The dortokidae are a family of poorly known basal pan-pleurodiran turtles that live throughout Europe from the Early Cretaceous to the Paleogene.
The fossil remains 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.
Originally found on the Isle of Wight beach, the turtle fossil is an almost complete shell with cervical, dorsal, and caudal vertebrae, scapulae, pelvic girdle, and appendicular bones. Sadly, the skull was missing.
Lead author, Megan Jacobs, said: “This is an amazing discovery because it’s the first time this type of turtle has been found in the UK. Even more exciting is that we used a new radiometric dating technique to determine the fossil’s age beyond any doubt. And to top it off, CT scanning revealed all the tiny bones inside. It’s incredible for what looks like a rolled beach pebble!”
Megan and colleagues dissected minerals from inside the turtle shell. They analyzed them for uranium and lead, establishing that the turtle was from the Lower Cretaceous period, around 127 million years ago.
The fossil was initially found on the foreshore at Brook Bay on the southwest coast of the Isle of Wight by fossil collector Steve Bur. This is the first radiometric dating used on a fossil from the Wessex Formation on the Isle of Wight.
The researchers used cutting-edge micro CT scanning at the University of Portsmouth’s Future Technology Centre to discern tiny bones.
The new turtle described here is a pan-pleurodiran, the oldest record of this lineage in the UK, corresponding to the alone found in the country’s Mesozoic levels. It belongs to the Dortokidae family and is related to the spanish lower cretaceous dortokid eodortoka orellana.