name of the species comes from its place of discovery – the Salina shale formations of Pittsford, New York. Eurypterus quebecensis Kjellesvig-Waering, 1958 – Silurian, Canada Has six raised scales on the posterior margin of the carapace but does not possess pustule ornamentation. It is named after the location it was recovered from Quebec, Canada. Eurypterus remipes DeKay, 1825 – Silurian, USA, Canada = Carcinosoma trigona (Ruedemann, 1916) – Silurian, USA The most common Eurypterus species. Has four raised scales at the posterior margin of the carapace. Appendages I to IV has two spines on each podomere. Postabdomen has small epimera. Pretelson has small, semiangular epimera with imbricate scale ornamentation at the margins. The telson has serrated margins along most of its length. It is very similar to E. lacustris and can often only be distinguished by the position of the eyes. The specific name means 'oar-foot', from Latin ('oar') and ('foot'). Found in New York and Ontario. Eurypterus serratus (Jones & Woodward, 1888) – Silurian, Sweden Similar to E. pittsfordensis and E. leopoldi but can be distinguished by the dense angular striations on their styliform telson. The specific name means 'serrated', from Latin ('sawn [into pieces]'). Originally discovered from Gotland, Sweden. Eurypterus tetragonophthalmus Fischer, 1839 – Silurian, Ukraine & Estonia = Eurypterus fischeri Eichwald, 1854 – Silurian, Ukraine = Eurypterus fischeri var. rectangularis Schmidt, 1883 – Silurian, Estonia Four raised scales on the posterior margin of the carapce. Appendages II to IV each have two spines on each podomere. Postabdomen has small epimera. The pretelson has large, rounded epimera with imbricate scale ornamentation at the margins. Telson has imbricate scale ornamentations at the margins of the base which become serrations towards the tip. The specific name means 'four-edged eye', from Greek ( 'four'), ( 'angle'), and ( 'eye'). Found in the Rootsiküla Formation of Saaremaa (Ösel), Estonia, with additional discoveries in Ukraine, Norway, and possibly Moldova and Romania. The list does not include the large number of fossils previously classified under Eurypterus. Most of them are now reclassified to other genera, identified as other animals (like crustaceans) or pseudofossils, or remains of doubtful placement. Classification is based on Dunlop et al.(2011). Paleobiology Eurypterus belongs to the suborder Eurypterina, eurypterids in which the sixth appendage had developed a broad swimming paddle remarkably similar to that of the modern-day swimming crab. Modeling studies on Eurypterus swimming behavior suggest that they utilized