Key to Australian Tetraponera Species

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The following key to Australian Tetraponera is based on Ward (2001)[1].

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, head width 0.49-0.93mm => Tetraponera allaborans
  • 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, head width 0.63-1.48mm => 2

2

  • 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; scapes shorter than eye length (SI3 0.83-0.98) => 3
  • 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; scapes longer than eye length (SI3 1.02-1.55) => 4

3

  • Short standing pilosity (0.03-0.05 mm in length) common on most body surfaces, including sides of head, dorsum of head (CSC 15-25), and mesosoma (MSC 30-56) => Tetraponera nixa
  • Standing pilosity much less common on head (CSC 0-6), absent or sparse on the sides when head is observed in full-face view; standing hairs generally sparse on mesosome (MSC usually <10), but occasionally quite common; if MSC >20 then some hairs relatively long (0.10-0.20 mm in length) => Tetraponera nitida

4

  • Petiole short and very broad (PL/HW 0.57-0.59; PWI 0.79-0.88); postpetiole about 1.4× broader than long; frontal carinae widely separated (FCI 0.19-0.20) => Tetraponera tucurua
  • Petiole longer and less broad (PL/HW 0.62-0.96; PWI 0.33-0.70); postpetiole approximately as long as, or longer than, broad; frontal carinae less widely separated (FCI 0.12-0.19) => 5

5

  • Posterior half of petiolar sternite flat or weakly convex in profile; petiole relatively slender (PLI 0.37-0.61, PWI 0.33-0.57); eyes larger (REL 0.36-0.45); punctures on head between compound eyes relatively coarse, mostly 0.010-0.020 mm in diameter; propodeum somewhat elevated (PDI 1.10-1.34), its dorsal face usually convex in profile, inclined downward posteriorly, and grading insensibly into declivitous face => Tetraponera laeviceps
  • Posterior half of petiolar sternite with prominent ventral protrusion; petiole usually more robust (PLI 0.57-0.80, PWI 0.50-0.70) and eyes tending to be smaller (REL 0.30-0.41); punctures on head between compound eyes finer, mostly 0.005-0.015 mm in diameter; propodeum lower in profile (PDI 1.00-1.19), its dorsal usually flatter and more strongly differentiated from the declivitous face => 6

6

  • Small species (head width 0.73-0.81mm); petiole with short anterior peduncle and large globose node, with steep anterior and posterior faces (FW/PH 0.51-0.62); punctures on head and pronotum mostly very fine, about 0.005 mm in diameter => Tetraponera rotula
  • Larger species (head width 0.80-1.44mm), with less globose petiolar node, the anterior and posterior faces more gently sloping (FW/PH 0.60-0.88); punctures on head and mesosome mostly larger, approximately 0.010-0.015 mm in diameter => Tetraponera punctulata

References

  1. 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.