Turtles are more closely related to birds and dinosaurs than to lizards and snakes, scientists have found.
Researchers from the California Academy of Sciences used a next-generation genetic sequencing technique called Ultra Conserved Elements (UCE) to reconstruct a robust turtle 'tree of life' and fill-in existing knowledge gaps.
The new genetic tree uses an enormous amount of data to refute the notion that turtles are most closely related to lizards and snakes.
Instead, researchers place turtles in the newly named group "Archelosauria" with their closest relatives: birds, crocodiles, and dinosaurs.
Scientists believe the new group will be the largest group of vertebrates to ever receive a new scientific name.
The study findings also resolve an evolutionary mystery surrounding softshell turtles - a bizarre group of scale-less turtles with snorkel-like snouts.
Until now, studies linked softshell turtles with a smaller semi-aquatic group called mud turtles, despite the fact that softshells appear in the fossil record long before their mud-loving counterparts.
The study places softshells in a league of their own on the evolutionary tree, quite far removed from any turtle relatives. Their long independent history helps explain their striking looks as well as their ancient presence in the fossil record.
"The turtle tree of life based on fossil turtle anatomy didn't match up with the timing of their appearance in the fossil record, as well as their geography," said study coauthor James Parham, Assistant Professor of Geological Sciences at Cal State Fullerton, and turtle expert.
"But the tree of life generated at the Academy's Center for Comparative Genomics is consistent with time and space patterns we've gathered from the fossil record. These new testing techniques help reconcile the information from DNA and fossils, making us confident that we've found the right tree," Parham said.
The research is published in the journal Molecular Phylogenetics and Evolution.
