1495 Vombisidris tibeta, a New Myrmicine Ant Species from Tibet, China with a Key to the Known Species of Vombisidris Bolton of the World (Hymenoptera: Formicidae) by Zheng-Hui Xu1 & Na-Na Yu1 ABSTRACT 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. Key words: Hymenoptera, Formicidae, Vombisidris, new species, key. INTRODUCTION Since the establishment of the myrmicine ant genus Vombisidris Bolton (1991), 16 species of the genus were recorded in the world (Bolton, 1995, 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 aus- tralis 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 (1995, 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) 1Key Laboratory of Forest Disaster Warning and Control in Yunnan Province, College of Forestry, Southwest Forestry University, Kunming, Yunnan Province 650224, China, E-mail: xuzhenghui1962@163.com 1496 Sociobiolog y Vol. 59, No. 4, 2012 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 prepara- tion 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 man- dibular 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 1497 Xu, Z.H. & N-N. Yu — Ant Species from Tibet 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 pos- terior 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). KEY TO KNOWN SPECIES OF VOMBISIDRIS OF THE WORLD BASED ON THE WORKER CASTE (All figures cited are in the Appendix) 1 - Subocular groove entirely absent (Papua New Guinea) (Figs. 1-3)……… ...........................................................................................V. bilongrudi (Taylor) - Subocular groove at least present from mandibular insertion to the eye… …………………................................................................................................…….2 1498 Sociobiolog y Vol. 59, No. 4, 2012 2 - Subocular groove incomplete, running from mandibular insertion to the anteroventral margin of the eye, never beyond the eye (Papua New Quinea) (Figs. 4-6)……………............................................................V. acherdos Bolton - Subocular groove complete, running from mandibular insertion to the anteroventral margin of the eye, then passing through a shallow angle and continuing along the side to the lateroccipital margin………......................3 3 - In profile view, dorsum of mesonotum with a pair of short vertical sharp teeth at each side. Anterior 2/3 of the first gastral tergite longitudinally rugulose (Indonesia) (Figs. 7-9) ......................................... V. philax Bolton - In profile view, dorsum of mesonotum without a pair of vertical sharp teeth, at most with a pair of blunt prominence. First gastral tergite smooth… ………………………………………….........................................................................4 4 - In profile view, petiolar node dome-like or roughly triangular, dorsum roundly convex, without distinctly differentiated dorsal face………………… ……….....…………………............................................................................…………5 - In profile view, petiolar node roughly trapezoidal, with distinctly differ- entiated dorsal face, anterodorsal and posterodorsal corners more or less distinct……..................................................................……………………………..10 5 - In profile view, metanotal g roove shallow but obviously de - pressed…….............................................................................……………………….6 - In profile view, metanotal groove entirely absent .................................... 7 6 - In full face view, occipital margin weakly concave. Anterior clypeal margin strongly convex. In profile view, propodeal spines weakly curved down, longer than propodeal dorsum. Postpetiolar node evenly convex (China: Tibet) (Figs. 10-13)…………………………..….......................…V. tibeta sp. nov. - In full face view, occipital margin weakly convex. Anterior clypeal margin weakly convex. In profile view, propodeal spines straight, as long as propo- deal dorsum. Postpetiolar node strongly convex (China: Hunan Province) (Figs. 14-15)………………..........................V. umbrabdomina Huang et Zhou 7 - In profile view, petiolar node roughly triangular, dorsal corner dis- tinct……………….......................................................................................…………8 - In profile view, petiolar node dome-like, dorsal corner indis- tinct……………..............................................................................