Searching for the missing link of reptiles: Scientists continue the search for a mysterious four-legged snake

Complete the links in the evolutionary chain with a fossil record of a “four legged snake” Connecting lizards and snakes first is the desire of paleontologists.

But a sample previously believed to fit the requirements Not the missing piece of the puzzle, according to a new study by Journal of Systematic Paleontology led by a paleontologist Michael Caldwell of the University of Alberta.

“It has long been understood that Snakes are members of a lineage of four-legged vertebrates that have lost limbs as a result of evolutionary specializationSaid Caldwell, lead author of the study and professor of earth sciences, biology, and atmospheric sciences.

“Somewhere in the ancient fossil record of a snake is an ancient form that still had four legs. Thus, It has always been expected to find a four-legged snake as a fossil”.

employment Article published in the magazine Science in 2015A team of researchers has reported the discovery of what is believed to be an example of the first known fossil of a four-legged snake, an animal they named Tetrapodovis embraced.

“If properly interpreted on the basis of preserved anatomy, This will be a very important discovery.”, Diego Caldwell.

Caldwell explained that the new study of Tetrapodovis revealed a series of mischaracterizations of the anatomy and morphology of the specimen, Traits that initially seemed to be closely shared with snakes, suggesting that this could be the most sought after quadrupedal python.

“There are many evolutionary questions that can be answered by finding a four-legged snake fossil, but only if it is real. The main conclusion of our team is that Tetrapodovis It’s not actually a snake and it’s been misclassifiedInstead, all aspects of their anatomy are consistent with the anatomy observed in a group of extinct marine lizards from the Cretaceous period known as dolicosaurs“.

Caldwell pointed to evidence for this conclusion, It was hidden in the rock from which the fossil was extracted.

When the rock containing the specimen was opened and discovered, the skeleton and skull ended up on opposite sides of the slab, With a natural mold keep the shape of each one on the other side,” Caldwell said. “The original study only described the skull and omitted the natural mold, which retained several features that illustrate this. Tetrapodovis It didn’t have a snake skull, not even a primitive skull.”