Notopalaeognathae is a clade that contains the order Rheiformes (rheas), the clade Novaeratitae (birds such as the kiwis and the emus), the order Tinamiformes (tinamous) and the extinct order Dinornithiformes (the moas).[3] The exact relationships of this group have only recently been understood, with tinamous and the moas sharing a common ancestor[4][5][6][7] and the kiwis being more closely related to emus and cassowaries.[6] The extinct elephant birds of Madagascar have recently been identified as closest relative to the kiwis.[6] The rheas are either the basal most branch of notopalaeognaths[8] or the sister group to Novaeratitae.[3] The sister group to Notopalaeognathae is Struthionidae (the ostrich family).