…………………..9 8 - In profile view, propodeal spines about as long as propodeal declivity. Post- petiolar node evenly convex. In dorsal view, lateral sides of petiolar node 1499 Xu, Z.H. & N-N. Yu — Ant Species from Tibet convex. Head and alitrunk blackish brown, gaster lighter brown (India) (Fig. 16)……………............................…………………………….V. occidua Bolton - In profile view, propodeal spines distinctly longer than propodeal declivity. Postpetiolar node strongly convex. In dorsal view, lateral sides of petiolar node almost straight. Head and alitrunk yellowish brown, gaster blackish brown (India) (Fig. 17)…....................V. humboldticola Zacharias et Rajan 9 - In full face view, occipital corners roundly prominent. Eyes evenly convex. Anterior clypeal margin without a middle notch (Indonesia) (Figs. 18- 20)………................................................................……………..…V. nahet Bolton - In full face view, occipital corners rounded. Eyes strongly extruding. Anterior clypeal margin with a middle notch (Malaysia) (Figs. 21-23)…… ……............................................................…………………..……..V. regina Bolton 10 - In profile view, metanotal groove strongly depressed and trench- like…….......................................................................................…...………...……11 -- In profile view, metanotal groove vestigial to absent, without a trench-like notch………..................................................................................................…….13 11 - In profile view, promesonotum nearly straight, anterodorsal corner angled. Propodeal spines about two times as long as propodeal dorsum (Brunei) (Figs. 24-26......................................................................……V. xylochos Bolton -- In profile view, promesonotum weakly convex, anterodorsal cor- ner rounded. Propodeal spines about as long as propodeal dor- sum………………………………………......................................………………..……12 12 - In full face view, lateral sides of head divergent behind eyes. In profile view, anterior peduncle shorter than the dorsal face of petiolar node. First gastral tergite finely superficially reticulate (Indonesia) (Fig. 27)…………… ………………………………….........................................…………..V. lochme Bolton -- In full face view, lateral sides of head nearly parallel behind eyes. In profile view, anterior peduncle about as long as the dorsal face of petiolar node. First gastral tergite almost completely smooth (Malaysia) (Fig. 28- 30)…………..............................………………………………..………V. dryas Bolton 13 - In profile view, anterior peduncle of petiole relatively short, shorter than the dorsal face of petiolar node, the dorsal face nearly straight (Malaysia) (Fig.31)……….................................................................…..…V. harpeza Bolton -- In profile view, anterior peduncle of petiole relatively long , about 1500 Sociobiolog y Vol. 59, No. 4, 2012 as long as the dorsal face of petiolar node, the dorsal face weakly con- vex……………………………………….....................................................…………..14 14 - In profile view, anterodorsal corner of petiolar node blunt- ly ang led, hig her than posterodorsal corner, the latter round- ed……………………......................………………………………………………......…..15 - - In p r o f i l e v i e w, b o t h a n t e r o d o r s a l a n d p o s t e r o d o r s a l corners of p etiolar no de bluntly prominent, at the same le v- el……………..................……………………………………………………………………16 15 - In full face view, occipital margin straight. In profile view, propodeal spines relatively short, shorter than or about as long as propodeal decliv- ity. Ventral face of petiole nearly straight. Dorsal surface of alitrunk with short blunt hairs (Australia) (Figs. 32-34 ..................V.australis (Wheeler) -- In full face view, occipital margin evenly convex. In profile view, propo- deal spines relatively long, longer than propodeal declivity. Ventral face of petiole concave. Dorsal surface of alitrunk with moderate long tapered hairs (Australia) (Figs. 35-37)….................…………….…V. renateae (Taylor) 16 - In full face view, occipital margin nearly straight. Anterior clypeal margin weakly convex. Dorsal surface of alitrunk with short blunt hairs. Color yel- low to lighter brown (Indonesia) (Figs. 38-40)…........ V. jacobsoni (Forel) -- In full face view, occipital margin weakly convex. Anterior clypeal margin strongly convex. Dorsal surface of alitrunk with moderate long tapered hairs. Color blackish brown (Philippines) (Figs. 41-43)……………………… …………………………......................................……V. philippina Zettel et Sorger DESCRIPTION OF NEW SPECIES Vombisidris tibeta sp. nov. Figs. 10-13 Holotype worker: TL 3.9, HL 0.83, HW 0.68, CI 82, SL 0.65, SI 96, ED 0.23, PW 0.53, AL 1.13. 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 1501 Xu, Z.H. & N-N. Yu — Ant Species from Tibet 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. In dorsal view, lateral sides of pronotum roundly convex. Lateral sides of mesonotum without prominence. Propodeal spines weakly curved inward. Lateral sides of petiole nearly straight, slightly widened backward; petiolar node longer than broad, length : width = 2:1. Postpetiole wider than peti- ole, lateral sides weakly convex; postpetiolar node wider than long, width : length = 1.2:1. 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 punc- tured. 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 sub- decumbent 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. 1502 Sociobiolog y Vol. 59, No. 4, 2012 Paratype workers: TL 4.0-4.1, HL 0.85-0.88, HW 0.70-0.73, CI 82-83, SL 0.63-0.65, SI 89-90, ED 0.24, PW 0.53-0.58, AL 1.15-1.25 (2 individuals measured). As holotype worker, but metanotal groove even more shallow, sting extruding in one worker. Holotype worker: China: Tibet, Medog County, Damu Town, Damu Village, 1200m, collected from a canopy sample in the valley tropical rainforest, 2011.VII.20, Xia Liu leg., No.A11-3928. Paratypes: 2 workers, with the same data as holotype worker, and both collected from canopy samples respectively, but Nos. A11-3876, A11- 3943. Comparative notes: This new species is close to V. umbrabdomina Huang et Zhou, but in full face view, occipital margin weakly concave in the middle; anterior clypeal margin strongly convex; in profile view, propodeal spines weakly curved down backward, and distinctly longer than propodeal dorsum; postpetiolar node evenly convex. Etymology: The new species is named after the type locality “Tibet”. Biological notes: According to the collection data, all the 3 workers of the species were collected from canopy samples separately. It seems this species lives in the valley tropical rainforest and forages on the plants. ACKNOWLEDGMENTS This study is supported by the National Natural Science Foundation of China (Nos. 31260521, 30870333) and the Key Subject of Forest Protection of Yunnan Province. We thank the following persons or Institution for their special helps in this study: Xia Liu (PhD Candidate of Forest Protection, Beijing Forestry University, Beijing ) who collected the type specimens with us; Daniela Magdalena Sorger (Natural History Museum, Vienna) who sup- plied a valuable paper and permitted to use the figures in her paper; Robert W. Taylor (Australian National Insect Collection, Canberra), Barry Bolton (The Natural History Museum, London), Merry Zacharias & Priyadarsanan Dharma Rajan (Ashoka Trust for Research in Ecolog y and the Environ- ment, Bangalore), and Jian-Hua Huang & Shan-Yi Zhou (Guangxi Normal University, Guilin) who granted permission to cite figures in their papers; 1503 Xu, Z.H. & N-N. Yu — Ant Species from Tibet California Academy of Sciences (San Francisco) who permitted the use of the images of V. acherdos Bolton, V. bilongrudi (Taylor), V. nahet Bolton, V. philax Bolton, and V. australis (Wheeler) on the Antweb.org (http://www. antweb.org/); Martin Pfeiffer (National University of Mongolia, Ulaanbaatar) who permitted the use of the images of V. dryas Bolton, V. philippina Zettel et Sorger, V. regina Bolton, and V. xylochos Bolton on the Antbase.net (http:// www.antbase.net/). REFERENCES Bolton, B. 1987. A review of the Solenopsis genus-group and revision of Afrotropical Monomorium Mayr. Bulletin of the British Museum (Natural History) (Entomolog y) 54: 263-452. Bolton, B. 1991. New myrmicine ant genera from the Oriental region. Systematic Entomology 16: 1-13. Bolton, B. 1995. A new general catalogue of the ants of the world. Harvard University Press, 504 pp. Cambridge, Massachusetts. Bolton, B. 2003. Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute 71: 1-370. Bolton, B. 2012. An online catalog of the ants of the world. http://www.antcat.org/. Forel, A. 1915. Fauna Simalurensis. Hymenoptera Aculeata, Fam. Formicidae. Tijdschrift voor Entomologie 58: 22-43. Huang, J. & Zhou, S. 2006. Vombisidris Bolton, a new record genus in China, with description of a new species. Acta Zootaxonomica Sinica 31: 206-207. Sorger, D. M. 2011. Redescription and history of Vombisidris jacobsoni (Forel, 1915). Revue Suisse de Zoologie 118: 149-155. Taylor, R. W. 1989. Australian ants of the genus Leptothorax Mayr. Memoirs of the Queensland Museum 27: 605-610. Wheeler, W. M. 1934. An Australian ant of the genus Leptothorax Mayr. Psyche 41: 60- 62. Zacharias, M. & Rajan, P. D. 2004. Vombisidris humboldticola (Hymenoptera: Formicidae): a new arboreal ant species from an Indian ant plant. Current Science 87: 1337-1338. Zettel, H. & Sorger, D. M. 2010. On the ants (Hymenoptera: Formicidae) of the Philippine Islands: IV. The genus Vombisidris Bolton 1991. Entomologica Austriaca 17: 37-44. Appendix starts on page 1504 1504 Sociobiolog y Vol. 59, No. 4, 2012 Figs. 1-3: Worker of Vombisidris bilongrudi (Taylor); 1. Head and body in profile view; 2. Head in full face view; 3. Alitrunk, petiole, and postpetiole in dorsal view. (Drawn from Antweb images, pilosity and sculpture omitted) Figs. 4-6: Worker of Vombisidris acherdos Bolton; 4. Head and body in profile view; 5. Head in full face view; 6. Alitrunk and petiole in dorsal view. (Drawn from Antweb images, pilosity and sculpture omitted) Figs. 7-9: Worker of Vombisidris philax Bolton; 7. Head and body in profile view; 8. Head in full face view; 9. Alitrunk and petiole in dorsal view. (Drawn from Antweb images, pilosity and sculpture omitted) Figs. 10-13: Worker of Vombisidris tibeta sp. nov.; 10. Head and body in profile view; 11. Head in full face view; 12. Mandible in dorsal view; 13. Body in dorsal view. (Pilosity and sculpture omitted) 1505 Xu, Z.H. & N-N. Yu — Ant Species from Tibet Figs. 24-26: Worker of Vombisidris xylochos Bolton; 24. Head and body in profile view; 25. Head in full face view; 26. Alitrunk and petiole in dorsal view. (Drawn from Antbase images, pilosity and sculpture omitted) Figs. 18-20: Worker of Vombisidris nahet Bolton; 18. Head and body in profile view; 19. Head in full face view ; 20. Alitrunk, petiole, and postpetiole in dorsal view. (Drawn from Antweb images, pilosity and sculpture Figs. 21-23: Worker of Vombisidris regina Bolton; 21. Head and body in profile view; 22. Head in full face view; 23. Alitrunk, petiole, and postpetiole in dorsal view. (Drawn from Antbase images, pilosity and sculpture omitted) Figs. 14-17: Workers of Vombisidris Bolton; 14- 15: Worker of V. umbrabdomina Huang et Zhou; 16: Worker of V. occidua Bolton; 17: Worker of V. humboldticola Zacharias et Rajan; 14, 16, 17. Head and body in profile view; 15. Head in full face view. 1506 Sociobiolog y Vol. 59, No. 4, 2012 Figs. 35-37: Worker of Vombisidris renateae (Taylor); 35. Head and body in profile view; 36. Head in full face view; 37. Alitrunk, petiole and postpetiole in dorsal view. (Drawn from figures of Taylor, 1989, pilosity and sculpture omitted) Figs. 27-30: Workers of Vombisidris Bolton; 27: Worker of V. lochme Bolton; 28-30: Worker of V. dryas Bolton; 27, 28. Head and body in profile view; 29. Head in full face view; 30. Alitrunk and petiole in dorsal view. (27. Cited from Bolton, 1991; 28-30. Drawn from Antbase images; Pilosity and sculpture omitted) Figs. 31-34: Worker and Queen of Vombisidris Bolton; 31: Worker of V. harpeza Bolton; 32-34: Queen of V. australis (Wheeler); 31, 32. Head and body in profile view; 33. Head in full face view; 34. Alitrunk, petiole, and postpetiole in dorsal view. (31. Cited from Bolton, 1991; 32- 34. Drawn from Antweb images; Pilosity and sculpture omitted) 1507 Xu, Z.H. & N-N. Yu — Ant Species from Tibet Figs. 38-40: Worker of Vombisidris jacobsoni (Forel); 38. Head and body in profile view; 39. Head in full face view; 40. Body in dorsal view. (Drawn from figures of Sorger, 2011, pilosity and sculpture omitted) Figs. 41-43: Worker of Vombisidris philippina Zettel et Sorger; 41. Head and body in profile view; 42. Head in full face view; 43. Body in dorsal view. (Drawn from Antbase images, pilosity and sculpture omitted)