Two of the described species are known from only a single worker, making this one of the rarest groups of ants in the world.

[2] The single specimen of S. anderseni was caught in a pitfall trap, and nothing is known about its biology.

[3] Stereomyrmex dispar is 3.2 mm long and black, with yellowish brown mandibles, antennae, legs and terminal segments of gaster.

S. anderseni is only 2 mm long, has a very different petiolar and postpetiolar structure and is paler in color.

[4] The genus was originally named in honor of Maurice Willows Jr., who collected the type specimen of S.