East Riding Museums

Fossil ichthyosaur ribs. Light grey to buff, partially obscured by concretions. From Speeton clay (found at grid reference TA 146761). Ichthyosaurs were large sea-dwelling reptiles of the Mesozoic period (about 248-66 million years ago). They had a shape resembling dolphins in many respects, with fins and a powerful tail for swimming. Their long jaws were packed with large numbers of small, sharp teeth. They had large eyes and nostrils near the top of the skull to enable easier breathing when surfacing from underwater.