Key to Tetraponera males of the Oriental and Australian regions

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This male key is based on: 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 will permit males to be identified at least to species-group. The allaborans-group is taken no farther than this, but all the species in the nigra-group for which males are known (11 of 20 species) have been included in the key, accompanied by cautionary notes regarding some of the related species whose males are as yet undiscovered. Some of the most distinctive features of the males reside in characteristics of the terminalia, and assessing these usually requires dissection.

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1

  • Mesoscutum densely punctate or punctate-reticulate and (sub)opaque; larger species, HW > 1.20 . . . . . 2
  • Mesoscutum with scattered punctures mostly separated by their diameters or more, and interspaces weakly to strongly shining; smaller species, on average, range of HW approximately 0.50-1.45 . . . . . 3

2

return to couplet #1

  • Head sublucid, with relatively small eyes (REL2 - 0.42); hypopygium semicircular; distal end of paramere lacking digitiform lobes; aedeagal plate elongaterectangular in profile (Pakistan to southern China, south to Sumatra and Java; introduced to the Seychelles) . . . . . Tetraponera rufonigra
  • Head opaque, with larger eyes (REL2 - 0.52); hypopygium subrectangular; distal end of paramere with a pair of digitiform lobes; aedeagal plate triangular in profile (Myanmar to Vietnam, south to Palawan, Borneo, Sumatra and Java) . . . . . Tetraponera pilosa

3

return to couplet #1

  • Forewing with one cubital cell; anterolateral arms of hypopygium not protruding forward nor subtended by a lamellate, sclerotized extension; distal end of paramere with a very deep, obliquely transverse, dorsal impression; external face of aedeagus with a longitudinal carina that ends on the posterior margin, not terminating in a tooth or spine................................................ allaborans-group
  • Forewing usually with two cubital cells; anterolateral arms of hypopygium protruding forward and subtended by a lamellate, sclerotised extension; distal end of paramere lacking a deep transverse impression; external face of aedeagus with an arched carina terminating at or near a sharp posteroventral tooth or spine (nigra-group) ... 4

4

return to couplet #3

  • Large species (HW 1.03-1.44, LHT 1.17-1.72; n = 9), with disproportionately long scapes (SI2 0.27-0.33) and legs (LHT/HL 1.06-1.45); distal end of paramere, as seen in dorsal view, not notably narrowed . . . . . 5
  • Smaller species, on average (HW 0.67-1.24, LHT 0.60-1.15; n = 28), with shorter scapes (SI2 0.20-0.28) and legs (LHT/HL 0.74-1.08); distal end of paramere, as seen in dorsal view, conspicuously narrowing towards tip . . . . . 7

5

return to couplet #4

  • Head broader than long (CI 1.07-1.17; n = 6); posteromedial margin of hypopygium thickened but not deflected dorsally . . . . . 6
  • Head longer than broad (CI 0.86-0.92; n = 3); posteromedial margin of hypopygium not thickened but with a thin ligulate extension that is deflected dorsally (India and Nepal, east to southern China, south to West Malaysia) . . . . . Tetraponera binghami (Note: T. buops may also key out here.)

6

return to couplet #5

  • Anterior portion of mesoscutum strongly narrowed and constricted; posterior margin of hypopygium convex; distal end of paramere, as seen in posterior view, with a deep mesial excavation; posterior half of aedeagus with a single oblique carina on its external face (north-east India to China, south to Sumatra, Java, Borneo and Palawan) . . . . . Tetraponera attenuata
  • Anterior portion of mesoscutum not strongly constricted; posterior margin of hypopygium concave; distal end of paramere, as seen in posterior view, lacking a deep mesial excavation; posterior half of aedeagus with a pair of oblique carinae on its external face (Pakistan to Thailand, south to Borneo and Java) . . . . . Tetraponera nigra

