Key to Tetraponera of the Oriental and Australian regions

This worker 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 excludes Tetraponera vivax and Tetraponera volucris, two species known only from the queen caste.

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Tetraponera

1

 * Head with three distinct ocelli; in dorsal view pronotal humeri appearing subangulate; head densely punctate, and lacking extensive shiny interspaces between the punctures; large species, HW 1.14-2.07 . . . . . 2


 * Head almost always lacking ocelli, very rarely with two or three faint ocelli (in a few large workers of T. nigra and T. punctulata); pronotal humeri varying from narrowly to broadly rounded, but not subangulate; head usually less densely punctate and with conspicuous shiny interspaces between the punctures (always the case in species with HW > 1.1 0); size variable (HW 0.49-1.48) . . . . . 3

2
return to couplet #1
 * Larger species (HW 1.62-2.07), with smaller eyes (REL2 0.35-0.37); usually bicolored, the dark head and gaster contrasting with the orange-brown mesosoma (the latter infuscated in some populations); standing pilosity common on the mesosoma dorsum, including the propodeum, MSC 20-66 (Pakistan to southern China, south to Sumatra and Java; introduced into the Seychelles) . . . . . Tetraponera rufonigra


 * Smaller species (HW 1.14-1.51), with larger eyes (REL2 0.49-0.56); body unicolorous dark brown; standing pilosity sparse on the mesosoma dorsum, absent from the propodeum, MSC 3-6 (Myanmar to Vietnam, south to Palawan, Borneo, Sumatra and Java) . . . . . Tetraponera pilosa

3
return to couplet #1
 * Mandible slender, with three teeth on the masticatory margin, and 1-2 denticles on the basal margin; basal margin of mandible much longer than masticatory margin; posteroventral margin of petiole in the form of a thin, ventrally protruding hood, which is distinctly separated from the helcium venter when the postpetiole is in its normal horizontal position; mesosternum densely pubescent; abdominal tergite IV sparsely pubescent, the appressed hairs separated by their lengths or more; relatively small species, HW 0.49-0.93 (allaborans-group) . . . . . 4


 * Mandible more robust, with four teeth on the masticatory margin, and 0-1 denticles on the basal margin; basal margin of mandible subequal to, or shorter than, masticatory margin; posteroventral margin of the petiole closely associated with the helcium venter, although it may be flanked by ventrolateral flanges; most of the mesosternum devoid of pubescence; abdominal tergite IV usually densely pubescent; size variable, HW 0.63-1.48 (nigra-group) . . . . . 4 4

4
return to couplet #3
 * Small, black species (HW 0.58-0.61, LHT 0.50-0.52), with disproportionately small eyes (REL 0.32-0.34), short scapes (SI2 0.42-0.45) and broad profemur (FI 0.47-0.48); pronotal dorsum rounding into sides, lateral margins poorly developed; mesopropodeal impression lacking a distinct metanotal plate but may be bisected by a weak transverse ridge that interrupts the longitudinally rugulate sculpture (Thailand) . . . . . Tetraponera connectens


 * Size, color, scapes and profemur variable but if small (HW <0.65 and LHT <0.55) and black, then eyes larger (REL 0.35-0.41); either lateral pronotal margins better developed or mesopropodeal impression with a distinct, flattened metanotal plate . . . . . 5

5
return to couplet #4
 * Mesopropodeal impression with irregular longitudinal rugulae, interrupted by a small, raised transverse welt (metanotal plate), which is bounded laterally by the metanotal spiracles and which lacks rugulate sculpture; pronotum lacking distinct lateral margins, the dorsum rounding gently into the sides, as seen in posterior view; profemur short and broad, FI 0.44-0.53; dark brown to black species . . . . . 6


 * Mesopropodeal impression with irregular longitudinal rugulae, sometimes crossed at the midpoint by a broken transverse rugule, but lacking a raised metanotal plate; pronotum with more or less distinct lateral margins, which vary from sharp to blunt-edged; in posterior view pronotal dorsum meeting the sides at a sharply rounded angle; profemur usually more slender (FI 0.36-0.48); color variable . . . . . 9

6
return to couplet #5
 * Median clypeal lobe subtriangular, protruding, and pointed; petiole narrow in dorsal view (DPW/MTW 0.61-0.64) (Borneo) . . . . . Tetraponera apiculata


 * Median portion of clypeus broadly convex, not prominently protruding and pointed; petiole broader in dorsal view (DPW/MTW 0.65-0.73) . . . . . 7

