Tetraponera atra

Apart from the type locality in Irian Jaya, there are records of T. atra from several sites in Papua New Guinea. Collections with habitat data are from “rainforest”, “lowland rainforest” and “dry evergreen forest”. (Ward 2001)

Identification
Ward (2001) - This species is closely related to Tetraponera laeviceps and Tetraponera mimula, but it can be distinguished by the much denser punctate sculpture on the head and mesosoma dorsum, which renders these parts of the body more or less opaque. T. atra is also larger on average, with disproportionately longer legs and scapes (see keys). Even among the small series of specimens examined there is considerable variation in the shapes of the pronotum, propodeum and petiole. The petiolar node is notably lower and thinner in two specimens from eastern Papua New Guinea. Sculpture also varies somewhat, especially on the side of the pronotum, which can range from smooth and shiny to punctulate and subopaque.

Although the holotype queen of T. atra is apparently lost, there are enough details in the original description to associate the name with the opaque, densely sculptured species recognised here. In particular, Donisthorpe's (1949) description of the color, sculpture, pilosity, head shape, mandibular dentition, petiole shape (long with a thin peduncle) and size (8.5 mm long) of the type specimen allows one to eliminate all other New Guinea species for which the queen is known (Tetraponera allaborans, Tetraponera laeviceps, Tetraponera modesta, Tetraponera nitida, Tetraponera punctulata and Tetraponera rotula). The original description approaches that of the T. laeviceps queen except that T. atra is described as being 'rather dull, clothed with fine pubescence' and having 'mesonotum more distinctly punctured than pronotum, which is very finely punctured'. These are characteristic features of the species that is here assigned the name T. atra. Moreover, although there is one other New Guinea species (T. mimula), for which the queen is unknown, the worker of this species has a shiny integument and relatively short petiole, so its queen almost certainly does not correspond to that of T. atra.

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea.

Nomenclature

 *  atra. Tetraponera atra Donisthorpe, 1949b: 493 (q.) NEW GUINEA. Ward, 2001: 620 (w.).

Worker
Ward (2001) - HW 0.94-1.04, HL 1.04-1.18, LHT 0.84-1.00, CI 0.86-0.90, FCI 0.12-0.14, REL 0.38-0.42, REL2 0.44--0.47, SI 0.61-0.62, SI3 1.29-1.39, FI 0.41-0.44, PLI 0.38-0.51, PWI 0.33-0.45, PDI 1.24-1.31, LHT/HW 0.90-0.96, CSC 0-2, MSC 0-2.

Medium-large species, with broad head; clypeus short, its anteromedial portion protruding only slightly beyond level of the anterolateral clypeal margin; frontal carinae moderately well separated, the distance between them subequal to maximum scape width; eye relatively large (see REL and REL2 values); scape rather long (SI2 0.53-0.55; SI3 > 1.26); pro femur slender; pronotum slightly to moderately expanded laterally (PrWM/MTW 1.15-1.30), its anteromedial portion flat or weakly concave; lateral pronotal margins blunt-edged; mesopropodeal impression well marked but short, consisting of a pit-shaped depression, flanked by lateral ridges; propodeum conspicuously elevated, markedly higher than wide, dorsal face moderately to strongly convex in profile, and rounding insensibly into declivitous face; legs rather long, LHT/HL 0.79-0.86; petiole long and slender, with well differentiated anterior peduncle; petiolar node somewhat variable in height and width (see range of PLI and PWI values); postpetiole as long as, or longer than, wide; metabasitarsal sulcus well developed, lying in a darkened patch of cuticle and adjacent to a low carina that occupies 0.5-0.7x the length of the basitarsus. Dorsum of head, mesosoma and petiole covered with dense, subcontiguous punctures which render much of the surface opaque; cephalic punctures mostly 0.015-0.020 mm in diameter; mesosomal and petiolar punctures smaller, and tending to become effaced on the sides (especially pronotum) where the integument is correspondingly shinier; postpetiole and gaster finely puncticulate, sublucid; lower malar area rugulopunctate. Standing pilosity very scarce, present on gaster and apex of head, and on the following dorsal surfaces: posterior half of head (0-2), pronotum (0-2), petiole (0-3), and postpetiole (0-3); short appressed pubescence forming a rather dense cover on most of body including abdominal tergite IV Black to dark brownish-black, appendages lighter (medium brown to yellowish-brown), especially scape, first several funicular segments, protibia and tarsi.

Type Material
Ward (2001) - Holotype queen (by monotypy), Maffin Bay, Indonesia (E. S. Ross) [type not in, apparently lost].