Polacanthids in Detail
Not much is known about the polacanthid family, but there are differences that allow for it to be distinguished from the other two families. Until recently the polacanthids were included with the nodosaurid family. The polacanthids lacked a club on their tail, which caused them to be placed in that family. They were first reclassified as a subfamily, but later became a full-fledged family in its own right. What sets them apart is that the polacanthids have the skeleton of a nodosaurid, but the skull of a ankylosaurid. Polacanthids arrived during the mid Jurassic and inhabited North America and Europe.
Gargoyleosaurus