Anochetus rectangularis

Anochetus rectangularis is found in north-western Western Australia, the Top End of the Northern Territory and from Cape York south into at least south-eastern Queensland. Biologically, this species is found primarily in dry sclerophyll and savannah woodlands with only the occasional record from rainforest. Nests are in soil generally under rocks or logs but it is also known to nest in termite mounds as well as the unoccupied nests of Iridomyrmex purpureus.

Identification
Sculpture on front of head extending only slightly beyond eyes; pronotum smooth dorsally, sculptured laterally; mesonotum smooth and without sculpturing; petiolar node in side view tapering gradually to apex in the form of an inverted “V”, with the striations fading towards the summit; propodeal angle sharply rounded. This species is similar to A. turneri but differs in having the anterior face of the petiolar node uniformly concave rather than angular. It differs from the otherwise similar Anochetus rufolatus and Anochetus rufostenus in the more narrowly tapering petiolar node (when viewed laterally) which lacks striations near the summit, and in the more sharply angular propodeal angle.

Key to Australian Anochetus Species

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

There are two old collections of this species from New South Wales made by W. W. Froggatt, one from Warrah and the other from Bombala. Both of these sites are well south of other more modern records for this species and the Bombala site, at over 700m elevation, is far colder and wetter than any other locality known for the genus. Warrah is located much further north at approximately 500m elevation and two additional species, Anochetus armstrongi and Anochetus graeffei, occur in this same general area. Thus while it is likely that A. rectangularis does extend into northern New South Wales it is highly likely that the Bombala record is in error and the species does not occur this far south. In any event, the species has clearly reached the limit of the main part of its range by southern Queensland and is at best rare in northern New South Wales. In northern Australia this species is currently unknown from the Kimberley Region. Whether this is a true absence or lack of collecting effort is uncertain at the present time.

Nomenclature

 *  rectangularis. Anochetus rectangularis Mayr, 1876: 86 (w.) AUSTRALIA. Senior synonym of diabolus: Brown, 1978c: 558 (see also p. 597). See also: Shattuck & Slipinska, 2012: 16.
 * diabolus. Anochetus rectangularis var. diabolus Forel, 1915b: 35 (w.) AUSTRALIA. Junior synonym of rectangularis: Brown, 1978c: 558.

Description
Worker description. Sculpturing on front of head extending slightly beyond eyes. Scapes not reaching posterolateral corners ('lobes') of head; with limited pubescence and a limited number of erect hairs. Pronotum smooth dorsally, striate laterally and anterior section with transverse wrinkles and ridge. Mesonotum smooth and shining. Dorsum of propodeum flattened, with coarse striate-rugose or striate sculpture and with inclined short hairs. Metapleuron with distinct transverse striations. Petiolar node slightly rounded laterally and moderately concave dorsally; in side view tapering gradually to V-shaped apex; weak striations fade dorsally. Hind tibiae with erect hairs limited to outer surfaces. Colour yellow-brown to dark brown, head yellow-brown, antennae, mandibles and legs yellow.

Measurements. Worker (n = 6): CI 88–91; EI 22–25; EL 0.23–0.26; HL 1.08–1.18; HW 0.95–1.06; HFL 0.89–0.99; ML 1.30–1.40; MandL 0.55–0.62; MTL 0.64–0.70; PronI 63–65; PronW 0.62–0.67; SL 0.85–0.92; SI 85–90.

Additional References

 * Shattuck, S.O. & Slipinska, E. 2012. Revision of the Australian species of the ant genus Anochetus (Hymenoptera Formicidae). Zootaxa 3426, 1–28.