Nesomyrmex nitidus Csosz & Fisher

Csosz, Sandor & Fisher, Brian L., 2016, Taxonomic revision of the Malagasy Nesomyrmexmadecassus species-group using a quantitative morphometric approach, ZooKeys 603, pp. 105-130 : 120-125

Taxon classification Animalia Hymenoptera Formicidae

Nesomyrmex nitidus Csosz & Fisher sp. n. Figs 13-15, Table 2

Type material investigated.

Holotype: CASENT0163151, collection code: BLF24792: MADAGASCAR, Prov. Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, N -16.81753, E 49.29498, alt 360 m, B.L. Fisher et al. 2_25_2010, (1w, CAS);

Paratypes: two workers and one gyne from the same locality under CASENT codes: CASENT0163112, collection code: BLF24794: MADAGASCAR, Prov. Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, N -16.81753, E 49.29498, alt 360 m, B.L. Fisher et al.2_25_2010, (1w, CAS); CASENT0162145, collection code: BLF24570: MADAGASCAR, Prov. Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, N -16.7633, E 49.26692, alt 520 m, B.L.Fisher et al.2_26_2010, (1w, CAS); CASENT0161445, collection code: BLF25001: MADAGASCAR, Prov. Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, N -16.81209, E 49.29216, alt 460 m, B.L. Fisher et al.2_22_2010, (1q, CAS);

Material examined.

