It may be my incompetence at using the NaturMapr functionality but I currently cannot find any earlier or other record on the system of another sighting of Swamp Wallabies on Tuggeranong Hill. As I see one or two swamp wallabies almost every morning when I go for an early stroll I find this surprising. On the other hand, they seem very cautious, almost furtive, and much more inclined to hop away than either of the other two local macropod species, so I have found them difficult to capture in a photograph. I also remember one visiting my garden (which abuts Tuggeranong Hill) in the drought of the early 1990s. This may indicate they have been present for some years, though I am sure their abundance has always been well below that of Eastern Greys or Red-necked Wallabies.
Excellent photo Chris. I havent seen the stripe on the back of this wallaby in other photos. Yours is by far the best photo. (Or could there be more than one such wallaby on Mt Majura? - I doubt it).
May be acromelanism as seen in 'sealpoint' siamese cats. Apparently the same genes are involved in Leucism and Acromelanism so acromelanism may be a form of leucism, or they may be different forms of the same thing.