Strumigenys atopogenys

Identification
Bolton (2000) - A member of the Strumigenys extemena-group. Together with Strumigenys carinognatha and Strumigenys tarbosyne this species is isolated within the group by the strange morphology of the basidorsal mandible, as described above and under those two species. The structure is more strongly developed in carinognatha and tarbosyne than in atopogenys as in the first two the basidorsal mandible has a concave area bounded by a raised and acute carina, whereas in atopogenys the same area is flat and bounded by a low blunt ridge. Cephalic standing pilosity is also different. S. tarbosyne has two transverse rows of erect remiform hairs on the head close to the highest point of the vertex and carinognatha has a single pair of erect hairs in this position. In contrast atopogenys is entirely without standing hairs on the head.

Elsewhere in the group mandibular structure falls into two forms. In Strumigenys extemena and Strumigenys deinognatha the masticatory margin of the mandible is considerably elevated above the level of the outer margin so that when the masticatory margins are engaged they form the highest point, from which the oblique dorsal surfaces slope steeply away on each side. The mandibles of the remaining 4 species, Strumigenys acheron, Strumigenys aello, Strumigenys ocypete and Strumigenys podarge, lack these specialisations and in shape are more or less normal for Pyramica although ocypete does have a short straight carina mid-dorsally at the base of each mandible.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia.

Nomenclature

 *  atopogenys. Pyramica atopogenys Bolton, 2000: 417 (w.) INDONESIA (Sumatra). Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 115

Worker
Holotype. TL 2.0, HL 0.48, HW 0.42, CI 88, ML 0.16, MI 33, SL 0.24, SI 57, PW 0.27, AL 0.52. Basal half of dorsal surface of mandible flat, the flat area sloping upwards anteriorly to approximately the midlength of the mandible as seen in full-face view, distal to which the dorsum of the mandible commences to curve downward. At the apex of the upward- sloping surface is a low blunt arched ridge that traverses the dorsum from the masticatory margin to close to the outer margin and then extends posteriorly toward the basal-external angle of the mandible. Mandible smooth and shining, the basal tooth the largest. Dorsum of head behind clypeus mostly smooth, not uniformly reticulate-punctate. Leading edge of scape rounded at its broadest point, without a projecting subbasal lobe and without a large anteriorly-directed specialised hair at its point of maximum curvature. Hairs on leading edge of scape microscopic and difficult to see, all curved toward the apex of the scape. Vertex of head with a conspicuous transverse crest across its width, the crest forming the highest point of the vertex. Dorsum of head without standing hairs and without orbicular hairs. Eye of a single ommatidium. Dorsal surfaces of alitrunk and petiole without standing hairs but numerous short erect simple hairs are present on the postpetiole and first gastral tergite. Pronotum flat dorsally, marginate dorsolaterally; mesonotum forming a single separate convexity between pronotum and propodeum. Propodeal teeth absent but the declivity with a broad lamella extending its entire height.

Paratypes. TL 2.0-2.1, HL 0.48-0.53, HW 0.45-0.48, CI 90-91, ML 0.16-0.17, MI 32-33, SL 0.24-0.28, SI 53-56, PW 0.27-0.29, AL 0.52-0.60 (2 measured).

Type Material
Holotype worker, Indonesia: Sumatra, Jambi, W Mt Tujuh Lake, 1400 m., 14.xi.1989, #17 (Agosti, Lobi & Burckhardt).

Paratypes. 2 workers with same data as holotype (AMNH, ).