Discothyrea banna

This species has only been collected in Mengla County of Xishuangbanna Prefecture in closed forest at 900 metres above sea level or higher. Discothyrea banna is sympatric with Discothyrea diana and they have even been collected together within a single 20 m by 20 m survey plot. (Xu et al. 2014)

Identification
Xu et al. (2014) - Close to Discothyrea kamiteta but in full-face view, posterior margin of head straight, anterior clypeal margin weakly convex; in lateral view, dorsum of mesosoma weakly convex, posterodorsal corner of propodeum rounded, propodeal lobes rounded; petiolar node relatively long and thick, height/length ratio = 1.7:1. This new species is also close to Discothyrea bryanti, but in full-face view, posterolateral corners of head narrowly rounded; frontal carinae reaching to 1/2 of head-length; anterior clypeal margin not crenulate; antennae 9-segmented.

Distribution based on Regional Taxon Lists
Palaearctic Region: China.

Castes
Known only from the worker caste.

Nomenclature

 *  banna. Discothyrea banna Xu, Burwell & Nakamura, 2014: 35, figs 1-6 (w.) CHINA.

Worker
Holotype: TL 2.8, HL 0.78, HW 0.68, CI 87, SL 0.55, SI 81, ED 0.10, PW 0.53, MSL 0.83, PL 0.20, PH 0.38, DPW 0.30, LPI 188, DPI 150. Paratypes: TL 2.5–2.9, HL 0.78–0.85, HW 0.65–0.70, CI 81–85, SL 0.53–0.58, SI 79–85, ED 0.09–0.10, PW 0.48–0.58, MSL 0.80–0.90, PL 0.20–0.25, PH 0.35–0.40, DPW 0.28–0.35, LPI 156–178, DPI 122–163 (10 individuals measured). As holotype.

In full-face view, head longer than broad, roughly trapezoidal and narrowed anteriorly. Posterior margin nearly straight, posterolateral corners rounded. Sides evenly convex, deeply notched in front of mandibular insertions. Mandibles triangular, masticatory margin edentate, apical tooth acute. Anterior margin of clypeus weakly convex. Frontal lobes confused each other and formed a large roughly rhombic frontal area, distinctly longer than broad, lateral corners bluntly angled and more than 90°, anterolateral margins straight, posterolateral margins weakly concave. Frontal carinae relatively long and well separated, extending posteriorly to 1/2 of head-length. Antennae 9-segmented, apices of scapes reaching to 2/3 of distance from antennal sockets to posterolateral corners. Eyes moderately large and convex, with 6 ommatidia on maximum diameter, located at mid-length of sides. In posterior view, frontal area weakly elevated and roughly rhombic, with a broad base, anterior margin weakly convex, lateral corners acutely angled.

In lateral view, dorsum of mesosoma weakly convex and sloping down posteriorly, promesonotal suture and metanotal groove absent. Posterodorsal corner of propodeum rounded, declivity weakly concave. Propodeal lobes large and rounded. Petiolar node high, roughly triangular and narrowed upward, anterior and dorsal faces forming a single arch, strongly convex, anterodorsal corner indistinct. Subpetiolar process short, very bluntly angled ventrally and translucent. First gastral segment large, about 2/3 of the total length of gaster. Constriction between the two basal gastral segments broad and deep.

In dorsal view, mesosoma trapezoidal and narrowed posteriorly, humeral corners bluntly angled, lateral margins nearly straight, posterior margin weakly concave medially. Petiolar node transverse and trapezoidal, length/width ratio = 1:1.5, widening posteriorly, anterior margin nearly straight, lateral and posterior margins straight, anterolateral corners bluntly angled.

Mandibles finely punctured. Head, mesosoma, petiole, and first gastral segment densely and coarsely punctured, interface much smaller than puncture diameter. Punctures on first gastral segment even larger, and foveolate on its sides. Rest gastral segments finely punctured and relatively shining. Whole body covered with dense, suberect to subdecumbent short pubescence, without standing hairs. Scapes and tibiae with dense decumbent short pubescence, without standing hairs. Colour reddish brown. Apical antennal segments, legs, and gastral apex yellowish brown. Eyes black.

Type Material
Holotype: worker, China: Yunnan Province, Mengla County, Shangyong Town, Manzhuang Village, 21°25.119’N, 101°41.191’E, 980 m, 23. III. 2012, collected from a ground sample in semi-evergreen monsoon forest, Wenxia Cui leg., No. A12-311.

Paratypes: 3 workers, same data as holotype; 1 worker, same data as holotype but collected from a soil sample, No. A12-330; 9 workers, same data as holotype but 21° 25.174’ N, 101° 41.033’ E, 1000 m, 22. III. 2012, Congfeng Luo leg., Nos. A12-208 (7 workers), A12-209 (1 worker), A12-200 (1 worker); 1 worker, same data as holotype but 21° 25.718’ N, 101° 41.169’ E, 900 m, 14. VIII. 1997, Yunfeng He leg., No. A97-1672; 2 workers, same data as No. A97-1672 but 10. III. 1998, Taiyong Liu leg., Nos. A98-321 and A98-413; 1 worker, China: Yunnan Province, Mengla County, Mengla Town, Bubang Village, QCASsite 1000-4, 21.621° N, 101.571° E, 995 m, July 2012, collected in rainforest by Berlese method, Akihiro Nakamura & Chris J. Burwell leg., No. A12-1808; 1 worker, same data as No. A12-1808 but QCASsite 1000-5, 21.621° N, 101.574° E, 985m, No. A12-1809; 2 workers, same data as No. A12-1808 but QCASsite 1200-5, 21.594° N, 101.561° E, 1212 m, collected in rainforest by bark spray method, Nos. A12-1810 and A12-1811.

Etymology
The specific epithet refers to “Banna”, an abbreviation of Xishuangbanna, the prefecture within which the type locality of this species is situated.

Determination Clarifications
The Discothyrea specimens from Yunnan Province, that were formerly identified as D. sauteri Forel (Xu, 1999) and Discothyrea sp.1 (Xu, 2002), present the same species, here described as D. banna.

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
 * Skarbek C. J., M. Noack, H. Bruelheide, W. Hardtle, G. von Oheimb, T. Scholten, S. Seitz, M. Staab. 2019. A tale of scale: plot but not neighbourhood tree diversity increases leaf litter ant diversity. Journal of Animal Ecology DOI: 10.1111/1365-2656.13115
 * Xu Z., C. J. Burwell, and A. Nakamura. 2014. Two new species of the proceratiine ant genus Discothyrea Roger from Yunnan, China with a key to the known Oriental species. Asian Myrmecology 6: 33-41.