Myrmoteras cuneonodum

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 : 547-548

Myrmoteras cuneonodum Xu

( Fig. 1 –A, 2)

Myrmoteras cuneonodum Xu, 1998: 125 . Holotype worker: Sanchahe, 950 m, Mengyang Town, Jinghong County, Yunnan Province, Feb. 28, 1997, No. A97-79 (Yuchu Lai) [Southwest Forestry College, Yunnan, China] (not examined).

Non-type material examined. Vietnam: 2 workers, Northern Middle Vietnam, Nghe An Prov., Pu Mat NP., Pha Lai Forest Station, 23 v 2006, leg. K. Eguchi (Eg 23iii06-10); 1 worker, same national park as above, Khe Kem waterfall near forest station, ca. 200–300 m alt., 18 0 58’N –104 0 49’E, 17 iii 2006, leg. K. Eguchi; 3 workers, Northern Vietnam, Vinh Phuc Prov., Tam Dao NP., ca. 950 m alt., 21 0 27’N –105 0 38’E, leg. V. T. B u i; 5 workers, Hanoi, Ba Vi NP., ca. 400 m alt., 21 0 03’N –105 0 22’E, leg. V. T. B u i (BTV01-BVI-91); 1 worker, Northern Vietnam, Ninh Binh Prov., Cuc Phuong NP., 10–11 August 1998, leg. Sk. Yamane. Thailand: 1 worker, Nakhonratchasima Prov., Khao Yai NP., hill green forest, 11 vii 1998, leg. W. Jaitrong; 1 worker, same national park, 30 v 2000, leg. Sk. Yamane; 3 workers, same national park, ca. 600–650 m alt., 1 vi 2000, leg. W. Jaitrong; 1 worker, NE Thailand, Nakhon Ratchasima Prov., Wang Nam Kheao distr., Sakhaerat ERS, DEF, 17 vii 2009, leg. W. Jaitrong (WJT09- TH2218); 1 worker, E Thailand, Chanthaburi Prov., Khao Soi Dao WS, 3 vi 2001, leg. Sk. Yamane.

Worker measurements and indices. TL 3–3.5, HL 0.92–1.00 (0.95), HW 0.92–0.98 (0.95), EL 0.58–0.62 (0.60), ML 1.21–1.33 (1.27), SL 0.92–1.02 (1.00), PrW 0.52–0.58 (0.55), HfL 0.94–1.04 (1.00), CI 98–102 (100), SI 100–108 (104). (5 non-type workers were measured.)

Worker description. Body yellowish brown; mandible and leg pale yellow. Body with sparse standing hairs; dorsum of head and pronotum often with faint pubescence. Clypeus faintly rugose; frons irregularly rugose; vertex of head (including occipital lobe) smooth; frontal sulcus wide and deep, reaching median ocellus; anterior clypeal margin concave; mandible with ca. 10 teeth; two tiny denticles present between first (apical) and second (penultimate) teeth; the posterior one of the two very tiny; one relatively large denticle present between second and third teeth, and between third and fourth teeth; palp formula 6,4. Orbital grooves present, but narrow and shallow; scape distinctly shorter than funicular segments combined; funicular segments longer than broad. Pronotum in lateral view flattened dorsally; anteriormost part of pronotum rugose transversely; dorsum of pronotum smooth or faintly rugoso-punctate; dorsum of mesonotum rugoso-punctate; side of mesonotum with several irregular rugae; mesopleuron smooth; metapleuron and lateral face of propodeum obliquely rugose; metanotal groove shallow; dorsal face of propodeum transversely rugose; propodeum in lateral view relatively strongly convex. Petiolar node in lateral view with a vertical anterior face and steep posterior slope; ventral outline of petiole beneath the node slightly sinuate or concave.

Remarks. Up to now 26 species are known in the subgenus Myagroteras (Zettel & Sorger, 2011) . However, most of them were based on a single or a few specimens from a restricted area. Colony series were examined very rarely. Our species seems closely related to M. estrudae Agosti (holotype examined) from Sumatra and M. cuneonodum Xu (holotype not examined) from Yunnan, southern China. All these have a smooth pronotal dorsum. Compared with M. estrudae , in our species the propodeal side is much more strongly sculptured (often metapleuron also sculptured) and the propodeal dorsum is densely transversely striate. In the latter condition it is more similar to M. cuneonodum (see Xu, 1998, p. 125), and we tentatively identified our species as M. cuneonodum . However, among the specimens examined we have found variation in the sculpture of pronotum, propodeum and side of mesosoma. Furthermore, in some specimens the propodeum is very convex dorsally, the condition approaching that of M. karnyi Gregg from the Mentawai Islands, Sumatra. We need more material derived from colonies to evaluate the status of so many species recently described in this subgenus. In Khao Yai National Park in northeastern Thailand, nests were found in soil at altitudes between 600 and 1,000 m.

Distribution. S. China, Vietnam, Thailand.

Figures

FIGURE 1. Left mandibles in dorsal view. A. Myrmoteras cuneinodum; B. M. jaitrongi; C. M. concolor.