Myrmoteras jaitrongi Bui, Eguchi & Yamane, 2013, sp. nov.

Myrmoteras jaitrongi sp. nov.

(Figs. 1 –B, 5)

Type material. Holotype worker from Thailand, Narathiwat Province, South-West Balahala: tropical rainforest, 7 xi 2002, leg. W. Jaitrong, WJT02-TH325 (THNHM-2002-3850) [THNHM]. Paratype: 1 worker from the same locality as holotype, 25 ix 2001, leg. S. Hasin 2001 [SKYC].

Non-type material examined. Malaysia: 6 workers from Selangor, Ulu Gombak, vii–x 1992, leg. F. Ito, FI92MG; 1 worker, same locality, ca. 250 m alt., 5 vii 1999, leg. Sk. Yamane.

Worker measurements and indices. TL 3.5, HL 0.98– 1.02 (1.00), HW 0.88– 0.94 (0.92), EL 0.62– 0.67 (0.65), ML 1.35– 1.42 (1.39), SL 1.12– 1.23 (1.17), PrW 0.54– 0.62 (0.58), HfL 1.17– 1.31 (1.24), CI 90– 92 (91), SI 126– 131 (128). (Holotype and 2 non-type workers were measured.)

Worker description. Body yellowish brown; gaster slightly darker than the mesosoma and petiole; legs yellowish. Body with sparse standing hairs, but without pubescence (clypeus with a few short appressed hairs). Clypeus weakly punctured or rugoso-punctate; frons mainly granulate, but area around antennal insertion finely rugoso-punctate; vertex of head (including occipital lobe) shining; frontal sulcus very feeble, visible as a very short trace running backward until the middle of frons. Anterior clypeal margin concave. Mandible with 9–10 teeth, and with two denticles between first and second teeth; third tooth much shorter than second and fourth teeth; palp formula 5,3. Orbital grooves virtually absent. Scape shorter than funicular segments combined. Funicular segments each longer than broad. Pronotum in lateral view with its dorsal outline gently sloping upward; dorsum of pronotum feebly punctured medially, almost smooth laterally; dorsum of mesonotum transversely and finely striate and its lateral face irregularly longitudinally or obliquely rugose; mesopleuron, metapleuron and propodeum smooth; metanotal groove shallow; propodeum in lateral view very weakly convex posterodorsally. Petiolar node round dorsally; ventral outline of petiole beneath the node slightly concave.

Etymology. The specific name is dedicated to Dr. Weeyawat Jaitrong, who offered us valuable material.

Remarks. Myrmoteras jaitrongi sp. nov. and M. barbouri Creighton, 1930 share the very small third tooth of mandible (called ‘the denticle between the penultimate tooth and the one proximad to it’ by Moffett, 1985). In this respect and the number of maxillary pulp segments (5), M. jaitrongi is closely related to M. barbouri, for which we could not examine the type material (Java). Our specimens may correspond to the smaller individuals of M. barbouri sensu Moffett (1985, p. 21) from the Malay Peninsula. However, M. jaitrongi differs from M. barbouri in the following respects: total body length including mandibles remarkably smaller (slightly more than 5 mm vs. 6.7–6.9 mm), dorsum of mesothorax rather regularly and transversely striate (irregularly or longitudinally rugose in M. barbouri), rugae on side of mesothorax more distinct in its posterior portion than in anterior portion (according to Creighton, 1930, five rugae present extending across the anterior half of the sides in M. barbouri), and generally much paler body colour (light brown vs. ferruginous; according to Creighton mesonotum and propodeum even tinged with black in M. barbouri).

Distribution. Southern Thailand and West Malaysia.