Technomyrmex pratensis

A forest species that has been collected from litter samples.

Identification
T. pratensis is immediately diagnosed by its reduced palp formula, deeply cleft clypeal margin, characteristic cephalic setae, short stocky body and short scape. Its nearest relative appears to be the Afrotropical Technomyrmex lasiops, which closely resembles pratensis (including PF 5,3) but has a different arrangement of setae on the head.

All the samples are treated as belonging to a single, size-variable, species, but because of variations in pilosity, particularly the presence in some samples of erect setae on the dorsal (outer) surfaces of the middle and hind tibiae, there may be more than one real species here. The possibility is currently doubted as the number of such setae varies from 0 - 3, does not appear consistent in single nest-samples, and may well be size-related as the larger the Individual the more setae appear to develop. Similarly, larger workers have pubescence that is denser and more elevated than in smaller individuals. Other indications of allometric variation among the relatively few samples available include the observations that with increasing size (i.e. as HW increases) CI tends to increase while SI and OI tend to decrease.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, Philippines. Oriental Region: India, Thailand, Vietnam. Palaearctic Region: China.

Nomenclature

 *  pratensis. Tapinoma pratensis Smith, F. 1860b: 97 (w.) INDONESIA (Batjan I.). Combination in Iridomyrmex: Donisthorpe, 1932c: 460; in Technomyrmex: Shattuck, 1992c: 161. Senior synonym of javanum, setiferum: Bolton, 2007a: 95.
 * setiferum. Tapinoma setiferum Emery, 1900d: 695, fig. 11 (w.) INDONESIA (Sumatra). Combination in Technomyrmex: Wheeler, W.M. 1927h: 99. Junior synonym of pratensis: Bolton, 2007a: 95.
 * javanum. Tapinoma setiferum var. javanum Forel, 1905c: 22 (w.q.m.) INDONESIA (Java). Combination in Technomyrmex: Shattuck, 1992c: 161. Junior synonym of pratensis: Bolton, 2007a: 95.

Worker
Bolton (2007) - TL 2.6 - 3.5, HL 0.70 - 0.94, HW 0.63 - 0.92, SL 0.56 - 0.76, PW 0.45 - 0.56, WL 0.82 - 1.06 (25 measured). Indices: CI 90 - 102, SI 83 - 97, OI 20 - 25, EPI 78 - 85, DTI 105 - 120.

Palp formula 5,3. Dorsum of head behind clypeus with 5 pairs of long setae arranged in two parallel rows: in profile the first seta above the torulus; second and third setae along the frontal carina, the third at about the level of the posterior margin of the eye; fourth seta dorsal, between posterior margin of eye and posterior margin of head; fifth seta at the posterior margin and much longer than the maximum diameter of the eye. Scape without erect setae but pubescence on scape and side of head usually denser and more elevated in larger individuals, sparser and more reclinate in smaller workers. Anterior clypeal margin with a deep and very conspicuous U-shaped median incision that is usually slightly longer than broad; inner margin of incision meets the anterior clypeal margin in an acute angle at each side. Posterior margin of head in full-face view with a distinct median impression. Eyes located in front of the midlength of the head and in full-face view set well in from the side, distinctly failing to break the outline of the side but closer to the sides in smaller than in larger workers. Mesosoma short and stout (DTI, above), in profile the mesonotum convex; the propodeal dorsum rounds into the declivity. Number of setal pairs on mesosoma: pronotum 1 - 4 (number tends to increase with size, but not always so); mesonotum 2 - 4 (in larger workers 1 - 3 pairs of much shorter secondary setae may also be present among the main setae); propodeal dorsum 0; lateral margin of propodeal declivity 1 - 3, always a strong pair at the level of the spiracle. Gastral tergites 1 - 4 each with numerous long strong setae, the longest on the first tergite much longer than the maximum diameter of the eye. Smaller workers and populations from the north of the species' range without erect setae on the dorsal (outer) surfaces of the middle and hind tibiae, but larger workers, particularly from the south of its range, with 1 - 3 erect tibial setae present; tibial pubescence elevated. Head, mesosoma and petiole brownish yellow to brown, the gaster the same colour to distinctly darker. Legs uniformly coloured, the same as the mesosoma to slightly lighter; tarsi the same colour as the tibiae.

Type Material
Bolton (2007) - Syntype workers, Indonesia: Bayan I, “Bac.20” (A. R. Wallace) [examined].

Tapinoma pratensis

Four worker syntypes in. Labelled “Bac 20.”