caiman crocodilus), the researchers were able to unravel the evolutionary relationships between these species. They also delved into previously published research on the skeletal characteristics and evolutionary connections of alligator species.
The study uncovered distinctive features of the A. munensis skull. These include a wide and short snout, a tall skull, a reduced number of tooth sockets, and nostrils positioned far from the snout's tip. Additionally, the researchers noted similarities between the skulls of A. munensis and the Chinese alligator, such as a small opening in the roof of the mouth, a ridge atop the skull, and an elevated ridge behind the nostrils.
Based on their findings, the scientists propose that A. munensis and the Chinese alligator are closely related, possibly sharing a common ancestor in the lowlands of the Yangtze-Xi and Mekong-Chao Phraya river systems. They speculate that geological shifts, specifically the rising elevation of the southeastern Tibetan Plateau between 23 and five million years ago, could have led to population isolation and the subsequent evolution of these two distinct species.
Furthermore, the researchers discovered large tooth sockets toward the back of A. munensis's mouth, suggesting that it possessed formidable teeth capable of crushing shells. This observation led the team to hypothesize that A. munensis may have consumed hard-shelled prey, including snails, in addition to other animals.
The study significantly contributes to our understanding of the evolution of Asian alligators. By examining the unique skull characteristics and exploring the interconnections between different species, the researchers have shed light on the ancient history and evolutionary adaptations of these fascinating reptiles.
Source: Nature Publishing Group