Myrmoteras opalinum

The two nests were found in soil, in a lowland forest in southern Thailand.

Identification
Bui, Eguchi and Yamane (2013) - This is a relatively small species, easily separated from other Indo-Chinese congeners by the milk- white colour of the coxae and femora of the mid- and hind legs, and the femora of all legs that are distinctly paler than the tibiae.

Distribution
Southern Thailand

Distribution based on Regional Taxon Lists
Oriental Region: Thailand.

Nomenclature

 *  opalinum. Myrmoteras opalinum Bui, Eguchi & Yamane, 2013: 553, fig. 7 (w.) THAILAND.

Worker
TL 3.5–4.0, HL 1.04–1.10 (1.06), HW 1.02–1.10 [1.08] (1.06), EL 0.65– 0.69 [0.67] (0.67), ML 1.31–1.37 (1.34), SL 1.21–1.30 [1.29] (1.27), PrW 0.63–0.67 (0.67), HfL 1.31–1.40 (1.37), CI 96–102 [98] (99), SI 118–120 (119). (Holotype and 5 paratype and non-type workers were measured.)

Head and mesosoma brown, slightly with reddish tinge; petiole and gaster dark brown; mid- and hind coxae and femora whitish yellow; femora of all legs distinctly paler than tibiae. Body with erect hairs; dorsum of head and pronotum and first gastral tergite with pubescence; lateral face of gastral tergite I and II with sparse pubescence (often abraded away). Clypeus and lower frons densely rugoso-punctate; area around antennal insertion finely rugoso-striate. Anteriormost part of pronotum with faint, transverse rugoso-punctatation, and remainder portion smooth or faintly and sparsely punctate; dorsum of mesonotum longitudinally or irregularly rugose; lateral face of mesonotum with several irregular rugae; mesopleuron, metapleuron and lateral face of propodeum smooth or faintly and sparsely punctured; dorsum of propodeum with faint, transverse rugoso-punctation. Frontal sulcus faint but reaching median ocellus (sometimes interrupted); anterior clypeal margin concave; mandible with 8 teeth that reduce in size from apical to basal teeth; two denticles present between first and second teeth; palp formula 6,4; orbital groove absent; scape distinctly shorter than funicular segments combined; funicular segments each longer than broad. Pronotum in lateral view with flat dorsal outline; mesonotum as long as high; propodeum in lateral view roundly convex posterodorsally. Petiolar node in lateral view with vertical anterior face and steep posterior slope; ventral outline of petiole beneath the node slightly sinuate.

Type Material
Holotype worker from southern Thailand, Surat Thani Province, Tai Rom Yen NP., nest in soil, 12 x 2011, leg. Sk. Yamane (TH11-SKY-045) THNMH. Paratypes: 9 workers from the same colony as holotype; 7 workers from the same locality, 12 x 2011, leg. Sk. Yamane (TH11-SKY-50) [,, THNHM, , VNMN

Etymology
The specific name refers to the milk-white colour of the coxae and femora of the mid- and hind legs.

References based on Global Ant Biodiversity Informatics

 * Zryanin V. A. 2015. Important supplements to the ant fauna of Vietnam. Proceedings of the 10th ANeT International Conference, 23-26 October 2015, University of Kelaniya, Sri Lanka. 24.