Key to Australian Dolichoderus species based on workers

1. Propodeum with elongate spines (Fig. 2).................................................................. 2

-. Propodeum lacking spines (Fig. 1)....................................................................... 13

2. Pronotum with elongate spines (Fig. 5) ( doriae group)........................................................ 3

-. Pronotum rounded, lacking spines (Fig. 2) ( scabridus group).................................................. 8

3. Pronotal spines directed laterally and dorsally (Fig. 10).............................................. extensispinus

-. Pronotal spines directed anteriorly and approximately parallel to the longitudinal axis of the body (Fig. 7)............... 4

4. Pronotal spines long, in dorsal view a line drawn between their tips lies anterior of the pronotal collar (Fig. 7)...... dentatus

-. Pronotal spines short, in dorsal view a line drawn between their tips intersects the pronotal collar (Fig. 8)............... 5

5. First gastral tergite with abundant short erect hairs.......................................................... 6

-. First gastral tergite generally lacking erect hairs, but occasionally with a few very short, scattered hairs present........... 7

6. Legs yellow, strongly contrasting with black body; propodeal spines and sometimes antennae dark red to red-brown, lighter in colour than nearby body regions (Fig. 8).............................................................. doriae

-. Legs dark brown to black, generally similar in colour to the body or at most slightly lighter in colour than body; tips of propo- deal spines and antennae very dark brown to black and similar in colour to nearby body regions (Fig. 5)............ clarki

7. First gastral tergite with abundant appressed very fine pubescence (Fig. 9)..................................... etus

-. First gastral tergite with a few scattered, very small appressed hairs (Fig. 12)................................. gordoni

8. In front view, propodeal spines directed upward at angle of greater than 60° to horizontal plane (may be almost vertical), the angle between them approximately 45° (Fig. 2).................................................. angusticornis

-. In front viewed, propodeal spines directed upward at angle of 45° or less to horizontal plane, the angle between them at least 90° (Fig. 21)........................................................................................ 9

9. Dorsum of petiolar node angular; when viewed from the front base of propodeal spines narrow, the spines forming a “V” with a narrowly rounded angle between their bases; legs long (Fig. 21) (Western Australia).............................. 10

-. Dorsum of petiolar node broad, weakly convex to weakly concave; when viewed from the front, base of propodeal spines broad, the spines forming a “U” with a broad concavity connecting their bases (sometimes this region flat or weakly convex); legs short (Fig. 14) (South Australia and eastward)......................................................... 12

10. Legs entirely light red or orange (Fig. 27)............................................................. ypsilon

-. Femora dark reddish-brown or black, tibiae varying from dark brown to light red.................................. 11

11. Legs bicoloured, dark femora contrasting with more lightly coloured tibiae (Fig. 21)....................... rufotibialis

-. Legs uniformly coloured dark red-brown to reddish-black (Fig. 16).......................................... niger

12. Legs dark red-brown, at most only slightly lighter in colour than the body (Fig. 14)............................ inferus

-. Legs yellowish-red, distinctly lighter than the colour of the body (Fig. 23).................................. scabridus

13. Posterior face of propodeum weakly concave, separated from the dorsal face by at most a weakly defined angle; sculpturing on head minimal, either essentially absent or consisting of very fine reticulations (Fig. 3) ( australis group)............... 14

-. Posterior face of propodeum strongly concave, separated from the dorsal face by a distinct carina; sculpturing on head consist- ing of large, shallow to moderately deep fovea (Fig. 24) ( scrobiculatus group).................................... 18

14. Head yellowish-red (Fig. 22).......................................................................... 15

-. Head dark reddish-brown to black (Fig. 3)................................................................ 17

15. Dorsum of propodeum falling away posteriorly so that the angle is below the level of the metanotal groove (Fig. 19).. parvus

-. Dorsum of propodeum evenly convex, the angle at approximately the same level as the metanotal groove (Fig. 15)...... 16

16. Head and dorsum of pronotum finely reticulate, the surfaces matte (Fig. 15).................................. kathae

-. Head and dorsum of pronotum smooth, the surfaces shiny (Fig. 22)........................................ rutilus

17. First tergite of gaster with elongate erect hairs but lacking appressed pubescence (Fig. 3)...................... australis

-. First tergite of gaster with both elongate erect hairs and fine, silvery appressed pubescence (Fig. 13)............. goudiei

18. Pubescence on first gastral tergite abundant, the individual hairs overlapping (Fig. 26)............................ 19

-. Pubescence on first gastral tergite sparse, the individual hairs generally not overlapping, or hairs absent (Fig. 20)........ 21

19. Dorsum of pronotum essentially smooth, the sculpturing at most very fine, the surface shiny; metanotal groove relatively deep (Fig. 6) (SA, southern WA).......................................................................... clusor

-. Dorsum of pronotum heavily sculptured, the surface dull; metanotal groove relatively weekly developed (Fig. 24) (north-east- ern NSW, Qld)...................................................................................... 20

20. Gaster similar in colour to body (both dark brown to black) (Fig. 24).................................. scrobiculatus

-. Gaster much lighter in colour compared to body (body dark brown to black, gaster dull yellow) (Fig. 26).......... turneri

21. Tibiae lacking erect hairs (Fig. 25)................................................................. semiorbis

-. Tibiae with erect or suberect hairs (Fig. 1)................................................................. 22

22. Dorsum of propodeum elongate (longer than posterior face) and weakly convex, the carina separating dorsal and posterior faces produced as sharp shelf; pale markings present near lower margin of eye (Fig. 1).................... albamaculus

-. Dorsum of propodeum shorter (at most approximately the same length as the posterior face) and strongly convex, the carina separating dorsal and posterior faces a narrow carina; without pale markings near lower margin of eyes (Fig. 20)........ 23

23. Dorsum of propodeum highly arched and often with flat or even weakly concave sections; posterior face of propodeum deeply concave and often nearly semicircular; in dorsal view the pronotum with strongly developed shoulders, the area between the shoulders weakly convex to weakly concave (Fig. 20)................................................... reflexus

- Dorsum of propodeum more weakly and evenly convex, occasionally with a flat or nearly flat section posteriorly; posterior face of propodeum less deeply concave and much less semi-circular; in dorsal view the pronotum with only weakly defined shoulders, the area between the shoulders more strongly convex to flat (Fig. 18).................................. 24

24. Gaster yellowish red and lighter in colour than mesosoma (Fig. 18)........................................ omicron

-. Gaster dark brown to black, darker than mesosoma when mesosoma is lightly coloured (similar to mesosoma in colour when entire body dark brown to black)....................................................................... 25

25. Head and pronotum weakly and superficially areolate, the overall sculpturing pattern indistinct (Fig. 4)........... canopus

-. Dorsum of head and pronotum with large but shallow and closely spaced foveae, the lateral pronotum distinctly striate, the overall sculpturing pattern very distinct (Fig. 17)........................................................... 26

26. Head reddish to reddish-brown and lighter in colour than dark brown to black gaster; mesosoma and gaster with both erect hairs and scattered, appressed pubescence (Fig. 17)................................................. nigricornis

-. Head dark brown to black and similar in colour to gaster; mesosoma and gaster with erect hairs but little or no appressed pubescence (Fig. 11)............................................................................ formosus