Key to Tetraponera queens of the Oriental and Australian regions

This queen key is based on: [[Media:Ward 2001.pdf| Ward, P. S. 2001. Taxonomy, phylogeny and biogeography of the ant genus Tetraponera (Hymenoptera: Formicidae) in the Oriental and Australian regions. Invertebrate Taxonomy. 15:589-665. PDF]]

This key should be used with caution. The queen caste is not known for all species, and the limits of variation remain uncertain in species for which only a few specimens are known. When a range of metric measurements is cited in the key, this is followed by the sample size (e.g. HW 1.88-2.29; n = 5). The sample size is the same for all subsequent measurements given within the same lug of a couplet. There are four species in the nigra-group (out of 20) for which the queen caste is unknown (T. buops, T. mimula, T. nodosa and T. polita). I have inserted them in the key where I would expect the queens to come out, extrapolating from distinctive features of worker morphology. Such inferences are always accompanied by an explicit statement that the queen caste is actually unknown (e.g. couplet 6). The allaborans-group is keyed no farther than species-group because the queens are known for too few taxa in this group.

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1

 * Pronotal humeri subangulate; most of upper (dorsal) surface of head densely punctate, and lacking extensive shiny interspaces between the punctures; large species, HW 1.26-2.29 (n = 10) . . . . . 2


 * Pronotal humeri varying from narrowly to broadly rounded, but not subangulate; head usually lucid or sublucid, with conspicuous shiny interspaces between the scattered punctures; size variable . . . . . 3

2
return to couplet #1
 * Larger species (HW 1.88-2.29; n = 5), with disproportionately small eyes (REL2 0.33-0.36); body usually bicolored, the dark head and gaster contrasting with orange-brown mesosoma (the latter infuscated in some populations) (Pakistan to southern China, south to Sumatra and Java; introduced to the Seychelles) . . . . . Tetraponera rufonigra


 * Smaller species (HW 1.26-1.51; n = 5), with larger eyes (REL2 0.50-0.55); body unicolorous dark brown (Myanmar to Vietnam, south to Palawan, Borneo, Sumatra and Java) . . . . . Tetraponera pilosa

3
return to couplet #1
 * Forewing with one cubital cell; insertion of postpetiole into petiole shifted dorsad, and posteroventral margin of petiole developed as a semi-translucent, ventrally protruding hood, which is distinctly separated from the helcium when the postpetiole is in its normal horizontal position; mesosternum densely pubescent; relatively small species, range of HW approximately 0.55-1.08 (usually <0.90) .... allaborans-group


 * Forewing usually with two cubital cells; insertion of postpetiole into petiole not shifted dorsad, the posteroventral margin of the petiole closely associated with the helcium, although it may be flanked by ventrolateral flanges; most of the mesosternum devoid of pubescence; medium to large species, HW 0.72-1.59 (n = 81 )( nigra-group) . . . . . 4

4
return to couplet #3
 * Larger species, with long legs (HW 1.20-1.59, LHT 1.15-1.73; n = 18); standing pilosity common on dorsum of head, CSC 10-50 . . . . . 5


 * Smaller species, on average, with shorter legs (HW 0.72-1.49, LHT 0.56-1.25; n = 63); standing pilosity usually sparse on dorsum of head, CSC 0-24; if CSC >9, then HW <1.05 and LHT <0.90 . . . . . 8

5
return to couplet #4
 * Head very elongate (CI 0.59-0.62; n = 5) and petiole slender (PLI 0.37-0.42) . . . . . 6


 * Head broader (CI 0.68-0.83; n = 13); petiole shape variable (PLI 0.38-0.54) . . . . . 7

6
return to couplet #5
 * Large species (HW 1.35-1.50; n = 5), with small eyes (REL 0.22-0.24) and relatively slender profemur (FI 0.42-0.46) (India and Nepal, east to southern China, south to West Malaysia) . . . . . Tetraponera binghami


 * Queen caste unknown, but expected to be smaller (HW <1.30), with larger eyes (REL >0.30) and more robust profemur (FI >0.48) (Borneo) . . . . . Tetraponera buops

