Nesomyrmex flavigaster

This species is known from Madagascar’s most remote spots. The southern locality (Réserve Spéciale de Cap Sainte Marie, near Marovato), where it can be found in low vegetation of spiny forests in lowlands (200 m), seems the only known natural occurence of this species. The known northern samples were most probably introduced by humans in Nosy Be airport (urban garden) and Manerinerina (disturbed forest).

Identification
A member of the brevicornis species-group.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  flavigaster. Nesomyrmex flavigaster Csösz & Fisher, 2016: 146, figs 26-29 (w.) MADAGASCAR.

Worker
Body color: dark brown; black. Body color pattern: body concolorous, gaster pale yellow. Absolute cephalic size: 629 [546, 740]. Cephalic length vs. maximum width of head capsule (CL/CWb): 1.23 [1.13, 1.29]. Postocular distance vs. cephalic length (PoOc/CL): 0.43 [0.41, 0.46]. Postocular sides of cranium contour frontal view orientation: converging posteriorly. Postocular sides of cranium contour frontal view shape: broadly convex. Vertex contour line in frontal view shape: straight. Vertex sculpture: main sculpture absent, ground sculpture absent, smooth and shiny. Setal pits on head dorsum: inconspicuous with obscure demarcation. Gena contour line in frontal view shape: convex. Genae contour from anterior view orientation: converging. Gena sculpture: ground sculpture areolate, main sculpture absent; ground sculpture areolate, main sculpture costulate. Concentric carinae laterally surrounding antennal foramen: present. Eye length vs. absolute cephalic size (EL/CS): 0.23 [0.21, 0.25]. Frontal carina distance vs. absolute cephalic size (FRS/CS): 0.34 [0.33, 0.36]. Longitudinal carinae on median region of frons: absent. Smooth median region on frons: present. Antennomere count: 12. Scape length vs. absolute cephalic size (SL/CS): 0.62 [0.59, 0.66]. Median clypeal notch: present. Ground sculpture of submedian area of clypeus: present. Median carina of clypeus: absent. Metanotal depression: present. Dorsal region of mesosoma sculpture: imbricate, main sculpture absent. Lateral region of pronotum sculpture: imbricate, main sculpture absent; inconspicious areolate ground sculpture, main sculpture dispersed costate. Mesopleuron sculpture: ground sculpture areolate, main sculpture absent. Metapleuron sculpture: ground sculpture areolate, main sculpture absent. Petiole width vs. absolute cephalic size (PEW/CS): 0.22 [0.20, 0.22]. Dorsal region of petiole sculpture: ground sculpture areolate, main sculpture dispersed rugose. Postpetiole width vs. absolute cephalic size (PPW/CS): 0.31 [0.29, 0.33]. Dorsal region of postpetiole sculpture: ground sculpture smooth, main sculpture absent. Surface of first gastral tergite: imbricate sculpture absent.

Type Material
Holotype: CASENT0453374, collection code: BLF05530, Réserve Spéciale de Cap Sainte Marie, 12.3 km 262° W Marovato, -25.58167°, 45.16833°, alt 200 m, Fisher-Griswold Arthropod Team, 02.11.2002, (1w,, CASENT0453374); Paratypes: 25 workers from the same locality, collection code: BLF05530, CASENT0453367-73, CASENT0453376-90 (CASC).

Etymology
The name (flavigaster) refers to the light yellow gaster of this species, which is in sharp contrast to the dark brown color of the rest of the body.