Leptogenys rabebe

It nests in rotten logs and forages mainly in leaf litter.

Identification
Rakotonirina and Fisher (2014) - Worker. Mandible not closing tightly against clypeus at rest; eye small with maximum diameter less than greatest width of antennal scape; antennal scape short, extending beyond posterior cephalic margin by one-fifth of its apical portion.

Leptogenys rabebe can be confused with species in the toeraniva group but is easily differentiated by the discontinuous lamellate membrane on the lateral and anteromedian lobes of the clypeus, leaving a gap between the sides of the anteromedian lobe of the clypeus and mandibles when the latter are fully closed. Its prora is located near the anteroventral angle of third abdominal sternite. In the toeraniva group, the mandibles are capable of closing tightly against the clypeus and there is usually a large indentation between the prora and the rounded anteroventral angle of third abdominal sternite. Leptogenys rabebe closely resembles the species in the incisa group but these latter species have larger eyes whose maximum diameter is markedly greater than the maximum width of antennal scape and the mandible is more arched from the base to the apex.

Key to Malagasy Leptogenys

Distribution
This species is restricted to the northeast of Madagascar and has been collected from the transitional humid forest of Marotandrano near Mandritsara, the lowland rainforest of Ambatovaky, and the Montagne d’Akirindro of Makira.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  rabebe. Leptogenys rabebe Rakotonirina & Fisher, 2014: 159, figs. 40A, 129, 178 (w.) MADAGASCAR.

Worker
(3 specimens). HW: 0.95–1.00, HL: 1.22–1.24, CI: 77–82, SL: 1.03–1.10, SI: 102–115, PW: 0.79–0.80, WL: 1.79–1.82, PNH: 0.72–0.73, PNL: 0.48–0.54, PNW: 0.64–0.69, DNI: 119–143, LNI: 134–152.

Head longer than broad, widest at level of eyes, with slightly convex lateral border. Eye small, maximum diameter about half of greatest width of scape. Antennal scape relatively short, only about one-fifth of its length surpassing posterior cephalic margin. Anterior clypeal margin with narrow triangular median lobe, bordered with thin, semi-translucent lamella; lateral portion narrow and bordered by broad lamellate membrane; three peg-like setae projecting anteriorly from anterior margin of median lobe. Mandibles elongate and linear, not closing tightly against margin of clypeus when their apices cross one another; basal groove distinctly impressed. With mesosoma in dorsal view, metanotal groove impressed and transversely striate. In lateral view, petiolar node slightly higher than broad, with straight anterior and posterior faces and fairly convex dorsal margin. Subpetiolar process consisting of toothlike extension anteriorly followed by rounded lobe posteriorly, with indentation between them. In lateral view, helcium located approximately at mid-height of anterior margin of third abdominal segment; prora large and lobe-like; anteroventral angle of third abdominal sternite usually rounded. Prora and anteroventral angle of third abdominal sternite not separated by wide indentation. Constriction between third and fourth abdominal segments absent or very weakly visible. Sculpture of head dorsum rugulose-punctate or reticulate punctate anteriorly, becoming punctate posteriorly. In dorsal view, pronotum and petiolar node mostly smooth and shining, with scattered superficial punctures; mesonotum, propodeum, and third and fourth abdominal tergites shallowly punctate. Mesopleuron and metapleuron densely and finely rugose. Color dark brown to reddish-orange with brown or lighter appendages.

Type Material
Holotype worker: Madagascar, Toamasina, RS Ambatovaky, Sandrangato river, -16.8175, 49.295, 360 m, rainforest, ex rotten log, 25 Feb 2010 (B.L. Fisher et al.) collection code: BLF24761, specimen code: CASENT0163120.