Aenictus changmaianus

No biological information is available for A. changmaianus. However, it has been found in highland seasonal forests (hill evergreen forest) and disturbed areas in northern Thailand (900–1500 m). In eastern Thailand and southern Vietnam it has been collected from lowland seasonal forests (dry evergreen forest), secondary forests, and plantations (160–700 m), thus this species probably ranges from lowland to highland and inhabits both primary and disturbed forests. (Jaitrong & Hashimoto, 2012).

Identification
Jaitrong and Hashimoto (2012) - Aenictus changmaianus is very similar in general appearance to Aenictus minutulus and Aenictus minimus. However, A. changmaianus is separated from A. minimus by the dentition on the basal margin of the mandible and antennal scape being relatively longer than in the latter (scape index 67–72 in A. changmaianus; scape index 63–64 in A. minimus). It is distinguished from A. minutulus by the large metapleural gland bulla relatively small in A. minutulus).

Distribution
This taxon was described from Thailand. It is also known from Vietnam and Cambodia.

Nomenclature

 *  changmaianus. Aenictus changmaianus Terayama & Kubota, 1993: 68, figs. 2-4 (w.) THAILAND. See also: Jaitrong & Hashimoto, 2012: 31.

Worker
Jaitrong and Hashimoto (2012) - Measurements. Paratypes (n = 2): TL 2.00–2.05 mm; HL 0.48–0.50 mm; HW 0.39–0.40 mm; SL 0.28 mm; ML 0.63 mm; PL 0.14 mm; CI 78–84; SI 69–71. Non-type workers (n = 6): TL 1.95–2.60 mm; HL 0.50–0.58 mm; HW 0.38–0.50 mm; SL 0.26–0.35 mm; ML 0.58–0.80 mm; PL 0.13–0.19 mm; CI 75–89; SI 68–72.

Paratypes and non-types - Head in full-face view rectangular, clearly longer than broad, with almost parallel sides and shallowly concaved posterior margin. Antennal scape reaching midlength of head; antennal segment II longer than broad; III–IX each broader than long; terminal segment (X) distinctly longer than broad and 2.1 times as long as broad. Frontal carina very short, not extending beyond the level of posterior margin of torulus. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 1–4 denticles and a medium-sized basal tooth; basal margin with 2–3 small denticles.Mesosoma seen in profile almost flat or weakly convex dorsally; suture between mesopleuron and metapleuron present; metanotal groove indistinct; metapleural gland bulla large and transparent; distance between propodeal spiracle and metapleural gland bulla shorter than or almost as long as spiracular diameter (Fig. 1D). Propodeal junction obtusely angulated; declivity of propodeum with lateral carinae, but not demarcated basally by a transverse carina. Petiole excluding subpetiolar process almost as long as high, with its dorsal outline convex; subpetiolar process large, rectangular; anterior corner and posterior corner each acutely angulate. Postpetiole higher than long, slightly smaller than petiole and its dorsal outline convex. Femora and tibiae incrassate and widened.

Head including mandible and antennal scape smooth and shiny; promesonotum, dorsa of petiole and postpetiole smooth and shiny; mesopleuron densely reticulate, but shiny; metapleural gland bulla almost smooth and shiny; lateral faces of propodeum, petiole, and postpetiole weakly microreticulate. Legs entirely smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs mixed with sparse short hairs over the surface; longest pronotal hair 0.05 mm long. Ground color yellow.

Additional References

 * Jaitrong, W. & Hashimoto, Y. 2012. Revision of the Aenictus minutulus species group (Hymenoptera Formicidae Aenictinae) from Southeast Asia. Zootaxa 3426, 29-44.