Key to Stigmacros of the southwestern Australian Botanical Province

This worker key is based on: Heterick, B. E. 2009a. A guide to the ants of South-western Australia. Records of the Western Australian Museum, Supplement 76: 1-206. Part 2.

The key produced by McAreavey (1957) is, unfortunately, not easy to use, and may not reflect the outcome of a modern revision of the group; hence it has not been followed here.

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• Australia
• SWBP
• Stigmacros

1

• Dorsum of node with pair of spines directed posteriad (Figure 408) . . . . . 2

Figure 408.

• Dorsum of node unarmed, or nearly so (may be divided into pair of blunt lobes or vestigial denticles) (Figure 409) . . . . . 6

Figure 409.

2

return to couplet #1

• Propodeum armed with two pairs of stout spines; one pair at propodeal angles and one pair directly above propodeal spiracles, respectively (sub-genus Hagiostigmacros) (possibly two species represented here) (Figure 410) . . . . . Stigmacros spinosa

Figure 410.

• Propodeum armed with one pair of spines or denticles directly above propodeal spiracles, propodeal angles produced as weak or vestigial denticles (Figure 411) . . . . . 3

Figure 411.

3

return to couplet #2

• Head and mesosoma glossy black . . . . . Stigmacros brachytera (a few workers)

• Head and mesosoma yellow or reddish-brown . . . . . 4

4

return to couplet #3

• Process directly above propodeal spiracle a short denticle (Figure 412) . . . . . Stigmacros sp. JDM 832

Figure 412.

• Process directly above propodeal spiracle a stout spine (Figure 413) . . . . . 5

Figure 413.

5

return to couplet #4

• Yellow species; mesosoma and gaster with many erect setae, gaster also pubescent . . . . . Stigmacros sp. JDM 831

• Gaster and head brown, mesosoma and appendages light reddish brown; sparse erect setae present only on margins of gastral tergites and underside of gaster, gaster not pubescent . . . . . Stigmacros sp. JDM 622

6

return to couplet #1

• Gaster moderately to densely pubescent; cuticle of mesosoma microreticulate and usually matt, with many short, erect setae . . . . . 7

• Gaster, at most, with weak pubescence with appressed setulae normally sparse; cuticle of mesosoma often smooth, shining, rarely with erect setae (if present, these are normally long) . . . . . 9

7

return to couplet #6

• Black or dark brown species with orange or brownish appendages, petiolar node orange to black . . . . . Stigmacros sp. JDM 341

• Uniformly orange species . . . . . 8

8

return to couplet #7

• Propodeum with distinctly longitudinal impressed furrow; propodeal angles blunt (Figure 414); sculpture of head and mesosoma superficial, cuticle more-or-less shiny; pubescence on first gastral tergite dense . . . . . Stigmacros sp. JDM 396

Figure 414.

• Propodeum without longitudinal furrow or furrow vestigial and barely discernible; propodeal angles denticulate (Figure 415); cuticle of head and mesosoma finely microreticulate; dull; shagreenate; pubescence on first gastral tergite moderate, with short, appressed setae visibly separate . . . . . Stigmacros sp. JDM 829

Figure 415.

9

return to couplet #6

• Erect setae present on mesosoma; non-marginal, erect setae present on gastral tergites . . . . . 10

• Erect setae absent from mesosoma; if erect setae present on gaster, then confined to margins of tergites . . . . . 13

10

return to couplet #9

• Propodeum smoothly rounded without longitudinal furrow or lateral carinae (Figure 416) . . . . . Stigmacros sp. JDM 1046

Figure 416.

• Propodeum laterally carinate, longitudinal furrow present or absent (Figure 417) . . . . . 11

Figure 417.

11

return to couplet #10

• In profile, mesonotum convex, its dorsum smoothly rounded into its lateral surfaces (Figure 418) . . . . . Stigmacros inermis

Figure 418.

• In profile, mesonotum flat, its dorsal and lateral surfaces distinct, often separated by a strong carina extending fully or partly along the length of the mesonotum (Figure 419) . . . . . 12

Figure 419.

12

return to couplet #11

• In profile, dorsum of propodeum smoothly confluent with declivitous face; propodeal angle absent (Figure 420); erect setae present on all surfaces of mesosoma . . . . . Stigmacros pilosella

Figure 420.

• In profile, dorsal and declivitous faces of propodeum distinct; propodeal angle present (Figure 421); erect setae virtually confined to pronotum (one or two short setae may be evident on mesonotum) . . . . . Stigmacros stanleyi

Figure 421.

13

return to couplet #9

• In profile, pronotum and mesonotum flat and on same plane, or mesonotum weakly convex; mesonotum and often pronotum laterally carinate (Figure 422); ants bicoloured, head, mesosoma and gaster always black or shades of dark red-and-brown, appendages usually much lighter coloured, often yellow or orange. . . . . . 14

Figure 422.

