The cladogram presented below, covering all currently recognized eurypterid families, follows a 2007 study by O. Erik Tetlie. The stylonurine suborder follows a 2010 study by James Lamsdell, Simon J. Braddy and Tetlie. The superfamily "Megalograptoidea", recognized by Tetlie in 2007 and then placed between the Onychopterelloidea and Eurypteroidea, has been omitted as more recent studies suggest that the megalograptids were members of the superfamily Carcinosomatoidea. As such, the phylogeny of the Carcinosomatoidea follows a 2015 study by Lamsdell and colleagues.