There are extinct orders: the Lithornithiformes, the Dinornithiformes (moas), and the Aepyornithiformes (elephant birds). There are other extinct orders which have been allied with the Palaeognathae by at least one author, but their affinities are a matter of dispute: the Ambiornithiformes, the Gansuiformes, the Paleocursornithiformes, the Gobipterygidae.