• In profile, pronotum and mesonotum weakly to strongly convex; pronotum never carinate, dorsum of mesonotum usually smoothly rounded onto sides (Figure 423), occasionally with weak angle between dorsal and lateral surfaces; species concolorous light yellow or orange or shades of brown without strong contrast between body and appendages . . . . . 19

Figure 423.

14

return to couplet #13

• In dorsal view, head distinctly darker than mesosoma . . . . . 15

• In dorsal view, head same colour as, or slightly lighter than mesosoma . . . . . 16

15

return to couplet #14

• Propodeum with flat dorsal and declivitous faces, in profile, propodeal angle strong (Figure 424) . . . . . Stigmacros aemula

Figure 424.

• Propodeum with a short dorsal face merging imperceptibly into a long, smooth, slightly concave declivitous face (Figure 425); in profile propodeal angle very weak . . . . . Stigmacros epinotalis

Figure 425.

16

return to couplet #14

• In dorsal view, mesonotum with strong punctate-microreticulate sculpture, appearance dull . . . . . Stigmacros anthracina

• In dorsal view, mesonotum with very fine microreticulation or sculpture lacking, appearance shining . . . . . 17

17

return to couplet #16

• In profile, propodeum narrow, about 1/2 as wide as high, longitudinal furrow absent, propodeum with oblique outline (Figure 426); fine, microreticulate sculpture present on mesonotum . . . . . Stigmacros sp. JDM 1045

Figure 426.

• In profile, propodeum about as wide as high; longitudinal furrow present, propodeum with outline of anterior lateral carinae rectangular or describing an arc in a horizontal plane (Figures 427, 428); mesonotal sculpture absent. . . . . . 18

Figure 427.

Figure 428.

18

return to couplet #17

• Eye large, its width ≥ width of fore tibia; in full-face view (Figure 429a); dorsum of node bilobate (Figure 429b) . . . . . Stigmacros elegans

Figure 429a.

Figure 429b.

• Eye smaller, its width < width of fore tibia (Figure 430a); in full-face view, dorsum of node straight or slightly concave, meeting the sides at an angle (Figure 430b) . . . . . Stigmacros brachytera (most workers)

Figure 430a.

Figure 430b.

19

return to couplet #13

• Head, mesosoma, node, gaster, most of femora and extreme end of antenna chocolate, tips of femora, tibiae, tarsi and most of antenna ochraceous . . . . . Stigmacros reticulata

• Appearance not as above . . . . . 20

20

return to couplet #19

• Mesonotum smooth and shining; in profile, weakly convex (Figure 431); head and mesosoma nearly always concolorous yellow or light orange . . . . . 21

Figure 431.

• Mesonotum with distinct, though sometimes weak sculpture; in profile strongly convex (Figure 432); colour yellowish or brown, head often darker than mesosoma (S. occidentalis complex) . . . . . 24

Figure 432.

21

return to couplet #20

• In profile, dorsum of propodeum rounded before it meets denticles directly above the spiracles (Figure 433) . . . . . Stigmacros sp. JDM 1050

Figure 433.

• In profile, dorsum of propodeum angular or rectangular (S. pusilla complex) (Figure 434) . . . . . 22

Figure 434.

22

return to couplet #21

• In profile, propodeal angles denticulate, directed upward (Figure 435); larger (HW > 0.5 mm) . . . . . Stigmacros pusilla

Figure 435.

• In profile, propodeal angles not denticulate, directed laterally (Figure 436); smaller (HW < 0.5 mm) . . . . . 23

Figure 436.

23

return to couplet #22

• Eye moderate (eye width ≈ 0.25 × width of side of head capsule) . . . . . Stigmacros sp. JDM 115

• Eye large (eye width < 1/3 × width of side of head capsule) . . . . . Stigmacros sp. JDM 188

24

return to couplet #20

• Pale yellowish species, head concolorous with mesosoma or only slightly darker . . . . . 25

• Brownish species, head usually distinctly darker than mesosoma . . . . . 28

25

return to couplet #24

• Node deeply bilobate, lateral processes distinct denticles . . . . . Stigmacros sp. JDM 1067

• Node not deeply bilobate, lateral processes vestigial or absent . . . . . 26

26

return to couplet #25

• Eye width moderate (eye width, at most, only fractionally greater than greatest width of scape) . . . . . Stigmacros flava

• Eye large (eye width ≥ 3 x greatest width of scape) . . . . . 27

27

return to couplet #26

• In dorsal view, mesonotum as long as wide; (Figure 437) . . . . . Stigmacros sp. JDM 1135

Figure 437.

• In dorsal view, mesonotum 1.5 – 2 x as long as wide (Figure 438) . . . . . Stigmacros sp. JDM 443

Figure 438.

28

return to couplet #24

• Eye large, ≈ 3 times as wide as antennal scape at its widest point . . . . . Stigmacros termitoxena

• Eye smaller, ≈ as wide as antennal scape at its widest point . . . . . 29

29

return to couplet #28

• Node with small but distinct lateral denticles (Figure 439) . . . . . Stigmacros occidentalis

Figure 439.

• Node lacking lateral denticles (Figure 440) . . . . . Stigmacros glauerti

Figure 440.