Aenictus inflatus

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 : 6-7

Aenictus inflatus group

Diagnosis. Largest worker. Head in full-face view with occipital corner rounded; occipital margin lacking collar. Antenna long, consisting of 10 segments; antennal scape widened in apical half, reaching posterolateral corner of head in full-face view. Anterior clypeal margin roundly convex, lacking denticles. Mandible triangular; its masticatory margin with a large apical tooth, medium-sized subapical and basal teeth, with 4–5 denticles between subapical and basal teeth. Frontal carina very short, not extending beyond posterior margin of torulus; parafrontal ridge absent. With mesosoma in profile promesonotum convex dorsally and sloping gradually to metanotal groove; propodeum broader than pronotum, distinctly inflated. Legs slender. Subpetiolar process weakly developed or almost absent.

Head and first gastral segment entirely smooth and shiny. Body yellow to yellowish brown; head darker than other parts; typhlatta spot present, located at occipital corner.

Variation. The single species of this group, A. inflatus Yamane et Hashimoto, 1999 , is clearly polymorphic in the worker caste. Several very small workers were found among the type series and workers of other colonies. They are characterized by a relatively long head, short antennal scape reaching only midlength of head, and normal propodeum. The typhlatta spot is less pronounced in these specimens. Between the largest and smallest workers we have found a series of specimens that are intermediate in the development of propodeum and length of antenna and legs (see also Yamane & Hashimoto 1999).

Remarks. Yamane and Hashimoto (1999) erroneously mentioned that the antenna is 12-segmented when it was in fact 10-segmented. The smallest worker of this group is most similar to the worker of the A. wroughtonii group in having a yellowish and slender body, long legs and weakly developed subpetiolar process. But in the former, the anterior clypeal margin is convex, lacking denticles and the antennal scape reaches only the midlength of the head, while in the latter, the anterior clypeal margin is roundly convex with 5–10 denticles and the antennal scape attains or extends beyond posterolateral corner of the head. The inflated propodeum of A. inflatus contains a red liquid in living specimens; this liquid dissolves in alcohol.

Distribution. Borneo ( Sarawak).

Currently valid names for the Oriental, Indo-Australian, and Australasian forms. A. inflatus Yamane et Hashimoto, 1999 .