Strumigenys stygia

Identification
Bolton (1983) - S. stygia belongs to the core-species of the arnoldi-complex, which also includes Strumigenys arnoldi, Strumigenys traegaordhi, Strumigenys mesahyla and Strumigenys nimbrata. These four are separated from stygia as arnoldi lacks pronotal flagellate hairs, nimbrata has funicular segments 2 and 3 vestigial, and both mesahyla and traegaordhi do not have the postpetiole sculptured.

Distribution based on Regional Taxon Lists
Afrotropical Region: Angola, Cameroun, Kenya, Zimbabwe.

Nomenclature

 *  stygia. Strumigenys (Strumigenys) stygia Santschi, 1913b: 257 (diagnosis in key) (w.) KENYA. Santschi, 1914b: 113 (w.). See also: Brown, 1954k: 29; Bolton, 1983: 394; Bolton, 2000: 596.

Worker
Bolton (1983) - TL 1.9-2.1, HL 0.50-0.53, HW 0.40-0.43, CI 80-84, ML 0.18-0.21, MI 36-40, SL 0.26-0.28, SI 63-68, PW 0.24-0.25, AL 0.48-0.52 (7 measured).

Apical fork of each mandible with 2 teeth, without intercalary teeth or denticles. Each mandibular blade with 2 pre apical teeth, the proximal longer than the distal in each case. Upper scrobe margins convex, the eyes not visible in full-face view. Eyes small, the maximum diameter distinctly less than the maximum width of the scape. Preocular notch absent, ventral surface of head without a transverse preocular groove or impression. Antennal scapes curved in the basal third, the median third expanded and somewhat flattened, the convex leading edges of the scapes with a row of apically curved short broadly spoon-shaped hairs. Ground-pilosity of head relatively broad spoon-shaped hairs which are curved anteriorly and appear stud-like or scale-like in full-face view, the hairs on the dorsum anterior to the highest point of the vertex somewhat larger and more conspicuous than those posterior to this point. Hairs fringing the upper scrobe margins the same shape as those on the dorsum. Cephalic dorsum reticulate-punctate. Pronotal humeri each with a single fine flagellate hair. Mesonotum with a single pair of clavate standing hairs. Ground pilosity of dorsal alitrunk of sparse spoon-shaped to scale-like small hairs. Mesonotum depressed behind the level of the pair of hairs. Metanotal groove represented on the dorsum by a faint line. Sides of pronotum superficially reticulate or granular, pleurae and propodeum laterally smooth except for some weak patches of punctate sculpture peripherally. Pronotal dorsum densely punctate, usually with overlying weak longitudinal rugulae. Remainder of dorsal alitrunk reticulate-punctate. Dorsum of petiole node reticulate-punctate, postpetiole superficially granular to reticulate-punctate. Ventral spongiform strip of petiole narrow and inconspicuous. Ventral spongiform lobe of postpetiole equal to or slightly less than the exposed area of the postpetiole. Basigastral costulae conspicuous. Dorsal surfaces of petiole, postpetiole and gaster with stout standing hairs which are thickened or clavate apically. Colour light brown to medium brown.

Type Material
Bolton (1983) - Syntype workers, KENYA: Cave A at Shimoni, st. no. 9, xi.1911 (Alluaud &feannel) [examined].