Key to Australian Genera of Myrmicinae

1

 * Antennal scape, when laid back against the head in its normal resting position, passing either below the eye (Fig. a) or across its lower margin. Distinct, elongate depressions (antennal scrobes) which contain the entire antennae when at rest sometimes present on the front of the head, and when present, running below the eyes (Fig. b) => 2
 * Antennal scape, when laid back against the head in its normal resting position, passing above the eye and along the upper surface of the head (Fig. aa) (or, if the eyes are absent, then the scape passes along the upper surface of the head above where the eye would be expected to occur). Distinct, elongate depressions (antennal scrobes) which contain the entire antennae when at rest sometimes present on the front of the head, and when present, running above the eyes (Fig. bb) => 6

2

 * Antennae with 4 to 6 segments (including the scape) (Fig. a, with 6 segments). Palp formula 5:3 (outer (maxillary) palps with 5 segments, inner (labial) palps with 3 segments) (Fig. b) => 3
 * Antennae with 7 segments (including the scape) (Fig. aa). Palp formula 2:2 or less (outer (maxillary) and inner (labial) palps each with at most 2 segments) (Fig. bb) => 5

3

 * Mandibles thin and elongate, when fully closed they are separated by a broad gap for most of their length and touch only at the tips (Fig. a) => Epopostruma
 * Mandibles triangular to elongate-triangular, when fully closed they touch or nearly touch along their entire length (Fig. aa) => 4

4

 * Mandibles with teeth along their entire inner margins (Fig. a). In side view the base of the mandible angled downwards under the forward edge of the clypeus (Fig. b). Sides of the petiole and postpetiole with thin, wing-like flanges (best viewed from above - wings are absent from the postpetiole of one species but are present on the petiole) (Fig. c) => Colobostruma
 * Mandibles lacking teeth except near the base and tip (Fig. aa). In side view the section of the mandible near the clypeus straight (Fig. bb). Sides of the petiole rounded or with at most a slight ridge, the wing-like flanges (when present) found only on the postpetiole (Fig. cc) => Mesostruma

5

 * Mandibles thin and elongate, when fully closed they are separated by a broad gap for most of their length and touch only at the tips (Fig. a) => Rhopalothrix
 * Mandibles triangular, when fully closed they touch or nearly touch along their entire length (Fig. aa) => Eurhopalothrix

6

 * Antennae with 4 to 6 segments (including the scape) => 8
 * Antennae with 9 to 12 segments (including the scape) => 9

8

 * Antennae with 5 segments (including the scape), and with the third segment from the tip elongate and much longer than the other segments of the funiculus (Fig. a). Palp formula 5:3 (outer (maxillary) palps with 5 segments, inner (labial) palps with 3 segments) (Fig. b) => Orectognathus
 * Antennae with 4 or 6 segments (including the scape), and with the third segment from the tip about the same length or shorter than the other segments of the funiculus (Fig. aa). Palp formula 1:1 (both outer (maxillary) and inner (labial) palps with a single segment) (Fig. bb) => Strumigenys

9

 * Antennae with 9 segments (including the scape). Upper surface of the mesosoma forming a broad shield with thin, sharp lateral edges which project outwards over the sides of the mesosoma (Fig. a) => Meranoplus
 * Antennae with 9 to 12 segments (including the scape). Upper surface of the pronotum and mesonotum usually rounding gradually into the sides of the mesosoma (Fig. aa), or at most separated by a distinct angle or ridge, but never a thin flange-like projection => 10

10

 * Postpetiole attached to the upper surface of the gaster (Fig. a). Gaster when viewed from above roughly heart-shaped. Petiole without a node (Fig. b) => Crematogaster
 * Postpetiole attached to the front of the gaster (Figs aa, aa). Gaster when viewed from above not particularly heart-shaped. Petiole usually with a node (Fig. bb) but sometimes roughly cylindrical or barrel-shaped (Fig. cc) => 11

11

 * First and second segments of the antennae (those nearest the tip) much longer than the remaining segments (excluding the scape) and forming a conspicuous 2-segmented club (Fig. a) => 12
 * Antennae either without a distinct club, or with a club of 3 or more segments (Fig. aa) => 17

