Scientists have discovered the tiny remains of a 100-million-year-old baby snake (pictured) preserved inside of a piece of amber from Myanmar. The new species—dubbed Xiaophis myanmarensis—lived in the mid-Cretaceous period, before the Tyrannosaurus rex walked Earth, making this the oldest known baby snake fossil, and the first of its period to be discovered in a forested environment.
The fossil, which was just 5 centimeters in length (about the diameter of a golf ball), was missing its skull, so the team used microscopes and x-ray scanning to analyze the size, shape, and orientation of the bones. The researchers compared the new fossil’s bone structure to an existing database of snake fossils to see where it might fit into the evolutionary record. This revealed that snakes may have moved to forested environments from underwater and coastal regions earlier on that was previously thought, and that the mechanism through which snakes develop their spinal bones has changed very little over millions of years, the researchers report today in Science Advances.
Because the fossil is old and contains a young specimen, the researchers say it is valuable in studying how ancient snake embryos matured; particularly, the development of the joints linking their spinal columns and the closing of the tube that would become the spinal cord were among the last things to occur. Previous mid-Cretaceous snake fossils had only been found in or around water, but this new fossil suggests snakes also liked to hang out in forests, meaning they could have been part of a much greater number of prehistoric ecosystems.