A study led by Michael Caldwell, from the university of Alberta in Canada, has shed new light on the evolution of snakes from their legged ancestors. Four fossils found in England, Portugal and the United States that were previously thought to be lizards have been reevaluated and shown to actually be early serpents.
The new fossils were dated to 143-167 million years ago, pushing back the date of the earliest known snake by more than fifty million years. The fossils also contradict a theory which suggested that the characteristic long and thin facial structure of snakes evolved only after the loss of the legs.
The history of this discovery hails back to the 1990’s, when a very fragmented reptile fossil was found in England and interpreted to be a lizard, named Parvicursor. This finding was used as the basis for identifying three subsequent fossils uncovered in other parts of the world, all similar to Parvicursor and so thought to be similar lizards.