A comparison of characters among the orectolobids has resulted in a division of this group into an order with three suborders, eight families, and twelve genera. Sutorectus cannot be considered a valid genus. The orectolobids are the most primitive sharks with lamnoid vertebrae. The orectolobids probably represent an ancestral group from which the Lamniformes arose and may also be ancestral to the Carchariniformes. The orectolobids share characters with the Heterodontiformes, Squatiniformes, and the Pristiophoriformes, and it is believed that all of these sharks have a common hybodont ancestry.