This small, very striated black Polyrhachis (a very groovy ant... ) was found in Eastern coastal belt forest. Measures 6.8 - 7mm. Appears to be arboreal. I found 2 nests on the trunks (large branch in one case) of 2 different large, established trees. Both nests had a short, tubular nest entrance fashioned from grass/fibers somehow meshed together (see photos). The one nest was under bark and moss and the other extended into a superficial envelope - like pouch made against the side of the tree which was smooth without a thick bark. I have correlated with Antwiki and Antweb and it is an excellent match. Ants of SA p95.