Leptomyrmex rufithorax

L. rufithorax has been recorded in rainforest, wet sclerophyll and dry sclerophyll. Nests occur in soil, in and under logs, and under rocks.

Identification
Workers of L. rufithorax are large with a broad head that is round to flat at the postocular margin, and lacking a necklike constriction. The coloration of this species is distinctive: the head, mesosoma and first gastral tergite (3rd abdominal segment) are red, the distal 2/3 of the gaster and the legs, including the coxae, are black. This species occurs in central- and south-east Queensland, where its dark coxae in combination with pale mesosoma distinguish it from sympatric congeners. L. rufithorax may resemble some dark forms of Leptomyrmex erythrocephalus (in northern New South Wales), but in these forms the gaster is uniformly black and the femora are often pale basally. In L. rufithorax workers the femora and tibiae are entirely black, with joints and tarsi showing the only hint of orange. (Lucky and Ward 2010)

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  rufithorax. Leptomyrmex erythrocephalus var. rufithorax Forel, 1915b: 83 (w.) AUSTRALIA. Wheeler, W.M. 1934c: 91 (m.); Lucky & Ward, 2010: 54 (ergatoid q.). Subspecies of erythrocephalus: Wheeler, W.M. 1934c: 91. Raised to species: Lucky & Ward, 2010: 53. Senior synonym of basirufus: Lucky & Ward, 2010: 53.
 * basirufus. Leptomyrmex erythrocephalus subsp. basirufus Wheeler, W.M. 1934c: 90 (w.) AUSTRALIA. Junior synonym of rufithorax: Lucky & Ward, 2010: 53.

Worker
Lucky and Ward (2010) - measurements (n = 10) HL 2.17–2.36, HW 1.34–1.56, MFC 0.28–0.37, IOD 0.81–0.92, SL 3.73–4.07, EL 0.38–0.46, WL 4.04–4.35, PW 1.12–1.34, DPW 0.41–0.51, HTL 4.67–5.13, HTWmin 0.14–0.21, HTWmax 0.26–0.30, CI 0.61–0.66, SI 2.60–2.86, OI 0.09–0.11, HTC 0.47–0.77.

Larger species (HL 2.17–2.36, HW 1.34–1.56) with broad head (CI 0.61–0.66). Head widest at eyes, sides of head convex around eyes, genae concave, posterior to eyes rounding to slightly narrowed flat postocular margin. Posterior portion of head lacking neck-like constriction. Masticatory margin of mandible with approximately 15 teeth and denticles interspersed. Anterior clypeal margin medially concave. Eyes positioned toward posterior part of head. Eyes small, round, hairless, not surpassing lateral margins of head. Antennal scapes not compressed, extending beyond the posterior margin less than 2/3 of their length.

Pronotum short. Declivity of propodeum about half the length of the dorsal face, dorsal face with transverse impression at anterior end, propodeal angle very rounded. Petiolar node triangular in profile, summit convex and rounded, with slight longitudinal impression on dorsum, anterior and posterior faces, anterior face slightly shorter than posterior face, ventral surface of petiole concave. Gaster elliptical-elongate. Legs somewhat compressed.

Body surface slightly shining, finely shagreened. Mandibles with a row of coarse punctures along margin. Pubescence fine. Greyish pilosity minimal, confined to clypeus, venter and gaster. Body and head rufotestaceous, with legs and gaster black. Head and antennae deep reddish orange, femora and tibiae dark brown, joints and tarsi yellow. Gaster black, but first segment rufotestaceous with dark outer margin.

Queen
Lucky and Ward (2010) - Head broader than in worker. Three ocelli deeply set into head in triangular formation, the anteriormost one largest, the posterior two smaller. Pronotum, mesonotum and propodeum voluminous, convex. Dorsal face of propodeum high, convex. Petiole broader than high, with distinct medial impression. Gaster globose, larger than in worker. Scapes, femora and tibiae broad, robust. Surface of body appearing dusty, not shining. Queen coloration as in workers.

Male
Lucky and Ward (2010) - (n = 3) HL 1.70–1.80, HW 1.26–1.33, SL 0.38–0.44, EL 0.62–0.63, HTL 4.26–4.50, CI 0.73–0.76, SI 0.29–0.33, SI2 0.66–0.76.