Colobostruma cerornata

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Colobostruma cerornata
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Colobostruma
Species: C. cerornata
Binomial name
Colobostruma cerornata
Brown, 1959

Colobostruma cerornata P casent0900008.jpg

Colobostruma cerornata D casent0900008.jpg

Specimen Label

This rare species is known from a limited number of collections scattered across Western Australia, South Australia and Victoria. So far it has only been found in heath habitats.

Identification

Shattuck (2000) - The only species in the genus with spatulate hairs on the head and which lacks wings on the lateral surfaces of the postpetiole, these surfaces being approximately vertical and rounding gradually from the dorsal surface to the ventral surface. It is also the only species with spongiform tissue on the petiole, postpetiole and gaster.

Keys including this Species

Distribution

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

The following is modified from Brown (1959): The type locality (Dempster Head) is a large, rounded gneissic-outcrop hill with low heath-like shrubs and some dwarf wattles and mallee. Paratypes were taken at the type locality and on the sand plain about 8 km. northeast of the old (abandoned) Thomas River Station, about 65 miles east of Esperance, near the end of January, 1955. All specimens were taken at night by sweeping the low heath-like vegetation. This is one of a peculiar large-eyed, depigmented fauna of ants, including three species of Colobostruma, found foraging at night on low heath-like vegetation of the coastal plain of this isolated part of Western Australia.

Beyond what is stated in the introduction at the top of this page, little is know about the biology of Colobostruma cerornata. 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.

  • cerornata. Colobostruma cerornata Brown, 1959c: 1, figs. 1, 2 (w.) AUSTRALIA. See also: Shattuck, in Bolton, 2000: 39.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Shattuck (2000) - This rare species is known from a limited amount of material collected in Western Australia, South Australia and Victoria. The single South Australian specimen is an ergatoid queen and thus differs significantly from other worker-based material currently available and it will not be considered further. The single Victorian specimen differs from the known Western Australian specimens in having fewer spatulate hairs on the dorsal surface of the head, weaker sculpture on the alitrunk and less well developed spongiform cuticle on the petiole, postpetiole and base of gaster. A case might be made for treating these specimens as belonging to separate taxa. However, the paucity of material and the large distance between them (over 1500 km.) would suggest caution in interpreting these morphological differences, especially given that they share many characters (such as eye size, head and mandible shape, sculpturing and body colour) and differ in relatively few.

Description

Worker

Shattuck (2000) - TL 2.2 - 2.3, HL 0.53 - 0.54, HW 0.43 - 0.47, CI 81 - 87, ML 0.15 - 0.20, MI 28 - 38, SL 0.27 - 0.30, SI 57 - 70, PW 0.28 - 0.36, AL 0.58 - 0.63 (2 measured). 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. Eyes unusually large. Mandibles narrow, elongate. Hairs present on dorsum of head, spatulate. Posterior margin of head broadly concave. Antenna with 4 segments, the scape gently curved and without a subbasal lobe. In dorsal view the widest point of the pronotum is at the humeral angles. Propodeum high, its posterior face slightly less than the height of the petiolar node and with broad, thin lamellae; in profile the dorsum of the alitrunk broadly convex, the metanotal groove shallow but present. Lateral postpetiole with its sides approximately vertical, not expanded outwards. Sides of petiole, postpetiole and base of gaster with spongiform cuticle, the amount varying from extensive (in Western Australian specimens) to slight (in the Victorian specimen). First gastral tergite smooth, superimposed with low carinae on the anterior one-third. Body colour uniform yellow.

Type Material

Paratype Specimen Labels
  • Holotype, worker, Dempster Head (also called Telegraph Hill) at Esperance, Western Australia, Australia, Museum of Comparative Zoology.
  • Paratype, 3 workers, Dempster Head (also called Telegraph Hill) at Esperance, Western Australia, Australia, Museum of Comparative Zoology.
  • Paratype, workers, 65mi. E Esperance, Thomas River Station, Western Australia, Australia.

References

  • Bolton, B. 2000. The ant tribe Dacetini. Mem. Am. Entomol. Inst. 65: 1-1028 (page 39, see also)
  • Brown, W. L., Jr. 1959c. Some new species of dacetine ants. Breviora 108: 1-11 (page 1, figs. 1, 2. worker described)
  • Heterick, B. E. 2009. A guide to the ants of South-western Australia. Records of the Western Australian Museum, Supplement 76:1-206. PDF
  • Shattuck, S. O. 1999. Australian ants. Their biology and identification. Collingwood, Victoria: CSIRO Publishing, xi + 226 pp. (page 131, see also)
  • 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.
  • Taylor, R. W. 1987a. A checklist of the ants of Australia, New Caledonia and New Zealand (Hymenoptera: Formicidae). CSIRO Div. Entomol. Rep. 41: 1-92 (page 22, checklist)
  • Taylor, R. W.; Brown, D. R. 1985. Formicoidea. Zool. Cat. Aust. 2:1- 149: 1-149, 30 (page 59, catalogue)