Key to Oriental and Sino-Japanese Leptanilla

The following key to Oriental Leptanilla species is based on Baroni Urbani (1977 ) as modified by Bharti & Kumar (2012 ).

1

 * Mandible with 2 teeth => 2
 * Mandible with 3 teeth => 3

2

 * Anterolateral lobes of clypeus present, 3rd antennal segment with a distinct basal peduncle, postpetiole large, pro-mesonotal suture narrow (Indonesia) => Leptanilla kebunraya
 * Anterolateral lobes of clypeus absent, 3rd antennal segment without distinct basal peduncle, postpetiole relatively small, pro-mesonotal suture wide (Malaysia) => Leptanilla butteli

3

 * Metanotal groove present => 4
 * Metanotal groove absent => 5

4

 * In full face view head roughly 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 (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 (China) => Leptanilla kunmingensis

5

 * Anterior margin of clypeus more or less straight or weakly to strongly convex => 6
 * Anterior margin of clypeus medially incised, bilobed => 9

6

 * Petiole longer ≥ 13 mm => 7
 * Petiole shorter ≤ 10 mm => 8

7

 * Body densely covered with short hairs which are longer and coarser on gaster; basal area of 2nd, 3rd and 4th gastral segments without hairs; petiole significantly longer, almost 1.6 times of its width (Japan) => Leptanilla morimotoi
 * Body with sparse, short hairs which are more rare on head and dorsum of mesosoma; petiole relatively short which is almost 1.3 times of its length (Sri Lanka) => Leptanilla besucheti

8

 * Clypeus slightly protruding anteriorly and with distinctly convex anterior margin, DPPTI 122.22–137.50, CI ≥ 82, PI 111–125 (Nepal) => Leptanilla buddhista
 * Clypeus not protruding anteriorly and with straight or weakly convex anterior margin; DPPTI 162.50–171.43, CI ≤ 81, PI 137.5–158 (China) => Leptanilla yunnanensis

9

 * Petiole, postpetiole and gaster covered with short and long hairs => 10
 * Petiole, postpetiole and gaster covered with either short or long hairs => 11

10

 * 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, PPTI 73.68–76.47; posterior head margin concave (India) => Leptanilla lamellata
 * Petiole with a weak subpetiolar process without lamella; petiolar process convex and anteriorly and posteriorly oblique; petiolar spiracle large and almost 2 times of postpetiolar spiracle, PPTI 84.62–85.71, posterior head margin almost straight or weakly concave (India) => Leptanilla escheri

11

 * Anterior margin of clypeus almost straight with a low median notch (China) => Leptanilla taiwanensis
 * Anterior margin of clypeus medially prominent with deep incision or anteriorly strongly produced and apically distinctly bilobed => 12

12

 * 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

 * In profile dorsal and posterior faces of propodeum forming a blunt angle, anterior portion of head with a pair of whitish markings or spots (Thailand) => Leptanilla thai
 * In profile dorsal and posterior faces of propodeum not forming a blunt angle, head without whitish markings or spots (Indonesia) => Leptanilla clypeata