Researchers have discovered a new turtle species that dates back to the Late Cretaceous. The species is closely related to today's sea turtles and represents a new ancestor of their modern counterparts.
Today's sea turtles are believed to have come from a single ancestor, the Peritresius Group, during the Late Cretaceous, about 100 to 66 million years ago. Previous studies have suggested that Peritresius was found only in North America. Recently discovered specimens in the southeastern United States, however, show that the genus was more widespread and was not confined to any particular region.
In the latest study, the researchers analyzed Sea Turtle fossils from Alabama and Mississippi marine deposits from the Alabama fossils in a whole new way. They named it Peritresius Martini after Mr. George Martin discovered the fossils. The results are based on anatomical features including the shape of the turtle shell. When researchers compared the properties of newly discovered species to Peritresius ornatus, they found that P. ornatus' skin modeled skin elements with blood vessels that allowed their bodies to maintain their internal core temperature or thermoregulation. This is probably why Peritresius kept warm and survived the extreme cold conditions during the Cretaceous, unlike many other extinct sea turtles.
The discovery suggests that Peritresius includes two anatomically distinct Late Cretaceous species and provides new insights into the evolutionary history of living marine turtles
says Drew Gentry of the University of Alabama at Birmingham, Alabama. "This discovery not only answers some important questions about the distribution and diversity of sea turtles at this time, but also provides further evidence that Alabama is one of the best places in the world to study some of the earliest ancestors of modern sea turtles." 1