FarmI wrote:

US possums are very different to those of Australia.

They must have a vast time of separate evolution.

US ones always make me
think of sticky beaks with those pointy little noses. I don't mean that in
a critical way, just that they look like they should be the gossips of the
animal kingdom.

In the US the eastern opossums have a less pointy nose than the western
species. Check out the picture on wikipedia of a Virginia one.

http://en.wikipedia.org/wiki/Opossum

The ones in California have a very pointed nose as you describe.