12

 * Rear face of the propodeum rounded or with at most low, rounded ridges or protuberances, but never with teeth, spines or thin flanges (Fig. a) => 13
 * Rear face of the propodeum armed with teeth or spines which vary from short and angular (Fig. aa) to long and thin, or occasionally propodeum with thin, elongate flanges => 14

13

 * Front margin of the clypeus just above the mandibles with a single central elongate hair or seta (Fig. a) which is often surrounded by paired hairs or setae. In side view the upper surface of the mesosoma with a distinct impression at the metanotal groove (Fig. b) => Solenopsis
 * Front margin of the clypeus just above the mandibles with pairs of elongate hairs or setae which straddle the mid-line of the head (Fig. aa). In side view the upper surface of the mesosoma smooth, without an impression at the metanotal groove (Fig. bb) => Rhopalomastix

14

 * Distinct, elongate depressions (antennal scrobes) present on the front of the head which contain the entire antennae when at rest (Fig. a). Eyes elongate and with the lower section narrowed into a point (Fig. b). All workers approximately the same size (monomorphic) => 15
 * Front of the head smooth and without elongate depressions (antennal scrobes) (Fig. aa). Eyes small and round (Fig. bb). Workers highly variable in size (dimorphic or polymorphic) => Carebara

15

 * Antennae with 10 segments (including the scape). Clypeus with a pair of weak, longitudinal ridges or sharp angles immediately below the antennal sockets which separate the central region from the lateral regions (clypeus longitudinally bicarinate) (Fig. a) => Mayriella
 * Antennae with 11 segments (including the scape). Clypeus smooth across its entire width and without longitudinal ridges or angles (Fig. aa) => Wasmannia

17

 * Area of the clypeus immediately below the antennal sockets raised into a sharp-edged ridge (Fig. a). Tip of the sting with a triangular to pennant-shaped extension projecting upwards from the shaft (visible only when the sting is extended) (Fig. b) => 18
 * Area of the clypeus immediately below the antennal sockets usually smooth (Fig. aa) although a carina is present in a few species (some Pristomyrmex, but here the underlying clypeus is broadly rounded). Tip of the sting thin and pointed (Fig. bb) or slightly flattened and swollen => 20

18

 * Pairs of spines or strong denticles present on the pronotal shoulders (immediately behind the head). In side view the mandibles tipped downwards relative to the upper surface of the head.  (Note that the tip of the sting lacks the extension found in the next two species, but that this character is not visible in many specimens where the sting in retracted into the tip of the gaster.) => Pristomyrmex
 * Pronotal shoulders (immediately behind the head) rounded. In side view the mandibles continuing a line along the dorsal surface of the head => 19

19

 * When viewed from the front, head shape roughly square or rectangular with a flat to weakly concave rear margin, weakly convex sides and with the front margin of the clypeus weakly convex, flat or weakly concave and covering only the extreme rear section of the mandibles (Fig. a). Lower surface of the petiole rounded from side to side (best viewed from below). Palp formula usually 4:3 (outer (maxillary) palps with 4 segments, inner (labial) palps with 3 segments), rarely with fewer segments (Fig. b). Propodeum near the insertion of the petiole often with a pair of spine-like flanges (Fig. c) although sometimes with rounded flanges => Tetramorium
 * When viewed from the front, head roughly heart-shaped with a concave rear margin, convex sides and with the front margin of the clypeus strongly arched and projecting forward over the rear section of the mandibles (Fig. aa). Lower surface of the petiole ridged and keel-like (best viewed from below). Palp formula 3:2 (outer (maxillary) palps with 3 segments, inner (labial) palps with 2 segments) (Fig. bb). Propodeum near the insertion of the petiole with short, rounded flanges (Fig. cc) => Rhoptromyrmex

20

 * Antennae with 10 or 11 segments (including the scape) => 21
 * Antennae with 12 segments (including the scape) => 28

21

 * Pairs of spines or strong denticles present on the pronotum, on the propodeum near the angle and near the attachment of the petiole (Fig. a) => Pristomyrmex
 * Spines or denticles usually absent from the mesosoma (Fig. aa), but if present, limited to near the propodeal angle => 22

22

 * In side view, the petiole and postpetiole are either low, rounded, and barrel-shaped (Fig. a), or the petiole is armed above with 1 to 3 small spines or teeth (Fig. b). Middle and hind legs with greatly swollen femora (and often tibiae as well) (Fig. c) => Podomyrma
 * In side view, the petiole and postpetiole with distinct, arched nodes on their upper surfaces (Fig. aa), the petiole sometimes with a sharp angle above, but never with a tooth or spine. Middle and hind legs with only weakly swollen femora and tibiae (Fig. cc) => 23

