Pterygotus

Pterygotus Temporal range: Middle Silurian - Late Devonian, 428–372.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossils of P. anglicus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Order:	†Eurypterida
Superfamily:	†Pterygotioidea
Family:	†Pterygotidae
Genus:	†Pterygotus Agassiz, 1839
Type species
†Pterygotus anglicus Agassiz, 1849
Species
17 valid species †P. anglicus Agassiz, 1849 †P. arcuatus Salter, 1859 †P. barrandei Semper, 1898 †P. bolivianus Kjellesvig-Waering, 1964 †P. carmani Kjellesvig-Waering, 1961 †P. cobbi Hall, 1859 †P. denticulatus Kjellesvig-Waering, 1961 †P. floridanus Kjellesvig-Waering, 1950 †P. gaspesiensis Russell, 1953 †?P. grandidentatus Kjellesvig-Waering, 1961 †?P. impacatus Kjellesvig-Waering, 1964 †P. kopaninensis Barrande, 1872 †P. lanarkensis Kjellesvig-Waering, 1964 †P. lightbodyi Kjellesvig-Waering, 1961 †P. ludensis Salter, 1859 †P. marylandicus Kjellesvig-Waering, 1964 †P. monroensis Sarle, 1902 6 dubious species †?P. australis McCoy, 1899 †?P. formosus (Dawson, 1861) †P. nobilis Barrande, 1872 †P. siemiradzkii Strand, 1926 †P. taurinus Salter, 1868 †?P. vernonensis Ruedemann, 1921
Synonyms
Genus synonymy Curviramus Ruedemann, 1935 Synonyms of P. anglicus P. atlanticus Clarke & Ruedemann, 1912 P. minor Woodward, 1864 Synonyms of P. barrandei P. beraunensis Semper, 1898

Pterygotus is a genus of giant predatory eurypterid, a group of extinct aquatic arthropods. Fossils of Pterygotus have been discovered in deposits ranging in age from Middle Silurian to Late Devonian, and have been referred to several different species. Fossils have been recovered from four continents; Australia, Europe, North America and South America, which indicates that Pterygotus might have had a nearly cosmopolitan (worldwide) distribution. The type species, P. anglicus, was described by Swiss naturalist Louis Agassiz in 1839, who gave it the name Pterygotus, meaning "winged one". Agassiz mistakenly believed the remains were of a giant fish; he would only realize the mistake five years later in 1844.

Pterygotus was among the largest eurypterids. Isolated fossil remains of a large chelicera (frontal appendage) suggests that the largest known species, P. grandidentatus, reached a body length of 1.75 metres (5.7 ft). Several other species, notably P. impacatus at 1.65 metres (5.4 ft) and P. anglicus at 1.6 metres (5.2 ft) were similarly gigantic. Pterygotus was surpassed in size by other giant eurypterids. Acutiramus was able to surpass 2 metres (6.6 ft), and Jaekelopterus could reach 2.6 metres (8.5 ft). Many species were considerably smaller than the largest species, such as P. kopaninensis at 50 centimetres (20 in).

Like its close relative Jaekelopterus, Pterygotus was a large and active predator noted for its robust and enlarged cheliceral claws that would have allowed it to puncture and grasp prey and a visual acuity (clarity of vision) comparable to that of modern predatory arthropods.