Fossilised fish. Dapedius (Dapedium sp.) is an enamel-scaled fish that lived primarily in the Triassic-Jurassic period (210-180 million years ago). Its strong, prominent teeth allowed it to feed on hard-shelled invertebrates such as mussels and sea urchins, while its moveable upper jaw could be protruded for a wider gape when eating larger prey. The pale yellow spiral on the left is an ammonite, a prehistoric mollusc that emerged in the early Devonian period (400 million years ago). It is likely that ammonites were also Depedius prey, as they did not become extinct until about 65 million years ago. Fossil found in Lyme Regis, Dorset, UK.