Key to Polyrhachis (Hagiomyrma) species

The following key to Polyrhachis (Hagiomyrma) species (based on the worker caste) is modified from Kohout (2013) as updated by Hoffmann (2015).

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• Hagiomyrma
• Polyrhachis

1

• Generally larger species (HL > 2.20) . . . . . 2

• Generally medium-sized or small species (HL < 2.15) . . . . . 14

2

return to couplet #1

• Pronotal dorsum with margins strongly converging anteriorly; occipital corners with distinct postocular carinae; anterior clypeal margin deeply emarginate medially (New Guinea and Bismarck Archipelago) . . . . . Polyrhachis metella

Head of Polyrhachis metella worker

Profile of Polyrhachis metella worker

• Pronotal dorsum more-or-less quadrate or only weakly converging anteriorly; occipital corners simply rounded, without postocular carinae; anterior clypeal margin medially with denticulate flange or simply truncate . . . . . 3

3

return to couplet #2

• Gaster with pubescence very much diluted, virtually lacking; head and mesosoma with long, rich golden pubescence (QLD, NSW, VIC) . . . . . Polyrhachis semiaurata

Head of Polyrhachis semiaurata worker

Profile of Polyrhachis semiaurata worker

• Gaster with golden or silvery pubescence identical or similar to that on dorsum of head and mesosoma . . . . . 4

4

return to couplet #3

• Pronotal humeri distinctly angular; dorsum of first gastral tergite strongly tranverse, laterally produced into narrowly rounded prominences (Cape York Pen., Mt Tozer, QLD) . . . . . Polyrhachis vernoni

Polyrhachis vernoni worker

Polyrhachis vernoni worker

• Pronotal humeri narrowly or widely rounded; dorsum of first gastral tergite less transverse, with sides widely rounded . . . . . 5

5

return to couplet #4

• Petiolar node relatively thick in profile with dorsum widely rounded or forming more-or-less flat platform; petiolar spines short, bases situated well below summit of dorsal convexity . . . . . 6

• Petiolar node in profile with anterior and posterior face converging towards narrowly rounded dorsum; petiolar spines longer, bases situated at lateral corners of dorsal summit . . . . . 7

6

return to couplet #5

• Pronotal dorsum with margins weakly converging anteriorly; propodeal spines subparallel; head in full face view with numerous hairs fringing lateral outline between eyes and mandibular bases (Cape York Pen., McIlwraith Range, QLD) . . . . . Polyrhachis darlingtoni

Polyrhachis darlingtoni worker

Polyrhachis darlingtoni worker

• Pronotal dorsum more-or-less quadrate; propodeal spines divergent head in full face view with no hairs fringing lateral outline between eyes and mandibular bases (Mt Abbott, QLD) . . . . . Polyrhachis burwelli

Polyrhachis burwelli worker

Polyrhachis burwelli worker

7

return to couplet #5

• Dorsum of gaster with golden or silvery pubescence and more-or-less distinct, dark reddish-brown, median patch, extending from dorsum of first gastral tergite towards apex . . . . . 8

• Dorsum of gaster with widely diffused patch of golden pubescence extending towards apex; reddish-brown median patch on gaster not evident . . . . . 12

8

return to couplet #7

• Median patch on gastral dorsum very dark and prominent . . . . . 9

• Median patch on gastral dorsum lighter and less prominent . . . . . 10

9

return to couplet #8

• Dorsum of pronotum with only a few, relatively short, erect hairs; hairs completely absent from mesonotum, propodeum, including declivity, and propodeal spines (central QLD) . . . . . Polyrhachis conciliata

Head of Polyrhachis conciliata worker

Profile of Polyrhachis conciliata worker

• Dorsum of mesosoma, including bases of propodeal spines, with numerous erect or semierect, long or medium length hairs (central QLD) . . . . . Polyrhachis callima

Head of Polyrhachis callima worker

Profile of Polyrhachis callima worker

10

return to couplet #8

• Pronotal dorsum with margins weakly converging anteriorly (Cooktown district, QLD) . . . . . Polyrhachis feehani

Polyrhachis feehani worker

Polyrhachis feehani worker

• Pronotal dorsum more-or-less quadrate or weakly converging posteriorly . . . . . 11

11

return to couplet #10

• Smaller species (HL 2.18-2.37); clypeus virtually straight in profile; dorsa of head and mesosoma with rich golden pubescence, radiating towards midline of mesosoma (Brisbane district, QLD) . . . . . Polyrhachis brisbanensis

