Polacanthus

The polacanth was an ankylosaurian dinosaur from the Early Cretaceous period of England. It was discovered on the Isle of Wight in 1865. The names come from the ancient Greek polys-/πολύς- "many" and akantha/ἄκανθα "thorn" or "prickle". It was an armored dinosaur with a row of spikes running down its sides and tail and an extra layer of spikes on its shoulders.

The polacanth was a medium-sized ankylosaur. The body had a thickened bone layer with osteoderms on its hips. It had a large "pelvic shield", a single fused sheet of dermal bone over its hips decorated with tubercles. 

The front body consists of five barbs on the right side and two on the left. The tail rows consisted of fifteen barbs that still exist, twenty-two shorter pairs, seven on the right and eight on the left.

Polacanthus preferred to live alone or in pairs or in three groups but did not tolerate more than six other dinosaurs in its enclosure. It reached about 5 meters in length and weighed 2 tons.