Myrmoteras opalinum, Bui, Viet Tuan, Eguchi, Katsuyuki & Yamane, Seiki, 2013

Bui, Viet Tuan, Eguchi, Katsuyuki & Yamane, Seiki, 2013, Revision of the ant genus Myrmoteras of the Indo-Chiese Peninsula (Hymenoptera: Formicidae: Formicinae), Zootaxa 3666 (4), pp. 544-558 : 553-555

Myrmoteras opalinum sp. nov.

( Fig. 7 )

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) [ACEG, MHNG, THNHM, SKYC, VNMN].

Worker measurements and indices. 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.)

Worker description. 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 rugosopunctation. 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.

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

Remarks. This is a relatively small species, easily separated from other Indo-Chinese congeners by the milkwhite 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. The two nests were found in soil, in a lowland forest in southern Thailand.

Distribution. Southern Thailand.

Figures

FIGURE 7. Myrmoteras opalium sp. nov. Holotype worker. A. Head, full-face view; B. Head and mesosoma, dorsal view; habitus, profile. Tai Rom Yen NP, Surat Thani Prov., S Thailand, 12 / x / 2011, Sk. Yamane (TH 11 - SKY- 050).