Strumigenys opaca

Identification
Bolton (2000) - In the measurements small workers tend to have the mandibles and scapes relatively longer than large workers. The mandibles of opaca are relatively the longest found in the Austral region. The MI range of 57-63 in opaca contrasts with a range of MI 26-55 for all other Austral species together, of which only very few have MI > 50.

This species is closely related to the Malesian Strumigenys wallacei. The two are differentiate easily as in profile the mesonotum of wallacei forms a prominent hump or bulge, with a nearvertical posterior declivity; in opaca the mesonotum is more or less evenly rounded. In addition the ventral spongiform appendage of the postpetiole is a well developed lobe in wallacei, the first gastral sternite is less extensively sculptured (some shagreening is usually present near the base) and the scapes average shorter (SI 68-80).

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  opaca. Strumigenys opaca Brown, 1954a: 86 (w.) AUSTRALIA. See also: Bolton, 2000: 984.

Worker
Bolton (2000) - TL 2.6-3.4, HL 0.70-0. 86, HW 0.57-0.78, CI 81-90, ML 0.44-0.52, MI 57-63, SL 0.50-0.64, SI 79-89, PW 0.30-0.37, AL 0.65-0.84 (20 measured).

Apical fork of mandible without intercalary denticles. In full-face view eyes completely visible, situated on a low tumulus and bounded anteriorly by the deep preocular notch. Scape shallowly sinuate in full-face view. Scrobe absent behind level of eye. Propodeal teeth free, subtended only by a narrow carina on each side of the declivity. Ventral spongiform strip on petiole slender, narrower than depth of peduncle. Postpetiole large and subglobular in profile. Ventral spongiform lobe on postpetiole a shallow rounded collar, the lateral lobe reduced to a thin flange except in the posterior corner where it is a little wider. Apicoscrobal hair absent; pronotal humeral hair absent. Dorsum of head and alitrunk with sparse spatulate ground-pilosity but without standing hairs. First gastral tergite with short stiff spatulate to remiform standing hairs. All surfaces of head, alitrunk, petiole and postpetiole finely densely reticulate-punctate, without smooth areas. First gastral tergite finely shagreenate-punctulate, the sculpture fading out posteriorly on the sclerite; without differentiated basigastral costulae or with costulae short and inconspicuous among the other sculpture. First gastral sternite finely reticulate-punctate at least basally and laterally, the mid-ventral area generally smooth or nearly so.

Type Material
Bolton (2000) - Holotype and paratype workers, AUSTRALIA: Queensland, Cape York Peninsula, McIlwraith Range, Lankelly Creek, vi.1932, Harvard Expd (P. J. Darlington) [examined].