Posted by: Pelodiscus on 2016/11/9 1:10:00 2066 reads

Fossils Ancient toothed turtles survived until 160m years ago

Ancient toothed turtles survived until 160m years ago
Today's turtles don't have teeth; they cut off their food using hard ridges on their jaws. But their ancestors were not so dentally challenged. A team of international researchers including Dr. Márton Rabi from the Biogeology Lab of the University of Tübingen has now discovered that turtles with remnants of teeth survived 30 million years later than previously thought. The researchers found evidence of this at a major excavation site in China's western Autonomous Region of Xinjiang. Up to now, the most recent finds of toothed turtles were 190 million years old. The new discovery also helps to fill in some of the puzzle pieces in the chelonian family tree and in the distribution of the family over many millions of years. The researchers have published their findings in the latest edition of BMC Evolutionary Biology.



The Xinjiang site of Wucaiwan is well known for the remarkable Middle to Late Jurassic dinosaur fossils found there. But among the extinct giants are the fossils of many other animals which shed light on the long evolutionary history of tortoises and turtles, of which more than 350 different species live around the world today. A team headed by study co-author Dr. Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing identified a previously unknown extinct chelonian species, naming it Sichuanchelys palatodentata – the turtle with a toothed palate. "Scientists had previously known that the earliest turtles still had teeth in their palates, a primitive feature they inherited from their reptilian ancestors," says lead author Dr. Walter Joyce from the University of Fribourg, Switzerland. "Previously, the last toothed turtle, however, was known from 30 million years older rocks. It is therefore a great surprise to find a toothed turtle that survived even longer."

Photo: Reconstruction of the newly discovered toothed turtle Sichuanchelys palatodentata from the Middle Jurassic site of Wucaiwan, Xinjiang, China. Credit: Lida Xing
Read the whole story at: http://phys.org/news/2016-11-ancient- ... urtles-survived-160m.html