Researchers in India have found the first fossil evidence of durophagous lizards (lizards adapted to eat hard-shelled prey) from the Late Cretaceous period. This is important because until now, we had not found evidence of such feeding adaptations in Indian lizard fossils. It adds a new ecological dimension to what we know about Cretaceous ecosystems in India.
“Durophagous” means animals with teeth and jaws suited for crushing hard food, like snails, clams, or crustaceans.
India contains a rich deposit of fossils
The fossils come from the Lameta Formation, near Padwar, Madhya Pradesh, central India. The Lameta Formation dates to the Late Cretaceous (Maastrichtian, ~70 million years ago), right before the dinosaurs went extinct. This is the same rock unit famous for dinosaur fossils (like Rajasaurus and titanosaurs).
The Deccan Traps in India are considered one of the largest volcanic eruptions since the dawn of visible life on Earth. The associated intertrappean sediments, which were deposited between Deccan lavaflows, are crucial for understanding changes in prehistoric life during the Cretaceous–Palaeogene transition.
Enlarged view of the intertrappean beds. Image credit: : Ravi Yadav and Sanjay Kumar Verma
The intertrappean beds contain a rich record of ancient animal and plant fossils. These include fossil fishes, frogs, snakes, lizards, turtles, crocodiles, rare dinosaurs, and mammals. But until now, researchers had not reported any durophagous lizard teeth from the Indian subcontinent’s fossil record. The discovery means that Cretaceous Indian lizards filled a wider ecological spectrum than previously recognized, and included hard-prey specialists.
“Such tooth morphotypes have not been previously reported from India and provide important insights into the paleobiodiversity of the Indian plate during its northward drift”, the researchers Ravi Yadav & Sanjay Kumar Verma said in their paper published last week. “Research on Late Cretaceous and Early Palaeogene localities in India is therefore vital for better understanding of their evolutionary history.”
The discovery expands our existing knowledge of life in the Cretaceous
The researchers recovered several isolated lizard teeth. These teeth are distinct because they show features linked to durophagy, such as broad, blunt crowns and thick enamel. The teeth also have flattened wear surfaces, which suggests that they were used for grinding or crushing.
SEM images of the Kesavi squamate teeth. IITR/VPL/INT-X/2022/ST-24: A, lateral view; B, occlusal view. IITR/VPL/INT-X/2022/ST-25: C, lateral view; D, occlusal view. IITR/VPL/INT-X/2022/ST-30: E, lateral view; F, occlusal view; I, enlarged lateral view. IITR/VPL/INT-X/2022/ST-28: G, lateral view; H, occlusal view. IITR/VPL/INT-X/2022/ST-23: J, lateral view; K, occlusal view. IITR/VPL/ INT-X/2022/ST-29: L, lateral view; M, occlusal view. Scale bar 1⁄4 200 mm. Image credit: : Ravi Yadav and Sanjay Kumar Verma
The teeth resemble those of living lizards like teiids, skinks, and agamids that crack hard prey today. However, researchers cannot narrow down the fossils to specific genus, though they can confirm that the teeth belong to to lizards (Squamata), because isolated teeth lack enough unique features.
We know that the Lameta Formation was a semi-arid floodplain with seasonal rivers, and it contained hard-shelled prey (snails, mollusks, arthropods). This further indicates that durophagous lizards would have fit well into this environment.
This discovery expands the record of Indian lizards. Since most known fossils are fragmentary jaws or vertebrae;,teeth like these provide direct evidence of diet. The find shows Indian lizard faunas before the Deccan volcanism and K–Pg extinction were more diverse and functionally rich.