In some cases, "Pterygotus" represents the only known eurypterid in its living environment. "P. bolivianus" was found only associated with trilobites of the genus "Metacryphaeus" in its type locality. "P. floridanus" has been found in an environment otherwise only known to have included gastropods (such as "Plectonotus"), ostracods, pelecypods, tentaculitides (such as "Tentaculites") and a diverse fauna of bivalves (including "Eoschizodus", "Pleurodapis", "Arisaiga", "Pterinopecten" and "Modiomorpha"). "P. gaspesiensis" from Canada has been recovered from an environment home to a diverse set of bivalves and gastropods as well as the trilobite "Phacops" and malacostracan "Tropidocaris", but no other known eurypterids.