Strumigenys labaris

Identification
Bolton (2000) - A member of the sphera complex in the Strumigenys arnoldi-group. S. labaris is most similar to Strumigenys admixta in the sphera-complex. In both species the upper scrobe margin has a distinct, broad lamellate rim or flange throughout its length. They are most easily distinguished by the shape of the postbuccal margin with head in ventral view. In labaris, the posterior and lateral margins of the postbuccal groove are rounded to bluntly marginate, and the posterolateral face of groove is more or less vertical or gently sloping, never concave. In admixta, the posterolateral and lateral margins of postbuccal groove have a lamellate rim and the posterolateral face of the groove is concave.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  labaris. Strumigenys labaris Fisher, in Bolton, 2000: 662 (w.) MADAGASCAR.

Worker
Holotype. TL 3.4, HL 0.85, HW 0.75, CI 88, ML 0.43, MI 51, SL 0.56, SI 74, PW 0.41, AL 0.83. Characters of sphera-complex. Each mandible with 1 preapical tooth, distance from preapical tooth to apicodorsal tooth approximately equal to length of preapical tooth. Upper scrobe margin bordered by a projecting laminar rim or flange throughout its length, eyes partially visible in full-face view. Eye very small, convex, its maximum diameter distinctly less than maximum width scape. Scape narrowed near base, slightly expanded and flattened in basal third; hairs on leading edge narrowly spatulate. Cephalic dorsum clothed with curved narrowly spatulate ground-pilosity; upper scrobe margin with hairs that are similar in size and shape to those on the dorsum. Cephalic dorsum with 4 pairs of long standing narrowly remiform hairs arranged as follows: transverse row of 3 pairs close to the occipital margin and 1 pair of erect hairs on vertex. Pronotal humeral hair absent; humeral angles rounded, posterolateral margin of pronotum bluntly marginate. Anterior margin of mesonotum with 1 pair of stout standing hairs. Propodeal spines with 1 pair of fine short, posteriorly curved hairs near anterior base. Alitrunk dorsum with very short curved ground-pilosity and concentrated on promesonotum. Dorsum of alitrunk in outline convex anteriorly, posterior mesonotum sharply depressed, propodeum gradually sloping to declivity. Metanotal groove represented by a shallow impression. Propodeal spines short, triangular, posterior margin with a narrow spongiform strip; propodeal lamella absent. Alitrunk dorsum densely reticulate-punctate. Sides of pronotum with faint longitudinally striolate sculpture anteriorly. Pleurae mostly smooth and shiny with reticulate-punctate sculpture peripherally. Petiole node in dorsal view approximately as long as broad. Postpetiole disc with weak longitudinally striolate sculpture on a fine punctulate surface. In profile ventral spongiform tissue of petiolar peduncle a narrow curtain that is continuous along the base of the peduncle, depth of curtain is distinctly greater than maximum width of eye. Ventral spongiform lobe of postpetiole moderately developed. Basigastral costulae short and sharply defined. Dorsal surface of petiole, postpetiole, and gaster with stout standing remiform to narrowly spatulate hairs which are slightly thickened apically. Colour medium brown.

Paratype. TL 3.0-3.4, HL 0.78-0.86, HW 0.66-0.75, CI 84-89, ML 0.39-0.45, MI 49-54, SL 0.52-0.57, SI 74-80, PW 0.35-0.40, AL 0.73-0.84 (6 measured). As holotype.

Measurements of this material extend the range shown by the type-series: HL 0.70-0.80, HW 0.58-0.67, CI 83, ML 0.37-0.42, MI 52-55, SL 0.46-54, SI 78-84 (3 measured).

Type Material
Holotype worker, Madagascar: 11.0 km. WSW Befingotra, Res. Anjanaharibe-Sud, 14°45'S, 49°27'E, 1565 m., 16.xi.1994, sifted litter (leaf mold, rotten wood), montane rainforest #1232 (4)-5. (B. L. Fisher). Paratypes. 6 workers with same data as holotype but coded (31)-4, (40)-4.