What is "sclerorhynchoidei"

Sclerorhynchoidei is an extinct suborder of sclerorhynchiform rays with saw-like rostrums. They include the orders Sclerorhynchidae and Ptychotrygonidae. They were a rather long-lived group, living from the Cretaceous to the early Eocene, until they became extinct for unknown reasons and were replaced by their close relatives the pristiformes.