Pogonomyrmex coarctatus

Robert A. Johnson, 2015, A taxonomic revision of South American species of the seed-harvester ant genus Pogonomyrmex (Hymenoptera: Formicidae). Part I, Zootaxa 4029 (1), pp. 1-142 : 18

Pogonomyrmex coarctatus -group

Workers in the P. coarctatus -group are diagnosed by the following characters: (1) first gastral tergum lacking striae, (2) large (HW = 1.97–3.99 mm), sometimes polymorphic, (3) numerous small, hair-bearing foveae scattered across cephalic dorsum (best viewed at>50x magnification) ( Figures 3 A, 8A), (4) part to all of cephalic dorsum with very fine, dense, longitudinal striae, (5) antennal scapes short, extending less than one-third the distance from posterior margin of eye to posterior corner of head, and (6) posterolateral margin of head with a carina that is much coarser than rugae on cephalic dorsum. All of these characters also diagnose queens, which are larger than those of all South American congeners (HW = 2.91–4.06 mm).