Scientists found the oldest known lizard fossil that dates back from 240 million years ago. During this time, dinosaurs were just emerging, and Earth only had the large landmass of Pangea.
Researchers say that this fossil belongs to the ancestor of today's lizards and snakes.
Oldest Known Lizard Fossil
The discovery of this new fossil moves back the timeline for the emergence of lizards on Earth by 75 million years. The fossil of the small lizard known as Megachirella wachtleri was found in rock in the Italian Alps. It is a member of the group of reptiles called squamates, which includes lizards, snakes, and worm lizards.
This discovery shows that squamates appeared far earlier than previously thought and that they were able to survive the mass extinction that occurred when the dinosaurs died out. All modern squamates evolved from the Megachirella wachtleri.
Researchers from the University of Bristol and the University of Alberta in Canada published their findings in the journal Nature. Prior to their findings, scientists believed that squamates had branched off from ancient reptiles prior to the Permian/Triassic mass extinction about 252 million years ago. During that mass extinction, 95 percent of marine life and 75 percent of terrestrial creatures went extinct.
The chameleon-sized Megachirella fossil was discovered 20 years ago. It was discovered in compacted sand and clay layers in the Dolomites mountain range in Italy. Originally, it had been misclassified as a different lizard relative.
Researchers were able to identify the fossil as Megachirella after performing a detailed analysis of the fossil. They also used a CT scan that revealed unseen physical characteristics, which included a tiny bone in the lower jaw that is found in other squamates.
They were able to create a 3D model of the fossil using the CT scan. This allowed them to examine the underside of the fossil, which was still embedded in rock.
To arrive at their conclusions, coauthor of the study Tiago Simoes says that he traveled to more than 50 museums and universities in 17 countries to collect fossil data and study living reptiles to understand their evolution.
Findings reveal that Megachirella lived along shorelines. The fossil of the Megachirella died in the Dolomites during a thunderstorm in the area. The area was once a series of islands that feature rich vegetation and fine sand beaches. The Megachirella in the fossil died when it was taken by a thunderstorm because the layer features plant and debris from land that went into the sea.