Aenictus baliensis, Jaitrong & Yamane, 2013

Jaitrong, Weeyawat & Yamane, Seiki, 2013, The Aenictus ceylonicus species group (Hymenoptera, Formicidae, Aenictinae) from Southeast Asia, Journal of Hymenoptera Research 31, pp. 165-233 : 173-175

Aenictus baliensis sp. n. Fig. 2A-C

Type material examined.

Holotype. INDONESIA: Worker from Bali, Ubud, Aji Lodge, 23.IV.1998, leg. K. Eguchi, Eg98-BALI-650 (MZB). Paratypes. Six workers, same data as holotype (SKYC, THNHM) and seventeen workers from Indonesia, Bali, Ubud, Aji Lodge, 23-24.IV.1998, leg. Sk Yamane (SKYC, THNHM).

Worker measurements

(holotype and paratypes, n = 7). TL 2.10-2.70 mm; HL 0.50-0.55 mm; HW 0.38-0.48 mm; SL 0.30-0.40 mm; ML 0.68-0.80 mm; PL 0.18-0.20 mm; CI 75-86; SI 79-86.

Worker description

(holotype and paratypes). Head in full-face view subrectangular, clearly longer than broad, sides weakly convex, posterior margin straight; occipital margin bearing a distinct carina. Antennal scape relatively short, not reaching 2/3 of head length. Frontal carina relatively long, slightly extending beyond the level of posterior margin of torulus. Parafrontal ridge absent. Anterior clypeal margin concave, concealed by curved anterior extension of frontal carina. Masticatory margin of mandible with large acute apical tooth followed by a medium-sized subapical tooth, 4 denticles, and a medium-sized basal tooth; basal margin almost straight. Maximum width of gap between anterior clypeal margin and mandibles about 1.8 times as broad as maximum width of mandible. Promesonotum weakly convex dorsally and sloping gradually to metanotal groove; mesopleuron relatively long, demarcated from metapleuron by indistinct groove; metapleural gland bulla relatively large, its maximum diameter about 2.4 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile with feebly convex dorsal outline; propodeal junction angulate, nearly right-angled; declivity of propodeum widely and shallowly concave, encircled with a rim. Petiole slightly longer than high, with its dorsal outline convex; subpetiolar process low and subrectangular. Postpetiole shorter than petiole, with its dorsal outline roundly convex.

Head including mandible and antennal scape entirely smooth and shiny. Promesonotum smooth and shiny except for anteriormost portion punctate; propodeal dorsum and metapleuron smooth and shiny; mesopleuron and lateral face of propodeum shagreened; petiole entirely smooth and shiny except for lateral face superficially reticulate; postpetiole smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs; longest pronotal hair 0.15-0.18 mm long. Head, petiole, gaster, and legs yellowish brown; mesosoma reddish brown.

Etymology.

The specific name is after the type locality, Bali Island of Indonesia.

Distribution.

Bali ( Fig. 26A ).

Bionomics.

So far this species has been known only from the type locality near a lowland secondary forest.

Remarks.

Aenictus baliensis is similar to Aenictus longicephalus , Aenictus minipetiolus and Aenictus wiwatwitayai in having a mandible with more than 4 teeth and smooth and shiny propodeum. It is most similar in general appearance to Aenictus minipetiolus , but can be separated from the latterby the straight basal margin of the mandibles (distal 2/3 of basal margin of mandible straight, proximal 1/3 sloping gradually to the base of mandible in the latter), pronotum with dense standing hairs (a few hairs, less than 10 in the latter), and body size being smaller than in the latter (TL 2.10-2.70 mm, HW 0.38-0.48 mm in Aenictus baliensis ; TL 2.70-3.10 mm, HW 0.54-0.65 mm in Aenictus minipetiolus ).

Figures

Figure 2. Aenictus baliensis (holotype). A Head in full-face view B body in dorsal view C body in profile.

Figure 26. Distribution of Aenictus ceylonicus group. A Aenictus baliensis, Aenictus gonioccipus, Aenictus longicephalus, Aenictus minipetiolus, Aenictus pilosus B Aenictus appressipilosus, Aenictus cylindripetiolus, Aenictus itoi, Aenictus jawadwipa, Aenictus sundalandensis.