Colobostruma unicorna

The only known nest was found in open sclerophyll under rocks in soil on slope of ridge, and in nests of Polyrhachis ammon and  Bothroponera mayri (= Pachycondyla mayri'').

Identification
Shattuck (2000) - The raised frontal lobes and extreme lateral margins of the clypeus combined with a projection on the centre of the clypeus will readily separate this species from all others in the genus, including the similar Colobostruma bicorna.

Key to Australian Colobostruma Species

Distribution
Mid to southern coastal Queensland

This taxon was described and is only known from Australia.

Nomenclature

 *  unicorna. Colobostruma unicorna Shattuck, in Bolton, 2000: 46, figs. 37, 48 (w.q.) AUSTRALIA.

Worker
HOLOTYPE WORKER. TL 3.0, HL 0.70, HW 0.60, CI 86, ML 0.14, MI 20, SL 0.32, SI 53, PW 0.39, AL 0.80. Anterior region of head raised slightly above the posterior region and separated from it by a rounded angle, thus the head weakly but not obviously phragmotic. In full-face view ridge immediately in front of eye weakly concave. Frontal lobes immediately above the antennal insertions and the lateral margins of clypeus immediately above the mandibular insertions raised above the surrounding surface of the head; the centre of the clypeus with a distinct, raised pointed projection. Mandibles broadly triangular. Hairs absent from dorsum of head. Posterior margin of head deeply concave. Antenna with 5 or 6 segments, when 6-segmented the fourth funicular segment from the base is much shorter than the third segment. Scape weakly elbowed and without a subbasal lobe. In dorsal view the widest point of the pronotum is at the humeral angles. Propodeum high, its declivity approximately the same height as the petiolar node and with broad, thin lamellae; in profile the dorsum of the alitrunk flat with a weak convexity at the metanotal groove. Petiole with a broad, irregular ventral lamella. Lateral postpetiole drawn outwards into thin 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 smaller than the posterior windows. First gastral tergite with delicate reticulate sculpture which is stronger anteriorly and weaker posteriorly, the anterior one-third superimposed with low, closely spaced carinae. Body colour honey yellow, dorsum of head slightly darker.

Type Material
Holotype worker, Australia: Queensland, Mt Coot-tha, Brisbane, 300-800 ft, 29. x ii. 1 964, open scerophyll, under rocks in soil on slope of ridge, found in nests of Polyrhachis ammon and Bothroponera mayri (B.B. Lowery). Paratypes. 16 workers and one queen with same data as holotype (ANIC,, ).