Aenictus glabrinotum

The type series and non-type material examined were collected from lowland rainforests.

Identification
Jaitrong and Yamane (2011) - A. glabrinotum is a distinct species of the A. currax group in having very few standing hairs on the head and promesonotum.

Key to Aenictus species groups / Key to Aenictus currax group species

Distribution
Borneo (Sabah, Sarawak, and E. Kalimantan).

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

Castes
Known only from the worker caste.

Nomenclature

 *  glabrinotum. Aenictus glabrinotum Jaitrong & Yamane, 2011: 16, figs. 5-7 (w.) BORNEO.

Worker
Measurements. Holotype and paratype workers (n = 6): TL 3.10–4.05 mm; HL 0.75–0.90 mm; HW 0.62–0.83 mm; SL 0.43–0.70 mm; ML 1.00–1.37 mm; PL 0.28–0.33 mm; CI 83–94; SI 68–85.

(holotype and paratypes). Head in full-face view slightly longer than broad, with sides slightly convex and posterior margin concave; occipital carina complete, not interrupted medially. Antennal scape relatively short, extending slightly beyond midlength of head; 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. Parafrontal ridge absent. Anterior margin of clypeus lacking denticles; median portion of clypeal margin almost straight or feebly concave. Masticatory margin of mandible with a large apical tooth followed by a small subapical tooth and 3–4 denticles, which are only slightly smaller than subapical teeth; basal margin bearing 3–4 denticles. Promesonotum in profile weakly convex dorsally and sloping to metanotal groove. Propodeum in profile with almost straight or feebly convex dorsal outline; propodeal junction rounded; declivity of propodeum shallowly concave, and encircled with a thin rim; area below propodeal spiracle distinctly impressed; opening of propodeal spiracle clearly circular with its diameter about 1.6 times as long as diameter of postpetiolar spiracle. Petiole clearly longer than high, with its dorsal outline convex; subpetiolar process relatively low, with its ventral outline straight or weakly convex, and anteroventral corner bluntly produced or roundly angled. Postpetiole almost as long as petiole and clearly longer than high.

Head entirely smooth and shiny; mandible extensively smooth, without fine striation; antennal scape dorsally smooth and ventrally superficially sculptured. Pronotum smooth and shiny except the anterior portion punctate; mesonotum smooth and shiny; mesopleuron finely and densely punctate; metapleuron and lateral face of propodeum with fine rugulae and very minute sculpture but partly smooth; dorsum of propodeum smooth and shiny. Petiole with dorsal surface smooth and shiny, and anterior and lateral faces finely punctate. Postpetiole entirely smooth and shiny. Legs smooth and shiny.

Head with one or two long hairs on vertex (often completely hairless); ventral surface of head also with few (often no) standing hairs. Dorsum of mesosoma usually without standing hairs. Petiole and postpetiole each with only a pair of standing hairs. Hairs on hind femur very short, never overlapping each other; mid and hind tibiae with short appressed hairs only. Entire body dark reddish-brown, with a relatively large typhlatta spot on occipital corner; anterior border of the spot diluted into ground color.

Type Material
Holotype. Worker from Borneo, Sabah, Danum Valley, 29 IV 2000, C. Brühl leg. CB-00-05 (UMS). Five paratype workers, same data as holotype.

Etymology
The specific name is a noun meaning the (promeso)notum without standing hairs.