Nesomyrmex striatus

This species is known to occur in montane rainforests between elevations of 900 m and 1125 m (mean: 1054 m) of the southeastern part of Madagascar.

Identification
A member of the sikorai species-group.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  striatus. Nesomyrmex striatus Csösz & Fisher, 2016b: 25, figs. 3, 15A-C (w.m.) MADAGASCAR.

Worker
Body color: black. Body color pattern: concolorous. Absolute cephalic size: 842 μm [775, 889]. Cephalic length vs. Maximum width of head capsule (CL/CWb): 1.155 [1.117, 1.192]. Postocular distance vs. cephalic length (PoOc/CL): 0.460 [0.441, 0.472]. Postocular sides of cranium contour, anterior view orientation: converging posteriorly. Postocular sides of cranium contour, anterior view shape: convex. Vertex contour line in anterior view shape: straight to feebly convex. Vertex sculpture: main sculpture parallel costate, ground sculpture smooth. Gena contour line in anterior view shape: convex. Gena contour from anterior view orientation: strongly converging. Gena sculpture: rugoso-reticulate with feeble areolate ground sculpture. Concentric carinae laterally surrounding antennal foramen: present. Eye length vs. absolute cephalic size (EL/CS): 0.219 [0.209, 0.232]. Frontal carina distance vs. absolute cephalic size (FRS/CS): 0.288 [0.282, 0.294]. Longitudinal carinae on median region of frons: present. Smooth median region on frons: present. Antennomere count: 12. Scape length vs. absolute cephalic size (SL/CS): 0.794 [0.779, 0.813]. Median clypeal notch count: present. Median carina of clypeus: absent. Spine length vs. absolute cephalic size (SPST/CS): 0.241 [0.219, 0.26]. Minimum spine distance vs. absolute cephalic size (SPBA/CS): 0.242 [0.204, 0.26]. Apical spine distance vs. absolute cephalic size (SPTI/CS): 0.244 [0.191, 0.266]. Propodeal spine shape: curving upward. Apical distance of pronotal spines vs. absolute cephalic size (PSTI/CS): 0.666 [0.649, 0.686]. Metanotal depression: present. Dorsal region of mesosoma sculpture: costate with smooth ground sculpture. Lateral region of pronotum sculpture: areolate ground sculpture, main sculpture areolate. Mesopleuron sculpture: smooth ground sculpture, superimposed by dispersed rugulae. Metapleuron sculpture: fine areolate ground sculpture, superimposed by coarse rugae. Petiole width vs. absolute cephalic size (PEW/CS): 0.243 [0.229, 0.253]. Dorsal region of petiole sculpture: ground sculpture smooth, main sculpture absent. Postpetiole width vs. absolute cephalic size (PPW/CS): 0.362 [0.351, 0.373]. Dorsal region of postpetiole sculpture: ground sculpture smooth, main sculpture absent.

Type Material
Holotype worker: Madagascar: Prov. Toliara, Anosy Region, Anosyenne Mts., 31.2 km NW Manantenina, 1125 m, -24.13894 N, 47.06804 E, 26. ii.2015, collection code: BLF36533; CASENT0393121, Fisher et al. (, CASENT0393121); Paratypes: 5 workers and a male with the same label data (CAS).

Etymology
The name refers to the coarse, striate/costate surface sculpturing on the head and mesosoma.