Key to Australian Ant Subfamilies

1

 * Mesosoma attached to the gaster with a single, distinct segment (the petiole), the segment being set off by a distinct constriction in front and either a distinct constriction (Fig. a) or a shallow impression (Fig. b) behind => 2
 * Mesosoma attached to the gaster with two segments (the petiole and postpetiole), each segment being set off by distinct constrictions (Fig. aa) => 13

2

 * Petiole with distinct front and top faces but without a separate rear face, the rear section of the petiole being attached to the gaster by its entire height (Fig. a). The upper surfaces of the petiole and gaster separated by at most a shallow impression (Fig. b) => 3
 * Petiole with distinct front and rear faces, the rear section of the petiole being set off from the gaster by a distinct constriction (Figs aa, bb) => 4

3

 * Upper plate of the second segment of the gaster (second gastral tergite) strongly arched so that it forms the rear-most part of the gaster when viewed from the side, the remaining segments being pushed forward underneath the first segment of the gaster (Fig. a) => Proceratiinae
 * Upper plate of the second segment of the gaster (second gastral tergite) only weakly arched and located in the middle of the gaster, the rear-most part of the gaster pointing rearward or directly down (Fig. aa) => Amblyoponinae

4

 * Gaster with a slight but distinct impression between the first and second segments (Fig. a) as this junction differs in structure from the junctions between the remaining segments. Or, in some cases (species of Discothyrea) the gaster is highly modified and the impression is weak or essentially absent, but these have the tip of the gaster directed downwards and located along the lower surface of the body (Fig. b)=> 5
 * Gaster uniform in outline, without an impression between the first and second segments (Fig. aa) and with this junction essentially the same as the junction between the remaining segments. The tip of the gaster always directed rearwards (Fig. bb) => 10

5

 * Upper surface of the tip of the gaster (the pygidium) flattened and with a row of small spines or peg-like teeth along its outer and trailing edge (Fig. a) => Cerapachyinae
 * Upper surface of the tip of the gaster (the pygidium) rounded and without a row of spines or teeth on its outer and trailing edge (Fig. aa) => 6

6

 * Frontal lobes reduced to a narrow, sharp ridge between the antennal sockets and with the antennal insertions clearly visible when viewed from the front (Fig. a) => Proceratiinae
 * Frontal lobes distinct and expanded towards the sides so they cover and hide at least the inner part of the antennal sockets (Fig. aa) => 7

7

 * Forward sections of the frontal lobes and the antennal sockets very close together and at most separated by a very narrow triangle of the clypeus which extends rearward between them (Fig. a) (sometimes the clypeus does not extend back between the frontal lobes and they are touching throughout their length) => Ponerinae
 * Forward sections of the frontal lobes and the antennal sockets widely separated by the broadly rounded or triangular rear section of the clypeus which extends between them (Fig. aa) => 8

8

 * Front of the head with a distinct central ridge or carina that extends, uninterrupted, from just above the mandibles to near the top of the head, this ridge generally being distinctly broader than other ridges on the head (when others are present) => Heteroponerinae
 * Front of the head either lacking a distinct central ridge or when one is present, it is similar in size and structure to other ridges on the head or is interrupted, especially between the bases of the mandibles, and is not continuous => 9

9

 * Tibiae of the hind legs each with two comb-like (pectinate) spurs, one large and one small (Fig. a) (note that the teeth on the small spur can be difficult to see). Underside of the gaster immediately below the attachment of the gaster gently rounded (Fig. b) => Ponerinae
 * Tibiae of the hind legs each with at most a single comb-like (pectinate) spur (Fig. aa) (sometimes the spur is absent). Underside of the gaster immediately below the attachment of the petiole with a ridge and often projecting slightly forward (Fig. bb) => Ectatomminae

10

 * Mandibles elongate and linear, with teeth only at the extreme tip (Fig. a), and attached close together along the front margin of the head (Fig. b) => Ponerinae
 * Mandibles triangular, with teeth along the entire inner margin (Fig. aa), and with their attachments at the outer corners of the front margin of the head (Fig. bb) => 11

11

 * Sting present and usually visible at the tip of the gaster (Fig. a). Length of petiole about the same as the length of the first gastric segment (Fig. b) => Myrmeciinae
 * Sting absent (Fig. aa). Length of petiole much shorter than the length of the first gastric segment (Fig. bb) (one exception, but here an acidopore is present – see next couplet) => 12

12

 * Tip of the gaster with a circular or semicircular opening (acidopore) which is often fringed with short hairs (Fig. a) => Formicinae
 * Tip of the gaster slit-like and never with a fringe of short hairs (Fig. aa) => Dolichoderinae

13

 * Mandibles very long, more or less straight, with teeth along their entire inner margin (Fig. a), and attached near the outer corners of the front margin of the head (Fig. b). Larger species, usually over 8 mm in total length => Myrmeciinae
 * Mandibles generally triangular (Fig. aa), but if elongate then there are no teeth along the inner margin and they are attached near the middle of the front margin of the head (Fig. cc). Smaller species, generally under 8 mm in total length => 14

14

 * Eyes almost always present, conspicuous and with many facets (Fig. a) but absent in a few species. Frontal lobes present and expanded towards the sides so they cover the inner part of the antennal bases where they are inserted into the head when viewed from the front (Fig. b) => 15
 * Eyes absent or at most with only 1 facet (Fig. aa). Frontal lobes absent so that the bases of the antennae are completely visible where they are inserted into the head when viewed from the front (Fig. bb) => 16

15

 * First segment of the mesosoma (pronotum) connected to the second segment (mesonotum) by a flexible joint (Fig. a). Hind tibial spur comb-like (pectinate) (Fig. b). Tarsal claws toothed (Fig. c). Eyes very large and elongate (Fig. d). Body elongate and slender => Pseudomyrmecinae
 * First segment of the mesosoma (pronotum) fused to the second segment (mesonotum) (Fig. aa). Hind tibial spur either simple (without comb-like teeth) (Fig. bb) or absent. Tarsal claws simple (Fig. cc). Eyes generally small and round (Fig. dd). Body short and compact => Myrmicinae

16

 * Antennae with 10 segments (including the scape). Overall body length over 3mm => Aenictinae
 * Antennae with 12 segments (including the scape). Overall body length less than 2.5mm => Leptanillinae