Gaoligongidris planodorsa

According to the rich collections, the new species is mainly found in subalpine moist evergreen broadleaf forest, sometimes habitats in the monsoon evergreen broadleaf forest and shrubs between the altitudes of 1500-2000m. The species is obviously nesting in the soil, and foraging on the ground. (Xu 2012)

Identification
This species, as the only species of the genus, can be determined by its generic distinctions:

Xu (2012) - At first glance, the new genus is somewhat similar to Lophomyrmex Emery of the tribe Pheidolini by the following characters: 11-segmented antennae, long propodeal spines, large propodeal spiracles, and long petiolar peduncle. However, the genus obviously belongs to the tribe Stenammini by the following characters: median portion of clypeus longitudinally bicarinate, anterior clypeal margin nearly straight in the middle portion; masticatory margins of mandibles with only 6 teeth; antennae short, apices of the scapes failed to reach occipital corners, the third segment of antennal club counting from apex distinctly reduced in volume and much shorter than the second one; pronotum without teeth, prominences, or lateral margins; head and alitrunk strongly sculptured.

The new genus is close to the Indo-Australian genus Lasiomyrma Terayama & Yamane in the tribe Stenammini, but with anterior clypeal margin not angled, metanotal groove deeply impressed, propodeal spiracles large, propodeal spines long and slender, petiolar peduncle longer than the node.

Distribution
Known only from the Yunnan Province, China.

Distribution based on Regional Taxon Lists
Palaearctic Region: China.

Caste
Known only from the worker caste.

Nomenclature

 *  planodorsa. Gaoligongidris planodorsa Xu, 2012: 336, figs. 1-7 (w.) CHINA.

Worker
Holotype: TL 2.6, HL 0.67, HW 0.65, CI 98, SL 0.43, SI 67, ED 0.10, PW 0.42, AL 0.73.

Head square, as broad as long. Occipital margin nearly straight, occipital corners roundly prominent. Lateral sides weakly convex. Mandibles subtriangular, masticatory margin with 6 teeth, which decrease in size from apex to base. Median portion of clypeus bicarinate and extruding forward, anterior margin nearly straight. Posterior clypeal extension about as broad as the frontal lobes. Frontal carinae and antennal scrobes absent. Antennae short, 11-segmented, apex of scape reached to 3/4 of the distance from antennal socket to occipital corner. The apical 3 segments form the antennal club, apical segment 2.5 times as long as the preceding one; the third segment counting from apex weakly enlarged, about 1/2 length of the second one. Eyes moderately large, situated in front of the midpoints of the lateral sides of the head, with about 12 ommatidia in the maximum diameter.

In profile view, pronotum and mesonotum form a high plateau which gently slopes down backward, posterodorsal corner of mesonotum bluntly angled and steeply slopes down to the metanotal groove. Promesonotal suture absent. Metanotal groove deeply impressed. Propodeum low, dorsum short and straight. Propodeal spines long, sharp, and straight, laterally compressed, about as long as propodeal dorsum. Declivity weakly concave, lateral sides marginate. Propodeal spiracles large and circular, well before the declivity margins, and high up on the sides. Propodeal lobes small and bluntly angled at apex. Metapleural gland bullae large and roughly triangular. Petiolar node triangular, anterior face straight, posterior face weakly convex, anterior peduncle longer than the node, ventral face weakly concave under the node, and weakly convex before the concavity, subpetiolar process absent. Postpetiolar dorsum roundly convex, slightly lower than petiolar node, ventral face with 2 small convexities. In dorsal view, promesonotum nearly triangular, narrowed backward. Lateral sides of mesonotum marginate, lateroposterior corners rightly angled. Postpetiolar node about 1.4 times as broad as petiolar node, lateral sides of postpetiole roundly convex.

Mandibles densely longitudinally striate. Head densely reticulate, but the vertex longitudinally striate, interfaces finely punctured. Alitrunk densely coarsely punctured, but pronotal dorsum densely reticulate. Petiole and postpetiole densely finely punctured, but dorsum of postpetiolar node finely longitudinally striate. Gaster smooth and shining, but the first tergite with short basal costulae, which distinctly shorter than the postpetiolar node. Dorsum of head with dense erect short hairs. Dorsum of alitrunk with sparse erect to suberect longer hairs and abundant decumbent pubescence. Petiole, postpetiole, and gaster with abundant suberect hairs and decumbent pubescence. Scapes and tibiae with dense subdecumbent to decumbent short hairs. Color yellowish brown, but dorsum of head and middle portion of gaster blackish brown.

Paratype: TL 2.3-2.6, HL 0.60-0.67, HW 0.57-0.65, CI 89-100, SL 0.37-0.43, SI 63-67, ED 0.10-0.12, PW 0.37-0.42, AL 0.70-0.80 (10 individuals measured). As holotype, but color brownish yellow to yellowish brown.

Type Material
Holotype: worker, China: Yunnan Province, Tengchong County, Jietou Town, Datang Village, 2000m, collected from a soil sample in the subalpine moist evergreen broadleaf forest on the west slope of Gaoligong Mountain, 1999.V.1, Ji-Guai Li leg., No.A99-195.

Paratypes: 20 workers, with the same data as holotype, plus others (see Xu 2012) from various locations and collections.

Etymology
The name of the new species is descriptive of the “plane” promesonotal “dorsum” of alitrunk in profile view.

References based on Global Ant Biodiversity Informatics

 * Fontanilla A. M., A. Nakamura, Z. Xu, M. Cao, R. L. Kitching, Y. Tang, and C. J. Burwell. 2019. Taxonomic and functional ant diversity along tropical, subtropical, and subalpine elevational transects in southwest China. Insects 10, 128; doi:10.3390/insects10050128
 * Guénard B., and R. R. Dunn. 2012. A checklist of the ants of China. Zootaxa 3558: 1-77.
 * Song Y., Z. Xu, C. Li, N. Zhang, L. Zhang, H. Jiang, and F. Mo. 2013. An Analysis on the Ant Fauna of the Nangun river Nature Reserve in Yunnan, China. Forest Research 26(6): 773-780.
 * Xu Z.-H. 2012. Gaoligongidris planodorsa, a new genus and species of the ant subfamily Myrmicinae from China with a key to the genera of Stenammini of the world (Hymenoptera: Formicidae). Sociobiology 59: 331-342.