China with a Key to the Known Species of Vombisidris Bolton of the World ( Hymenoptera : Formicidae ) by

Seventeen species of the myrmicine ant genus Vombisidris Bolton are recognized in the world. A new species collected from the south slope of Himalaya Mountain, V. tibeta sp. nov., is described. A key to the 17 known species of the genus is provided based on the worker caste. Illustrations are provided for each species.


INTRODUCTION
Since the establishment of the myrmicine ant genus Vombisidris Bolton (1991), 16 species of the genus were recorded in the world (Bolton, 1995(Bolton, , 2012)).Firstly, 9 species of the genus were described by Bolton (1991) with the erection of the genus.Secondly, 3 species described in other genus before 1991 were transferred to Vombisidris by Bolton (1991), i.e.Leptothorax australis Wheeler, 1934, L. bilongrudi Taylor, 1989, and L. renateae Taylor, 1989.Thirdly, 1 species described in other genus, Atopula jacobsoni Forel, 1915, was transferred to Vombisidris by Bolton (1995Bolton ( , 2003) ) and Sorger (2011).Fourthly, 3 species of the genus were described after 1991, i.e.Vombisidris humboldticola Zacharias et Rajan, 2004, V. umbrabdomina Huang et Zhou, 2006, and V. philippina Zettel et Sorger, 2010.It is difficult to have a complete grasp of the total 16 species of the genus due to the following shortcomings.Firstly, the detailed information of Atopula jacobsoni Forel, 1915, was excluded from the papers of Taylor (1989) and Bolton (1991).Fortunately, Sorger (2011) had sufficiently improved the description and illustrations of the species.Secondly, Bolton (1991) provided good illustrations and descriptions for the profile characters of the 9 species described, but without illustrations and good descriptions of the full face characters of the head, which are very useful for the identification of the species.Thirdly, the other 3 species described after 1991 were published separately and without a key relating them to the formerly known ones, and the profile figure of V. humboldticola Zacharias et Rajan is not clear.
So, it is necessary to produce a good key with sufficient illustrations for the known species of the genus, in order to facilitate identification of the species.Recently, the high quality images of 9 species of the genus are presented on the AntWeb and Antbase, which provides as good references for the preparation of the key.
In the Ant Diversity Investigation of Southeastern Tibet, a new species of Vombisidris was found in the valley tropical rainforest of Medog County, the south slope of the Himalaya Mountain.The new species is described.A key to the 17 known species of the genus of the world is provided based on the worker caste.However, illustrations of the worker caste of V. australis (Wheeler), and illustrations of the full face head of V. harpeza Bolton, V. lochme Bolton, V. occidua Bolton, and V. humboldticola Zacharias et Rajan are still absent from this paper.

MATERIALS AND METHODS
The worker caste of V. tibeta 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.
Illustrations of the worker caste of V. acherdos Bolton, V. bilongrudi (Taylor), V. nahet Bolton, and V. philax Bolton, and illustrations of the queen caste of V. australis (Wheeler), were drawn from the AntWeb images.Illustrations of the worker caste of V. dryas Bolton, V. philippina Zettel et Sorger, V. regina Bolton, and V. xylochos Bolton were drawn from the AntBase images.And illustration of the worker caste of V. humboldticola Zacharias et Rajan was drawn from the figure of Zacharias & Rajan (2004).
In full face view, head roughly rectangular, longer than broad.Occipital margin weakly concave in the middle, occipital corners rounded.Lateral sides weakly convex.Mandibles triangular, masticatory margin with 3 apical teeth, a long deastema, and 2 blunt basal teeth.Anterior clypeal margin strongly convex, posteriorly extended portion very broad, about 2.5 times as broad as frontal lobes.Antennae 12-segmented, apices of scapes just reached to occipital corners, antennal clubs 3-segmented.Frontal carinae fine and long, extended backward and close to the occipital corners.Eyes large, situated slightly before the midpoints of the lateral sides.
In profile view, subocular groove complete, running from mandibular insertion to the lateroccipital margin.Promesonotum weakly convex, promesonotal suture vestigial on the dorsum.Metanotal groove shallowly notched.Propodeal dorsum straight and weakly slope down backward.Propodeal spines strong and long, slightly curved down backward, about 1.8 times as long as propodeal dorsum.Declivity weakly concave, about as long as propodeal dorsum.Propodeal spiracle small and circular, high up on the side.Propodeal lobes moderately developed, rounded at apices.Petiolar node elongate and dome-like, both anterior and posterior faces gently slope down, without distinct dorsal face; anterior peduncle very short, spiracle situated at about the mid-length of the peduncle; ventral face weakly convex about in the middle, and weakly concave afterwards; anteroventral corner acutely toothed.Postpetiolar node evenly convex, ventral face nearly straight.
Mandibles smooth and shining, sparsely punctured.Head and alitrunk coarsely reticulate.Clypeus and lateral sides of metanotum longitudinally striate.Propodeal declivity longitudinally striate and densely finely punctured.Petiole and postpetiole finely reticulate and densely finely punctured.Gaster smooth and shining, basal costulae distinct, about 1/2 length of the postpetiole.Dorsal surfaces of head and body with sparse suberect to subdecumbent tapered hairs and abundant decumbent pubescence.Scapes with abundant suberect to subdecumbent tapered hairs and dense decumbent pubescence.Tibiae with sparse subdecumbent tapered hairs and abundant decumbent pubescence.Color brownish yellow, middle portion of gaster black, legs yellow.