First fossilized snake embryo ever discovered rewrites history of ancient snakes

The first-ever discovery of an ancient snake embryo, preserved in 105-million-year-old amber, provides important new information on the evolution of modern snakes, according to a new study led by University of Alberta paleontologists.

"This snake is linked to ancient snakes from Argentina, Africa, India and Australia," explained paleontologist Michael Caldwell, lead author and professor in the Department of Biological Sciences. "It is an important—and until now, missing—component of understanding snake evolution from southern continents, that is Gondwana, in the mid-Mesozoic."

Caldwell and his international team, including collaborators from Australia, China and the United States, have tracked the migration of these ancient Gondwanan snakes beginning 180 million years ago when they were carried by tectonic movements of continents and parts of continents, from Australia and India, to Madagascar and Africa, and finally to Asia, in modern-day India and Myanmar.

The amber fragment in which the specimen was found also provided important clues about its environment.

"It is clear that this little snake was living in a forested environment with numerous insects and plants, as these are preserved in the clast," explained Caldwell. "Not only do we have the first baby snake, we also have the first definitive evidence of a fossil snake living in a forest."

Using CT scans, the scientific team studied the ancient snake and compared it with the young of modern snakes. Their results yielded unexpected insight into the development and embryology of the ancient specimen, including the formation of the vertebrae and notochord.

"All of these data refine our understanding of early snake evolution, as 100-million year-old snakes are known from only 20 or so relatively complete fossil snake species," said Caldwell. "There is a great deal of new information preserved in this new fossilized baby snake."

The paper, "A Mid-Cretaceous Embryonic-to-Neonate Snake in Amber From Myanmar," was published in Science Advances.