Tetraponera nigra

Habitats from which the species has been recorded include tropical dry forest, riparian forest, semideciduous forest, rainforest, “kerangas woodland” and mangrove. Most nest series come from dead twigs or branches but Doyle McKey collected colonies from live stems of Stereospermum personatum (Kabini, Karnataka) and from live thorns of Acacia horrida (19 km E Oothu, Tamil Nadu), indicating that the species is a facultative inhabitant of live plant cavities. (Ward 2001)

Identification
Ward (2001) - Workers of T. nigra can be distinguished from those of related species (Tetraponera attenuata, Tetraponera binghami and Tetraponera buops) by the short robust petiole (PLI >0.50). In addition, T. nigra workers can be separated from those of T. attenuata by the sparser pubescence on the pronotum and from those of T. binghami and T. buops by the better-developed background sculpture on the head (interspaces between cephalic punctures finely reticulate as opposed to predominantly smooth and shiny). The head is also generally broader in T. nigra (CI rarely <0.80) than in T. binghami and T. buops (CI 0.70-0.78).

Tetraponera nigra workers exhibit variation in pilosity (especially the number of standing hairs on the mesosoma dorsum: see range of MSC values), integument sculpture, propodeum shape, and head shape, at both local and broad geographical scales. Variation in head shape is even more pronounced in the queens, with CI ranging from 0.68 to 0.82 in a sample of five queens from southern India. The queen with the most elongate head (CI 0.68) is part of a nest series from Kabini, Karnataka (D. McKey #46), taken from live branches of Stereospermum personatum. The workers in this series also have unusually long heads (CI- 0.76-0.77), but a second Stereospermum nest series from the same locality (D. McKey #47) has otherwise similar workers whose heads are more typically broad: CI 0.82-0.85 (no queen available from this second series). This would appear to be yet another example of the substantial within-population variation that can occur in Tetraponera species.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, Philippines. Oriental Region: Bangladesh, India, Laos, Sri Lanka, Thailand. Palaearctic Region: China.

Nomenclature

 *  nigra. Eciton nigrum Jerdon, 1851: 112 (w.q.) INDIA. Combination in Pseudomyrma: Smith, F. 1858b: 159; in Sima: Roger, 1863b: 25; Stitz, 1925: 117; in Tetraponera: Smith, F. 1877b: 68; Wheeler, W.M. 1919e: 64; Donisthorpe, 1942d: 454. Senior synonym of atrata: Dalla Torre, 1893: 54; Emery, 1895k: 464. Senior synonym of fergusoni, insularis, krama, petiolata: Ward, 2001: 634.
 * atrata. Tetraponera atrata Smith, F. 1852: 44, 3 figs. (w.) INDIA. Junior synonym of nigra: Dalla Torre, 1893: 54; Emery, 1895k: 464.
 * petiolata. Tetraponera petiolata Smith, 1877b: 70 (w.q.m.) SRI LANKA. Combination in Sima: Emery, 1887b: 445 (footnote); in Sima (Tetraponera): Emery, 1921f: 26; in Tetraponera: Chapman & Capco, 1951: 81. Junior synonym of nigra: Forel, 1903a: 709; revived from synonymy: Bingham, 1903: 113; returned to synonymy of nigra: Ward, 2001: 634.
 * insularis. Sima nigra var. insularis Emery, 1901f: 113 (w.q.) SRI LANKA. Combination in S. (Tetraponera): Emery, 1921f: 26; in Tetraponera: Chapman & Capco, 1951: 80. Junior synonym of nigra: Ward, 2001: 634.
 * fergusoni. Sima nigra r. fergusoni Forel, 1902c: 248 (w.) INDIA. Combination in S. (Tetraponera): Emery, 1921f: 26; in Tetraponera: Chapman & Capco, 1951: 81. Raised to species: Bingham, 1903: 114; Collingwood, 1962: 225. Subspecies of nigra: Emery, 1921f: 26; Ward, 1990: 488. Junior synonym of nigra: Ward, 2001: 634.
 * krama. Sima nigra var. krama Forel, 1912d: 105 (q.) INDONESIA (Java). Combination in S. (Tetraponera): Emery, 1921f: 26; in Tetraponera: Chapman & Capco, 1951: 80. Junior synonym of nigra: Ward, 2001: 634.

Worker
Ward (2001) - HW 0.99-1.38, HL 1.18-1.60, LHT 1.00-1.48, CI 0.76-0.89, FCI 0.13-0.17, REL 0.28-0.33, REL2 0.32-0.38, SI 0.60-0.70, SI3 1.55-2.07, FI 0.38-0.42, PLI 0.52-0.64, PWI 0.41-0.51, PDI 1.02-1.10, LHT/HW 0.93-1.11, CSC 10-24, MSC 6-50.

Relatively large, black species; head moderately broad (CI usually >0.80); clypeus short, its anteromedial margin convex and often weakly crenulate; distance between frontal carinae equal to or exceeding maximum scape width; eyes relatively small (see REL, REL2 and SI3 values); with head in full-face view lateral margins rounding into straight or slightly convex posterior margin; profemur slender; pronotum with lateral margins weakly to moderately developed; mesopropodeal impression well developed and relatively open, flanked by low metanotal tubercles that are usually clearly visible in profile; propodeum slightly higher than wide, dorsal face rounding gradually into the declivitous face and varying from somewhat flattened to strongly convex in profile; legs long relative to head size, LHT/HL 0.81-0.97; petiole with distinctly differentiated peduncle and node; petiole less than twice as long as high (PLI >0.50) and 2.0-2.4x longer than broad; postpetiole varying from slightly longer than broad to broader than long; metabasitarsal sulcus well developed, often darker than the surrounding cuticle, and lying adjacentto a raised ridge of variable length (from 0.2 x to 0.6x the length of the basitarsus). Integument with numerous small punctures, the interspaces sublucid and finely reticulate; sculpture becoming more effaced, and integument correspondingly shinier, on side of mesosoma and on petiole, postpetiole and gaster; punctures on dorsum of head and mesosoma mostly 0.005-0.015 mm in diameter and separated by one to several diameters; lower malar area with coarser punctures, sometimes intermixed with irregular longitudinal rugulae. Standing pilosity common on much of body (CSC >9, MSC usually > 10), often grading into shorter suberect and decumbent pubescence; the latter may be especially conspicuous on the propodeum, petiolar and postpetiolar nodes, gaster and legs, but is generally absent from the pronotum where the pubescence consists mostly of short, appressed hairs. Black to brownish-black, appendages usually more or less concolorous, but scape and first several funicular segments may be lighter.

Type Material
Ward (2001) - Syntypes, workers, queens, southern India [types lost]. From original description: “rare in Malabar, but tolerably common in parts of the Carnatic”.