Aenictus khaoyaiensis

This species inhabits both lowland primary and disturbed forests.

Identification
A member of the ceylonicus group. Aenictus khaoyaiensis is similar to Aenictus watanasiti.

Distribution based on Regional Taxon Lists
Oriental Region: Thailand.

Castes
Known only from the worker caste.

Nomenclature

 *  khaoyaiensis. Aenictus khaoyaiensis Jaitrong & Yamane, 2013: 194, figs. 10A-C (w.) THAILAND.

Worker
(holotype and paratypes, n = 10). TL 2.45–3.00 mm; HL 0.50–0.60 mm; HW 0.48–0.60 mm; SL 0.38–0.43 mm; ML 0.78–0.93 mm; PL 0.21–0.25 mm; CI 95–100; SI 65–79.

Head in full-face view subrectangular, almost as long as broad, sides weakly convex, posterior margin almost straight or feebly concave. Antennal scape relatively short, slightly extending beyond 1/2 of head length. Frontal carina relatively long, slightly extending beyond the level of posterior margin of torulus. Parafrontal ridge almost absent. Anterior clypeal margin feebly concave, concealed by curved anterior extension of frontal carina. Masticatory margin of mandible with 4 denticles, including a large apical tooth; basal margin feebly concave. Maximum width of gap between anterior clypeal margin and mandibles about 2.8 times as broad as maximum width of mandible. Promesonotum strongly convex dorsally and sloping gradually to metanotal groove; mesopleuron demarcated from metapleuron by a shallow groove; metapleural gland bulla relatively large, its maximum diameter 2.3–2.8 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile extremely lower than pronotum and relatively short with feebly convex dorsal outline; propodeal junction angulate, overhanging the declivitous face of propodeum; the declivity broadly and shallowly concave, encircled with a distinct rim. Petiole almost as long as high, with its dorsal outline slightly elevated posteriorly; subpetiolar process low, with its anteroventral corner angulate and ventral margin weakly convex. Postpetiole subrectangular, almost as long as petiole, with its dorsal outline slightly elevated posteriorly.

Head entirely smooth and shiny. Mandible very finely striate. Antennal scape superficially sculptured but somewhat shiny. Promesonotum smooth and shiny except for anteriormost portion punctate; mesopleuron wrinkled and reticulate; in addition mesopleuron with several irregular longitudinal rugae; metapleuron reticulate partly smooth and shiny; petiole entirely reticulate; postpetiole reticulate except for dorsal faces smooth and shiny. Legs smooth and shiny except basalmost portions of femora and tibiae micropunctate.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with relatively dense decumbent hairs; longest pronotal hair 0.18–0.20 mm long. Head including mandible and antennal scape, gaster and legs yellowish brown; mesosoma, petiole and postpetiole reddish brown but petiole and postpetiole paler than mesosoma.

Type Material
Holotype. THAILAND: Worker from NE. Thailand, Nakhon Ratchasima Prov., Khao Yai N.P., tropical rainforest, 31.V.2000, leg. Sk. Yamane, TH00-SKY-35 (THNHM). Paratypes. Forty-four workers, same data as holotype (BMNH, MCZC, SKYC, THNHM).

Etymology
The specific name is after the type locality, Khao Yai National Park, northeastern Thailand.