Colobostruma bicorna

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Colobostruma bicorna
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Colobostruma
Species: C. bicorna
Binomial name
Colobostruma bicorna
Shattuck, 2000

This rare species is known from only a single collection made in Sydney, NSW, nesting in soil.

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.

Keys including this Species

Distribution

Only known from Sydney, New South Wales.

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Beyond what is stated in the introduction at the top of this page, little is know about the biology of Colobostruma bicorna. Until further studies reveal more about this species we can infer that its natural history and biology should be similar to other species in this genus. In general Colobostruma can be locally common although they are often overlooked. Most species have small colonies with less than 100 workers, and workers will lie motionless when disturbed. Nests can occur in soil usually under rocks, in cracks in rocks or in rotten logs. Only a single rainforest species is known to nest arboreally. Foraging is usually on the ground at night but occasionally they are found foraging on mallee. They are also commonly found in leaf litter.

Castes

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

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

Type Material

  • Paratype, worker, French's Forest, St. Ives, Sydney, New South Wales, 700 ft., Australia, 16 October 1956, Australian National Insect Collection; edge of laterite plateau, nest in yellow sand beside Camponotus consobrinus.
  • Paratype, 11 workers, French's Forest, St. Ives, Sydney, New South Wales, 700 ft., Australia, 16 October 1956, Australian National Insect Collection; edge of laterite plateau, nest in yellow sand beside Camponotus consobrinus.

Description

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.

References

  • Shattuck, S. O. 2000. Genus Colobostruma. Genus Mesostruma. Genus Epopostruma. Pp. 31-67 in: Bolton, B. The ant tribe Dacetini. Mem. Am. Entomol. Inst. 65: 1-1028 (page 45, worker described)