7
return to couplet #5
 * Dense suberect pubescence conspicuous on dorsum of mesosoma, petiole and postpetiole; petiole slender, PLI 0.38--0.46 and PLI HL 0.77-0.83 (n = 6) (north-east India to China, south to Sumatra, Java, Borneo and Palawan) . . . . . Tetraponera attenuata


 * Suberect pubescence variably developed, usually relatively sparse and inconspicuous on at least the pronotum and anterior peduncle of petiole; petiole shorter and higher, PLI 0.47-0.54 and PL/HL 0.64-0.74 (n = 7) (Pakistan to Thailand, south to Borneo and Java) . . . . . Tetraponera nigra

8
return to couplet #4
 * Petiole with a pair of acute, posteroventral teeth, formed from ventrolateral extensions of the petiolar sternite; pronotum with dense punctate sculpture on its anterior quarter which contrasts with the shiny (and less densely sculptured) posterior half of head and with the more sparsely punctate posterior regions of the pronotum; scape length less than, or equal to, eye length (SI3 0.85-0.99; n = 12) . . . . . 9


 * Petiole lacking a pair of posteroventral teeth; pronotal sculpture variable but punctures more evenly distributed, not concentrated solely on the anterior quarter (although they may be sparse medially) and usually not occurring in a density that contrasts strongly with that of the posterior half of the head; scape length usually greater than eye length (SI3 1.01-1.40; n = 61) . . . . . 12

9
return to couplet #8
 * Head and petiole very elongate (CI 0.66, PLI 0.38 and PWI 0.32, in the only known queen specimen) (Thailand, West Malaysia) . . . . . Tetraponera notabilis


 * Head slightly less elongate (CI 0.67-0.73; n = 11); petiole much shorter (PLI 0.54-0.61, PWI 0.42-0.46) . . . . . 10

10
return to couplet #9
 * Small species (HW 0.74-0.91; n = 11); frontal carinae moderately well separated (MFC 0.10-0.14, FCI 0.13-0.16); pubescence generally sparse on postpetiole, the hairs separated by their lengths or more . . . . . 11


 * Queen caste not known but expected to be larger (HW >0.92) with frontal carinae more widely separated and with dense pubescence on the postpetiole (Borneo) . . . . . Tetraponera nodosa

11
return to couplet #10
 * Short standing pilosity (0.03-0.08 mm in length) common on dorsum of head (CSC - 24; n = 1) and on sides of head, when head is observed in full-face view (northern Australia) . . . . . Tetraponera nixa


 * Standing pilosity much less common on head (CSC 0-4; n = 10), absent or sparse on the sides when head is observed in full-face view (India to southern China, south to northern Australia) . . . . . Tetraponera nitida

12
return to couplet #8
 * Legs short (LHT/HL 0.51-0.62; n = 13) and petiole relatively slender in dorsal view (PWI 0.39-0.47); species found west of Wallace's line (India to the Philippines, Borneo, Sumatra and Java) . . . . . 18


 * Either legs longer (LHT/HL ~0.62) and/or petiole broader (PWI >0.50); species found east of Wallace's line (Australia, New Guinea, and adjacent islands) . . . . . 13

13
return to couplet #12
 * Frontal carinae widely separated (FCI 0.24-0.25; n = 5); profemur very short and broad (FI 0.54-0.56, FW/PL 0.47-0.53); postpetiole 1.2-1.3x broader than long (Australia) . . . . . Tetraponera tucurua


 * Frontal carinae less widely separated (FCI 0.15-0.21; n = 33); profemur generally more slender (FI 0.44--0.54, FW/PL 0.33-0.48); postpetiole varying from slightly (1.1 x) broader than long to longer than broad . . . . . 14

14
return to couplet #13
 * Posterior half of petiolar sternite flat or weakly convex in profile; head broader (CI 0.74-0.85; n = 13) and petiole relatively long and slender (PLI 0.41-0.54; but probably greater than this in T. mimula, for which the queen is unknown); punctures on dorsum of head between compound eyes larger, about 0.015-0.020 mm in diameter . . . . . 15


