Aenictus montivagus

Judging from the type series and non-type material examined this species inhabits highland forests (1000–1600 m alt.). Most colonies were encountered in the daytime.

Identification
This species is most similar to Aenictus hodgsoni in body shape but can be distinguished from it as follows: mesopleuron, metapleuron and propodeum entirely sculptured, with about 20 fine longitudinal rugulae, except for a small smooth area above the propodeal spiracle (dorsal face of propodeum more extensively smooth and shiny in the latter); subpetiolar process weakly developed and low (well developed and triangular in the latter); declivity of propodeum encircled with a very thin rim (declivity without a rim and seen from back tapering above in the latter); legs entirely smooth and shiny (femora extensively superficially reticulate and shiny, and tibiae very finely reticulate in the latter).

Distribution
This taxon was described from Borneo, (Sabah, Malaysia).

Nomenclature

 *  montivagus. Aenictus montivagus Jaitrong & Yamane, 2011: 41, figs. 54-56 (w.) BORNEO.

Worker
Measurements. Worker holotype and paratypes (n = 9): TL 3.70–4.00 mm; HL 0.73–0.78 mm; HW 0.63–0.68 mm; SL 0.60–0.68 mm; ML 1.13–1.20 mm; PL 0.28–0.30 mm; CI 87–90; SI 92–100.

Holotype and paratypes - Head in full-face view longer than broad, with sides and posterior margin slightly convex; occipital carina complete. Antennal scape relatively short, extending only slightly beyond 2/3 of head length; antennal segments II–X each longer than broad; II almost as long as each of III–VI. Frontal carina very short, not extending beyond the level of posterior margin of torulus. Anterior margin of clypeus bearing 6–7 denticles. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 4 denticles and a medium-sized basal tooth; basal margin bearing 3–4 smaller teeth. Promesonotum in profile convex dosally; propodeum slightly lower than promesonotum, and its dorsal outline almost straight; propodeal junction roundly angulate; declivity of propodeum shallowly concave, encircled with a very thin rim. Petiole distinctly longer than high, dorsally weakly convex; subpetiolar process weakly developed and low, its apex directed downward; postpetiole distinctly shorter than petiole.

Head including mandible and antennal scape entirely smooth and shiny. Pronotum smooth and shiny, with its anteriormost portion punctate; mesothorax, metapleuron and propodeum entirely sculptured, the sculpture comprising ca. 20 fine longitudinal rugulae, but often with dense punctures; a small smooth area present near spiracle. Petiole and postpetiole entirely smooth. Legs entirely smooth and shiny.

Hairs on dorsa of head and pronotum more abundant than in other species; mesonotum and propodeum dorsally with several standing hairs; longest pronotal hair 0.23–0.25 mm long. Entire body dark reddish-brown. Typhlatta spot smaller than in other species, located anterior to occipital corner.

Type Material
Holotype worker from Borneo, Sabah, Taman Kinabalu, 1,500 m alt., 7 I 1998, Sk. Yamane leg., SB98- SKY-05 (UMS). Eight paratype workers, same data as holotype and 12 paratype workers from Borneo, Sabah, Kinabalu Park, 1,600 m alt., 6 II 2001, Sk. Yamane leg., SB01-SKY-03 (SKYC, THNHM).

Etymology
The specific name is an adjective pertaining wondering in the mountain.