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) Author Jaitrong, Weeyawat Author Yamane, Seiki text Zootaxa 2011 3128 1 46 journal article 45801 10.5281/zenodo.207090 a51dd241-f273-4211-8dd3-e2fd556a8e43 1175-5326 207090 Aenictus ceylonicus group Diagnosis. Antenna 10-segmented; scape reaching or extending beyond half of head length, but not reaching the occipital corner of head in full-face view. Mandible linear; its basal and lateral margins almost parallel; masticatory margin with large apical tooth followed by medium-sized subapical tooth; between subapical tooth and basal tooth 0–6 small denticles present. With mandibles closed, a gap present between mandibles and anterior margin of clypeus. Anterior clypeal margin weakly concave or almost straight, lacking denticles. Frontal carina short and thin, reaching or slightly extending beyond the level of posterior margin of torulus; anterior curved extension of frontal carina reaching or extending beyond the level of anterior clypeal margin in full-face view; parafrontal ridge absent. Promesonotum usually convex dorsally and sloping gradually to propodeum. Subpetiolar process developed. Head and first gastral tergite smooth and shiny. Body yellowish, reddish or dark brown; typhlatta spot absent. Remarks. The A. ceylonicus group is a unique group easily separated from the other groups by the following characteristics: mandible linear; a gap present between mandibles and anterior margin of clypeus when mandibles are closed; anterior clypeal margin almost straight or feebly concave, lacking denticles. Our concept roughly agrees with Wilson’s (1964) definition of the “ ceylonicus group”, but three species, A. biroi , A. javanus and A. piercei , should be removed from his list since they have triangular mandibles and different conditions of the anterior clypeal margin. All these species belong to three different species groups. Distribution. India , Sri Lanka , southernmost part of Japan (?), S. China , Taiwan , Vietnam , Thailand , Borneo (Sabah and Sarawak ), Philippines , Aru Island, New Guinea ( Papua ), and Australia (Queensland). Currently valid names for the Oriental, Indo-Australian, and Australasian forms. A. acerbus Shattuck, 2008 ; A. ceylonicus (Mayr, 1866) ; A. doryloides Wilson, 1964 ; A. exiguus Clark, 1934 ; A. exilis Wilson, 1964 ; A. fuchuanensis Zhou, 2001 ; A. henanensis Li et Wang, 2005 ; A. nganduensis Wilson, 1964 ; A. orientalis Karavaiev, 1926 ; A. schneirlai Wilson, 1964 ; A. thailandianus Terayama et Kubota, 1993 ; A. turneri Forel, 1900 .