Ciurcopterus
| Ciurcopterus Temporal range: Late Silurian, | |
|---|---|
| Fossil specimen of C. ventricosus | |
| Restoration of C. ventricosus | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Order: | †Eurypterida |
| Superfamily: | †Pterygotioidea |
| Family: | †Ciurcopteridae |
| Genus: | †Ciurcopterus Tetlie & Briggs, 2009 |
| Type species | |
| †Ciurcopterus ventricosus Kjellesvig-Waering, 1948 | |
| Species | |
| |
Ciurcopterus is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of Ciurcopterus have been discovered in deposits of Late Silurian age in North America. Formerly classified as part of the family Pterygotidae, but placed into a separate family Ciurcopteridae in a 2025 paper, the genus contains two species, C. sarlei from Pittsford, New York and C. ventricosus from Kokomo, Indiana. The genus is named in honor of Samuel J. Ciurca, Jr., who has contributed significantly to eurypterid research by discovering a large amount of eurypterid specimens, including the four specimens used to describe Ciurcopterus itself.
Ciurcopterus was formerly classed as the most basal (primitive) known member of the Pterygotidae, and combined characteristics of more derived members of the family with features of close relatives of the group, such as Slimonia. Measuring 70 centimetres (28 inches) in length, Ciurcopterus was relatively large though smaller than many pterygotids, which would grow to become the largest known arthropods to have ever lived.