Chordata Bateson, 1885 - chordates Class Elasmobranchii Bonaparte, 1838 see Subclass Elasmobranchii Bonaparte, 1838 Subclass Selachii see Subdivision Selachii Order Tectospondyli Suborder Squaloidei Müller & Henle, 1838 see Order Squaliformes Compagno, 1973 Family Somniosidae Jordan, 1888 - sleeper sharks