An armoured jawless fish (a Cephalaspis, which is a kind of osteostracan). This creature evolved as it adapted to the transition from open sea to freshwater conditions in the Ludlow area towards the end of the Silurian.
Pachycephalosaurus - the ROM - Kendra Spence Pachycephalosaurus is a genus of pachycephalosaurid dinosaurs. The type species, P. wyomingensis, is the only known species. It lived during the Late Cretaceous Period of what is now North America.