Colobostruma biconvexa

This rare species is limited to coastal Queensland. It is limited to rainforest (or occasionally wet sclerophyll) and has so far only been found in leaf litter samples (Ants Down Under).

Identification
Shattuck (2000) - Colobostruma biconvexa is most similar to Colobostruma biconcava. C. biconcava differs in having the posterior faces of the petiole and postpetiole weakly concave, whereas these faces are convex in biconvexa. Additionally, biconcava is known from the Australian Capital Territory and South Australia while biconvexa is known only from Queensland.

Distribution
Known only from Queensland.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  biconvexa. Colobostruma biconvexa Shattuck, in Bolton, 2000: 35 (w.q.) AUSTRALIA.

Worker
HOLOTYPE WORKER. TL 2.1, HL 0.52, HW 0.48, CI 92, ML 0.13, MI 25, SL 0.28, SI 58, PW 0.29, AL 0.55. Anterior region of head rounding gradually from the dorsal to lateral surfaces, not phragmotic. In full-face view ridge immediately in front of eye weakly concave. Frontal lobes and lateral margins of the clypeus smooth and relative to the surrounding surface of the head. Mandibles broadly triangular. Hairs absent from dorsum of head. Posterior margin of head shallowly concave, the medial region nearly flat. Antenna generally 4-segmented, when 5-segmented the third funicular segment from the base much shorter than the second segment; the second segment approximately one-third longer than the first segment. Scape elbowed and without a subbasal lobe. In dorsal view the widest point of the pronotum is at the humeral angles. Propodeum high, its posterior face greater in height than the petiolar node and with broad, thin lamellae; in profile the dorsum of the alitrunk nearly flat to gently and weakly arched. Lateral postpetiole drawn outwards into the flange-like wings, the wings with translucent windows along both their anterior and posterior margins, the windows separated by a narrow band of thickened integument, the anterior windows reduced to narrow bands along the leading edge. Posterior faces of the petiole and postpetiole convex. First gastral tergite superimposed with weakly defined reticulate sculpturing, its anterior one-quarter with a series of low longitudinal carinae. Body colour uniform honey yellow, the gaster sometimes with a complete or incomplete, weakly infuscated medial band.

Type Material
Holotype worker, Australia: Queensland, Mt Cook National Park, 15˚29’S 145˚16’E, 10-12.v.1981, rainforest, litter (berlesate) (A. Calder & J. Feehan).

Paratypes. 11 Workers and one queen, with same data as holotype (ANIC,, ).