Pterygotus (name meaning "Winged One") is a genus of large eurypterid that originated during the Late Silurian Era in what is now North America and Europe. A giant sea scorpion the size of a crocodile, it was a distant ancestor of the modern-day crab and was also among the largest arthropods ever to live.
Thought to have been extinct for 400 million years, there are still some that remain alive on Primeval Island. In fact, they are among the most common eurypterid there, alongside Megalograptus, Brontoscorpio, and Jaekelopterus.