Key to Australian Aphaenogaster Species

1. Majority of hairs on venter of head located laterally and forming a distinct psammophore, only scattered hairs on central portion => 2

-. Hairs on venter of head randomly distributed and not forming a distinct psammophore => 3

2. Eye relatively large (EI greater than 21); scape relatively long (SI greater than 106) => Aphaenogaster mediterrae

-. Eye relatively small (EI less than 21); scape relatively short (SI less than 106) => 4

3. 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 => 5

-. Posterior margin of head broadly arched in full face view, the arch beginning at the occipital collar and with at most a weak angle separating the posterior and lateral margins of the head (often posterior and lateral margins forming a continuous surface) => 6

4. Petiolar node (in dorsal view) wider than long; mandibular sculpture composed of irregularly sized striations (occurring in Western Australia) => Aphaenogaster poultoni

-. Petiolar node (in dorsal view) approximately square; mandibular sculpture composed of regularly sized striations (occurring in South Australia and eastward) => Aphaenogaster barbigula

5. Scape relatively short (SI less than 125) (occurring in eastern Queensland and north eastern New South Wales) => Aphaenogaster pythia

-. Scape relatively long (SI greater than 135) (occurring in Northern Territory) => Aphaenogaster reichelae

6. Shorter erect hairs on mesosomal dorsum (especially those on mesonotum) with blunt tips; dorsal surfaces of propodeum and propodeal spines connected through a gentle concavity (so that the base of each spine is at approximately the same level as the dorsal surface of the propodeum) => Aphaenogaster longiceps

-. Erect hairs on mesosomal dorsum tapering to sharp points; dorsal surfaces of propodeum and propodeal spines connected through a gentle concavity followed by a gentle convexity (so that the base of each spine is raised slightly above the dorsal surface of the propodeum) => 7

7. Head relatively narrow, scape relatively long (occurring in northern Northern Territory and northern Western Australia) => Aphaenogaster kimberleyensis

-. Head relatively broad, scape relatively short (occurring in Queensland) => Aphaenogaster barbara