Aenictus pfeifferi

Inhabits primary rainforests from 40 to 700 m elevation.

Identification
Jaitrong and Yamane (2011) - A member of the currax group. This species is very similar to Aenictus currax, Aenictus diclops, Aenictus huonicus, Aenictus parahuonicus and Aenictus wayani. However, it is easily separated from them by the head having only 2 standing hairs on the vertex (in the others the head with some shorter standing hairs in addition to two long hairs on vertex) and long pronotal hairs shortest (0.23–0.25 mm) among the members of this group (except in A. glabrinotum that has no hairs on promesonotum) (see A. huonicus).

Key to Aenictus species groups

Distribution
Known from Borneo (Sabah and Sarawak).

This taxon was described from Borneo.

Nomenclature

 *  pfeifferi. Aenictus pfeifferi Zettel & Sorger, 2010b: 116, figs. 1-4, 13 (w.) BORNEO. See also: Jaitrong & Yamane, 2011: 21.

Worker
Jaitrong and Yamane (2011) - Measurements (n = 10 including the four paratypes): TL 4.35–5.20 mm; HL 0.93–1.13 mm; HW 0.80–1.03 mm; SL 0.60–0.88 mm; ML 1.35–1.75 mm; PL 0.33–0.38 mm; CI 86–93; SI 75–85.

Redescription of worker (Paratype and non-types). Head in full-face view slightly longer than broad, with sides slightly convex and posterior margin almost straight or feebly concave; occipital carina complete, not interrupted medially. Antennal scape extending only 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. Parafrontal ridge almost absent. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth and 5–6 denticles; basal margin with a series of ill-defined denticles. Mesosoma relatively elongate and stout; promesonotum in profile convex dorsally and sloping gradually to metanotal groove; mesopleuron clearly demarcated from metapleuron by a groove. Propodeum in profile with weakly 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 2.4–2.5 times as long as diameter of postpetiolar spiracle. Petiole slightly longer than high, with its dorsal outline convex; subpetiolar process weakly developed and triangular, with its ventral outline feebly convex, and anteroventral corner roundly angulate or produced. Postpetiole almost as long as petiole, with its dorsal outline convex.

Head entirely smooth and shiny; mandible finely striate in basal 1/2 to 2/3, and smooth in apical and peripheral parts; antennal scape dorsally smooth but ventrally sculptured. Pronotum smooth and shiny except for the anteriormost portion punctate; mesonotum smooth and shiny; mesopleuron macroreticulate, bearing several longitudinal rugae; metapleuron superficially sculptured and shiny. Propodeum dorsally entirely smooth and shiny; lateral face of propodeum wrinkled but shiny. Petiole and postpetiole entirely smooth and shiny. Legs smooth and shiny.

Vertex with a pair of long standing hairs; mesosoma dorsally with relatively sparse standing hairs mixed with sparse short decumbent hairs; longest pronotal hair 0.23–0.25 mm long. Hairs on legs generally short and appressed to surface; mid- and hind tibiae without outstanding long hairs on outer face; hairs on fore femur also short and decumbent. Entire body light brown to brown, with a rather large typhlatta spot on the occipital corner.

Type Material
Jaitrong and Yamane (2011) - The holotype and 74 paratype workers from Borneo, Sarawak, Gunung Mulu N.P. (four paratypes were examined,  and ).