Colobostruma bicorna

This rare species is known from only a single collection made in Sydney, NSW, nesting in soil (Ants Down Under).

Identification
Shattuck (2000) - This rare species, known from only a single collection, can be recognised by the raised frontal lobes and extreme lateral margins of the clypeus. Colobostruma unicorna also has these regions raised but that species also has a raised projection on the centre of the clypeus while bicorna has this region smooth.

Key to Australian Colobostruma Species

Distribution
Only known from Sydney, New South Wales.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  bicorna. Colobostruma bicorna Shattuck, in Bolton, 2000: 45 (w.) AUSTRALIA.

Worker
HOLOTYPE WORKER. TL 3.0, HL 0.67, HW 0.66, CI 99, ML 0.18, MI 27, SL 0.30, SI 45, PW 0.39, AL 0.76. 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 anteriorly, essentially flat medially and posteriorly. Frontal lobes immediately above the antennal insertions and the lateral margins of clypeus immediately above the mandibular insertions raised slightly but distinctly above the surrounding surface of the head, the centre of the clypeus smooth. Mandibles broadly triangular. Hairs absent from dorsum of head. Posterior margin of head deeply concave. Antenna with 6 segments, the scape elbowed and without a subbasal lobe. In dorsal view the widest point of the pronotum is at the humeral angles. Propodeum high, its declivity slightly less than the height of the petiolar node and with broad, thin lamellae; in profile the dorsum of the alitrunk weakly convex. 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 sculpturing which is stronger anteriorly and fades posteriorly, the anterior one-quarter superimposed with low, closely spaced carinae. Body colour honey yellow, dorsum of head and especially clypeus slightly darker.

Type Material
Holotype worker, Australia: New South Wales, French's Forest, St Ives, Sydney, 700 ft, 16.x.1956, edge of laterite plateau, nest in yellow sand beside Camponotus consobrinus (B.B. Lowery).

Paratypes 11 workers with same data as holotype (ANIC).