Pterygotus was a large marine arthropod that lived from the Silurian to Devonian. It hunted by hiding under the ground and appear and grab its prey and crush them to pieces. Pterygotus was a good parent taking care of its babies who will not leave the parent until there exoskeleton is hard enough like modern day Scorpions. They may give live birth like mammals and modern day Scorpion. Pterygotus was big enough to eat any prey like Brontoscopio, Dawsonoceratidae and Dipleura.