the posterior borders of the plates. In the middle of the tergites, the ornamentation is more pronounced than at their borders, taking the form of semi-lunar (almost moon-shaped) scales. Further back on the eurypterids' body, these scales change into larger scales grouped into large longitudinal ridges. On the borders of the later tergites, these large scales protrude and form structures similar to crenulations. The longitudinal ridges divide the tergites of Vernonopterus into axial (spine) and pleural (ribs) parts, which differentiates it from all other hibbertopterids. History of research The holotype and only known specimen of Vernonopterus was discovered by local fossil hunter Robert Dunlop in coal measures at Mount Vernon near Airdrie in Lanarkshire, Scotland in 1884. The fossil, at the present stored at the Royal Scottish Museum with the specimen number 1957.1.4992, consists of a series of fragmentary tergites. It wasn't described scientifically until 1905, when British geologist Ben Peach described the specimen and assigned it to a new species of the genus Glyptoscorpius (a name today recognized as synonymous with Adelophthalmus) as G. minutisculptus. Peach's description has been criticized by later researchers as inadequate and in some ways misleading. Peach considered the fossil's horizon to prove that Glyptoscorpius was a land animal since it was preserved alongside plant fossils. The specific name minutisculptus refers to the ornementation that covers the entirety of the preserved portions of the animal. The specimen was given a more complete description by British geologist Charles D. Waterston in 1957, who instead referred it to the genus Eurypterus as E. minutisculptus. By this time it had been encased in a collar of "fibrenyle" packaging (a type of plastic) to give strength to and preserve the very fragile fossil. Features revealed during Waterston's second examination of the fossil in 1968 made it clear that the eurypterid was not congeneric with known species of Eurypterus, nor part of the eurypterine suborder (eurypterids that possessed swimming paddles) at all. Instead, Waterston inferred that E. minutisculptus had very clearly been a broad-bodied and large eurypterid, although any detailed statements about the prosoma (head), appendages and the telson (the posteriormost division of the body, often taking the shape of a tail spike) could not be made as those portions of the body were unknown. Waterston created a new genus to contain the species, Vernonopterus, with the name deriving from the location where the fossil had been found, Mount Vernon.