Polyrhachis brisbanensis worker

Polyrhachis brisbanensis worker

• Larger species (HL 2.28-2.62); clypeus sinuate in profile; dorsa of head and mesosoma with pubescence mostly silvery, diffused into pale golden along midline of mesosoma (central QLD) . . . . . Polyrhachis brutella

Polyrhachis brutella worker

Polyrhachis brutella worker

12

return to couplet #7

• Petiolar spines subparallel, shorter than distance between their bases; dorsa of head and mesosoma with evenly distributed golden pubescence . . . . . 13

• Petiolar spines divergent, about as long as or longer than distance between their bases; body pubescence unevenly distributed with head distinctly less pubescent than dorsum of mesosoma (QLD, NSW, VIC) . . . . . Polyrhachis ammon (in part - also #44)

Polyrhachis ammon worker

Polyrhachis ammon worker

13

return to couplet #12

• Smaller species (HL 2.02-2.24); propodeal spines widely divergent; petiolar spines strongly downturned (QLD) . . . . . Polyrhachis uncaria (in part - also #44)

Polyrhachis uncaria worker

Polyrhachis uncaria worker

• Larger species (HL 2.21-2.40); propodeal spines subparallel; petiolar spines more-or-less horizontal (Hann Tbld, QLD) . . . . . Polyrhachis dougcooki

Polyrhachis dougcooki worker

Polyrhachis dougcooki worker

14

return to couplet #1

• Dorsum of mesosoma distinctly short and wide; propodeal spiracles situated on prominent, laterally projecting tubercles; petiolar dorsum strongly transverse, armed with very short spines . . . . . 15

• Dorsum of mesosoma more-or-less elongated; propodeal spiracles relatively flat, not situated on prominent tubercles; petiolar dorsum armed with spines of various lengths . . . . . 16

15

return to couplet #14

• Head and mesosoma with distinct, closely appressed, golden pubescence; dorsum of gaster with only a few, medium length hairs and no pubescence (Cape York Pen., QLD) . . . . . Polyrhachis diversa

Polyrhachis diversa worker

Polyrhachis diversa worker

• Head and mesosoma without appressed pubescence; dorsum of gaster with very fine, closely appressed, pale golden pubescence (QLD) . . . . . Polyrhachis tubifera

Head of Polyrhachis tubifera worker

Profile of Polyrhachis tubifera worker

16

return to couplet #14

• Head and mesosoma generally black, with only mouthparts, pronotal collar, spines and appendages occasionally reddish-brown . . . . . 24

• Head and mesosoma not black, coloured or multi-coloured . . . . . 17

17

return to couplet #16

• Lateral margins of promesonotum strongly converging posteriorly (PMI > 190) . . . . . 18

• Lateral margins of promesonotum less strongly converging posteriorly (PMI < 180) or subparallel . . . . . 20

18

return to couplet #17

• Generally smaller species (HL 1.31-1.56); antennal scapes virtually circular in cross-section; dorsum of gaster with distinct, thick silvery or golden, appressed pubescence (New Guinea, WA, NT, QLD) . . . . . Polyrhachis schenckii

Head of Polyrhachis schenckii worker

Profile of Polyrhachis schenckii worker

• Generally larger species (HL 1.53-1.75); antennal scapes somewhat flattened, oval in cross-section; appressed pubescence on dorsum of gaster very sparse or lacking . . . . . 19

19

return to couplet #18

• Antennal scapes relatively short (SI 123); greatest width of pronotal dorsum near its mid-length; propodeal spines obliquely elevated from bases (NT) . . . . . Polyrhachis isolata

Polyrhachis isolata worker

Polyrhachis isolata worker

• Antennal scapes relatively long (SI 134-143); greatest width of pronotal dorsum across humeri; propodeal spines horizontal (Cape York Pen., QLD) . . . . . Polyrhachis injinooi

Polyrhachis injinooi worker

Polyrhachis injinooi worker

20

return to couplet #17

• Head, mesosoma and gaster metallic green, with front of head, anterior portion of pronotum and appendages orange or reddish-brown (QLD) . . . . . Polyrhachis lydiae

Head of Polyrhachis lydiae worker

Profile of Polyrhachis lydiae worker

• Head, mesosoma and gaster not metallic green, mostly medium to dark reddish-brown or red with gaster distinctly darker . . . . . 21

21

return to couplet #20

• Head and mesosoma conspicuously red or orange-red; gaster very dark brown; appendages reddish-brown (WA, NT, QLD) . . . . . Polyrhachis bohemia

Head of Polyrhachis bohemia worker

Profile of Polyrhachis bohemia worker

• Head and mesosoma almost uniformly medium to dark reddish- brown with gaster usually a shade lighter; appendages reddish-brown . . . . . 22

