In 1921, Ruedemann described an eurypterid fauna from the Vernon Formation of Pittsford, New York. Among them, the species "P. vernonensis" was erected based on two small short carapaces. The outline and position of the eyes suggest an assignation to the genus "Pterygotus", differing from "P. monroensis" in being nearly rectangular in shape and with a straight transverse frontal margin. He suggested a relationship with "Slimonia", but he did not assigned it due to the lack of more material indicative of the latter. Although it was later placed on the genus "Waeringopterus", Samuel J. Ciurca Jr. and O. Erik Tetlie concluded in 2007 that the holotype does not really have eyes and is nothing more than an incomplete body segment. Therefore, they regarded the species as a "nomen dubium".