Pogonomyrmex naegelii

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 : 104

Pogonomyrmex naegelii -group

Workers in the P. naegelii -group are diagnosed by the following characters: (1) first gastral tergum lacking striae or striae restricted to base or rarely extending beyond the base, (2) small (HW = 1.06–1.33 mm), (3) psammphore poorly-developed, consisting of short to medium-length hairs scattered across ventral side of head, (4) superior and inferior propodeal spines well-developed, inferior spines>0.5–1.0x length of superior spines, (5) in profile, ventral process of postpetiole large and bulbous, its height much greater than its length, and (6) concolorous tannishbrown, occasionally with blackish gaster. Queens in the P. naegelii -group are diagnosed by: (1) first gastral tergum lacking striae or with faint to moderately strong longitudinal striae near base that sometimes extend over anterior one-half of tergum, (2) small (HW <1.30 mm), (3) psammophore poorly-developed, consisting of short to medium-length hairs scattered across ventral side of head, (4) inferior propodeal spines triangular, moderately to well-developed, (5) in profile, ventral process of postpetiole large and bulbous, its height much greater than its length (for only alate queens), (6) concolorous tannish-brown, occasionally with blackish gaster, and (7) anterior margin of clypeus flat.