7

return to couplet #4

  • Second funicular segment notably elongate, its length approaching the combined lengths of scape and fourth funicular segment (LF2/(SL + LF4) 0.82-1.00; n = 11); distal end of paramere, as seen in dorsal view, with saucer-shaped mesial concavity only partly visible . . . . . 8
  • Second funicular segment not notably elongate, its length considerably less than the combined lengths of scape and fourth funicular segment (LF2/(SL + LF4) 0.47-0.72; n = 17); distal end of paramere, as seen in dorsal view, with saucer-shaped mesial concavity fully visible . . . . . 10

8

return to couplet #7

  • Petiole lacking posteroventral teeth; eyes slightly smaller (REL2 0.53-0.58; n = 6); posteromedial margin of hypopygium convex in ventral view; distal end of paramere, when seen in posterior view, with well-developed, lamellate margin, which conceals the preceding saucer-shaped concavity . . . . . 9
  • Petiole with a pair of posteroventral teeth formed by angular extensions of the petiolar sternite; eyes larger (REL2 0.59-0.61; n = 5); posteromedial margin of hypopygium narrowly concave in ventral view; distal end of paramere, when seen in posterior view, lacking well-developed, lamellate margin, the preceding saucer-shaped concavity easily visible (India to southern China, south to northern Australia) . . . . . Tetraponera nitida (Note: T. nixa, T. nodosa and T. notabilis also expected to key out here.)

9

return to couplet #8

  • Smaller species (HW 0.76-0.81; n = 3), with shorter legs (LHT/HL 0.77-0.96); distal end of paramere lacking ventral protrusion (Borneo, Palawan) . . . . . Tetraponera inversinodis
  • Larger species (HW 0.87-0.92; n = 3), with disproportionately longer legs (LHT/HL 1.03-1.05); distal end of paramere with blunt posteroventral protrusion (Malay Peninsula south and east to Sumatra, Java, Borneo and the Philippines) . . . . . Tetraponera difficilis (Note: with more material these differences may narrow.)

10

return to couplet #7

  • Anterior portion of mesoscutum strongly narrowed and constricted; antenna very short, owing to unusually short funicular segments, such that second funicular segment shorter than scape (LF2/SL 0.72-0.85; n = 6) and combined lengths of funicular segments 2-4 about twice scape length ((LF2 + LF3 +LF4)/SL 1.83-2.15); distal end of paramere, as seen in posterior view, narrowly excavate mesially) . . . . . 11
  • Anterior portion of mesoscutum not strongly constricted; antenna longer, second funicular segment as long as or longer than scape (LF2/SL 1.00-1.69; n = 11) and combined lengths of funicular segments 2-4 much more than twice scape length ((LF2 + LF3 +LF4)/SL 3.03-4.52); distal end of paramere, as seen in posterior view, not narrowly excavate mesially . . . . . 12

11

return to couplet #10

  • Larger species (HW 0.85, LHT 1.03; n = 1) with disproportionately long legs (LHT/HL 1.08) (New Guinea) . . . . . Tetraponera atra
  • Smaller species (HW 0.68-0.79, LHT 0.71-0.85; n = 5) with shorter legs (LHT/HL 0.98-1.05) (New Guinea and adjacent islands; northern Australia) . . . . . Tetraponera laeviceps (Note: T. mimula expected to key out here.)

12

return to couplet #10

  • Eye small (REL2 0.43-0.45; n = 3); distal end of paramere, as seen in dorsal view, lacking beak-like mesial protrusion (Australia) . . . . . Tetraponera tucurua
  • Eye larger (REL2 0.48-0.57; n = 8); distal end of paramere, as seen in dorsal view, with beak-like mesial protrusion . . . . . 13

13

return to couplet #12

  • Smaller species (HW 0.80-0.87; n = 3) with large eyes (REL2 0.57) (New Guinea, northern Australia) . . . . . Tetraponera rotula
  • Larger species (HW 0.91-1.24; n = 5) with smaller eyes (REL2 0.48-0.52) (New Guinea, Australia) . . . . . Tetraponera punctulata