Aenictus gonioccipus, 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 : 189-191

Aenictus gonioccipus sp. n. Fig. 9A-C

Type material examined.

Holotype. INDONESIA: Worker from Sulawesi, Minasha Prov., Dumoga Bone N.P., E-Side, vic. Duluduo, 0˚35'N 124˚54'E, 100 m alt., 4-9.XII.2000, leg. A. Schulz, 598 (MHMW). Paratypes. Four workers, same data as holotype (MHMW).

Worker measurements

(holotype and paratypes, n = 5). TL 3.05-3.25 mm; HL 0.63-0.65 mm; HW 0.60-0.63 mm; SL 0.50-0.53 mm; ML 1.05-1.08 mm; PL 0.25-0.28 mm; CI 96; SI 83-88.

Worker description

(holotype and paratypes). Head in full-face view slightly longer than broad, sides weakly convex and posterior margin almost straight; occipital margin bearing a distinct carina; with head in profile occipital corner angulate, nearly right-angled. Antennal scape reaching 2/3 of head length. Frontal carina relatively short, not reaching the level of posterior margin of torulus. Parafrontal ridge incomplete. Anterior clypeal margin concave, lacking denticles and concealed by curved anterior extension of frontal carina. Masticatory margin of mandible with large acute apical tooth followed by a medium-sized subapical tooth, 4-5 denticles, and a medium-sized basal tooth; basal margin weakly concave. Maximum width of gap between anterior clypeal margin and mandibles about 2.3 times as broad as maximum width of mandible. Promesonotum strongly convex dorsally and sloping gradually to metanotal groove that is indistinct; mesopleuron not clearly demarcated from metapleuron. Propodeum in profile with weakly convex dorsal outline; propodeal junction developed into a high, thin transverse ridge, which in profile appears a large, acute tooth overhanging propodeal declivity; the declivity shallowly concave, and encircled with a rim; metapleural gland bulla relatively small, its maximum diameter about 2.1-2.5 times as long as distance between propodeal spiracle and metapleural gland bulla. Petiole subsessile, almost as long as high but its node short, with dorsal outline elevated posteriorly; subpetiolar process generally very low, subrectangular with its anteroventral and posteroventral corners angulate, and margin between the corners almost straight. Postpetiole slightly longer than petiole, with its dorsal outline convex.

Head and gaster smooth and shiny; basal half of antennal scape densely microreticulate but apical half superficially microreticulate and shiny; mandible finely striate. Promesonotum smooth and shiny except for anteriormost portion reticulate and posteriormost portion punctate; mesopleuron, metapleuron, and propodeum entirely reticulate; in addition, mesopleuron with 4-5 longitudinal rugae. Petiole entirely reticulate; postpetiole reticulate (the reticulation weaker than in petiole) except its dorsum smooth and shiny. Basal 1/3 and apical 1/3 of femora sculptured, median swollen area smooth and shiny; tibiae microreticulate, partly smooth and shiny.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with dense decumbent hairs; longest pronotal hair 0.28-0.30 mm long. Head and gaster reddish brown; antenna, mesosoma, petiole and postpetiole dark reddish brown; legs reddish brown to dark reddish brown.

Etymology.

The specific name refers to the angulated occipital corner seen in profile.

Distribution.

Sulawesi ( Fig. 26A ).

Bionomics.

So far this species has been known only from the type locality located in the lowland (100 m alt.).

Remarks.

Aenictus gonioccipus is a distinct species and can be separated from the other members of the group by having the posterolateral corner of head in profile angulated and nearly right-angled (corner is rounded in the other species).

Figures

Figure 9. Aenictus gonioccipus (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.