22

return to couplet #21

• Pronotal humeri produced into dilated, dorsally shallowly concave, rounded prominences; head and mesosoma with more-or-less distinct, vermiculate sculpturation . . . . . 23

• Pronotal humeri narrowly rounded; body sculpturation reticulate- punctate, not vermiculate (Cape York Pen., QLD) . . . . . Polyrhachis capeyorkensis

Polyrhachis capeyorkensis worker

Polyrhachis capeyorkensis worker

23

return to couplet #22

• Head and mesosoma reticulate-punctate, shallowly vermiculate- rugose on vertex of head and dorsum of mesosoma; colour almost uniformly medium reddish-brown, appendages and spines a shade lighter (QLD) . . . . . Polyrhachis lachesis

Head of Polyrhachis lachesis worker

Profile of Polyrhachis lachesis worker

• Head and mesosoma with very distinct, vermiculate-rugose sculpturation; colour mostly black or very dark reddish-brown on most dorsal surfaces; appendages and spines distinctly lighter (Indonesia, New Guinea, Cape York, QLD) . . . . . Polyrhachis paxilla (in part - also #31)

Head of Polyrhachis paxilla worker

Profile of Polyrhachis paxilla worker

24

return to couplet #16

• Antennal scapes with at least a few short, bristle-like hairs along leading edge . . . . . 25

• Antennal scapes without any hairs along leading edge . . . . . 35

25

return to couplet #24

• Promesonotal lateral margins only very weakly converging posteriorly (PMI < 140); petiole in lateral view rather low with very short, curved spines (NT) . . . . . Polyrhachis nourlangie

Polyrhachis nourlangie worker

Polyrhachis nourlangie worker

• Promesonotal lateral margins more strongly converging posteriorly (PMI > 150); petiole in lateral view distinctly higher with longer spines of various configurations . . . . . 26

26

return to couplet #25

• Outline of head in full face view with numerous, bristle-like hairs fringing margin between eyes and mandibular bases . . . . . 27

• Outline of head in full face view without hairs, or at most with only a few, inconspicuous, very short hairs fringing margin between eyes and mandibular bases . . . . . 27a

27

return to couplet #26

• Head, mesosoma and petiole very distinctly and evenly, rather coarsely, reticulate-punctate; petiole in profile with posterior face distinctly convex and swollen towards base (Nth QLD) . . . . . Polyrhachis tenebra

Polyrhachis tenebra worker

Polyrhachis tenebra worker

• Head, mesosoma and petiole finely reticulate-punctate with sculpture somewhat longitudinally rugulate-striate on vertex of head; petiole in profile with posterior face only weakly convex (New Ireland, New Guinea, Cape York Pen.) . . . . . Polyrhachis semiobscura

Head of Polyrhachis semiobscura worker

Profile of Polyrhachis semiobscura worker

27a

• Petiole armed with rather massive, bull horn-shaped spines (NT only) => Polyrhachis kohouti

Head of Polyrhachis kohouti worker

Profile of Polyrhachis kohouti worker

• Petiole armed with slender, acute spines, mostly curved into shape of first gastral segment or downcurved => 28

28

return to couplet #26

• Petiolar spines distinctly downcurved, hook-like (only WA) . . . . . Polyrhachis ammonoeides

Head of Polyrhachis ammonoeides worker

Profile of Polyrhachis ammonoeides worker

• Petiolar spines more-or-less horizontal or obliquely elevated, never hook-like . . . . . 29

29

return to couplet #28

• Promesonotal lateral margins distinctly converging posteriorly (PMI > 190) . . . . . . 30

• Promesonotal lateral margins less strongly converging posteriorly (PMI < 180) . . . . . 31

30

return to couplet #29

• Antennal scapes relatively short (SI < 141); petiole in profile with posterior face only weakly convex towards base (Nth QLD) . . . . . Polyrhachis stricta

Polyrhachis stricta worker

Polyrhachis stricta worker

• Antennal scapes relatively long (SI > 154); petiole in profile distinctly swollen towards base (NT) . . . . . Polyrhachis weiri

Polyrhachis weiri worker

Polyrhachis weiri worker

31

return to couplet #29

• Pronotal dorsum with humeri produced into dilated, distinctly rounded prominences; head and mesosoma with distinct, vermiculate sculpturation (Indonesia, New Guinea, Cape York) . . . . . Polyrhachis paxilla (in part - also #23)

Head of Polyrhachis paxilla worker

Profile of Polyrhachis paxilla worker

• Pronotal dorsum with humeri rounded or subangular, not distinctly dilated; head and mesosoma reticulate-punctate . . . . . 32