MADAGASCAR: BLF1888(24) (collection code: BLF01888, 1w, CAS): Prov. Antsiranana, R.S. Manongarivo, 12.8 km 228° SW Antanambao, N -13.97667, E 48.42333, alt 780 m, B.L. Fisher, 10_12_1998; CASENT0059931 (collection code: BLF12392, 1w, CAS): Prov. Fianarantsoa, 7.6 km 122 º Kianjavato, Forêt Classée Vatovavy, N -21.4, E 47.94, alt 175 m, B.L. Fisher et al., 6_6_2005; CASENT0067500 (collection code: BLF12687, 1w, CAS): Prov. Toamasina, Parc National Mananara-Nord, 7.1 km 261° Antanambe, N -16.455, E 49.7875, alt 225 m, B.L. Fisher et al., 11_16_2005; CASENT0068002 (collection code: BLF12780, 2w, CAS): Prov. Toamasina, Res. Ambodiriana, 4.8 km 306° Manompana, along Manom pana river, N -16.67233, E 49.70117, alt 125 m, B.L.Fisher et al., 11_18_2005; CASENT0076214 (collection code: BLF09620, 1w, CAS): Prov. Antsiranana, Forêt de Binara, 7.5 km 230° SW Daraina, N -13.255, E 49.61667, alt 375 m, B.L. Fisher, 12_2_2003; CASENT0077523 (collection code: BLF09713, 1w, CAS): Prov. Antsiranana, Forêt de Binara, 9.1km 233° SW Daraina, N -13.26333, E 49.60333, alt 650-800 m, B.L. Fisher, 12_4_2003; CASENT0107046 (collection code: BLF11562, 1w, CAS), CASENT0107052 (collection code: BLF11562, 1w, CAS): Prov. Antsiranana, Forêt Ambato, 26.6 km 33° Ambanja, N -13.4645, E 48.55167, alt 150 m, B.L. Fisher, 12_9_2004; CASENT0107060 (collection code: BLF11610, 1w, CAS): Prov. Antsiranana, Forêt Ambato, 26.6 km 33° Ambanja, N -13.4645, E 48.55167, alt 150 m, B.L. Fisher, 12_10_2004; CASENT0110675 (collection code: BLF11220, 1w, CAS): Prov. Antsiranana, Ambondrobe, 41.1km 175° Vohemar, N -13.71533, E 50.10167, alt 10 m, B.L. Fisher, 11_30_2004; CASENT0129913 (collection code: BLF15100, 1w, CAS): Prov. Toliara, Parc National Andohahela, Col de Tanatana, 33.3km NW Tolagnaro, N -24.7585, E 46.85367, alt 275 m, B.L. Fisher et al., 11_22_2006; CASENT0136588 (collection code: BLF18628, 1w, CAS): Prov. Antsiranana, Forêt d’Ampombofofo, N -12.09949, E 49.33874, alt 25 m, B.L. Fisher et al., 11_21_2007; CASENT0151045 (collection code: BLF22399, 1w, CAS): Prov. Toamasina, Parc National de Zahamena, Sahavorondrano River, N -17.75257, E 48.85725, alt 765 m, B.L. Fisher et al., 2_23_2009; CASENT0151511 (collection code: BLF23080, 1w, CAS): Prov. Mahajanga, Réserve forestière Beanka, 50.2 km E Maintirano, N -17.88756, E 44.47265, alt 153 m, B.L.Fisher et al., 10_31_2009; CASENT0151914 (collection code: BLF22603, 1w, CAS, CASENT0151914): Prov. Antsiranana, Betaolana Forest, along Bekona River, N -14.52996, E 49.44039, alt 880 m, B.L. Fisher et al., 3_5_2009; CASENT0152470 (collection code: BLF22141, 1w, CAS, CASENT0152470): Prov. Toamasina, Parc National de Zahamena, Tetezambatana forest, near junction of Nosivola and Manakambahiny Rivers, N -17.74298, E 48.72936, alt 860 m, B.L. Fisher et al., 2_19_2009; CASENT0155948 (collection code: BLF22797, 1w, CAS): Prov. Mahajanga, Réserve forestière Beanka, 50.2 km E Maintirano, N -18.02649, E 44.05051, alt 250 m, B.L. Fisher et al., 10_19_2009; CASENT0156676 (collection code: BLF22969, 1w, CAS): Prov. Mahajanga, Réserve forestière Beanka, 53.6 km E Maintirano, N -18.04014, E 44.53394, alt 272 m, B.L. Fisher et al., 10_25_2009; CASENT0162145 (collection code: BLF24570, 2w, CAS): Prov. Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, N -16.7633, E 49.26692, alt 520 m, B.L. Fisher et al., 2_22_2010; CASENT0162819 (collection code: BLF24484, 1w, CAS): Prov. Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, N -16.76912, E 49.26704, alt 475 m, B.L. Fisher et al., 2_21_2010; CASENT0163112 (collection code: BLF24794, 1w, CAS), CASENT0163151 (collection code: BLF24792, 1w, CAS): Prov. Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, N -16.81753, E 49.29498, alt 360 m, B.L. Fisher et al., 2_25_2010; CASENT0205731 (collection code: BLF25790, 1w, CAS): Prov. Toliara, Makay Mts., N -21.25864, E 45.16412, alt 500 m, B.L. Fisher et al., 12_8_2010; CASENT0208609 (collection code: BLF25261, 1w, CAS): Prov. Toliara, Makay Mts., N -21.21985, E 45.32396, alt 500 m, B.L. Fisher et al., 11_25_2010; CASENT0245134 (collection code: BLF26356, 1w, CAS): Prov. Antananarivo, Ankalalahana, N -19.00659, E 47.1122, alt 1375 m, B.L. Fisher et al., 3_29_2011; CASENT0261123 (collection code: BLF27634, 2w, CAS): Prov. Fianarantsoa, Andrambovato along river Tatamaly, N -21.51082, E 47.40992, alt 1063 m, B.L. Fisher et al., 10_24_2011; CASENT0419627 (collection code: BLF04344, 1w, CAS): Prov. Mahajanga, Parc National Tsingy de Bemaraha, 2.5 km 62° ENE Bekopaka, Ankidrodroa River, N -19.13222, E 44.81467, alt 100 m, Fisher-Griswold Arthropod Team, 11_11_2001; CASENT0419848 (collection code: BLF04434, 1w, CAS), CASENT0419849 (collection code: BLF04434, 1w, CAS): Prov. Mahajanga, Parc National Tsingy de Bemaraha, 10.6 km ESE 123° Antsalova, N -18.70944, E 44.71817, alt 150 m, Fisher-Griswold Arthropod Team, 11_16_2001; CASENT0422571 (collection code: BLF03132, 1w, CAS): Prov. Antsiranana, Montagne des Français, 7.2 km 142° SE Antsiranana (=Diego Suarez), N -12.32278, E 49.33817, alt 180 m, Fisher, Griswold et al., 2_22_2001; CASENT0422585 (collection code: BLF03426, 1w, CAS), CASENT0422593 (collection code: BLF03426, 1w, CAS), CASENT0422597 (collection code: BLF03426, 2w, CAS): Prov. Antsiranana, Nosy Be, Réserve Naturelle Intégrale de Lokobe, 6.3 km 112° ESE Hellville, N -13.41933, E 48.33117, alt 30 m, Fisher, Griswold et al., 3_19_2001; CASENT0422629 (collection code: BLF02859, 2w, CAS), CASENT0422651 (collection code: BLF02859, 1w, CAS): Prov. Antsiranana, Réserve Spéciale de l’Ankarana, 22.9 km 224° SW Anivorano Nord, N -12.90889, E 49.10983, alt 80 m, Fisher, Griswold et al., 2_10_2001; CASENT0422673 (collection code: BLF02660, 1w, CAS): Prov. Antsiranana, Réserve Spéciale d’Ambre, 3.5 km 235° SW Sakaramy, N -12.46889, E 49.24217, alt 325 m, Fisher, Griswold et al., 1_26_2001; CASENT0422690 (collection code: BLF03426, 1w, CAS), CASENT0422691 (collection code: BLF03426, 2w, CAS): Prov. Antsiranana, Nosy Be, Réserve Naturelle Intégrale de Lokobe, 6.3 km 112° ESE Hellville, N -13.41933, E 48.33117, alt 30 m, Fisher, Griswold et al., 3_19_2001; CASENT0443282 (collection code: BLF04234, 2w, CAS), CASENT0443283 (collection code: BLF04234, 2w, CAS), CASENT0443284 (collection code: BLF04234, 2w, CAS): Prov. Mahajanga, Parc National Tsingy de Bemaraha, 3.4 km 93° E Bekopaka, Tombeau Vazimba, N -19.14194, E 44.828, alt 50 m, Fisher-Griswold Arthropod Team, 11_6_2001; CASENT0474737 (collection code: BLF06448, 1w, CAS): Prov. Mahajanga, Parc National de Namoroka, 9.8 km 300° WNW Vilanandro, N -16.46667, E 45.35, alt 140 m, Fisher, Griswold et al., 11_4_2002; CASENT0484804 (collection code: BLF07511, 2w, CAS), CASENT0484870 (collection code: BLF07511, 2w, CAS), CASENT0484900 (collection code: BLF07511, 1w, CAS): Prov. Toliara, Parc National de Zombitse, 19.8 km 84° E Sakaraha, N -22.84333, E 44.71, alt 770 m, Fisher, Griswold et al., 2_5_2003; CASENT0490345 (collection code: BLF07384, 1w, CAS), CASENT0490346 (collection code: BLF07384, 2w, CAS): Prov. Fianarantsoa, Forêt d’Analalava, 29.6 km 280° W Ranohira, N -22.59167, E 45.12833, alt 700 m, Fisher, Griswold et al., 2_1_2003; CASENT0490719 (collection code: BLF07703, 2w, CAS), CASENT0491357 (collection code: BLF07762, 2w, CAS), CASENT0491554 (collection code: BLF07293, 1w, CAS): Prov. Fianarantsoa, Forêt d’Atsirakambiaty, 7.6 km 285° WNW Itremo, N -20.59333, E 46.56333, alt 1550 m, Fisher, Griswold et al., 1_22_2003; CASENT0491364 (collection code: BLF07761, 2w, CAS), CASENT0492591 (collection code: BLF07652, 2w, CAS), CASENT0492611 (collection code: BLF07652, 2w, CAS), CASENT0492612 (collection code: BLF07652, 2w, CAS): Prov. Fianarantsoa, Parc National d’Isalo, Sahanafa River, 29.2 km 351° N Ranohira, N -22.31333, E 45.29167, alt 500 m, Fisher, Griswold et al., 2_10_2003; CASENT0494326 (collection code: BLF09951, 1w, CAS): Prov. Antsiranana, Forêt de Bekaraoka, 6.8 km 60° ENE Daraina, N -13.16667, E 49.71, alt 150 m, B.L. Fisher, 12_8_2003; CASENT0495109 (collection code: BLF08147, 2w, CAS): Prov. Toamasina, Montagne d’Anjanaharibe, 18.0 km 21° NNE Ambinanitelo, N -15.18833, E 49.615, alt 470 m, Fisher, Griswold et al., 3_8_2003; CASENT0498718 (collection code: BLF10016, 2w, CAS), CASENT0498721 (collection code: BLF10016, 2w, CAS): Prov. Antsiranana, Forêt d’Ampondrabe, 26.3 km 10° NNE Daraina, N -12.97, E 49.7, alt 175 m, B.L. Fisher, 12_10_2003.

