The Dortokidae are a group of poorly known ancient pan-pleurodiran turtles, endemic to Europe with a range from the Early Cretaceous to the Paleogene. In a new paper in the journal Cretaceous Research, paleontologists report the oldest record of a pan-pleurodiran turtle in the United Kingdom, as well as the first and only occurrence of a dortokid in the UK.
The new specimen was found in the Early Cretaceous Wessex Formation of the Isle of Wight by fossil collector Steve Burbridge.
It comprises a relatively complete shell with post cranial elements within a calcite-filled shell vacuity.
The fossils are the earliest of a so-called side-necked pan-pleurodiran turtle, named as such because they fold their neck into their shell sideways when threatened.
“This is an amazing discovery because it’s the first time this type of turtle has been found in the UK,” said Dr. Megan Jacobs, a paleontologist at the University of Portsmouth.
“Even more exciting is that we used a new technique of radiometric dating to determine the age of the fossil beyond any doubt.”
“And to top it off, CT scanning revealed all the tiny bones inside. It’s really incredible for what looks like a rolled beach pebble!”
Dr. Megan and colleagues dissected minerals from inside the turtle shell and analyzed them for uranium and lead.
By measuring the ratio of lead to radioactive uranium, they established the turtle was from the Early Cretaceous epoch, around 127 million years ago.
They identified it as Eodortoka cf. morellana, a species of dortokid turtle previously known from Spain.
“We’ve nicknamed the turtle ‘Burby’ after Steve who very kindly donated the specimen to the Dinosaur Isle Museum at Sandown on the Isle of Wight,” Dr. Jacobs said.
The paleontologists also used cutting-edge micro CT scanning to discern various tiny bones.
This advanced imaging technique provided invaluable insight into the structure and composition of the turtle’s shell, without damaging…
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