32

return to couplet #31

• Petiolar node in profile with posterior face distinctly swollen towards base; clypeus in profile virtually straight or only very shallowly impressed anteriorly . . . . . 33

• Petiolar node in profile with posterior face not distinctly swollen, descending towards base in weakly convex line; clypeus in profile distinctly sinuate (Nth QLD) . . . . . Polyrhachis placida

Polyrhachis placida worker

Polyrhachis placida worker

33

return to couplet #32

• Dorsum of gaster with distinct, closely appressed, golden pubescence, completely hiding underlying sculpturation (Pilbara, WA) . . . . . Polyrhachis pilbara

Polyrhachis pilbara worker

Polyrhachis pilbara worker

• Dorsum of gaster with much diluted, silvery or golden, appressed pubescence . . . . . 34

34

return to couplet #33

• Dorsum of mesosoma with very short, erect, bristle-like hairs (Barrow I., WA) . . . . . Polyrhachis seducta

Head of Polyrhachis seducta worker

Profile of Polyrhachis seducta worker

• Dorsum of mesosoma with distinctly longer, posteriorly directed hairs that are up to half greatest diameter of eyes in length (Tanami Desert, NT) . . . . . Polyrhachis tanami

Polyrhachis tanami worker

Polyrhachis tanami worker

35

return to couplet #24

• Promesonotal lateral margins strongly converging posteriorly (PMI > 185) . . . . . 36

• Promesonotal lateral margins less strongly or weakly converging posteriorly (PMI < 180) . . . . . 37

36

return to couplet #35

• Dorsum of petiole with flat, strongly posteriorly sloping, triangular platform; petiolar spines obliquely elevated; propodeal spines subparallel or only weakly divergent; antennal scapes relatively short (SI < 142) (NT, QLD) . . . . . Polyrhachis trapezoidea

Head of Polyrhachis trapezoidea worker

Profile of Polyrhachis trapezoidea worker

• Dorsum of petiole narrowly rounded, without flat platform; petiolar spines horizontal; propodeal spines widely divergent; antennal scapes longer (SI > 160) (Paluma, Mt Elliot) . . . . . Polyrhachis aurora

Head of Polyrhachis aurora worker

Profile of Polyrhachis aurora worker

37

return to couplet #35

• Propodeal spines strongly divergent and long, distinctly longer than distance between their bases . . . . . 38

• Propodeal spines less strongly divergent or subparallel, distinctly shorter than distance between their bases . . . . . 39

38

return to couplet #37

• Dorsum of body without hairs, except a few, short hairs on apical gastral tergites; closely appressed pubescence very diluted with whole body superficially glabrous (NT, Nth QLD) . . . . . Polyrhachis cracenta

Polyrhachis cracenta worker

Polyrhachis cracenta worker

• Dorsum of mesosoma with rather sporadic hairs of various lengths; gaster with hairs more abundant, notably on venter; appressed, golden pubescence diluted on most body surfaces, except rather dense on gastral dorsum (WA, NT, Nth QLD) . . . . . Polyrhachis crawleyi

Head of Polyrhachis crawleyi worker

Profile of Polyrhachis crawleyi worker

39

return to couplet #37

• Dorsum of petiole with flat, transversely wide platform; dorsum of body with very abundant, long silvery hairs that are distinctly longer than greatest diameter of eyes; antennal scapes very short (SI < 125) (Cape York Pen., Nth QLD) . . . . . Polyrhachis thusnelda

Head of Polyrhachis thusnelda worker

Profile of Polyrhachis thusnelda worker

• Dorsum of petiole narrowly rounded without flat platform; body with relatively short, erect hairs or, at most, with only sporadic, variously curved, longer hairs (as in P. hoffmanni and P. denticulata); antennal scapes longer (SI > 125) . . . . . 40

40

return to couplet #39

• Dorsum of head and mesosoma with distinct, rather abundant, mostly golden, medially radiating pubescence . . . . . 41

• Dorsum of head and mesosoma with rather diluted, mostly silvery, variously scattered pubescence . . . . . 45

41

return to couplet #40

• Petiolar node in side view with anterior and posterior faces subparallel towards base; antennal scapes rather short (SI < 137) (Nth QLD) . . . . . Polyrhachis electra

Polyrhachis electra worker

Polyrhachis electra worker

• Petiolar node in side view with anterior and posterior faces converging dorsally; posterior face descending towards base in oblique, almost straight line . . . . . 42

42

return to couplet #41

• Dorsum of mesosoma distinctly slender (PMI > 167); propodeal spines obliquely elevated from bases; petiolar spines widely divergent, very slender and long, about as long as distance between their bases (QLD, NSW) . . . . . Polyrhachis angusta

