James, specimens shown here were trying to drag this leaf into one of many entrances into a small subterranean colony in a bare mound (no vegetational thatch) of packed dirt. I don't see too many all black ants of this size in our area. Dominant Formica in our area are usually black and red and seem to fit into into the Rufa group, I think. I'm hoping for correction or confirmation of identity. I can provide multiple images from a short video clip if required. Thank you!