The Scorpaeniformes are a diverse order of ray-finned fish, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of species with over 1,320. They are known as "mail-cheeked" fishes due to their distinguishing characteristic, the suborbital stay: a backwards extension of the third circumorbital bone (part of the lateral head/cheek skeleton, below the eye socket) across the cheek to the preoperculum, to which it is connected in most species.