Anillomyrma decamera

Eguchi et al. (2009) - K. Eguchi and V.T. Bui collected workers of Anillomyrma decamera in a well-developed dry forest in the southern coastal part of Vietnam, by underground bait-trapping; baits (pork sausage) were buried in sandy soil. On the other hand, J. Caceres, a colleague of D.M. General, collected A. decamera in abandoned agricultural land that had isolated stands of abaca plants (Musaceae: Musa textilis NÉE) and jackfruit trees (Moraceae: Artocarpus heterophyllus LAM.), and was overgrown with tall grasses, upright and creeping bamboos and tree ferns. Ant samples were obtained by sifting a soil core sample taken from a deep sandy loam of volcanic origin. Bolton (1987) collected A. tridens on sandy ground in a lowland rain forest. These facts suggest that the distribution of this species may be affected by soil type. Emery (1901) mentioned that the type material of A. decamera was collected from termite nest(s). Anillomyrma may actively hunt soil invertebrates, including termites, using its well-developed sting to envenomate prey, and it may also scavenge animal matter under the ground.

Identification
Eguchi et al. (2009) - Body sculpture absent except for hair-pits, which are most conspicuous on head and pro-mesonotum; dorsum of head, promesonotum and gaster relatively densely covered with short suberect to decumbent hairs. Head in full-face view roughly rectangular, longer than broad; mandible with 4 distinct teeth of which basal one is smaller than the others and 3rd almost as large as 2nd (preapical tooth); antennal scape short, reaching only 7 / 10 - 3 / 4 of distance from anterior margin of clypeus to posterior margin of head; apical antennal segment more than 3 times as long as preapical segment. Dorsum of mesosoma in lateral view flat; posterior slope of propodeum in lateral view hardly expanding posterodorsad. Petiolar peduncle in lateral view gradually thickened toward node.

Anillomyrma tridens is morphologically very similar to Anillomyrma decamera. The only conspicuous morphological characters separating the two species are as follows: head slightly longer than broad, masticatory margin of mandible of A. tridens having 3 distinct teeth as mentioned by Bolton (1987) (but very small 4th tooth rarely present); the 3rd tooth of A. tridens much larger than 2nd; posterior slope of propodeum in lateral view ex-panding posterodorsad more strongly in A. tridens than in A. decamera; petiolar peduncle in lateral view more slender in A. tridens than in A. decamera.

Distribution
Eguchi et al. (2009) - India: Bihar (Bolton 1987). Sri Lanka: Anuradhapura. Vietnam: Ba Ria – Vung Tau; “Van Phu”. China: “Jungshan”. Philippines: Luzon.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Philippines. Oriental Region: India, Sri Lanka, Taiwan, Vietnam. Palaearctic Region: China.

Biology
Very rare subterranean ants.

Hosoishi et al. (2015) collected workers of this species by Winkler extraction in a lowland forest in Koh Kong Province, Cambodia. Among the Indochinese fauna, A. decamera is known from Vietnam (Eguchi et al., 2011). The collected specimens agree well with the description of A. decamera in having the 4-toothed masticatory margin of the mandible, and the posterior slope of propodeum weakly expanding posterodorsad (Eguchi et al., 2011).

Castes
Known only from the worker caste.

Nomenclature

 *  decamera. Monomorium decamerum Emery, 1901e: 117 (w.) SRI LANKA. Combination in Monomorium (Anillomyrma): Emery, 1913b: 261; in Anillomyrma: Ettershank, 1966: 98. Senior synonym of continentis: Eguchi, Bui, et al. 2009: 33. See also: Bolton, 1987: 274.
 * continentis. Anillomyrma decamera subsp. continentis Wheeler, W.M. 1927h: 96 (w.) VIETNAM. Junior synonym of decamera: Eguchi, Bui, et al. 2009: 33.

Worker
Eguchi et al. (2009) - Type material (3 syntype workers of “Anillomyrma decamera ssp. continentis”, but 2 measured for PW and WL): CI 79 - 82, HL 0.34 - 0.35 mm, HW 0.27 - 0.29 mm, PW 0.19 mm, SI 66 - 67, SL 0.18 - 0.19 mm, WL 0.46 - 0.48 mm; Vietnamese material (5 workers from BTN16xii08-18): CI 80 - 83, HL 0.37 - 0.38 mm, HW 0.30 - 0.32 mm, PW 0.21 - 0.23 mm, SI 67 - 72, SL 0.21 - 0.22 mm, WL 0.46 - 0.48 mm; Philippine material (3 workers from Isarog): CI 83 - 87, HL 0.33 - 0.37 mm, HW 0.28 - 0.32 mm, PW 0.19 - 0.22 mm, SI 61 - 65, SL 0.18 - 0.19 mm, WL 0.43 - 0.47 mm; Chinese material (3 workers from Jungshan, but 2 measured for WL): CI 85 - 86, HL 0.34 - 0.35 mm, HW 0.29 - 0.30 mm, PW 0.20 - 0.22 mm, SI 66 - 67, SL 0.20 mm, WL 0.47 mm.

Type Material
Eguchi et al. (2009) - Syntype workers, Sri Lanka: Anuradhapura, W. Horn leg., 1899,. Two syntypes examined.