AntWiki page for Dorymyrmex bicolor
Their common name is "pyramid ant" and I believe it is for their little point on their propodeum.
Somewhat numerous ant in the yard, I enjoyed finding their little conical nest entrances that evoked the classic "ant mound" stereotype.
Though oftentimes they would have a pretty inconspicuous hole in the ground as an entrance.
Don't have much to say about these gals, unfortunately! Being so small, it was a bit difficult to observe them, so I tended to prefer the larger tenants in the yard.