Aenictus

Jaitrong, Weeyawat & Yamane, Seiki, 2011, Synopsis of Aenictus species groups and revision of the A. curra x and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae), Zootaxa 3128, pp. 1-46 : 4-5

Key to Aenictus species groups based on the worker caste

1. Antenna 8–9-segmented.................................................................. A. silvestrii group

- Antenna 10-segmented................................................................................. 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 interme- diate 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