Leptogenys ambo

Leptogenys ambo is known only from the montane rainforests in the north of Madagascar. It has been collected from a pitfall trap in Anjanaharibe-Sud, and foraging on the forest floor in Marojejy. One single worker was found nesting in a rotten log in the RS Manongarivo.

Identification
A member of the saussurei species group. Rakotonirina and Fisher (2014) - Worker. Mandible short and robust, capable of closing tightly against clypeus; anterior clypeal margin medially projecting into triangular lobe; clypeus with sharp edge or lamella. Eye large, maximum diameter larger than maximum width of antennal scape. Dorsum of head and mesosoma distinctly sculptured; with mesosoma in dorsal view, metanotal groove indistinct; petiolar node in dorsal view, with straight posterior margin.

This species can be distinguished from the rest of the saussurei group by the indiscernible metanotal groove and the absence of a median excision on the posterior margin of the petiolar node as seen dorsally.

Key to Malagasy Leptogenys

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  ambo. Leptogenys ambo Rakotonirina & Fisher, 2014: 118, figs. 37A, 137, 144 (w.) MADAGASCAR.

Worker
(3 specimens). HW: 1.01–1.21, HL: 1.55–1.75, CI: 65–70, SL: 1.38–1.64, SI: 129–140, PW: 0.92–1.08, WL: 2.30–2.65, PNH: 0.83–1.04, PNL: 0.82–0.98, PNW: 0.70–0.86, DNI: 86–98, LNI: 101–116.

Head distinctly elongate, sides almost straight and diverging slightly anteriorly along length; posterior margin roughly straight. Eye placed anteriorly, the center closer to base of mandible than to midlength of lateral outline of head. Clypeus with median lobe terminating into double small teeth anteriorly; lateral border fringed with semi-translucent lamella. Lamellate membrane of mandibular inner margin rounding into basal preapical tooth, followed by median blunt angle, then sharp apical tooth. In dorsal view, metanotal groove absent; with mesosoma in profile, mesopleural sulcus indistinct, suture between metapleural and propodeum lacking. In dorsal view posterior margin of petiole straight, not medially excised. In profile, anterolateral portion of head from level of eye finely rugose, usually superimposed with large punctures. With head in dorsal view, dorsum densely punctate or reticulate-rugose, with large punctures between them; punctures sparser towards posterior cephalic margin. Mandible with longitudinal striolae and scattered punctures. In dorsal view, pronotum punctate; rest of dorsum of mesosoma sparsely punctulate. In profile, mesopleuron and lower half of lateral surface of propodeum generally smooth, with scattered punctures; upper half of lateral surface of propodeum finely rugulose apart from punctures. Petiolar node dorsally with scattered punctures; in profile, lower half of lateral surface generally smooth, and upper surface finely rugulose with superimposed punctures. Gaster smooth between scattered, small punctures.

Type Material
Holotype worker: Province Antsiranana, RS Manongarivo, 14.5 km 220° SW Antanambao, -13.9983, 48.4167, 1175 m, montane rainforest, ex rotten log, 19–25 Oct 1998 (B.L. Fisher) collection code: BLF01951, specimen code: CASENT0175361.