Leptogenys barimaso

A few localities in the northeast of Madagascar harbor L. barimaso. The species is known to occupy not only the natural littoral and humid forests, but also the disturbed and fragmented forest habitats in the region. Leptogenys barimaso forages on the ground and in leaf litter, but it also hunts on lower vegetation. Its nests are mainly in rotten logs and rarely in rotten branches on the forest floor.

Identification
A member of the imerinensis complex of the incisa species group. Rakotonirina and Fisher (2014) - Worker. Small peg-like setae present from near anterior border of narrowly semi-circular anteromedial clypeal lobe; mandible with inner margin evenly and slightly concave; antennal scape long (SI> 130), more than apical third surpassing posterior cephalic margin; eye breaking outline of sides of head; dorsum of head and body with standing hairs longer than maximum diameter of eye; posterior margin of petiolar node without constriction immediately above posteroventral angle.

Leptogenys barimaso is similar to Leptogenys chrislaini and Leptogenys lavavava, but in L. barimaso the inner margin of the mandible is evenly concave, the anteromedian portion of the clypeus is narrow with a rounded lobe, and abdominal tergites III and IV have long standing hairs whose length is greater than the maximum diameter of the eye. The abrupt projection of the anterior margin of the clypeus into a narrowly angulate lobe, the subquadrate head, the strongly curved basal portion of the mandible, and the shorter hairs on abdominal tergites III and IV render L. chrislaini separable from L. barimaso. In L. lavavava, the median portion of clypeus is projecting anteriorly into a toothlike spine and the basal portion of mandible is remarkably curved, extending laterally beyond the widest level of the sides of the head.

Key to Malagasy Leptogenys

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  barimaso. Leptogenys barimaso Rakotonirina & Fisher, 2014: 79, figs. 55B, 58C, 59A, 97, 113 (w.) MADAGASCAR.

Worker
(7 specimens). HW: 1.16–1.36, HL: 1.45–1.65, CI: 80–84, SL: 1.66–2.00, SI: 133–147, PW: 0.93–1.07, WL: 2.41–2.87, PNH: 0.80–0.94, PNL: 0.82–1.00, PNW: 0.75–0.93, DNI: 88–96, LNI: 91–102.

In full-face view, head elongate and broader in front than behind; side noticeably convex and diverging anteriorly throughout length. Eye large and distinctly convex, breaking line of lateral cephalic border. Antennal scape markedly long, with more than one third its length extending beyond posterior cephalic margin. Anterior clypeal margin extending suddenly into a narrowly rounded median lobe which is bordered by a yellow-orange lamella. Mandible long and narrow, inner margin broadly concave and leaving a gap between clypeus and blades when closed; basal groove narrow. Preapical tooth or denticle may be present on each blade. In full-face view, hypostomal teeth not visible. Mesosoma in dorsal view, with impressed and transversely rugulose metanotal groove; in profile, overall shape short and high; posterolateral border of propodeum without toothlike lobe. In lateral view, petiolar node more or less elongate, dorsal outline of node convex and posterior margin inclined anteriorly; in dorsal view, node longer than broad. Constriction between abdominal segments III and IV distinct. Mandibular blade covered with interrupted short and fine striation and scattered punctures. Dorsum of head, mesosoma and petiolar node coarsely reticulate-rugose, with large punctures or foveae in between; some punctures widely spaced; declivitous surface transversely rugulose. Dorsum of head and body with long standing hairs longer than greatest diameter of eye; pubescence reduced. Color black to reddish-brown, with dark brown to lighter appendages.

Type Material
Holotype worker: Madagascar, Toamasina, Montagne d'Akirindro 7.6 km 341° NNW Ambinanitelo, -15.2883, 49.5483, 600 m, rainforest, ex rotten branch on ground, 17–21 Mar 2003 (Fisher, Griswold et al.), collection code: BLF08268, specimen code: CASENT0496058. Paratypes: 5 workers with same data as holotype but specimen coded as: CASENT0496059, CASENT0496057, CASENT0247235, CASENT0247236, CASENT0247237 (CASC,, , ).