Key to Polyrhachis (Aulacomyrma) species

This worker key is based on: *Kohout, R.J. 2007a. Revision of the subgenus Aulacomyrma Emery of the genus Polyrhachis F. Smith, with descriptions of new species (pp. 186-253). In Snelling, R.R., Fisher, B.L. and Ward, P.S. (eds). Advances in ant systematics: homage to E.O. Wilson – 50 years of contributions. Memoirs of the American Entomological Institute. 80:690 pp.

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• Aulacomyrma
• Polyrhachis

1

• Anterior face of first gastral segment distinctly concave medially, accomodating posterior face of petiole; concavity delimited dorso-medially by acute or blunt margin that is often raised above dorsal surface of segment . . . . . 2

• Anterior face of first gastral segment medially truncate or convex; if weakly concave then concavity too shallow to accommodate posterior face of petiole and its dorsal border rounded, without distinct margin . . . . . 3

2

return to couplet #1

• Mesosomal dorsum distinctly marginate laterally along its entire length; margins interrupted only at sutures . . . . . 10

• Mesosomal dorsum with ill-defined margins, formed in part by outermost dorsal striae or with margins completely lacking and dorsum rounding onto the sides in laterally uninterrupted curve . . . . . 27

3

return to couplet #1

• Sculpture of mesosomal dorsum consisting of mostly longitudinal striae, that weakly converge anteriorly on pronotal dorsum . . . . . Polyrhachis bedeloweryi

• Sculpture of mesosomal dorsum with striae forming variously curved, transverse, V-, U- or semicircular-shaped pattern . . . . . 4

4

return to couplet #3

• Eyes convex or protuberant, clearly breaking cephalic outline in full face view . . . . . 5

• Eyes flattened and somewhat sunk into shallow concavity in cephalic sculpture, at most touching but not extending beyond lateral cephalic outline in full face view . . . . . 9

5

return to couplet #4

• Petiole with both faces distinctly striate . . . . . 6

• Petiole with both faces finely reticulate-punctate or shagreened . . . . . 8

6

return to couplet #5

• Mesosoma distinctly antero-posteriorly compressed; propodeal declivity very high, vertical to main axis of body . . . . . Polyrhachis gressitti

• Mesosoma relatively long, not antero-posteriorly compressed; propodeal declivity relatively low, oblique to main axis of body . . . . . 7

7

return to couplet #6

• Pronotal dorsum rather massive, particularly anteriorly, distinctly convex in lateral view; petiole with lateral spines curved outwards and backwards; first gastral segment uniformly finely reticulate-punctate . . . . . Polyrhachis kokoda

• Pronotal dorsum in lateral view only moderately convex anteriorly, rather flat towards promesonotal suture; petiole with short, upturned lateral teeth; first gastral segment distinctly longitudinaly striate laterally, finely reticulate-punctate dorsally . . . . . Polyrhachis decora

8

return to couplet #5

• Pronotal humeri with short, acute spines; dorsal petiolar margin with pair of short intercalary teeth and pair of blunt angular projections situated between them and lateral petiolar teeth . . . . . Polyrhachis breviata

• Pronotal humeri with broadly-based, angular teeth and lateral margins distinctly raised and continuous to midlength of the pronotum; dorsal petiolar margin jagged, without distinct intercalary teeth . . . . . Polyrhachis pelecta

9

return to couplet #4

• Larger species (HL > 1.56); petiole finely shagreened with sharp dorsal margin bearing pair of short, acute, intercalary teeth . . . . . Polyrhachis roomi

• Smaller species (HL <1.40); petiole with both faces distinctly transversely striate; dorsal margin blunt, intercalary teeth lacking . . . . . Polyrhachis mamba

10

return to couplet #2

• Clypeus unsculptured, smooth and shiny . . . . . 11

• Clypeus sculptured as rest of head . . . . . 13

11

return to couplet #10

• Petiole with dorsal margin entire; head smooth and very shiny . . . . . Polyrhachis maai

• Petiole with dorsal margin medially emarginate with a pair of intercalary teeth flanking emargination; head distinctly, mostly longitudinally, striate . . . . . 12

12

return to couplet #11

• Petiole strongly transverse, with rather distinct, acute intercalary teeth; propodeal dorsum terminating in very prominent, somewhat upturned, tooth-like prominences, with blunt apices; mandibles distinctly reddish-brown; pilosity and pubescence very sparse to absent . . . . . Polyrhachis roberti

