Class Mammalia Linnaeus, 1758 - mammals Subclass Acrotheria Averianov & Lopatin, 2011 Infraclass †"Triconodonta" Osborn, 1888 [paraphyletic] see Order Triconodonta Osborn, 1888 Order †Amphidontoidea Prothero, 1981 [monotypic] Family †Amphidontidae Simpson, 1925