Aenictus minutulus

This species has been collected from both primary and disturbed lowland rainforests.

Identification
A member of the minutulus species group. Aenictus minutulus is very similar in general appearance to Aenictus changmaianus and Aenictus minimus (see under Aenictus changmaianus for details).

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia.

Castes
Known only from the worker caste.

Nomenclature

 * . Aenictus minutulus Terayama & Yamane, 1989: 601, figs. 7-10 (w.) INDONESIA (Sumatra: Mentawei Is).
 * Status as species: Bolton, 1995b: 60; Pfeiffer, et al. 2011: 32; Jaitrong & Hashimoto, 2012: 36 (redescription); Wong & Guénard, 2016b: 37 (in key).

Worker
Jaitrong and Hashimoto (2012) - Measurements. Paratype workers (n = 2): TL 1.90–1.95 mm; HL 0.45 mm; HW 0.38–0.39 mm; SL 0.25–0.26 mm; ML 0.63 mm; PL 0.15–0.16 mm; CI 83–86; SI 67–68. Non-type workers (n = 10): TL 1.7–2.40 mm; HL 0.43–0.53 mm; HW 0.33–0.48 mm; SL 0.23–0.33 mm; ML 0.55–0.75 mm; PL 0.14–0.20 mm; CI 76–90; SI 65–71.

Paratypes - Head in full-face view rectangular, clearly longer than broad, with almost parallel sides and almost straight or weakly concave posterior margin. Antennal scape reaching midlength of head; antennal segment II longer than broad; III as long as broad; IV–VI each slightly broader than long; VII–IX each as long as broad and III slenderer than IV–VI; terminal segment longer than broad, 2.0 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, 1–2 denticles, and medium-sized basal tooth; basal margin with 3–4 small denticles. Mesosoma in profile almost straight dorsally; metanotal groove indistinct; metapleural gland bulla relatively small; distance between propodeal spiracle and metapleural gland bulla clearly longer than spiracular diameter (Fig. 4D). Propodeum in profile with straight dorsal outline; propodeal junction bluntly angulate; declivity of propodeum shallowly concave, seen from back distinctly convergent above, with lateral carinae, but not demarcated basally by a transverse carina. Petiole almost as long as high, with its dorsal outline convex; subpetiolar process large, subretangular, with anterior and posterior corners each acutely angulate. Postpetiole almost as long as petiole, its dorsal outline convex.

Head including mandible and antennal scape smooth and shiny; mesonotum and lateral face of propodeum microreticulate; remainder of mesosoma smooth and shiny. Dorsa of petiole and postpetiole smooth and shiny; lower 1/2 of lateral faces of petiole and postpetiole microreticulate and opaque. 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 0.10 mm long. Ground color light brownish yellow; antennae, legs and gaster yellow.

References based on Global Ant Biodiversity Informatics

 * Borowiec M. L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys 608: 1–280.
 * Jaitong W., and Y. Hashimoto. 2012. Revision of the Aenictus minutulus species group (Hymenoptera: Formicidae: Aenictinae) from Southeast Asia. Zootaxa 3426: 29-44.
 * Jaitrong W. 2015. A revision of the Thai species of the ant genus Aenictus Shuckard, 1840 (Hymenoptera: Formicidae: Dorylinae). The Thailand Natural History Museum Journal 9(1): 1-94.
 * Jaitrong, W., and Y. Hashimoto. "Revision of the Aenictus minutulus species group (Hymenoptera: Formicidae: Aenictinae) from Southeast Asia." Zootaxa 3426 (2012): 29-44.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
 * Terayama M.; Yamane, S. 1989. The army ant genus Aenictus (Hymenoptera, Formicidae) from Sumatra, with descriptions of three new species. Japanese Journal of Entomology 57:597-603.