Hi Korinne, thanks for this sighting. You were about right with the size, being about the same as Doleromyrma, but this ant is Stigmacros. There are only a few sightings of Stigmacros on CNM as these ants are small and easily overlooked. There are quite a few species around Canberra but their taxonomy is not good, so IDing to species is difficult. Cheers, Jon