Polyrhachis angusta worker

Polyrhachis angusta worker

• Dorsum of mesosoma not distinctly slender (PMI < 167); propodeal spines more-or-less horizontal or weakly downturned; petiolar spines subparallel or only weakly divergent, distinctly shorter than distance between their bases . . . . . 43

43

return to couplet #42

• Petiolar spines divergent, obliquely elevated from bases; propodeal spines virtually parallel along entire length (Nth QLD) . . . . . Polyrhachis elegantula

Polyrhachis elegantula worker

Polyrhachis elegantula worker

• Petiolar spines only weakly divergent or subparallel, horizontal or downturned; propodeal spines weakly divergent with tips curved outwards . . . . . 44

44

return to couplet #43

• Petiolar spines horizontal; dorsum of gaster with wide median patch of golden pubescence, laterally diffused into pale golden and silvery on sides and venter . . . . . Polyrhachis ammon (in part - also #12)

Polyrhachis ammon worker

Polyrhachis ammon worker

• Petiolar spines strongly downturned from bases; whole dorsum of gaster with distinct, reddish-golden pubescence, lined with silvery pubescence on sides and venter . . . . . Polyrhachis uncaria (in part - also #13)

Polyrhachis uncaria worker

Polyrhachis uncaria worker

45

return to couplet #40

• Dorsum of mesosoma with rather long, variously curved, scattered hairs; hairs more abundant and posteriorly directed on gaster . . . . . 46

• Dorsum of mesosoma virtually lacking hairs or with only very short, much diluted hairs on dorsal body surfaces, including gaster . . . . . 47

46

return to couplet #45

• Promesonotal lateral margins strongly converging posteriorly (PMI > 170); body with variously curved, scattered hairs that are longer than half of greatest diameter of eyes; posterior face of petiolar node convex, but not distinctly swollen (Indonesia, New Guinea, Bismarck Archipelago, Torres Strait) . . . . . Polyrhachis denticulata

Head of Polyrhachis denticulata worker

Profile of Polyrhachis denticulata worker

• Promesonotal lateral margins rather weakly converging posteriorly (PMI < 145); body with variously curved hairs, most longer than greatest diameter of eyes; posterior face of petiolar node distinctly swollen towards base (Nth western QLD) . . . . . Polyrhachis hoffmanni

Polyrhachis hoffmanni worker

Polyrhachis hoffmanni worker

47

return to couplet #45

• Dorsum of petiole tranversely narrow, rather deeply concave between closely approximated bases of spines . . . . . 48

• Dorsum of petiole flat or very weakly concave; bases of spines separated by transversely wide dorsum of segment . . . . . 50

48

return to couplet #47

• Petiolar spines widely divergent, highly obliquely elevated; propodeal spines very slender, divergent; posterior face of petiolar node convex but not distinctly swollen (Geraldton, WA) . . . . . Polyrhachis clarki

Polyrhachis clarki worker

Polyrhachis clarki worker

• Petiolar spines parallel or only weakly divergent, moderately elevated; propodeal spines subparallel; posterior face of petiolar node distinctly swollen towards base . . . . . 49

49

return to couplet #48

• Smaller species (HL < 1.62); anterior clypeal margin truncate medially; bases of petiolar spines very closely approximated, spines subparallel; body sculpture very finely reticulate-punctate, semi- polished (WA, NT) . . . . . Polyrhachis anderseni

Polyrhachis anderseni worker

Polyrhachis anderseni worker

• Larger species (HL > 1.62); anterior clypeal margin with denticulate median flange; bases of petiolar spines more widely separated, spines weakly; body sculpture closely reticulate-punctate, distinctly opaque (NT, Gulf Country, QLD) . . . . . Polyrhachis archeri

Polyrhachis archeri worker

Polyrhachis archeri worker

50

return to couplet #47

• Petiole with posterior face distinctly swollen towards base; petiolar spines elevated from bases; head and mesosoma with rather sporadic, very short, bristle-like hairs, no hairs on dorsum of petiole; body sculpture closely reticulate- punctate, distinctly opaque (WA, NT, QLD) . . . . . Polyrhachis melanura

Head of Polyrhachis melanura worker

Profile of Polyrhachis melanura worker

• Petiole with posterior face only moderately convex towards base; petiolar spines horizontal; head, mesosoma and petiole with more abundant, marginally longer hairs; body sculpture finely reticulate-punctate, semi-polished (Nth and Central QLD) . . . . . Polyrhachis penelope

Head of Polyrhachis penelope worker

Profile of Polyrhachis penelope worker