Measuring 70 centimetres (28 inches) in length, Ciurcopterus was relatively large though smaller than many of the later members of its family, which would grow to become the largest known arthropods to have ever lived.

The specimen (USNM 88130, currently housed at the U.S. National Museum in Washington) preserves most of the body, excluding parts of the appendages and the end of the telson.

The new material allowed them to determine that P. ventricosus represented the most basal pterygotid eurypterid and the study helped provide evidence for the precise phylogenetic position of the family, showing that the Slimonidae (and not the Hughmilleriidae) was the most closely related group to the Pterygotidae.

Ciurcopterus has been noted as possessing a mix of features from both more primitive pterygotioids such as Slimonia and more derived members of the group firmly within the Pterygotidae.

[2] C. ventricosus, also referred to as the "Kokomo pterygotid" after the site of its discovery, does possess some smaller differences compared to the rest of the Pterygotidae, such as keels running down the dorsal side of the pretelson.

The cladogram also contains the maximum sizes reached by the species in question, which have been suggested to possibly have been an evolutionary trait of the group per Cope's rule ("phyletic gigantism").

[11] Fossils of various other organisms have also been recovered, including algal stromatolites, corals (such as Halysites), small cephalopods (such as Protokionoceras) and leperditiid ostracods.

[12] Geological features of the formation, such as the argillaceous (resembling clay) limestone, suggests that the Silurian environment of the region might have been quiet and lagoonal.

Though derived pterygotids, such as Acutiramus, Jaekelopterus and Pterygotus, had divergent and specialized ecological roles, more basal genera, such as Erettopterus, were more generalized predators.