 * Posterior half of petiolar sternite with prominent ventral protrusion; head more elongate (CI 0.62-0.75; n = 20) and petiole usually more robust (PLI 0.54-0.75); punctures on dorsum of head between compound eyes finer, mostly 0.005-0.015 mm in diameter . . . . . 17

15
return to couplet #14
 * Head densely punctate, opaque; larger species (HW 1.12-1.32, LHT 0.97-1.19; n = 3), with disproportionately long legs (LHT/HL 0.68-0.73) (New Guinea) . . . . . Tetraponera atra


 * Head less densely sculptured, the punctures separated by about their diameters and the interspaces shiny; smaller species (HW 0.91-1.02, LHT 0.77-0.85; n = 10), with shorter legs (LHT/HL 0.62-0.66) . . . . . 16

16
return to couplet #15
 * Frontal carinae moderately well separated (FCI 0.15-0.18; n = 10) and eyes relatively large (REL2 0.46-0.51); petiole generally long and slender (PLI 0.41-0.54) (New Guinea and adjacent islands; northern Australia) . . . . . Tetraponera laeviceps


 * Queen unknown but expected to have frontal carinae more widely separated (FCI >0.18), eyes smaller (REL2 <0.46), and petiole shorter and higher (PLI >0.54) (New Guinea) . . . . . Tetraponera mimula

17
return to couplet #14
 * Smaller species (HW 0.72-0.79; n = 4) with large eyes (REL 0.35-0.37); profemur slender (FI 0.44-0.49); punctures on dorsum of head and pronotum very fine, about 0.005 mm in diameter (New Guinea, northern Australia) . . . . . Tetraponera rotula


 * Larger species (HW 0.90-1.49; n = 16) with smaller eyes (REL 0.26-0.30); profemur usually more robust (FI 0.48-0.54); punctures on dorsum of head and pronotum mostly larger, approximately 0.010-0.015 mm in diameter (New Guinea, Australia) . . . . . Tetraponera punctulata

18
return to couplet #12
 * Standing pilosity relatively sparse on dorsum and sides of head (CSC <6) . . . . . 19


 * Standing pilosity common on dorsum and sides of head (CSC >10) . . . . . 22

19
return to couplet #18
 * Larger species (HL 1.92-2.18, LHT 1.06-1.12; n = 3); head elongate (CI 0.62-0.64) and clypeal margin adorned with prominent teeth or a medial protrusion . . . . . 20


 * Smaller species (HL 1.32-1.73, LHT 0.76-1.00; n = 10); head less elongate (CI 0.68-0.75) and clypeal margin lacking prominent teeth or protrusions . . . . . 21

20
return to couplet #19
 * Anterior clypeal margin edentate, with a prominent spatulate protrusion underlying the margin; frontal carinae moderately well separated (FCI 0.18-0.19; n = 2); eyes smaller, REL2 0.38-0.40 (Singapore, Borneo, Java) . . . . . Tetraponera vivax


 * Anterior clypeal margin with three strong, blunt teeth, but no underlying spatulate protrusion; frontal carinae very widely separated (FCI 0.27; n = 1); eyes larger, REL2 0.45 (Singapore) . . . . . Tetraponera volucris

21
return to couplet #19
 * Smaller species (HW 0.94-0.98, LHT 0.76; n = 4) with disproportionately larger eyes (REL2 0.50-0.52) and shorter profemur (FL/HL 0.50-0.51) (Borneo, Palawan) . . . . . Tetraponera inversinodis


 * Larger species (HW 1.05-1.26, LHT 0.88-1.00; n = 6) with smaller eyes (REL2 0.42-0.47) and longer profemur (FL/HL 0.51-0.56) (Malay Peninsula south and east to Sumatra Java, Borneo and the Philippines) . . . . . Tetraponera difficilis

22
return to couplet #18
 * Pronotum with sharp lateral margins; petiole relatively thin (PWI 0.42; n = 1); pubescence moderately dense on abdominal tergite IV, appressed hairs separated by about their lengths (India, West Malaysia) . . . . . Tetraponera aitkenii


 * Queen unknown, but expected to have weakly marginate pronotum, broader petiole (PWI >0.50), and sparse and inconspicuous pubescence on abdominal tergite IV (Borneo) . . . . . Tetraponera polita