Tetraponera microcarpa

In Hong Kong Snelling found foraging workers on a bamboo stalk on a wooded hillside. Ward also collected specimens in Hong Kong, from a dead twig of Daphniphyllum calycinum in disturbed secondary rainforest (with some exotic trees) along the west side of Shing Mun Reservoir.

Identification
A member of the Tetraponera allaborans species-group.

Ward (2001) - It has not been possible to examine the types of T. microcarpa, but among specimens that I have studied from China and Vietnam is a distinctive species that agrees closely with the original description of T. microcarpa. As I interpret it, this is a small, dark species superficially similar to Tetraponera allaborans but possessing shorter scapes in the worker (SI 0.52-0.57, SI2 0.41--0.44, SI3 1.10-1.20 v. 0.57-0.65, 0.46-0.57, and 1.21-1.53 in T. allaborans) and a more flattened and straight-sided pronotum. Additionally, among the few small (HW <0.70) workers of T. allaborans that potentially overlap in size with those of T. microcarpa, the latter can be distinguished by their wider petiole relative to pronotal width and petiole length (DPW/PrWM 0.54-0.58 v. 0.47-0.51; PWI 0.44-0.48 v. 0.34-0.43), and shorter petiole relative to head length (PL/HL 0.56-0.59 v. 0.60-0.70).

Workers of T. microcarpa differ from those of the T. modesta-complex by their pronotal margins being more sharp-edged, subparallel, and closer to one another (PrWM/ MTW 1.14-1.21 compared with 1.21-1.44 in the T. modesta-complex), by the flatter pronotal dorsum, and by their shorter scapes (SI 0.52-0.57, SI2 0.41-0.44 v. 0.58-0.68 and 0.45-0.54). Tetraponera microcarpa workers are also darker in color than those of Tetraponera modesta and Tetraponera crassiuscula, and differ from Tetraponera extenuata workers by the shorter legs (LHT/HW 0.76-0.83 v. 0.84-0.94).

Also characteristic (but not absolutely diagnostic) of T. microcarpa workers are the bidentate median clypeal lobe, which occurs occasionally in T. allaborans workers, and the broad profemur (FI 0.42-0.48, v. 0.36-0.45 in T. allaborans and 0.36-0.43 in the T. modesta-complex).

Distribution
Southern China and northern Vietnam.

Distribution based on Regional Taxon Lists
Oriental Region: Vietnam. Palaearctic Region: China.

Nomenclature

 *  microcarpa. Tetraponera microcarpa Wu & Wang, 1990: 515, fig. 1 (w.) CHINA. See also: Ward, 2001: 615.

Worker
Ward (2001) - HW 0.60-0.64, HL 0.73-0.83, LHT 0.46-0.51, CI 0.76-0.83, FCI 0.09-0.12, REL 0.36-0.40, REL2 0.46-0.50, SI 0.52-0.57, SI3 1.10-1.20, FI 0.42-0.48, PLI 0.53-0.59, PWI 0.44-0.48, PDI 1.01-1.15, LHT/HW 0.76-0.83, CSC 0-2, MSC 3-4.

Small species (HW <0.66), with somewhat elongate head (CI <0.85) and large eyes (REL2 >0.45); median clypeal lobe narrow, protruding moderately, its anterior margin concave and furnished with a pair of blunt lateral teeth, whose anterior reach exceeds that of the anterolateral clypeal margins; scape relatively short (see indices); pro femur somewhat short and broad; lateral pronotal margins sharp-edged; pronotum narrow in dorsal view (PrWM/HW 0.56-0.62; PrWM/MTW 1.14-1.21), with margins that are straight and diverge only slightly anteriorly; in posterior view, pronotum appearing relatively flat; mesopropodeal impression longitudinally rugulate, lacking a metanotal plate; propodeum generally low and broad, PDI-1.04 (somewhat more elevated in workers from Vietnam, where PDI - 1.10); in profile, propodeum appearing almost quadrate, the dorsal face somewhat flattened, and rounding rather suddenly into the straight declivitous face; petiole relatively short and high (see PLI and PWI values). Integument smooth and shiny, with scattered punctures and fine irregular lineations; malar area rather extensively longitudinally carinate, such sculpture extending about two-thirds of the distance from the mandibular insertions to the lower margin of the compound eye. Pilosity sparse, long standing hairs (>0.05 mm in length) scattered on gaster and apex of head, and elsewhere as follows: one supraocular pair; two pairs on pronotum, and one pair each on petiole and postpetiole; much shorter, inconspicuous appressed hairs scattered over body, becoming suberect on venter of head and petiole. Black or brownish-black, with petiole, postpetiole and appendages generally lighter medium-brown.

Type Material
Ward (2001) - Holotype, worker, Taishan County, Guangdong, China (Wu Jian); paratypes: 24 workers, same data as ho1otype; 2 workers, Fenyi County, Jiangxi, China (Wang Changlu) [not examined].

References based on Global Ant Biodiversity Informatics

 * Cheng D., Z. Chen, and S. Zhou. 2015. An analysis on the ant fauna of Jinzhongshan Nature Reserve in Gunagxi, China. Journal of Guangxi Normal University: Natural Science Edition 33(3): 129.137.
 * Eguchi K.; Bui T. V.; Yamane S. 2011. Generic synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), part I  Myrmicinae and Pseudomyrmecinae. Zootaxa 2878: 1-61.
 * Guénard B., and R. R. Dunn. 2012. A checklist of the ants of China. Zootaxa 3558: 1-77.
 * Li Z.h. 2006. List of Chinese Insects. Volume 4. Sun Yat-sen University Press
 * Lu Z., and Y. Chen. 2016. Effects of habitat on ant functional groups: a case study of Luchun County, Yunnan Province, China. Chinese Journal of Eco-Agriculture 24(5): 801-810.
 * Ward, P. S. 2001. Taxonomy, phylogeny and biogeography of the ant genus Tetraponera (Hymenoptera: Formicidae) in the Oriental and Australian regions. Invertebrate Taxonomy 15:589-665.
 * Xu Z. and Z.-Q. Chai. 2004. Systematic study on the ant genus Tetraponera F. Smith (Hymenoptera, Formicidae) of China. Acta Zootaxonomica Sinica 29(1): 63-76.
 * Zhang R. J., L. W. Liang, and S. Y. Zhou. 2014. An analysis on the ant fauna of Nonggang Nature Reserve in Guangxi, China. Journal of Guangxi Normal university: Natural Science Edition 32(3): 86-93.