Nesomyrmex bidentatus

Nesomyrmex bidentatus is found in rainforests and littoral rainforests along the coastline around the entirety of Madagascar.

Identification
Csősz and Fisher (2016) - A member of the angulatus species-group. Workers of N. bidentatus differ from those of Nesomyrmex clypeatus by having no median clypeal notch and from Nesomyrmex angulatus by the lack of an anterolateral pronotal corner. This species can be well separated from Nesomyrmex devius, Nesomyrmex exiguus, Nesomyrmex gracilis, and Nesomyrmex hirtellus based on its short and blunt spines and shorter apical spine distance (SPST/CS). This species is the most similar to Nesomyrmex fragilis: these two species can be separated by morphometrics.

Distribution
Csősz and Fisher (2016) - Nesomyrmex bidentatus is distributed in rainforests and littoral rainforests along the coastline around the entirety of Madagascar. This species occurs syntopically with its sister species N. fragilis in the western Antsisarana region.

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  bidentatus. Nesomyrmex bidentatus Csösz & Fisher, 2016: 18, figs. 7A-7C (w.q.m.) MADAGASCAR.

Worker
Body color: yellow. Body color pattern: concolorous. Absolute cephalic size (mm): 510 [419, 569] (n D 60). Cephalic length vs. maximum width of head capsule (CL/CWb): 1.277 [1.204, 1.352]. Postocular distance vs. cephalic length (PoOc/CL): 0.416 [0.398, 0.440]. Postocular sides of cranium contour frontal view orientation: converging anteriorly; parallel. Postocular sides of cranium contour frontal view shape: straight; feebly convex; convex. Vertex contour line in frontal view shape: straight; feebly convex. Vertex sculpture: main sculpture rugoso-reticulate, ground sculpture areolate. Gena contour line in frontal view shape: convex. Genae contour from anterior view orientation: converging; strongly converging. Gena sculpture: rugoso-reticulate with areolate ground sculpture. Concentric carinae laterally surrounding antennal foramen: absent. Eye length vs. absolute cephalic size (EL/CS): 0.264 [0.233, 0.311]. Frontal carina distance vs. absolute cephalic size (FRS/CS): 0.399 [0.376, 0.419]. Longitudinal carinae on median region of frons: absent. Smooth median region on frons: absent. Antennomere count: 12. Scape length vs. absolute cephalic size (SL/CS): 0.665 [0.634, 0.708]. Facial area of the scape absolute setal angle: 0-15°. Median clypeal notch: absent. Ground sculpture of submedian area of clypeus: present. Median carina of clypeus: present. Lateral carinae of clypeus: present. Median anatomical line of propodeal spine angle value to Weber length in lateral view: cannot be measured. Spine length vs. absolute cephalic size (SPST/CS): 0.264 [0.220, 0.335]. Minimum spine distance vs. absolute cephalic size (SPBA/CS): 0.346 [0.220, 0.335]. Apical spine distance vs. absolute cephalic size (SPTI/CS): 0.335 [0.303, 0.367]. Propodeal spine shape: triangular, blunt. Anterolateral pronotal corner: absent. Metanotal depression count: absent; inconspicuous if present. Dorsal region of mesosoma sculpture: rugulose with areolate ground sculpture. Lateral region of pronotum sculpture: areolate ground sculpture, superimposed by dispersed rugae. Mesopleuron sculpture: areolate ground sculpture, superimposed by dispersed rugae. Metapleuron sculpture: areolate ground sculpture, superimposed by dispersed rugae. Petiole width vs. absolute cephalic size (PEW/CS): 0.397 [0.331, 0.442]. Dorsal region of petiole sculpture: ground sculpture areolate, main sculpture dispersed rugose. Postpetiole width vs. absolute cephalic size (PPW/CS): 0.462 [0.425, 0.508]. Dorsal region of postpetiole sculpture: ground sculpture areolate, main sculpture dispersed rugose.

Type Material
Holotype worker: Madagascar: Prov. Mahajanga, P N Namoroka, 16.9 km 317° NW Vilanandro, 16°24:4’S, 45°18:6’E, 100 m, 12-16.xi.2002, collection code: BLF6646; CASENT0486461, Fisher et al.. Paratypes: Eighteen workers, a single gyne and a male with the same locality data (CASC).

Etymology
The name (bidentatus) refers to the short propodeal denticle pair of this species.

References based on Global Ant Biodiversity Informatics

 * Csősz S., and B. L. Fisher. 2016. Taxonomic revision of the Malagasy members of the Nesomyrmex angulatus species group using the automated morphological species delineation protocol NC-PART-clustering. PeerJ, DOI 10.7717/peerj.1796