23

 * Upper surface of the head with a pair of narrow and deep grooves (Fig. a) or very feeble depressions (Fig. b) (antennal scrobes) for the reception of the antennal scapes when at rest, which are bounded above by conspicuous or interrupted ridges (frontal carinae) => 24
 * Upper surface of the head lacking grooves for the reception of the antennal scapes (Fig. aa) => 25

24

 * Grooves on the upper surface of the head (antennal scrobes) narrow and deep, and partially overhung by the medial sections of the head so their lower surfaces are partially concealed when viewed from the front (Fig. a). Eyes small and located on the lower edge of the antennal scrobe (Fig. b). Front margin of the clypeus with a rectangular projection which extends forward over the rear section of the mandibles (Fig. c). In side view, the petiole and postpetiole with their upper surfaces broad and flat to weakly convex (Fig. d) => Metapone
 * Grooves on the upper surface of the head (antennal scrobes) broad and shallow and completely visible when viewed from the front (Figs aa, aa). Eyes large and located well below the antennal scrobe (Figs bb, bb). Front margin of the clypeus broadly convex and projecting only slightly forward over the extreme rear section of the mandibles (Fig. cc). In side view, the petiole and postpetiole with high, conical, pointed nodes on their upper surfaces (Fig. dd) => Peronomyrmex

25

 * Front margin of the clypeus just above the mandibles with a single central elongate hair or seta (Fig. a) which is often surrounded by paired hairs or setae => 25a
 * Front margin of the clypeus just above the mandibles with pairs of elongate hairs or setae which straddle the mid-line of the head (Fig. aa) => 26

25a

 * Eye minute, with 1 or 2 ommatidia => Syllophopsis
 * Eye moderate to large, with many ommatidia => Monomorium, Trichomyrmex

26

 * Upper surface of the mesosoma evenly convex and without a metanotal groove (Fig. a). When viewed from above the petiole and postpetiole are very broad, about the same width as the propodeum (Fig. b) => Stereomyrmex
 * Upper surface of the mesosoma interrupted by an impressed or angular metanotal groove (Fig. aa). When viewed from above the petiole and postpetiole are much narrower than the propodeum (Fig. bb) => 27

27

 * Clypeus with a pair of weak, longitudinal ridges or sharp angles immediately below the antennal sockets which separate the central region from the lateral regions (clypeus longitudinally bicarinate) (Fig. a). Propodeum rounded, lacking sharp angles or spines (Fig. b) => Adlerzia
 * Clypeus smooth across its entire width and without longitudinal ridges or angles (Fig. aa). Propodeum armed with sharp angles (Fig. bb) or short spines (Fig. cc) => Pheidole dispar

28

 * Front margin of the clypeus with a conspicuous, broad, bilobed appendage (the clypeal fork) which projects over the rear section of the mandibles (Fig. a) => Calyptomyrmex
 * Front margin of the clypeus broadly convex (Fig. aa) or with at most a pair of short teeth (Fig. bb) => 29

29

 * Sides of the head behind the eyes with an elongate ridge or groove on each side which starts at the mandibles and runs the length of the head, ending near the upper corners (Fig. a) => 30
 * Sides of the head behind the eyes either smooth or sculptured, but when sculptured, never with an elongate ridge or groove which runs the length of the head (Fig. aa) => 31

30

 * Ridge or groove on the side of the head passing well below the eye (Fig. a). Upper surface of the propodeum near the metanotal groove armed with low spines or small teeth (Fig. b). In side view, the petiole low and without a distinct node (Fig. c) => Myrmecina
 * Ridge or groove on the side of the head touching the eye (Fig. aa). Upper surface of the propodeum near the metanotal groove smooth (Fig. bb). In side view, the petiole with a distinct, arched node on its upper surface (Fig. cc) => Vombisidris

31

 * Front margin of the clypeus just above the mandibles with a single central elongate hair or seta (Fig. a) which is often surrounded by paired hairs or setae => 32
 * Front margin of the clypeus just above the mandibles with pairs of elongate hairs or setae which straddle the mid-line of the head, or with numerous hairs across most of its width, or lacking hairs (Fig. aa) => 33

