Technomyrmex obscurior

A collection of this species was made in a Schima-Castanopsis forest, with the ants being found under a stone.

Identification
Bolton (2007) - A member of the Technomyrmex bicolor group. The few samples currently grouped under this name, although coming from a relatively restricted area, show considerable variation in scape length, eye size, development of clypeal sculpture, degree of separation of metathoracic spiracle from metanotal groove and length of propodeal dorsum. It seems probable that further collections will allow a better resolution of the taxonomy. However, it should be noted that some characters are known to show variation in other species of the group and so would not certainly have species-rank value here. For instance SI shows notable variation in single series of Technomyrmex impressus, where the smallest workers have relatively much longer scapes than the largest.

The closest related species to obscurior is Technomyrmex antennus, but the latter has a short, deep propodeum and differently coloured middle and hind coxae.

Distribution based on Regional Taxon Lists
Oriental Region: Myanmar, Nepal. Palaearctic Region: China.

Nomenclature

 *  obscurior. Technomyrmex schimmeri var. obscurior Wheeler, W.M. 1928c: 31 (w.) CHINA. Raised to species: Bolton, 2007a: 94.

Worker
Bolton (2007) - TL 3.2 - 3.8, HL 0.71 - 0.96, HW 0.63 - 0.86, SL 0.90 - 1.05, PW 0.45 - 0.55, WL 0.95 - 1.35 (15 measured). Indices: CI 84-93, SI 122 - 143, OI 23 - 32, EPI 67 - 80, DTI 156 - 168.

Head behind clypeus, dorsum of mesosoma, declivity of propodeum and first gastral tergite all entirely lack setae. Gastral tergites 2 - 4 with long stout setae present that are slightly longer than the maximum diameter of the eye: second gastral tergite with 2 – 3 pairs, third and fourth tergites each with 3 - 4 pairs. Anterior clypeal margin with a distinct median notch that is semicircular to broadly U-shaped. The margins of the notch meet the lateral portions of the anterior margin through rounded curves, not sharp angles. Posterior margin of head indented medially. With head in full-face view the outer margins of the eyes fail to touch the outline of the convex sides of the head. Scape index > 120. Clypeal sculpture usually relatively coarse between posterior margin of notch and clypeal suture, usually shallowly reticulate-punctulate and generally more strongly developed than in the area between the frontal carinae. In dorsal view the metathoracic spiracles distinctly separated from the metanotal groove; distance separating them more than one spiracle diameter, usually obviously so. Mesosoma relatively long, DTI 156 - 168, usually > 160. In profile the propodeal dorsum long, flat or even slightly concave, its straight-line length greater than the depth of the declivity to the spiracle. In profile the head, mesosoma, petiole and gaster all the same shade of dark brown to blackish brown, or very nearly so. Anterior coxa brown; middle and hind coxae ivory-white to yellow and strongly contrasting with the mesosoma. All trochanters yellow. Femora and tibiae mostly brown, same colour as the mesosoma or slightly lighter but base and apex of each segment dull yellow. Tarsi off-white to yellow, lighter than the central portions of the femora and tibiae.

Type Material
Bolton (2007) - Syntype workers, China: Yi Leang (= Yiliang, Kunming Prov.?), 27.ii.1925 (F. Silvestri) [examined].