Aphaenogaster

Shattuck, S. O., 2008, Australian ants of the genus Aphaenogaster (Hymenoptera: Formicidae)., Zootaxa 1677, pp. 25-45 : 27-28

Aphaenogaster Mayr

Diagnosis. Antennae 12 segmented (including the scape) with a 4 segmented club (Fig. 9). In side view the propodeum depressed below the level of the pronotum and anterior region of the mesonotum, these two regions being connected by the steeply sloping posterior section of the mesonotum (Fig. 2). Monomorphic.

Aphaenogaster is most likely to be confused with Pheidole or possibly Pheidologeton . Workers of Aphaenogaster can be separated from those of Pheidole by the 4 segmented rather than 3 segmented club and the larger body size (over 3.4mm long), and from Pheidologeton by the 12 segmented antennae (11 segmented in Pheidologeton ). Additionally, both Pheidole and Pheidologeton have polymorphic workers while Aphaenogaster is monomorphic.

The Australian species of Aphaenogaster show differences which are little more than "variation on a theme." This is in contrast to the nearby Papua New Guinea fauna where morphological variation is considerable(Smith 1961). This difference suggests that the Australian fauna is composed of closely related species while that of PNG consists of several more distantly related lineages.

List of Australian species

barbara sp. n. (Queensland)

barbigula Wheeler (New South Wales, Queensland, South Australia, Victoria)

kimberleyensis sp. n. (northern Northern Territory, northern Western Australia)

longiceps (Smith) (ACT, New South Wales, southern Queensland, south-east South Australia, Victoria)

flava Emery (new synonymy)

ruginota Forel

mediterrae sp. n. (western South Australia, southern Western Australia)

poultoni Crawley (south-western Western Australia)

pythia Forel (Queensland, PNG)

reichelae sp. n. (northern Northern Territory)

Key to species of Australian Aphaenogaster based on workers

1. Majority of hairs on venter of head located laterally and forming a distinct psammophore, only scattered hairs on central portion (Fig. 4) ................................................................................................................... 2

- Hairs on venter of head randomly distributed and not forming a distinct psammophore (Fig. 2)..............4

2 Eye relatively large (EI greater than 21, Fig. 19); scape relatively long (SI greater than 106, Fig. 20)........ ...................................................................................................................................................... mediterrae

- Eye relatively small (EI less than 21, Fig. 19); scape relatively short (SI less than 106, Fig. 20)..............3

3. Petiolar node (in dorsal view) wider than long; mandibular sculpture composed of irregularly sized striations(Fig. 6) (occurring in Western Australia)................................................................................. poultoni

- Petiolar node (in dorsal view) approximately square; mandibular sculpture composed of regularly sized striations (Fig. 5) (occurring in South Australia and eastward)...................................................... barbigula

4. 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 (Fig. 15).................... 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) (Fig. 9) ................................................................................... 6

5. Scape relatively short (SI less than 125, Fig. 23) (occurring in e. Queensland and ne. New South Wales) ............................................................................................................................................................. pythia

- Scape relatively long (SI greater than 135, Fig. 23) (occurring in Northern Territory) .................. 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) (Fig. 10).................. 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) (Fig. 8)........................................................7

7. Head relatively narrow (Fig. 21), scape relatively long (Fig. 22) (occurring in n. Northern Territory and n. Western Australia).................................................................................................................. kimberleyensis

- Head relatively broad (Fig. 21), scape relatively short (Fig. 22) (occurring in Queensland)........... barbara