Stigmatomma zoma

Known from a single worker collected from the soil of a tropical rainforest.

Identification
Xu & Chu (2012) - This new species is close to Stigmatomma trilobum but in full-face view occipital corners bluntly angled; eyes present, each with about 6 facets; anterior clypeal margin with 2 simple teeth between the middle and lateral lobes; the middle lobe truncated at apex, and with a small denticle on each side; the lateral lobes simple, not bifid at apex.

Distribution based on Regional Taxon Lists
Palaearctic Region: China.

Castes
Known only from the worker caste.

Nomenclature

 *  zoma. Amblyopone zoma Xu & Chu, 2012: 1189, figs. 28-30 (w.) CHINA. Combination in Stigmatomma: Yoshimura & Fisher, 2014: 15.

Worker
Holotype worker: TL 4.5, HL 1.00, HW 0.85, CI 85, SL 0.48, SI 56, ED 0.05, ML 0.68, PW 0.58, AL 1.25, PL 0.48, PH 0.55, DPW 0.55, LPI 116, DPI 100.

In full-face view, head roughly trapezoidal, widened forward and longer than broad. Occipital margin widely weakly concave, occipital corners bluntly angled. Lateral sides weakly convex. Anterolateral corners acutely toothed. Mandibles elongate triangular, masticatory margin with a long apical tooth, a short subapical tooth, and 3 pairs of curved teeth; inner margin about as long as masticatory margin, with a pair of curved teeth, a short subbasal tooth, and a large basal tooth. Anterior clypeal margin roughly triangularly protruding, with a large middle lobe, and 3 teeth on each side, the most lateral tooth large and lobe-like; the large middle lobe truncated at apex, with a small denticle on each side. Antennae short, 12-segmented; apices of scapes reached to 4/7 of the distance from antennal sockets to occipital corners; funiculi incrassate toward apex. Eyes small, each with about 6 facets, and located behind the midpoints of the lateral sides of head.

In profile view, pronotum weakly convex. Promesonotal suture deeply notched. Mesonotum short and convex. Metanotal groove absent. Propodeal dorsum straight, about 1.5 times as long as declivity; posterodorsal corner very bluntly angled; declivity nearly straight. Dorsal and anterior faces of petiole nearly straight, anterodorsal corner nearly rightly angled; ventral face oblique and weakly concave; Subpetiolar process roughly rectangular, with a large elliptical sub-transparent fenestra, anteroventral corner prominent, ventral face straight, posteroventral corner toothed. Sternite of the first gastral segment ill developed, anteroventral corner toothed, and the segment looks narrower.

In dorsal view, mesothorax constricted. Propodeum widened backward. Petiole broader than long, width: length = 1.2:1, anterior and lateral sides weakly convex.

Mandibles longitudinally striate. Head densely punctured, interfaces appear as micro-reticulations. Pronotum densely punctured. Mesonotum, propodeum, petiole, and first gastral segment abundantly punctured. The middle longitudinal narrow strip on alitrunk without punctures. Lateral sides of mesothorax, metathorax, and propodeum longitudinally striate. Gastral segments 2-5 finely sparsely punctured. Dorsal surfaces of head and body with dense subdecumbent pubescence, gaster with sparse suberect hairs and dense subdecumbent pubescence. Scapes with sparse suberect hairs and dense decumbent pubescence. Tibiae with dense decumbent pubescence. Head brown, eyes grey. Body yellowish brown, legs yellow.

Type Material
Holotype: worker, China: Tibet, Medog County, Beibeng Town, Gangouhe, 740m, 2011.VII.19, collected from a soil sample in the valley tropical rainforest, Zheng-Hui Xu leg., No. A11-3676.

Etymology
The new species is named after a common female name “Zoma” widely used in Tibet.

References based on Global Ant Biodiversity Informatics

 * Liu X., Z. Xu, N. Yu, and C. Zhang. 2016. Distribution patterns of ant species ( Hymenoptera: Formicidae) in Galongla Mountains and Medog Valley of Southeastern Tibet. Scientia Silvae Sinicae 52(11): 88-95.
 * Xu Z.-H., and J. J. Chu. 2012. Four New Species of the Amblyoponine Ant Genus Amblyopone (Hymenoptera: Formicidae) from Southwestern China with a Key to the Known Asian Species. Sociobiology 59(4): 1175-1196.