Aphaenogaster poultoni

This species is restricted to a narrow semi-arid band across south-western Western Australia and is sympatric with A. mediterrae in south-central Western Australia. It is found in coastal scrub, Jarrah forests, dry sandy sclerophyll, mulga woodlands and mallee. Nests are in soil generally with a large crater at the entrance. An exceptionally large mating swarm was noted by McMillan (1977) (as A. barbigula).



Worker of A. poultoni

Nomenclature
Aphaenogaster poultoni Crawley, W. C. (1922). New ants from Australia (concluded from vol. ix. p. 449). Annals and Magazine of Natural History. (9) 10 : 16–36 (p. 17).

Type Material
 * Syntype, Beenup, Western Australia (UMO (Oxford): worker(s)).
 * Syntype, Beenup, Western Australia (WAM (Perth): 10 workers).
 * Syntype, Byford, Western Australia (QM (Brisbane): 18 workers).
 * Syntype, unspecified (MV (Melbourne): 1 worker).

Diagnosis
Majority of hairs on underside of head located laterally and forming a distinct psammophore; eye relatively small (EI less than 21); scape relatively short (SI less than 106); mandibular sculpture composed of irregularly sized striations; petiolar node (in dorsal view) wider than long. This species is most similar to A. barbigula. These two species can be separated by the pattern of sculpturing on the mandibles and the shape of the petiolar node.

There is a tendency for the head of A. poultoni to be more square (when viewed in full face view, the lateral and posterior margins are separated by an angle) compared to both A. barbigula and A. mediterrae (in which the head is essentially uniformly arched behind the eyes in full face view). However, all species show moderate variation in the shape of the head with essentially identical morphologies being found in some individuals of all three species. Thus while this character is indicative of A. poultoni it is not diagnostic.

Description
Posterior margin of head nearly flat in full face view, extending laterally of the occipital collar before passing through a distinct posterolateral corner into the lateral margin of the head. Majority of hairs on venter of head located laterally and forming a distinct psammophore, only scattered hairs on central portion. Mandibular sculpture composed of irregularly sized striations. Erect hairs on mesosomal dorsum tapering to sharp points. Propodeal spines reduced to small denticles or sharp angles. Petiolar node (in dorsal view) wider than long.

Distribution
Australian National Insect Collection