Aenictus philippinensis Chapman, 1963

Jaitrong, Weeyawat & Yamane, Seiki, 2012, Review of the Southeast Asian species of the Aenictus javanus and Aenictus philippinensis species groups (Hymenoptera, Formicidae, Aenictinae), ZooKeys 193, pp. 49-78 : 66-68

Aenictus philippinensis Chapman, 1963 Figs 912

Aenictus philippinensis Chapman 1963: 247, fig. 2.

Types.

Syntype workers from Philippines, Negros, Horns of Negros, 450 and 1,080 m (MCZC). We did not examine the type material of this species but specimens of a single colony from the type locality (Philippines, Negros) were examined.

Measurements.

Non-type workers (n = 10): TL 3.70-4.00 mm; HL 0.83-0.88 mm; HW 0.74-0.80 mm; SL 0.55-0.60 mm; ML 1.18-1.25 mm; PL 0.26-0.33 mm; CI 89-91; SI 74-77.

Description of worker.

Head in full-face view subretangular, slightly longer than broad, with sides weakly convex and posterior margin almost straight; occipital margin forming a narrow carina; seen in profile occipital corner of head rounded. Antennal scape relatively short, reaching only 2/3 of head length; antennal segment II almost as long as each of III-VI; terminal segment almost as long as VII+VIII+IX. Frontal carinae fused at the level of antennal base to form a single carina and extending beyond the level of the posterior margin of torulus, poorly developed in posterior half. Parafrontal ridge relatively long, extending less than 1/3 of head length, 0.25-0.28 mm long. Masticatory margin of mandible with a large apical tooth followed by a series of 6-7 denticles of same size. Mesosoma in profile with dorsally convex promesonotum and sloping gradually to metanotal groove; metanotal groove distinct and deep; mesopleuron relatively short, clearly dermacated from metapleuron by a deep groove; propodeum lower than mesonotum, weakly convex dorsally; propodeal junction right-angled; declivity of propodeum shallowly concave, encircled with a distinct rim. Petiole subsessile, slightly longer than high; subpetiolar process very low, its anteroventral corner bluntly angulate; postpetiole slightly longer than petiole and slightly longer than high, with its dorsal outline convex. Legs relatively long with apical halves of femora and tibiae somewhat swollen.

Head superficially reticulate and shiny; mandible very finely striate except along masticatory margin; antennal scape superficially shagreened. Promesonotum finely macroreticulate except dorsal face largely smooth and shiny; mesopleuron, metapleuron, and propodeum densely punctate/reticulate. Both petiole and postpetiole punctate except dorsal face of the latter smooth and shiny. Femora entirely superficially reticulate and shiny, partly smooth and shiny; tibiae weakly punctate.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with short hairs over surface; longest pronotal hair 0.17-0.20 mm long. Entire body reddish brown.

Non-type material examined.

Philippines: Negros Oriental, near Dumaguete, Apolong, Valencia, 26.XII.1998, Sk. Yamane leg., PH98-SKY-05 (SKYC, THNHM).

Distribution.

Philippines (Negros) (Fig. 12).

Bionomics.

Aenictus philippinensis is very probably restricted to the Philippines and probably sympatric with Aenictus rabori in at least Negros Oriental. Wilson (1964) cited the observation by Chapman: "the workers of a colony came from the hole in the ground, climbed up a nearby stump, and spent the next hour in which they were observed building a living pyramid in the center of the stump. Some tried to build out from the edge of the stump in a horizontal direction." We found a colony under a stone near a road.

Remarks.

Aenictus philippinensis is similar to Aenictus punctatus as they have sculptured head and mandible. However, they differ in some characters. The sculpturing on the head is much weaker in Aenictus philippinensis (superficially reticulate and shiny) than in Aenictus punctatus (finely punctate). Pronotal dorsum is smooth and shiny in Aenictus philippinensis , but finely punctate in Aenictus punctatus . Propodeal declivity is dorsally margined with a low rim in Aenictus philippinensis ; the rim is much more developed, in profile distinctly protruding posteriad in Aenictus punctatus .