Eurypteroidea are an extinct superfamily of eurypterids. It contains three families (Dolichopteridae, Eurypteridae, Strobilopteridae) and two genera of uncertain classification, Paraeurypterus and Pentlandopterus.[1]
Eurypteroidea, which lived from the Ordovician to Devonian periods, were characterized by their last pair of prosomal (head) appendages, which were developed as swimming legs, carrying paddles formed by the expansion of the two penultimate joints.[2]