Leptomyrmex flavitarsus

L. flavitarsus has been recorded in rainforest, including lowland secondary rainforest and montane rain¬forest. Nesting habits are unknown.

Identification
This species superficially resembles the two other dark species of Leptomyrmex known to occur in New Guinea, Leptomyrmex niger and Leptomyrmex melanoticus, but can be distinguished by the abundant pubescence on the head and body, especially the pronotum, which is lacking in the others. L. flavitarsus is also relatively larger and stouter (HW 1.18–1.45 mm; WL 3.25–3.68 mm) than the other two (L. niger HW 1.01–1.25 mm; WL 3.15–3.58 mm. L. melanoticus HW 0.99–1.06 mm; WL 3.32–3.76 mm), and closely resembles the pale Leptomyrmex puberulus, but is darker in color and lacks the pubescent eyes of L. puberulus. (Lucky and Ward 2010)

Key to New Guinean Leptomyrmex Species

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

Castes
Queens of Leptomyrmex flavitarsus have not been collected.

Nomenclature

 *  flavitarsus. Formica flavitarsus Smith, F. 1859a: 136 (w.) INDONESIA (Aru I.). Lucky & Ward, 2010: 34 (m.). Combination in Camponotus: Roger, 1863b: 4; in Camponotus (Tanaemyrmex): Emery, 1925b: 90; in Leptomyrmex: Shattuck, 1992c: 114.

Worker
Lucky and Ward (2010) – measurements (n = 10) HL 1.74–1.99, HW 1.18–1.45, MFC 0.21–0.29, IOD 0.66–0.90, SL 3.26–3.62, EL 0.28–0.43, WL 3.25–3.68, PW 0.89–1.04, DPW 0.34–0.43, HTL 3.68–4.19, HTWmin 0.12–0.14, HTWmax 0.18–0.23, CI 0.67–0.73, SI 2.47–3.03, OI 0.06–0.15, HTC 0.55–0.71.

Medium sized species (HW 1.18–1.45 mm; WL 3.25–3.68 mm) with broad head (CI 0.67–0.73), widest anterior to eyes. Sides of head convex, genae straight to slightly concave anteriorly. Behind the eyes, head gently rounding to flat postocular margin. Approximately 15 teeth and denticles interspersed along mastica¬tory margin of mandible. Anterior clypeal margin weakly concave. Eyes positioned posterior to midline of head, small and round, convex and hairless, not reaching lateral margins of head. Antennae not compressed, scapes surpassing posterior margin of head by 3/5 their length.

Dorsal face of propodeum approximately as long as declivitous face, dorsal face with a slight transverse impression on anterior end. Petiolar node thick (DPW 0.34–0.43 mm), with rounded summit; anterior face short and perpendicular to base, with shallow median longitudinal groove. Posterior face of petiole long, flat and sloping, ventral surface flat, not projecting. Gaster broadly elliptical. Legs long and slender.

Surface distinctly shagreened and shining throughout, subopaque. Pubescence long and brownish, distrib¬uted all over the body, but especially prominent on the head, pronotum and gaster. Black, bristle-like hairs on clypeus, venter and gaster. Body generally dark brown with the tarsi, femoro-tibial joints and antennal funiculus yellow.

Type Material
Formica flavitarsus

Two worker syntypes in. Labelled “Aru 14” and “Aru 45.” Donisthorpe (1932c: 452) records only one worker, but both specimens appear to come from the same series, and appear to have originally been mounted on a single card, that was later cut in half. Donisthorpe’s referral of this species to Camponotus is in error.