Campylocephalus  Campylocephalus is a genus of eurypterid, a group of extinct aquatic arthropods. Fossils of "Campylocephalus" have been discovered in deposits ranging from the Carboniferous period in the Czech Republic (the species "C. salmi") to the Permian period of Russia (species "C. oculatus" and "C. permianus"). The generic name is composed of the Greek words καμπύλος ("kampýlos"), meaning "curved", and κεφαλή ("kephalē"), meaning "head". It was a member of the hibbertopterid family of eurypterids and probably looked much the same as the other members of the family, "Hibbertopterus" and "Vernonopterus", in that it was a large, broad and heavy animal quite different from the famous swimming eurypterids (such as "Pterygotus" and "Eurypterus") which had been common during earlier periods. Like all other stylonurine eurypterids, "Campylocephalus" completely lacked swimming paddles. Hibbertopterids such as "Campylocephalus" were, as many other families within the stylonurine suborder, sweep-feeders. Sweep-feeding food strategies involve specialized appendages with blades that could be used by the animals to rake through the substrate of their living environments in search for small prey items. The species "C. permianus", known from deposits of Late Permian age in Russia, is the only species of "Campylocephalus" preserved well enough to allow for size estimates, published estimates putting its size at potentially 1.4 metres (4.6 feet) in length. This species was the last known surviving eurypterid, living just before or during the Permian–Triassic extinction event 251.9 million years ago. Before the extinction event, eurypterids had been declining in numbers and diversity for millions of years, "Campylocephalus" had been the only known genus of living eurypterids for more than 20 million years since the extinction of the related genus "Hastimima". Classified as a member of the hibbertopterid family of eurypterids, "Campylocephalus" was overall similar to the other members of the family.