Key to Aenictus species groups

The following key to Aenictus species groups has been modified from Jaitrong & Yamane (2011 ).

1

 * Antenna with 8 or 9 segments => A. silvestrii group
 * Antenna with 10 segments => 2

2

 * Anterior clypeal margin with denticles => 3
 * Anterior clypeal margin lacking denticles => 5

3

 * Typhlatta spot present; body black, dark brown to reddish brown => A. laeviceps group
 * Typhlatta spot absent; body yellow to yellowish brown => 4

4

 * Mandible subtriangular; masticatory margin with 3 teeth including large apical tooth => A. javanus group
 * Mandible triangular; masticatory margin with 9–12 teeth including large apical tooth => A. wroughtonii group

5

 * Anterior clypeal margin concave or almost straight; mandible linear; with mandibles closed a gap present between mandibles and anterior clypeal margin => A. ceylonicus group
 * Anterior clypeal margin convex; mandible triangular to subtriangular; with mandibles closed a gap absent between mandibles and anterior clypeal margin => 6

6

 * Typhlatta spot present; head entirely smooth and shiny => 7
 * Typhlatta spot absent; head sculptured or smooth and shiny => 9

7

 * Head in full-face view with occipital corner convex, with a distinct protuberance on occipital corner, which gives the head a unique “horned” appearance => A. currax group
 * Head in full-face view with occipital corner rounded, without lateral protuberance => 8

8

 * Subpetiolar process well developed, subtriangular with its apex directed downward; worker caste completely monomorphic; propodeum normal => A. leptotyphlatta group
 * Subpetiolar process weakly developed or almost absent; worker caste polymorphic; propodeum inflated in major and intermediate workers => A. inflatus group

9

 * Parafrontal ridge essentially absent; head entirely smooth and shiny => A. piercei group
 * Parafrontal ridge well developed; head entirely sculptured or rarely smooth => 10

10

 * First gastral segment micropunctate; subpetiolar process well developed, with posteroventral corner produced posteriad => A. hottai group
 * First gastral segment clearly smooth and shiny or weakly shagreened with smooth and shiny interspaces; subpetiolar process weakly developed or almost absent => 11

11

 * Mesonotum demarcated from mesopleuron by a conspicuous ridge; metanotal groove relatively deep and distinct => A. philippinensis group
 * Mesonotum not visibly demarcated from mesopleuron; metanotal groove indistinct => A. pachycerus group