Tetraponera rufonigra

The species nests in cavities in dead and living wood, and the workers can be rather aggressive (Bingham 1903). A colony that I encountered at Mandai, Singapore was occupying live beetle-bored branches of Sonneratia ovata and also extended into cavities in the bole of the tree. In Bangalore, India I found a nest in the primary stem of a Santalum album sapling. The nest inside the live stem conformed to the presumed burrows of a beetle larva (most likely a cerambycid), but also contained incomplete septa, apparently made of dirt that appeared to have been added by the Tetraponera workers. The nest in the Santalum sapling contained workers, eggs, larvae and a large, mature coccid. (Ward 2001)

Identification
Ward (2001) - This species can be recognised by the traits listed in the species-group diagnosis and in the key. Although no type specimens of Tetraponera rufonigra are currently known to exist, the species is so distinctive that its identity has never been in doubt. It shows modest variation in integument sculpture (especially the sheen of the head), petiole shape (see range of PLI and PWI values), and pilosity (see CSC and MSC values). More striking is the variation in the color of the mesosoma and petiole-these parts of the body are usually a light orange-brown that contrasts strongly with the dark head and gaster, thereby imparting a bicolored appearance. But in some populations, especially those from Sri Lanka, the middle part of the body can be heavily infuscated. The darkest Sri Lankan workers are essentially unicolored (the basis of Forel's “variety” ceylonensis).

Distribution
Widely distributed on the Indian subcontinent, and ranges through Southeast Asia as far south as Sumatra and Java. There is also an introduced population in the Seychelles.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia, Krakatau Islands, Malaysia, Singapore. Malagasy Region: Seychelles. Oriental Region: Bangladesh, Bhutan, Cambodia, India, Laos, Myanmar, Nepal, Nicobar Island, Pakistan, Sri Lanka, Thailand, Vietnam. Palaearctic Region: China.

Habitat
Ward (2001) - Habitats occupied by T. rufonigra include semideciduous woodland, mangrove, urban parkland, gardens, and “degraded coastal hill forest”.

Nomenclature

 *  rufonigra. Eciton rufonigrum Jerdon, 1851: 111 (w.) INDIA. Smith, F. 1875: 35 (q.). Combination in Pseudomyrma: Smith, F. 1858b: 159; in Sima: Roger, 1863b: 25; Emery, 1921f: 24; in Tetraponera: Smith, F. 1877b: 68; Wheeler, W.M. 1922a: 1015; Ward, 1990: 489. Senior synonym of ceylonensis, testaceonigra, yeensis: Ward, 2001: 649. See also: Bingham, 1903: 108.
 * yeensis. Sima rufonigra var. yeensis Forel, 1902c: 248 (q.) MYANMAR. Combination in Tetraponera: Chapman & Capco, 1951: 82. Junior synonym of rufonigra: Ward, 2001: 649.
 * testaceonigra. Sima rufonigra var. testaceonigra Forel, 1903d: 402 (w.) INDIA (Nicobar Is). Combination in Tetraponera: Chapman & Capco, 1951: 82. Junior synonym of rufonigra: Ward, 2001: 649.
 * ceylonensis. Sima rufonigra var. ceylonensis Forel, 1909e: 394 (w.q.) SRI LANKA. Combination in Tetraponera: Chapman & Capco, 1951: 81. Junior synonym of rufonigra: Ward, 2001: 649.

Worker
Ward (2001) - HW 1.62-2.07, HL 1.76-2.37, LHT 1.52-2.04, CI 0.87-0.95, FCI 0.13-0.16, REL 0.31-0.34, REL2 0.35-0.37, SI 0.58-0.63, SI3 1.61-1.74, FI 0.30-0.36, PLI 0.46-0.53, PWI 0.43-0.52, PDI 0.99-1.03, LHT/HW 0.86-0.98, CSC 12-24, MSC 20-66.

Large species, with broad head (CI >0.85); masticatory margin of mandible with five teeth; anteromedial lobe of clypeus narrow but prominently protruding; distance between frontal carinae exceeding maximum scape width; eyes relatively small; ocelli well developed; profemur slender (FI <0.38); pronotum with lateral margins well developed, and with humeri angulate, when seen in dorsal view; mesonotum descending suddenly to mesopropodeal impression, latter moderately long, consisting of a rugulose transverse furrow, flanked by low tubercles (containing metanotal spiracles); propodeum about as high as wide, dorsal face broad and flattened, and rounding gradually into the shorter declivitous face; petiole with short anterior peduncle and somewhat elongate and flattened node; anteroventral petiolar tooth usually prominent, directed ventrad; petiole varying from about 1.9-2.3x longer than broad; postpetiole longer than broad; metabasitarsal sulcus well developed, occupying about 0.7-0.8x length of the metabasitarsus; mesobasitarsal sulcus also present, occupying 0.5-0.6x length of mesobasitarsus. Head densely punctate; punctures separated by their diameters or less, interspaces sublucid to subopaque; mesosoma and petiole densely punctate to rugulopunctate, subopaque; punctures finer on postpetiole and gaster, and integument correspondingly shinier. Standing pilosity abundant on most of body (see CSC and MSC values), including mesonotum and propodeum; appressed pubescence common, moderately dense on abdominal tergite IV Head and gaster dark brown to brownish-black, mesosoma and petiole usually a constrastingly lighter orange-brown, postpetiole variable (less commonly mesosoma and petiole darker, approaching color of head and gaster); mandibles, antennae, protibia and tarsi medium-brown to yellowish-brown.

Type Material
Ward (2001) - Syntypes, workers, southern India [apparently lost]. Original description: “very common in the Carnatic, less so in Malabar”.