Pterygotioidea

Pterygotioidea (the name deriving from the type genus Pterygotus, meaning "winged one") is a superfamily of eurypterids, an extinct group of aquatic arthropods. Pterygotioids were the most derived members of the infraorder Diploperculata and the sister group of the adelophthalmoid eurypterids. The group includes the basal and small hughmilleriids, the larger and specialized slimonids and the famous pterygotids which were equipped with robust and powerful cheliceral claws.

Though the more basal representatives were small, Hunanopterus being the smallest of all pterygotioids at just in length, later members of the group, particularly in the Pterygotidae, would become the largest known arthropods to ever exist with several genera surpassing in length.