A recent study published in Scientific Reports details the discovery of a previously undiscovered ancient crocodile species in Thailand that has a close evolutionary relationship with the alligator (Alligatorsinensis).
The picture above shows an alligator, which is closely related to the newly discovered Thai alligator (Alligatormunensis). This groundbreaking study reveals unique skull features and provides a deeper understanding of the evolutionary context of Asian crocodiles.
Researchers Gustavo Darlim, Márton Rabi, Kantapon Suraprasit, Pannipa Tian and their team identified the new species by studying an almost complete skull fossil from Ban Si Liam in Thailand. They named the species Alligatormunensis in honor of the nearby Munn River.
The authors studied the remains and examined the evolutionary relationships between the crocodile and other species by comparing it with the remains of 19 specimens from four extinct crocodile species, the extant American crocodile (Alligator mississippiensis), the Chinese alligator (Chinese crocodile) and the spectacled crocodile (Caimancrocodilus). They also reviewed previously published studies on the skeletal characteristics and evolutionary relationships of alligator species.
The authors found several skull features unique to A. munensis, including a wide and short snout, a tall skull, a reduced number of alveoli, and a location of the nostrils away from the tip of the snout. Additionally, they noticed similarities between alligator and alligator skulls, such as a small opening in the roof of the mouth, a ridge on top of the skull, and a raised ridge behind the nostrils.
They believe that the two species are closely related and may have a common ancestor in the lowlands of the Yangtze-Xijiang and Mekong-Chao Phraya river systems. They speculate that the elevation of the southeastern Tibetan Plateau between 23 million and 5 million years ago may have caused the separation of different populations and the evolution of two different species.
The authors observed that A.munensis had large alveoli at the back of its mouth, suggesting that it may have had large teeth capable of crushing shells. Therefore, they believe that A.munensis may eat hard-shelled prey such as snails in addition to other animals.
The findings shed further light on the evolution of Asian alligators.