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 ) by

A new genus and species of the ant subfamily Myrmicinae collected from the Gaoligong Mountain Nature Reserve of the Hengduan Mountains, southwestern China, is described. The new genus, Gaoligongidris gen. nov., is close to Lasiomyrma Terayama & Yamane, but with anterior clypeal margin not angled, metanotal groove deeply impressed, propodeal spiracles large, propodeal spines long and slender, and petiolar peduncle longer than the node. The new genus is distributed in the Oriental region and belongs to the tribe Stenammini of Myrmicinae. A key to the known genera of Stenammini of the world based on worker and queen castes is provided.


INTRODUCTION
After the publication of the Identification Guide to the Ant Genera of the World (Bolton 1994), 14 new living genera of Myrmicinae have been established in the world.Of these, 12 genera have been recognized as valid ones, and 3 genera (Lasiomyrma Terayama & Yamane, 2000;Austromorium Shattuck, 2009;Propodilobus Branstetter, 2009) belong to the tribe Stenammini (Bolton 2011).
A new genus, Gaoligongidris gen.nov., was discovered in the ant diversity investigation of Gaoligong Mountain Nature Reserve, southwestern China.The type species, G. planodorsa sp.nov., is the only known species of the genus.The new genus is distributed in the Oriental region and belongs to the tribe Stenammini of Myrmicinae.Currently, 20 genera of Stenammini are recognized in the world (Bolton 1995(Bolton , 2011)).In order to understand the differentiation between the new genus and other ones, a key to the known genera of Stenammini is provided.

MATERIALS AND METHODS
The worker caste of the type species, G. planodorsa sp.nov., was collected by the sample-plot method.Descriptions and measurements were made under a XTB-1 stereo microscope with a micrometer.Illustrations were made under a Motic-700Z stereo microscope with illustrative equipment.
Standard measurements and indices are as defined in Bolton (1987), in addition, ED is supplemented: TL-Total Length: The total outstretched length of the ant from the mandibular apex to the gastral apex.
HL-Head Length: The length of the head proper, excluding the mandibles, measured in a straight line from the mid-point of the anterior clypeal margin to the mid-point of the occipital margin, in full-face view.In species where the occipital margin or the clypeal margin is concave, the measurement is taken from the mid-point of a transverse line spanning the anteriormost or posteriormost projecting points, respectively.
HW-Head Width: The maximum width of the head in full face view, excluding the eyes.
CI-Cephalic Index = HW×100 / HL.SL-Scape Length: The maximum straight line length of the antennal scape excluding the basal constriction or neck close to the condylar bulb.SI-Scape Index = SL×100 / HW.ED-Eye Diameter: The maximum diameter of the eye.PW-Pronotal Width: The maximum width of the pronotum in dorsal view.
AL-Alitrunk Length: The diagonal length of the alitrunk in profile view from the point at which the pronotum meets the cervical shield to the posterior base of the metapleuron.
All measurements are expressed in millimeters.
The type specimens are deposited in the Insect Collection, Southwest Forestry University (SWFU), Kunming, Yunnan Province, China.

DESCRIPTIONS OF NEW GENUS AND SPECIES
Gaoligongidris gen.nov.
Diagnosis of worker: Monomorphic terrestrial myrmicine ants with the following combination of characters.
Head square, occipital margin nearly straight.Palp formula 2, 2 (2 individuals dissected).Mandible triangular, with 6 sharp teeth which decrease in size from apex to base.
Median portion of clypeus longitudinally bicarinate, the posterior portion broadly inserted between the frontal lobes.Anterior clypeal margin extruding, nearly straight in the middle portion.
Anterior clypeal margin with a row of long setae, but lacking an isolated median seta.
Frontal lobes as broad as the posterior portion of clypeus which is inserted between them.
Frontal carinae and antennal scrobes absent.Antennae 11-segmented; scapes short, apices failed to reach occipital corners; antennal clubs 3-segmented, the third segment of the club counting from apex reduced in volume and much shorter than the second one.
Eyes moderately large, drawn out anteroventrally, located before the midpoints of lateral sides of the head.
Propodeum low, with a pair of long slender spines.Propodeal spiracles large and circular, well before the declivity margin and high up on the sides.
Propodeal lobes small and bluntly angled at apex.Metapleural gland bullae large and close to the propodeal spiracles.Tibial spurs absent from middle and hind legs.
Petiole with long anterior peduncle, the spiracles located about at the midlength of the peduncle, subpetiolar process absent.
Female and male: Unknown.

Comparison:
The new genus is close to the Indo-Australian genus Lasiomyrma  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.
Systematic position: Myrmicinae: Stenammini.Geographical range: Oriental.Discussion: 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.
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.
Etymology: The name of the new species is descriptive of the "plane" promesonotal "dorsum" of alitrunk in profile view.
Remarks: Currently, G. planodorsa sp.nov. is the only species in the new genus.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.