page_title: Pterygotidae
section_title: History of research
hierarchical_section_title: Pterygotidae / History of research
caption_attribution_description: ^^
context_page_description: Pterygotidae is a family of eurypterids, an extinct group of aquatic arthropods. They were members of the superfamily Pterygotioidea. Pterygotids were the largest known arthropods to have ever lived with some members of the family, such as Jaekelopterus and Acutiramus, exceeding 2 metres in length. Their fossilized remains have been recovered in deposits ranging in age from 428 to 372 million years old.
  One of the most successful groups of eurypterids, the pterygotids were the only eurypterid family to achieve a truly worldwide distribution. Several evolutionary innovations made the pterygotids unique among the eurypterids, with large and flattened telsons likely used as rudders to provide additional agility and enlarged chelicerae with claws. These claws were robust and possessed teeth which would have made many members of the group formidable predators. The strange proportions and large size of the pterygotid eurypterids led to the quarrymen who discovered the very first fossil remains of the group to give them the common name "Seraphims".
context_section_description: Due to their unique features within the Eurypterida, the Pterygotidae has attracted a lot of attention ever since their discovery. The first fossils found, discovered by quarrymen in Scotland, were referred to as "Seraphims" by the quarrymen. When describing Pterygotus itself in 1839, Louis Agassiz first thought the fossils represented remains of fish, with the name meaning "winged fish", and only recognized their nature as arthropod remains five years later in 1844.
  By 1859, 10 species (many of which would later be reassigned) had been assigned to Pterygotus. John William Salter recognized that it was possible to divide Pterygotus based on the morphology of the telsons of the species that had been assigned to it. He divided Pterygotus into subgenera, erecting Pterygotus (Erettopterus) for species with a bilobed telson.
  The family Pterygotidae was erected in 1912 by John Mason Clarke & Rudolf Ruedemann to constitute a group for the genera Pterygotus, Slimonia, Hastimima and Hughmilleria. Pterygotus would also designated as containing two "subgenera", Pterygotus (Curviramus) and Pterygotus (Acutiramus) in 1935, differentiated by the curvature of the denticles (teeth) of the chelicerae. The same year (1935), Leif Størmer named a new pterygotid genus, Grossopterus, and split Pterygotus into two other subgenera, Pterygotus (Pterygotus) and Pterygotus (Erettopterus), designating Pterygotus (Curviramus) as a junior synonym of Pterygotus (Pterygotus) and not recognizing Pterygotus (Acutiramus). A division into three subgenera of Pterygotus was proposed by Ferdinand Prantl and Alois Přibyl in 1948, retaining P. (Erettopterus) and P. (Pterygotus) but also restoring P. (Acutiramus) to subgenus level.
  Erik N. Kjellesvig-Waering emended the family in 1951, when the genera Hastimima, Hughmilleria, Grossopterus and Slimonia were referred to their own family, the Hughmilleriidae, which left Pterygotus as the only genus within the Pterygotidae. In 1961, Kjellesvig-Waering raised Erettopterus to the level of its own genus, recognizing two subgenera of Pterygotus; P. (Pterygotus) and P. (Acutiramus), as well as two subgenera of Erettopterus; E. (Erettopterus) and E. (Truncatiramus). Kjellesvig-Waering placed the primary taxonomical value on the morphology of the telson, considering potential differences in the chelicerae and metastoma (a large plate that is part of the abdomen) to be secondary in importance.
  Jaekelopterus, previously designated as a species of Pterygotus, was separated into a distinct genus in 1964 based on the supposed different segmentation of the genital appendage. These supposed differences would later turn out to be false, but briefly prompted Jaekelopterus to be classified within a family of its own, the "Jaekelopteridae". The error with the genital appendage was later discovered and rectified, making Jaekelopterus a member of the Pterygotidae once more. In 1974, Størmer raised the Pterygotus subgenera Acutiramus and Truncatiramus to the level of separate genera. Truncatiramus has later been recognized as representing a synonym of Erettopterus.
  In 1986, Paul Selden examined the fossil material of the enigmatic arthropod Necrogammarus and concluded that the specimen represents the infracapitulum and attached palp of a large pterygotid. The fossil likely belongs to either Erettopterus marstoni or Pterygotus arcuatus, both found in the same locality, but the lack of key diagnostic features in the Necrogammarus remains makes assignment to either impossible, and therefore, Necrogammarus is considered an unspecified pterygotid.
  In 2009, Pterygotus ventricosus was recognized as being distinct from, and far more basal than, other species in its genus and was thus named as the type species of a new genus, Ciurcopterus. Studies of specimens referred to this genus resolved long-standing contentiousness about the precise phylogenetic position of the Pterygotidae, providing evidence in the form of shared characteristics that Slimonia, not Herefordopterus or Hughmilleria as previously thought, was the closest sister taxon of the 
caption: Pterygotus and other eurypterids illustrated by Joseph Smit in 1896.
exif: {"Image ImageDescription": "Extinct monsters\nLondon :Chapman & Hall,1896.\nhttp://www.biodiversitylibrary.org/item/51560", "Image Software": "Adobe Bridge CS5", "Image DateTime": "2011:07:26 08:21:37", "Image Artist": "H.N. Hutchinson", "Image Copyright": "Public Domain", "Image ExifOffset": "246", "EXIF ExifVersion": "0221", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "1854", "EXIF ExifImageLength": "1189"}