Colobostruma sisypha

Colobostruma sisypha is the most commonly encountered species in the genus and is found along most of the east coast of Australia. It occurs in a wide range of forested habitats from rainforest through dry sclerophyll. Nests are found in soil under and between rocks.

Identification
Shattuck (2000) - Separated from most other species in the group by the 5- or 6-segmented antennae, the shallowly concave posterior margin of the head and the uniformly rounded dorsal surface of the head (without any indication of phragmatism). Separation from the morphologically similar Colobostruma mellea is discussed under that species. C. sisypha shows considerable variation in colour. The head varies from uniform yellow to yellow with an infuscated spot on the dorsal surface (above the compound eyes) and another on the clypeus. The gaster generally has an infuscated diamond near the centre of the first tergite with dark triangles laterally. However, the pattern on the gaster varies from being absent or essentially absent to being a dark band across the gaster. The variation in these colour patterns is continuous with little suggestion of obvious subsets.

Key to Australian Colobostruma Species

Distribution
Eastern coastal Australia.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  sisypha. Colobostruma sisypha Shattuck, in Bolton, 2000: 37, figs. 39-41, 46 (w.q.) AUSTRALIA.

Worker
HOLOTYPE WORKER. TL 2.6, HL 0.61, HW 0.56, CI 91, ML 0.15, MI 25, SL 0.30, SI 54, PW 0.36, AL 0.66. 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 clypeus smooth relative to the surrounding surface of the head. Mandibles broadly triangular. Hairs absent from dorsum of head. Posterior margin of head shallowly concave. Antenna with 5 or more segments, the segments of the funiculus often partially or completely subdivided into additional subsegments. Scape elbowed and without a subbasal lobe. In dorsal view the pronotal humeral angles only slightly wider than the anterior one-third of the pronotum. Propodeum high, its posterior face approximately the same height as the petiolar node and with broad, thin lamellae; in profile the dorsum of the alitrunk essentially flat or with a slight angle at the junction of the mesonotum and propodeum. 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 and the anterior windows smaller than the posterior windows. First gastral tergite superimposed with weakly defined reticulate sculpturing and with low, closely spaced carinae on the anterior one-quarter to one-third. Body colour yellow to yellow brown, upper surface of the head often with small areas of weak to strong infuscation immediately anterior to the posterior margin and on the posteromedial section of the clypeus, first gastral tergite sometimes with slightly infuscated, weakly defined spots medially and laterally or a medial band.

Type Material
Holotype worker, Australia: Queensland, Mt. Coot-tha, Brisbane, 300-800 ft, 29.xii.1964, open sclerophyll, under rocks in soil on slope of ridge, found in nests of Polyrhachis ammon and Bothroponera mayri (B.B. Lowery). Paratypes. 25 workers and one queen with same data as holotype (ANIC,, ).