Key to Oriental and Sino-Japanese Leptanilla

The following worker key is based on: [[Media:Wong, M.K.L., Guénard, B. 2016. Leptanilla hypodracos sp. n., a new species of the cryptic ant genus Leptanilla from Singapore.pdf|Wong, M.K.L., Guénard, B. 2016. Leptanilla hypodracos sp. n., a new species of the cryptic ant genus Leptanilla (Hymenoptera, Formicidae) from Singapore, with new distribution data and an updated key to Oriental Leptanilla species. ZooKeys 551: 129–144 (doi: 10.3897/zookeys.551.6686).]], which in turn is based on Baroni Urbani (1977) and Bharti and Kumar (2012).

1

 * Mandible with 2 teeth . . . . . 2


 * Mandible with 3 teeth or more . . . . . 3

2
return to couplet #1
 * Anterolateral lobes of clypeus present, 3rd antennal segment with a distinct basal peduncle, postpetiole large, promesonotal suture narrow (Java) . . . . . Leptanilla kebunraya


 * Anterolateral lobes of clypeus absent, 3rd antennal segment without distinct basal peduncle, postpetiole relatively small, promesonotal suture wide (W. Malaysia) . . . . . Leptanilla butteli

3
return to couplet #1
 * Mandible with 3 teeth . . . . . 4


 * Mandible with 4 irregular and with the fourth tooth (preapical) very small and difficult to distinguish (Hong Kong) . . . . . Leptanilla sp. cf. japonica

4
return to couplet #3
 * Metanotal groove present . . . . . 5


 * Metanotal groove absent . . . . . 6

5
return to couplet #4
 * In full-face view head approximately rectangular. Clypeus not protruding, anterior margin roundly convex. In profile view dorsum of petiole almost straight. In dorsal view postpetiolar node much wider than petiolar node (S. China) . . . . . Leptanilla hunanensis


 * In full-face view head distinctly narrowed anteriorly. Clypeus protruding, anterior margin concave. In lateral view dorsum of petiole roundly convex. In dorsal view postpetiolar node as wide as petiolar node (S. China) . . . . . Leptanilla kunmingensis

6
return to couplet #4
 * Anterior margin of clypeus more or less straight or weakly to strongly convex . . . . . 7


 * Anterior margin of clypeus medially incised, bilobed . . . . . 9

7
return to couplet #6
 * Petiole longer ≥ 0.13 mm (Sri Lanka) . . . . . Leptanilla besucheti


 * Petiole shorter ≤ 0.10 mm . . . . . 2

8
return to couplet #7
 * Clypeus slightly protruding anteriorly and with distinctly convex anterior margin, PPI = 122–138, CI ≥ 82, PI = 111–125 (Nepal) . . . . . Leptanilla buddhista


 * Clypeus not protruding anteriorly and with straight or weakly convex anterior margin, PPI = 163–171, CI ≤ 81, PI = 138–158 (S. China) . . . . . Leptanilla yunnanensis

9
return to couplet #6
 * Petiole, postpetiole and gaster covered with short and long hairs . . . . . 10


 * Petiole, postpetiole and gaster covered with either short or long hairs . . . . . 11

10
return to couplet #9
 * Petiole with an anteroventral lamellate subpetiolar process, ventral face of lamellate process weakly rounded; subpetiolar process with anteroventral and posteroventral corner obtusely angled and posterior face of subpetiolar process weakly concave; petiolar and postpetiolar spiracle almost equal in diameter, PPHI = 74–76; posterior head margin concave (N. India) . . . . . Leptanilla lamellata


 * Petiole with a weak subpetiolar process without lamella; petiolar process convex and anteriorly and posteriorly oblique; petiolar spiracle large with a diameter of almost 2 times the diameter of postpetiolar spiracle, PPHI = 85–86, posterior head margin almost straight or weakly concave (S. India) . . . . . Leptanilla escheri

11
return to couplet #9
 * Anterior margin of clypeus almost straight with a low median notch (Taiwan) . . . . . Leptanilla taiwanensis


 * Anterior margin of clypeus medially prominent with deep incision or anteriorly strongly produced and apically distinctly bilobed . . . . . 12

12
return to couplet #11
 * Anterior margin of clypeus medially prominent with a deep incision at its apical margin, SI ≥ 74 (Singapore) . . . . . Leptanilla havilandi


 * Anterior margin of clypeus with a broad median notch that makes it seem almost bilobed in dorsal view, SI ≤ 68 . . . . . 13

13
return to couplet #12
 * Clypeus strongly produced anteriorly and having a distinctly raised platform which is defined posteriorly; anterior portion of head lacking a pair of whitish markings . . . . . 14


 * Clypeus not strongly produced anteriorly and lacking a distinctly raised platform which is defined posteriorly; anterior portion of head with a pair of whitish markings (Thailand) . . . . . Leptanilla thai

14
return to couplet #13
 * In dorsal view petiolar node almost twice as long as wide and postpetiolar node almost as wide as long, PI = 60, PPI = 90; in profile view propodeal declivity is more angular. In full-face view, mandibles with a long and well-defined basal tooth (Singapore) . . . . . Leptanilla hypodracos


 * In dorsal view petiolar node almost as wide as long and postpetiolar node distinctly wider than long, PI = 82–100, PPI = 133–137; in profile view propodeal declivity is more rounded. In full-face view, mandibles lacking a long and well-defined basal tooth (Java) . . . . . Leptanilla clypeata