7
return to couplet #6
 * Larger species, with broad head (HW 0.82, CI 0.92) and large eyes (REL 0.42); anterior clypeal margin edentate and nonprotruding; petiole slender (PLI 0.51); mesopleuron extensively longitudinally carinulate (West Malaysia) . . . . . Tetraponera avia


 * Smaller, with more elongate head (HW 0.63-0.75, CI 0.73-0.84) and smaller eyes (REL 0.35-0.39); anterior margin of clypeus with a modestly protruding and crenulate median lobe; petiole more robust (PLI 0.58-0.67); mesopleuron predominantly smooth and shining . . . . . 8

8
return to couplet #7
 * Smaller species with more elongate head (HW 0.63-0.65, CI 0.73-0.75); eye larger in relation to scape length (SI3 1.19-1.21); petiole relatively slender (PLI 0.58-0.62) (Borneo, ?West Malaysia) . . . . . Tetraponera bita


 * Larger species with broader head (HW 0.73-0.75, CI 0.82-0.84); eye smaller in relation to scape length (SB 1.25-1.30); petiole shorter and more robust (PLI 0.63-0.67) (West Malaysia) . . . . . Tetraponera brevis

9
return to couplet #5
 * Small species (HW 0.60-0.64), with short scapes (SI 0.52-0.57, SI2 0.41-0.44); median clypeal lobe bidentate; pronotum relatively narrow (PrWM/MTW 1.14-1.21), with sharp, subparallel margins, as seen in dorsal view, and appearing rather flattened in posterior view; profemur broad (FI 0.42-0.48) (China, Vietnam) . . . . . Tetraponera microcarpa


 * Scapes longer (SI 0.57-0.68, SI2 0.45-0.57); median clypeal lobe usually with three or four teeth, or lacking teeth altogether, rarely with a pair of well developed teeth; size variable but if falling within the above range then usually the pronotal margins are soft-edged and convex in dorsal view and the profemur is more slender; dorsal surface of pronotum more convex in posterior view . . . . . 10

10
return to couplet #9
 * Larger species (HW 0.62-0.93, usually >0.70); body predominantly black, although petiole, postpetiole and limb appendages may be lighter in color; propodeum typically low and broad, such that PDI 0.91-1.09; in one rare aberrant morph with HW >0. 79 the propodeum is inflated and prominently raised; pronotal margin varying from sharp- to soft-edged, and maximum width of the pronotum generally occurring below the margin (widespread and highly variable species, distributed from India to southern China, south to New Guinea and northern Australia) . . . . . Tetraponera allaborans


 * Smaller species (HW 0.49-0.79), color variable but often with at least the postpetiole-and sometimes most of the body-yellow or orange-brown; if HW >0.65 then body mostly dark brown to black but propodeum notably tall (lateral view) and slender (posterior view), such that PDI 1.12-1.24; pronotal margin usually relatively soft-edged and occurring at the point of maximum width of the pronotum . . . . . 11

11
return to couplet #10
 * Small species (HW 0.64) with large eyes (REL 0.42); propodeum conical in profile, the prominent apex located far forward, so that the short inclined dorsal face of the propodeum rounds into a much longer, sloping declivitous face; petiole short and broad (PWI 0.54, PL/LHT 0. 72), subtriangular in profile and without a well differentiated anterior peduncle; castaneous brown (Borneo) . . . . . Tetraponera conica


 * Eyes smaller (REL 0.34-0.41); propodeum not conical in profile, the dorsal face convex and rounding gradually into a steep declivitous face of approximately the same length; petiole longer and narrower (PWI 0.38-0.54, PL/LHT 0.83-0.98), a differentiated anterior peduncle and posterior node evident in profile; size and color variable (modesta-complex) . . . . . 12

12
return to couplet #11
 * Small species (HW 0.53-0.61), with a relatively short, high petiole (PLI 0.60-0.68, PWI 0.46-0.54, PLISL 1.09-1.19); body and legs dark to medium brown (pronotum, petiole and postpetiole may be lighter in color); standing pilosity tending to be rather common, with 8-10 long setae often visible in profile on the promesonotum (but sparse or abraded in some specimens) (Thailand, West Malaysia, Borneo, Sumatra) . . . . . Tetraponera crassiuscula


 * Petiole more slender (PLI 0.45-0.59, PWI 0.38-0.48, PL/SL 1.20-1.41); standing pilosity relatively sparse, 1-2 pairs of long erect setae visible in profile on the pronotum, none on the mesonotum; size (HW 0.51-0.79) and color variable . . . . . 13