32

 * Postpetiole swollen, wider than long and much broader than the petiole when viewed from above (Fig. a). Outer (maxillary) palp with 5 segments => Cardiocondyla
 * Postpetiole approximately square, at most only slightly wider than long, and only slightly broader than the petiole when viewed from above (Fig. aa). Outer (maxillary) palp with 1 or 2 segments => Monomorium, Trichomyrmex

33

 * Node of the petiole about the same length as the petiole so that there is only a very short narrow section (peduncle) in front of the node (Fig. a) => 34
 * Node of the petiole either much shorter than the length of the petiole and the petiole with a distinct narrow section (peduncle) in front of the node (Fig. aa), or the node lacking and the petiole low, rounded and barrel-shaped (Fig. bb) => 35

34

 * Upper surface of the head with a pair of shallow grooves (antennal scrobes) for the reception of the antennal scapes when at rest, these grooves bounded above by ridges (frontal carinae) (Fig. a). Palp formula 5:3 (outer (maxillary) palps with 5 segments, inner (labial) palps with 3 segments) (Fig. b). Lower surface of the petiole with a small tooth or angle (Fig. c) near the attachment with the propodeum. Propodeum armed with a pair of long, stout spines (Fig. d) => Romblonella
 * Upper surface of the head lacking grooves for the reception of the antennal scapes (Fig. aa). Palp formula 2:2 (both outer (maxillary) and inner (labial) palps with 2 segments each) (Fig. bb). Lower surface of the petiole near the propodeum with a large rounded or angular plate (Fig. cc). Propodeum rounded (Fig. dd) or at most with a pair of small, triangular teeth => Vollenhovia

35

 * When viewed from the front, the rear corners of the head are sharply angular or pointed (Fig. a). Upper surface of the head with a pair of shallow grooves (antennal scrobes) for the reception of the antennal scapes when at rest (Fig. b). Propodeum rounded and without spines (Fig. c). In side view the petiole is low, rounded, and barrel-shaped (Fig. d) => Dilobocondyla
 * When viewed from the front, the rear corners of the head are broadly to narrowly rounded (Fig. aa). Upper surface of the head with or without a pair of shallow grooves (antennal scrobes) for the reception of the antennal scapes when at rest (Fig. bb). Propodeum with or without a pair of spines or teeth (Fig. cc). In side view the petiole with a distinct, arched node on its upper surface (Fig. dd) => 36

36

 * In side view the propodeum is depressed below the pronotum and forward section of the mesonotum and the rear section of the mesonotum forms a steep slope between them (Fig. a) => 37
 * In side view the upper surface of the propodeum is approximately even with the pronotum and mesonotum so that the upper surface of the mesosoma forms a uniform arch interrupted only by the shallow metanotal groove (Fig. aa) => 38

37

 * Palp formula 2:2 or 3:2 (outer (maxillary) palps with 2 or 3 segments, inner (labial) palps with 2 segments) (Fig. b). Overall body size variable, but often less than 3.4 mm long. Workers with majors and minors but without intermediates (dimorphic) => Pheidole
 * Antennae with a 4 segmented club (Fig. aa). Palp formula 4:3 (outer (maxillary) palps with 4 segments, inner (labial) palps with 3 segments) (Fig. bb). Overall body size greater than 3.4 mm long. All workers approximately the same size (monomorphic) => Aphaenogaster

38

 * Eyes small, with at most 4 facets (ommatidia) in greatest diameter, and round or nearly round (Fig. a) => Pheidole antipodum
 * Eyes large, with 8 or more facets (ommatidia) in greatest diameter, and distinctly oval or elongate (Fig. aa) => 39

39

 * Upper surface of the head lacking grooves for the reception of the antennal scapes when at rest (Fig. a). Mandibles with 4 or 5 teeth (Fig. b). Tip of the sting broad, flat and rounded (visible only when sting extended) (Fig. c) => Austromorium
 * Upper surface of the head with or without a pair of shallow grooves (antennal scrobes) for the reception of the antennal scapes when at rest (Fig. aa). Mandibles with 6 to 10 teeth (Fig. bb). Tip of the sting a thin, sharp point (visible only when sting extended) (Fig. cc) => Lordomyrma