Tetramorium norvigi

Tetramorium norvigi inhabits the rainforests and montane rainforests of eastern Madagascar.

Identification
A member of the Tetramorium marginatum-species group

Hita Garcia and Fisher (2012) - Tetramorium norvigi is easily separable from the other species group members by the following character combination: propodeal spines long to very long, and usually straight-lined (PSLI 37 - 43); petiolar node triangular cuneiform and strongly anteroposteriorly compressed dorsally (LPeI 26 - 41; DPeI 195 - 325); mesosomal dorsum always with distinct irregular to longitudinal rugulae; body colouration usually yellow, in southern populations light brown.

Within the examined material of T. norvigi there is some variation that merits discussion. Generally, the specimens from the southern localities Manombo, Vevembe, Ivohibe, through Vatovavy and Ranomafana, up to Mantadia are of brownish colour, possess a more strongly sculptured mesosomal dorsum, and have a less transverse petiolar node (DPeI 195 - 267). The specimens from Andriantantely, Ambatovaky, up to the northern localities Anjanaharibe, Betaolana, and Marojejy are usually yellow, have less sculpture on the mesosomal dorsum, and a more transverse petiolar node (DPeI 280 - 325). However, there is a gradual overlap in colouration and mesosomal sculpture at the centre of the distribution range.

Distribution
The known distribution range starts at Manombo, Vevembe, and Ivohibe, and extends north to Betaolana, Anjanaharibe, and Marojejy. The available collection data indicates that T. norvigi lives in leaf litter, lower vegetation, or on the ground, and is found at elevations from 30 to 1200 m. (Hita Garcia and Fisher 2012)

Distribution based on Regional Taxon Lists
Malagasy Region: Madagascar.

Nomenclature

 *  norvigi. Tetramorium norvigi Hita Garcia & Fisher, 2012: 99, figs. 137, 144-146 (w.) MADAGASCAR.

Worker
HL 0.60 - 0.73 (0.68); HW 0.55 - 0.68 (0.62); SL 0.45 - 0.57 (0.51); EL 0.15 - 0.17 (0.16); PH 0.29 - 0.37 (0.34); PW 0.43 - 0.56 (0.49); WL 0.71 - 0.90 (0.82); PSL 0.22 - 0.31 (0.27); PTL 0.07 - 0.11 (0.09); PTH 0.25 - 0.30 (0.27); PTW 0.19 - 0.28 (0.24); PPL 0.19 - 0.23 (0.22); PPH 0.22 - 0.29 (0.26); PPW 0.22 - 0.30 (0.27); CI 90 - 94 (91); SI 80 - 84 (82); OI 24 - 26 (25); DMI 57 - 64 (60); LMI 40 - 44 (42); PSLI 37 - 43 (40); PeNI 43 - 57 (49); LPeI 26 - 41 (35); DPeI 195 - 325 (262); PpNI 50 - 60 (54); LPpI 78 - 87 (82); DPpI 116 - 130 (123); PPI 98 - 123 (112) (16 measured).

Head longer than wide (CI 90 - 94). Anterior clypeal margin medially impressed. Frontal carinae moderately developed, ending between posterior eye margin and posterior head margin, usually fading out shortly after to posterior eye margin. Antennal scrobes absent. Antennal scapes of moderate length, not reaching posterior head margin (SI 80 - 84). Eyes moderate to large (OI 24 - 26). Mesosomal outline in profile flat to weakly convex, strongly marginate from lateral to dorsal mesosoma; promesonotal suture and metanotal groove absent; mesosoma comparatively high, compact, and stout (LMI 40 - 44). Propodeal spines very long, spinose, and acute (PSLI 37 - 43), usually thin and straight-lined, rarely weakly back-curved; propodeal lobes inconspicuous, small, and triangular. Petiolar node in profile triangular cuneiform, strongly anteroposteriorly compressed dorsally, between 2.4 to 3.9 times higher than long (LPeI 26 - 41), anterior and posterior faces not parallel, node in dorsal view strongly transverse and between 1.9 to 3.3 times wider than long (DPeI 195 - 325). Postpetiole in profile approximately rounded and weakly anteroposteriorly compressed, approximately 1.1 to 1.3 times higher than long (LPpI 78 - 87), in dorsal view between 1.1 to 1.3 times wider than long (DPpI 116 - 130). Postpetiole in profile appearing more voluminous than petiolar node, in dorsal view approximately as wide as petiolar node to weakly wider (PPI 98 - 123). Mandibles generally mostly unsculptured, smooth, and shining, sometimes weak rugulae present, less commonly fully striate; clypeus always with distinct median longitudinal ruga and one or two weaker and shorter rugulae laterally; cephalic dorsum between frontal carinae with four to eight longitudinal rugulae, rugulae ending at or close to posterior head margin, median ruga distinct and diverging approximately at eye level into two rugulae running to posterior clypeal margin, rugulae between median rugula and frontal carinae often interrupted or shorter; lateral and ventral head mostly reticulate-rugose to longitudinally rugose, sometimes weakly developed, especially posteriorly. Ground sculpture on head usually moderately developed, sometimes faint. Mesosoma laterally mostly unsculptured, only sculpture present posteroventrally; dorsal mesosoma with irregular, longitudinal rugulae, sometimes with stronger, longitudinal rugae (in southern populations). Waist segments and gaster unsculptured, smooth, and shiny. All dorsal surfaces of body with abundant, long, erect, fine pilosity, hairs on mesosomal dorsum not restricted to lateral margins. Body usually of uniform yellowish colour, in southern populations light brown.

Type Material
Holotype worker, MADAGASCAR, Toamasina, Montagne d'Anjanaharibe, 19.5 km 27° NNE Ambinanitelo, 15.17833 S, 49.635 E, 1100 m, montane rainforest, beating low vegetation, collection code BLF8151, 12.-16.III.2003 (B.L. Fisher, C. Griswold et al.) (CASENT0489037). Paratypes, 12 workers with same data as holotype (: CASENT0489101; CASC: CASENT0488986; CASENT0489031; CASENT0489038; CASENT0489041; CASENT0489084; CASENT0489098; CASENT0489103; CASENT0489171; CASENT0489191; CASENT0489198; MHNG: CASENT0489227); one worker with same data as holotype except sampled from sifted litter and collection code BLF8150 (: CASENT0038391); one worker with same data as holotype except sampled from rotten log and collection code BLF8211(: CASENT0497974); one worker with same data as holotype except sampled from pitfall trap and collection code BLF8153 (: CASENT0048693); one worker with same data as holotype except sampled from yellow pan trap and collection code BLF8154 (CASC: CASENT0048741); nine workers with same data as holotype except sampled from dead branch above ground and collection code BLF8247 (CASC: CASENT0497948; CASENT0497949; CASENT0497950).

Etymology
The new species is named in honor of Peter and Kris Norvig for their support to discover and identify life on earth.

References based on Global Ant Biodiversity Informatics

 * Garcia H. F. and B. L. Fisher. 2012. The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy regiontaxonomy of the T. bessonii, T. bonibony, T. dysalum, T. marginatum, T. tsingy, and T. weitzeckeri species groups. Zootaxa 3365: 1-123