Aenictus breviceps

Identification
A member of the laeviceps species group.

Jaitrong and Yamane (2011) - This species has been confused with the closely related Aenictus laeviceps, and has been synonymized with it in the past. However, it can be distinguished from the latter as follows: mesonotum, metanotum, and propodeum partly smooth and shiny in A. breviceps (entirely punctate in A. laeviceps); propodeal junction rounder than in A. laeviceps; pronotum with 2–4 hairs (without hairs in A. laeviceps, but in 2 colonies, SU07-SKY-199 and SU08-Kei282, from Sumatra pronotum with 2 standing hairs). A. breviceps is also quite similar to Aenictus sonchaengi and Aenictus rotundicollis, all sharing the same number of standing hairs (2) on the vertex. However, this species is separated from A. sonchaengi by the condition of hairs on the pronotum (2–4 standing hairs in A. breviceps; more than 4 hairs in A. sonchaengi). A. breviceps and A. rotundicollis share the pronotum with 2–4 standing hairs, but the promesonotum in profile is much more weakly convex in A. breviceps than in A. rotundicollis and A. sonchaengi. Aenictus laeviceps occurs from eastern Thailand to the Philippines except on Java, and sympatric with A. sonchaengi in southern Thailand and Borneo, and with A. rotundicollis in Borneo. Aenictus breviceps, on the other hand, is confined to Java.

Key to Aenictus species groups

Distribution
This taxon was described, and is only known, from Java Indonesia.

Nomenclature

 *  breviceps. Aenictus fergusoni var. breviceps Forel, 1912d: 105 (w.) INDONESIA (Java). Junior synonym of laeviceps: Wilson, 1964a: 467. Revived from synonymy and raised to species: Jaitrong & Yamane, 2011: 32.

Worker
Jaitrong and Yamane (2011) - Measurements. Worker lectotype and paralectotypes (n = 7): TL 3.75–3.95 mm; HL 0.80–0.85 mm; HW 0.70–0.75 mm; SL 0.70–0.73 mm; ML 1.25–1.27 mm; PL 0.25–0.28 mm; CI 85–94; SI 96–103.

Redescription(lectotype and paralectotypes). Head in full-face view slightly longer than broad, with sides and posterior margin slightly convex; occipital margin carinate, but not forming a collar. Antenna long; scape relatively long, almost reaching the posterolateral corner of head; antennal segments II–X each longer than broad, II almost as long as each of III and IV. Frontal carina short, not extending beyond the posterior margin of torulus; parafrontal ridge absent. Anterior margin of clypeus bearing 7–8 denticles. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 4–6 denticles and a medium-sized basal tooth; basal margin bearing 1–2 denticles. Promesonotum in profile convex dosally; propodeum distinctly lower than promesonotum, and in profile its dorsal outline almost straight; propodeal junction angulate; with propodeum in profile declivity straight. Petiole almost as long as high, in profile its dorsal outline weakly convex; subpetiolar process well developed, its lobe surmounted by a thin, acute flange that is directed downward and backward; postpetiole almost as long as petiole, with its node strongly convex dorsally.

Head entirely smooth and shiny. Mandible punctate except on masticatory and outer margins. Antennal scape shagreened with smooth and shiny interspaces. Pronotum smooth and shiny, its anteriormost portion punctate, and lateral face irregularly sculptured in anterior portion; mesopleuron sculptured; anepisternum with several irregular longitudinal rugulae, while katepisternum with dense punctures; metapleuron almost smooth and shiny except for posterior portion punctate; propodeal dorsum almost smooth and shiny except for areas in front of propodeal junction which is macroreticulate with smooth and shiny bottoms; area below propodeal spiracle punctate. Petiole shagreened with smooth and shiny interspaces. Postpetiole entirely very superficially microsculptured and shiny.

Head with a pair of standing hairs on vertex; mesosoma with 2–3 standing hairs on promesonotum. Entire body dark reddish-brown. Typhlatta spot located anterior to occipital corner.

Type Material
Jaitrong and Yamane (2011) - Aenictus fergusoni var. breviceps: Seven syntype workers on three pins (one on a pin, three on another, three on the other) from Java, Gunung Gedeh (, examined). One worker among them (middle on a pin) is selected as the lectotype, the others as paralectotypes.

Additional References

 * Forel, A. 1912. Ameisen aus Java beobachtet und gesammelt von Edward Jacobson. 3 Theil. Notes from the Leyden Museum, 34, 97–112.
 * Jaitrong, W. & Yamane, S. 2011. Synopsis of Aenictus species groups and revision of the A. currax and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae). Zootaxa, 3128, 1–46.