Key to Stigmatomma species in or possible in the Southeastern United States
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Head, in full face view, with a tooth or sharp point on each side of head near the point of mandible insertion; mandible in full face view slender and not expanded near base

  Head, in full face view, lacking tooth or sharp point on side of head near mandible insertion point; mandible, in full face view, expanded near base, basal portion triangular  (known only from North Carolina)

Note: Until recently, North America species in the genus Stigmatomma were placed in the genus Amblyopone. This change was included in a recent paper by Yoshimura and Fisher (2012): Yoshimura M, Fisher BL (2012) A Revision of Male Ants of the Malagasy Amblyoponinae (Hymenoptera: Formicidae) with Resurrections of the Genera Stigmatomma and Xymmer. PLoS ONE 7(3): e33325. doi:10.1371/journal.pone.0033325