• Petiole about as wide as high, with rather blunt, short intercalary teeth; propodeal dorsum terminating in rounded angles; mandibles, except narrow masticatory border, black; pilosity and pubescence moderately abundant but not concealing underlying sculpture . . . . . Polyrhachis simulans

13

return to couplet #10

• Eyes moderately convex, in full face view exceeding, even if only marginally, lateral outline of head . . . . . 14

• Eyes rather flat, in full face view sometimes almost level with, but not exceeding lateral outline of head . . . . . 25

14

return to couplet #13

• Propodeal dorsum separated from declivity by distinct, transverse ridge that may be straight, curved or arched and somewhat weakened medially . . . . . 15

• Propodeal dorsum not separated from declivity by transverse ridge or margin; both surfaces meeting in medially uninterrupted, although abrupt, curve . . . . . 18

15

return to couplet #14

• Lateral margins of mesonotal-propodeal dorsum confluent, converging posteriorly and terminating in blunt angles with their posterior margins continued medially, forming almost straight, transverse ridge that may be somewhat weakened medially . . . . . Polyrhachis parva

• Lateral margins of mesonotal-propodeal dorsum not confluent; margins of mesonotum converging posteriorly, those of propodeum subparallel or diverging, terminating posteriorly in pair of distinct spines, laterally directed teeth or rounded prominences with their posterior margins continued medially, forming more-or-less inward bowed, somewhat arched, transverse ridge . . . . . 16

16

return to [[#15 |couplet #1]5]

• Propodeal dorsum armed posteriorly with very distinct, long, outwards, backwards and weakly downwards directed spines; their posterior margins forming a deeply, inwardly bowed and distinctly medially arched, transverse ridge . . . . . Polyrhachis wilsoni

• Propodeal dorsum armed posteriorly with short teeth or rounded prominences; their posterior margins forming a weakly inwardly bowed ridge, that may be somewhat weakened medially . . . . . 17

17

return to couplet #16

• Propodeal teeth acute, broad-based and directed outwards; first gastral segment only very finely longitudinally striate laterally; numerous hairs and appressed pubescence present on all body surfaces . . . . . Polyrhachis wardi

• Propodeal teeth reduced to small, rounded prominences in dorsal view; first gastral segment distinctly longitudinally striate laterally; hairs and appressed pubescence virtually absent from most body surfaces . . . . . Polyrhachis exarata

18

return to couplet #14

• Sculpture of mesosomal dorsum consisting of longitudinal, widely-spaced striae, with only about 13 striae spread across width of pronotal dorsum; mesonotal-propodeal dorsum distinctly transverse, almost twice as wide as long . . . . . Polyrhachis sulcifera

• Sculpture of mesosomal dorsum consisting of mostly longitudinal, narrowly-spaced striae, with about 20 or more striae spread across width of pronotal dorsum; mesonotal-propodeal dorsum only marginally wider than long . . . . . 19

19

return to couplet #18

• Smaller species (HL <1.10) . . . . . 20

• Larger species (HL >1.20) . . . . . 21

20

return to couplet #19

• Sides of mesosomal dorsum subparallel; propodeal dorsum terminating posteriorly in distinct, rounded angles with their posterior margins weakly curved inwards, continuing medially for some distance but failing to meet . . . . . Polyrhachis minima

• Sides of mesosomal dorsum distinctly converging posteriorly; propodeal dorsum completely unarmed, descending into declivity across its full width . . . . . Polyrhachis gentilis

21

return to couplet #19

• Dorsum of pronotum transversely convex between lateral margins . . . . . 22

• Dorsum of pronotum virtually flat . . . . . Polyrhachis planata

22

return to couplet #21

• Propodeal dorsum terminating in dentiform angles, that are not distinctly raised above its surface; striae on pronotal dorsum converging anteriorly . . . . . 23

• Propodeal dorsum terminating in distinct teeth; their lateral margins raised, leaving the posterior margin of propodeum weakly concave medially; striae on pronotal dorsum longitudinal, more-or-less parallel, not converging anteriorly . . . . . Polyrhachis lumi

23

return to couplet #22

• Vertex with transverse, strongly bowed, almost semicircular striae; lateral margins of mesonotal-propodeal dorsum confluent, converging posteriorly, not distinctly incised at metanotal groove (New Guinea) . . . . . Polyrhachis sculpta

