The species "P. nobilis", described in 1872, is based on a small and fragmentary chelicera found in what today is the Czech Republic. The arrangement of teeth seen in this claw, though most teeth are not preserved, was noted by researcher Max Semper in 1897 as sharing little to no resemblance with what is seen in the type species of "Pterygotus", "P. anglicus", and was noted to in fact be more similar to what is seen in "P. buffaloensis" and "P. bohemicus". Today "P. buffaloensis" is considered a junior synonym of "P. bohemicus", which has been reclassified as part of the closely related genus "Acutiramus". The fragmentary remains of "P. nobilis" makes further studies of its precise identity difficult, Semper suggested that it may be synonymous with "Acutiramus bohemicus", but noted that the "questions its identity can not be answered from the material available to me".