Is there some support for (Neo-)Gondwanan origin of Anseriformes( and probably Galloanserae) ? What is the zoogeographical explanation of presence of Black Swan in Australia (Cygnus ater) and Black-necked Swan in South America (Cygnus melanocoryphus). And Brazilian "Coscoroba" (Coscoroba coscoroba)...is it a primitive swan?