Checking for coconut ants. This stump had some frass. Nearby logs had extensive old frass. However the inhabitants under this stump had very strong formic acid odour. I wonder whether they had displaced coconut ants or just moved in after.
Hi RAllen, this ant looks likely to be Doleromyrma or Tapinoma, both small ants with similar body shape, but I can't tell from the photos. Interesting that they have taken over what very likely seems to be an old Papyrius nest. Cheers, Jon