Pterichthyodes milleri, Placoderm Pachycephalosaurus had an oval outline

had an oval outline

5 million years ago having existed for approximately 11

human hunting was likely a strong contributing factor

4 inches high

Pterichthyodes milleri, Placoderm Pachycephalosaurus had an oval outlinePterichthyodes is a genus of antiarch placoderm fishes from the Devonian period. Its fossils have been discovered in Sandwich Fish Beds of Ouoyloo, Orkney Islands, Scotland. They were one of the first species recognized for what they were, as their fossils are common in the Old Red Sandstone formation studied by geologists in the early 19th century. Due to their extreme divergence from modern day fish, they were a puzzle unsolved until Charles Darwin