Leptogenys antongilensis

Leptogenys antongilensis is limited to the lowland rainforest of northeastern Madagascar. It mainly forages on the forest floor and nests in rotten logs and rotten tree stumps, though foraging behavior may also occur on lower vegetation.

Identification
A member of the imerinensis complex of the incisa species group. Rakotonirina and Fisher (2014) - Worker. Anteromedian border of clypeus above semi-translucent lamella with anteriorly projecting peg-like setae; antennal scape relatively long (SI: 132–138), more than a third of apical portion extending beyond posterior cephalic margin; inner margin of mandible blades generally convex and distinctly broadest at mid-length; mesosoma with three visible segments, no other impression as a sclerite in appearance on dorsum of propodeum..

This species is generally similar to Leptogenys manja, but can be easily identified by the fine longitudinal striation on its mandible and the convex inner margin of the blades. In L. manja, the mandibles are smooth and the inner margin of the blades is evenly concave. It can be separated from Leptogenys tatsimo by its three-segmented mesosoma and the narrow lamella bordering the anterior clypeal margin.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  antongilensis. Leptogenys incisa var. antongilensis Emery, 1899f: 272 (w.) MADAGASCAR. Combination in L. (Machaerogenys): Emery, 1911d: 100. Raised to species: Emery, 1911d: 100.

Worker
Rakotonirina and Fisher (2014) - (8 specimens). HW: 1.49–1.58, HL: 1.86–1.97, CI: 80–82, SL: 2.03–2.13, SI: 132–138, PW: 1.22–1.30, WL: 3.13–3.40, PNH: 0.88–0.94, PNL: 0.96–1.05, PNW: 0.87–0.95, DNI: 88–94, LNI: 88–94.

Head subrectangular, slightly broader in front than at the posterior; sides slightly convex and diverging. Posterior margin of head very weakly concave. Eye protruding and projecting beyond lateral margins of head. Antennal scape very long, almost reaching posterior cephalic margin at midpoint. Clypeus with broad, triangular anteromedian lobe; anterior clypeal margin bordered with more or less wide, semi-transparent lamella. Mandible elongate, inner margin convex and blades broadest at midlength, but not capable of closing tightly against clypeus when their apices intersect. Hypostomal teeth short and notvisible with head in full-face view. Mesosoma elongate and relatively low in lateral view; in dorsal view three sections visible, no additional suture present posterior of metanotal groove. With petiole in dorsal view, node longer than broad, and fairly broader than high in profile; posterior margin inclined anteriorly and anterior face vertical, both forming convex lines to rounded dorsal margin. Mandible longitudinally striate, striation occasionally interrupted by smooth spaces and scattered piligerous punctures. Dorsum of head, mesosoma, and petiolar node densely and finely reticulate-punctate to densely and finely reticulate-rugose, with sparse small punctures between sculptures. Third and fourth abdominal tergites smooth and shiny, with small punctures. Body covered with thin erect hairs and pubescence. Black in color; appendages and gaster with brown apical section.

Type Material
Rakotonirina and Fisher (2014) - Lectotype worker, present designation, Madagascar, Toamasina, Bia di Antongil, 1897–1898 (A. Mocquerys), AntWeb CASENT0102015. Paralectotype worker with same data as lectotype but with CASENT0102016 (MSNG) [examined].

References based on Global Ant Biodiversity Informatics

 * Emery C. 1911. Hymenoptera. Fam. Formicidae. Subfam. Ponerinae. Genera Insectorum 118: 1-125.
 * Fisher B. L. 1997. Biogeography and ecology of the ant fauna of Madagascar (Hymenoptera: Formicidae). Journal of Natural History 31: 269-302.
 * Fisher B. L. 2003. Formicidae, ants. Pp. 811-819 in: Goodman, S. M.; Benstead, J. P. (eds.) 2003. The natural history of Madagascar. Chicago: University of Chicago Press, xxi + 1709 pp.
 * Rakotonirina J. C., and B. L. Fisher. 2014. Revision of the Malagasy ponerine ants of the genus Leptogenys Roger (Hymenoptera: Formicidae). Zootaxa 3836 (1): 001163.