Nesomyrmex gibber (Donisthorpe, 1946)

Csosz, Sandor & Fisher, Brian L., 2016, Taxonomic revision of the Malagasy Nesomyrmexmadecassus species-group using a quantitative morphometric approach, ZooKeys 603, pp. 105-130 : 114-116

Taxon classification Animalia Hymenoptera Formicidae

Nesomyrmex gibber (Donisthorpe, 1946) Figs 7-9, Table 2

Type material investigated.

Holotype: "Ireneopone gibber , H. Donistorphe, 1946 TYPE" Mauritius, Calebasses Mt., 22. X. 1944, No 72 leg. R. Mamet (1w, BMNH, London, U.K., CASENT0102303), [type specimen was morphometrically not investigated, AntWeb images were used for comparison]

Material examined.

MAURITIUS: MCZENT0578588 (1w, MCZ), MCZENT0578589 (1w, MCZ), MCZENT0578590 (1w, MCZ), MCZENT0578591 (1w, MCZ), MCZENT0578592 (1w, MCZ), MCZENT0578593 (1w, MCZ, CASENT0178539): Le Pouce Mt., N -20.19, E 57.52, alt 700-800 m, W.L. Brown, 1_29_1977; CASENT0922013, (collection code: PSW10502, 1w, PSW, CASENT0922013): Basin Blanc, Mauritius, N -20.45, E 57.4667, alt 500 m, P.S. Ward, 5_06_1989.

Description of workers.

Body color: brown. Body color pattern: Body concolorous. Absolute cephalic size: 724 [655, 752]. Cephalic length vs. Maximum width of head capsule (CL/CWb): 1.17 [1.14, 1.18]. Postocular distance vs. cephalic length (PoOc/CL): 0.41 [0.39, 0.42]. Postocular sides of cranium contour frontal view orientation: converging posteriorly. Postocular sides of cranium contour frontal view shape: convex. Vertex contour line in frontal view shape: straight; slightly concave. Vertex sculpture: main sculpture absent, ground sculpture areolate. Gena contour line in frontal view shape: convex. Genae contour from anterior view orientation: converging; strongly converging. Gena sculpture: ground sculpture areolate, main sculpture absent. Concentric carinae laterally surrounding antennal foramen: absent. Eye length vs. absolute cephalic size (EL/CS): 0.25 [0.24, 0.26]. Frontal carina distance vs. absolute cephalic size (FRS/CS): 0.33 [0.32, 0.34]. 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): 0.80 [0.78, 0.82]. Median clypeal notch: present. Ground sculpture of submedian area of clypeus: present. Median carina of clypeus: absent. Lateral carinae of clypeus: absent. Metanotal depression: present. Dorsal region of mesosoma sculpture: ground sculpture areolate, main sculpture absent. Lateral region of pronotum sculpture: ground sculpture areolate, main sculpture absent. Mesopleuron sculpture: ground sculpture areolate, main sculpture absent. Metapleuron sculpture: ground sculpture areolate, main sculpture absent. Petiole width vs. absolute cephalic size (PEW/CS): 0.21 [0.20, 0.23]. Anterior profile of petiolar node contour line in lateral view shape: concave. Dorso-caudal petiolar profile contour line in lateral view shape: strongly convex. Dorsal region of petiole sculpture: ground sculpture areolate, main sculpture absent. Postpetiole width vs. absolute cephalic size (PPW/CS): 0.30 [0.27, 0.32]. Dorsal region of postpetiole sculpture: ground sculpture areolate, main sculpture absent.

Diagnosis.

This species is easily distinguished from all the other taxa treated in this revisionary work by the presence of the conspicuous mesothoracic hump on the mesosoma of workers (Fig. 9).

Biology and distribution.

Endemic to Mauritius island. Occur in rainforests in higher altitude between 500 and 800 meters, (mean = 714 m). This species van be collected on low vegetation and in dead stems.