• Vertex longitudinally striate; lateral margins of mesonotal-propodeal dorsum distinctly incised at metanotal groove; mesonotal margins converging posteriorly, propodeal margins more-or-less parallel-sided . . . . . 24

24

return to couplet #23

• Femora distinctly bicolored; light reddish-brown with very dark brown apices; eyes only moderately convex, in full face view just marginally breaking lateral outline of head (Bismarck Archipelago) . . . . . Polyrhachis dohrni

• Femora unicolored, very dark brown or black; eyes convex, clearly extending beyond lateral outline of head (Umboi Island) . . . . . Polyrhachis umboi

25

return to couplet #13

• Anterior face of first gastral segment with acute margin that is moderately raised above face of segment; legs distinctly light, mostly yellow or reddish-yellow . . . . . Polyrhachis pallipes

• Anterior face of first gastral segment with blunt margin that is not raised above face of segment; legs generally dark reddish-brown or black . . . . . 26

26

return to couplet #25

• Eyes situated close to lateral outline of head in full face view; pronotal dorsum with greatest width at about midlength of segment (New Ireland) . . . . . Polyrhachis abdita

• Eyes situated well away from lateral outline of head in full face view; pronotal dorsum with greatest width across humeri (Irian Jaya) . . . . . Polyrhachis variegata

27

return to couplet #2

• Propodeal dorsum separated from declivity by distinct, rather acute, transverse ridge . . . . . 28

• Propodeal dorsum not separated from declivity by transverse ridge; both surfaces

medially confluent . . . . . 29

28

return to couplet #27

• Eyes strongly protuberant, almost fully extending beyond lateral outline of head in full face view; mesonotal-propodeal dorsum strongly transverse, distinctly wider than long, sides subparallel . . . . . Polyrhachis orokana

• Eyes only moderately convex, situated in shallow depression in cephalic sculpture and only partly extending beyond lateral outline of head in full face view; mesonotal-propodeal dorsum about as long as width across posterior transverse ridge; sides of mesonotal-propodeal dorsum converging posteriorly . . . . . Polyrhachis impressa

29

return to couplet #27

• Petiole with dorsal margin entire . . . . . 30

• Petiole with dorsal margin more-or-less emarginate medially . . . . . 33

30

return to couplet #29

• Smaller species (HL <1.15) . . . . . 31

• Larger species (HL >1.34) . . . . . 32

31

return to couplet #30

• Petiole strongly transverse, both faces finely shagreened; propodeal dorsum terminating in a pair of small rounded prominences . . . . . Polyrhachis wamuki

• Petiole about as wide as high, both faces distinctly striate; propodeal dorsum terminating in downward and weakly inward curved angles . . . . . Polyrhachis snellingi

32

return to couplet #30

• Pronotal dorsum only weakly transversely convex, almost flat, with spines directed anteriorly; mesosomal dorsum with sides subparallel; mesosoma with prominent, regularly spaced, longitudinal striae, those on pronotal dorsum anteriorly converging; anterior face of first gastral segment with acute margin that is strongly raised above dorsal face of segment . . . . . Polyrhachis excellens

• Pronotal dorsum strongly transversely convex with spines directed more-or-less laterally; mesosomal dorsum with sides converging posteriorly so that pronotum is notably broader than propodeum; pronotal dorsum with inverse, narrowly U-shaped to semicircular striae; mesonotal-propodeal dorsum with V-shaped striae; anterior face of first gastral segment with acute margin that is only moderately raised above face of segment . . . . . Polyrhachis porcata

33

return to couplet #29

• First gastral segment finely shagreened . . . . . Polyrhachis annulata

• First gastral segment distinctly longitudinally striate laterally . . . . . 34

34

return to couplet #33

• Propodeal declivity oblique to main axis of body; femora of front legs very light, yellowish-brown, those of mid- and hind legs very dark, reddish-brown or black . . . . . Polyrhachis geometrica

• Propodeal declivity abrupt, vertical to main axis of body; femora of all three pairs of legs uniformly dark reddish-brown or black . . . . . 35

35

return to couplet #34

• Dorsal petiolar margin medially emarginate with distinct acute teeth flanking emargination; larger species (HL 1.37) . . . . . Polyrhachis monticola

• Dorsal petiolar margin only narrowly and shallowly emarginate without distinct teeth flanking emargination; smaller species (HL 1.12) . . . . . Polyrhachis retusa