Description of workers.

Body color: yellow. Body color pattern: Body concolorous. Absolute cephalic size: 496 [460, 574]. Cephalic length vs. maximum width of head capsule (CL/CWb): 1.23 [1.16, 1.35]. Postocular distance vs. cephalic length (PoOc/CL): 0.48 [0.46, 0.50]. 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 inconspuous, ground sculpture smooth. Gena contour line in frontal view shape: convex. Genae contour from anterior view orientation: 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): 0.26 [0.23, 0.27]. Frontal carina distance vs. absolute cephalic size (FRS/CS): 0.31 [0.29, 0.33]. 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): 0.74 [0.69, 0.78]. Median clypeal notch: variable. Ground sculpture of submedian area of clypeus: smooth; present. Median carina of clypeus: variable. Lateral carinae of clypeus count: present. Metanotal depression: variable. Dorsal region of mesosoma sculpture: areolate ground sculpture, superimposed by dispersed rugae. 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): 0.22 [0.19, 0.24]. Anterior profile of petiolar node contour line in lateral view shape: concave. Dorso-caudal petiolar profile contour line in lateral view shape: convex. Dorsal region of petiole sculpture: ground sculpture smooth, main sculpture absent. Postpetiole width vs. absolute cephalic size (PPW/CS): 0.33 [0.30, 0.36]. Dorsal region of postpetiole sculpture: ground sculpture smooth, main sculpture dispersed rugose.

Diagnosis.

Workers of Nesomyrmex nitidus cannot be confused with Nesomyrmex gibber because the conspicuous mesothoracic hump that is a diagnostic character of the latter species is absent in Nesomyrmex nitidus workers. This species also can be easily separated from dark phenotypes of Nesomyrmex madecassus based on color: the dark madecassus phenotypes are dark brown but the workers of Nesomyrmex nitidus are light yellow. Morphometric ratio (PoOC/CW) and discriminant D4 function helps to separate Nesomyrmex nitidus from ocher madecassus phenotypes; further details are given in Diagnosis under Nesomyrmex madecassus .

The workers of this species are the most similar to that of Nesomyrmex flavus . The broadly overlapping elevational distribution as well as qualitative and quantitative traits of Nesomyrmex flavus and Nesomyrmex nitidus workers hamper easy separation. A simplified discriminant D2 function with a greatly reduced character set for safe separation is provided in the diagnosis section of Nesomyrmex flavus .

Biology and distribution.

This species typically occurs in Madagascar’s rain forests at lower altitudes between 10 and 1550 meter, mean: 383 m (Fig. 3). This species is known to forage in low vegetation, nests can often be found in dead twigs, stems above ground or rarely in rotten logs at higher elevations.