This fossil of an ancient fish – Platysomus – is from the Permian age and is over 250 million years old. It was found in the Middridge Quarry in County Durham, a site considered to be of international significance because of the number of important fossils found there. It shows the shape and size of the whole fish, which would have been fairly flat with ray fins and thick scales. Studying fossils of scaled fish like this helped scientists understand how teeth, jaws and bones evolved.
Image courtesy of Middlesbrough Museum Service