Austroagrion watsoni is widespread in Australia, just missing from the far western edge, and also occurs in New Caledonia. With a vernacular name featuring “Billabongfly”, where else could it be?
We found our single example on our last visit of several to the dam in Stanley, near Beechworth, Victoria. It is an immature male without its colour developed and it took me a while to realize what it was. The key to it was that this psecies has a postocular bar rather than the postocular spots, with which we are more familiar. The antehumeral stripe is quite wide, too.