Tetramorium norvigi Hita Garcia & Fisher, 2012

Garcia, Francisco Hita & Fisher, Brian L., 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, pp. 1-123 : 99-102

Tetramorium norvigi Hita Garcia & Fisher sp. n.

(figs 137, 144, 145, 146)

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 ( BMNH: 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 ( CASC: CASENT0038391 ) ; one worker with same data as holotype except sampled from rotten log and collection code BLF8211( NHMB: CASENT0497974 ) ; one worker with same data as holotype except sampled from pitfall trap and collection code BLF8153 ( MCZ: 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) .

Diagnosis

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.

Description

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.

Notes

Tetramorium norvigi is another species only found in the rainforests or montane rainforests of eastern Madagascar. 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.

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, which leads us to treat all the material as one moderately variable species. It is still possible that there are two distinct species involved, but more material, especially from the southern and central localities of the distribution range, is necessary to support this hypothesis.

Tetramorium norvigi differs strikingly from the group members with a completely unsculptured mesosomal dorsum and dark brown to black colour: T. valky , T. hector , T. marginatum , and T. silvicola . The last species of the group, T. shamshir , is superficially morphologically close to T. norvigi but the two can be separated clearly from each other. The propodeal spines are always extremely long, very thick, and strongly back-curved in T. shamshir (PSLI 50–63), whereas they are long, but relatively shorter and thinner in T. norvigi (PSLI 37–43), and, if backcurved, they are only weakly so (as in the holotype of T. norvigi ). Furthermore, the petiolar node in lateral view is usually thickly cuneiform without being strongly anteroposteriorly compressed dorsally in T. shamshir versus triangular cuneiform and strongly anteroposteriorly compressed dorsally in T. norvigi . The postpetiolar shape also varies in both species, being relatively higher and stronger anteroposteriorly compressed in T. shamshir (LPpI 64– 73; DPpI 125–150) but more rounded and less anteroposteriorly compressed in T. norvigi (LPpI 78–87; DPpI 116– 130). Also, the distribution ranges of both species overlap and they occur in sympatry in the area around Anjanaharibe to Marojejy, but both species retain their characteristic diagnostic features and can be discriminated easily from each other.

Etymology

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

Material examined

MADAGASCAR: Amparihibe, II.–III.2003 (K.A. Jackson & D. Carpenter); Antsiranana, 6.5 km SSW Befingotra, Rés. Anjanaharibe-Sud, 14.75 S, 49.5 E, 875 m, rainforest, 26.X.1994 (B.L. Fisher); Antsiranana, 6.5 km SSW Befingotra, Rés. Anjanaharibe-Sud, 14.75 S, 49.5 E, 1000 m, rainforest, 29.X.1994 (B.L. Fisher); Antsiranana, 9.2 km WSW Befingotra, Rés. Anjanaharibe-Sud, 14.75 S, 49.46667 E, 1200 m, montane rainforest, 9.XI.1994 (B.L. Fisher); Antsiranana, Betaolana Forest, along Bekona River, 14.52996 S, 49.44039 E, 880 m, rainforest, 4.III.2009 (B.L. Fisher et al.); Antsiranana, Parc National de Marojejy, Manantenina River, 27.6 km 35° NE Andapa, 9.6 km 327° NNW Manantenina, 14.435 S, 49.76 E, 775 m, rainforest, 17.XI.2003 (B.L. Fisher); Fianarantsoa, Belle Vue trail, Ranomafana National Park, 21.2665 S, 47.42017 E, 1020 m, mixed tropical forest, 14.–21.I.2002 (R. Harin'Hala); Fianarantsoa, Forêt de Vevembe, 66.6 km 293° Farafangana, 22.791 S, 47.18183 E, 600 m, rainforest, transition to montane forest, 23.IV.2004 (B.L. Fisher et al.); Fianarantsoa, 7.6 km 122º Kianjavato, Forêt Classée Vatovavy, 21.4 S, 47.94 E, 175 m, rainforest, 6.–8.VI.2005 (B.L. Fisher et al.); Fianarantsoa, Parc National de Ranomafana, Vatoharanana River, 4.1 km 231° SW Ranomafana, 21.29 S, 47.43333 E, 1100 m, montane rainforest, 27.–31.III.2003 (B.L. Fisher, C. Griswold et al.); Fianarantsoa, 7 km W. Ranomafana National Park, montane rainforest, 900 m, 17.–23.II.1990 (W.E. Steiner); Fianarantsoa, 7 km W. of Ranomafana, montane rainforest, 900–1000 m, 20.I.1990 (W.E. Steiner); Fianarantsoa, Ranomafana National Park, Miaranony Village, 700 m, 20.II.1991 (A. Kingman); Fianarantsoa, R.S. Ivohibe, 7.5 km ENE Ivohibe, 22.47 S, 46.96 E, 900 m, rainforest, 7.–12.X.1997 (B.L. Fisher); Fianarantsoa, Réserve Speciale Manombo 24.5 km 228° Farafangana, 23.01583 S, 47.719 E, 30 m, rainforest, 20.IV.2006 (B.L. Fisher et al.); Fianarantsoa, Vatoharanana, 21.28955 S, 47.4304 E, 1100 m, stomach contents of Mantella baroni , 30.III.2003 (V.C. Clark); Toamasina, F.C. Andriantantely, 18.695 S, 48.81333 E, 530 m, rainforest, 4.–7.XII.1998 (H.J. Ratsirarson); Toamasina, P.N. Mantadia, 18.79167 S, 48.42667 E, 895 m, rainforest, 25.XI.–1.XII.1998 (H.J. Ratsirarson); Toamasina, Montagne d'Anjanaharibe, 18.0 km 21° NNE Ambinanitelo, 15.18833 S, 49.615 E, 470 m, rainforest, 8.– 12.III.2003 (B.L. Fisher, C. Griswold et al.); Toamasina, Montagne d'Anjanaharibe, 19.5 km 27° NNE Ambinanitelo, 15.17833 S, 49.635 E, 1100 m, montane rainforest, 12.–16.III.2003 (B.L. Fisher, C. Griswold et al.); Toamasina, Perinet, 27.IV.–3.V.1983 (J.S. Noyes & M.C. Day); Toamasina, Réserve Nationale Intégrale Betampona, Betampona 35.1 km NW Toamasina, 17.91801 S, 49.20074 E, 500 m, rainforest, 16.XI.2007 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.76912 S, 49.26704 E, 475 m, rainforest, 21.II.2010 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.7702 S, 49.26638 E, 475 m, rainforest, 23.II.2010 (B.L. Fisher et al.).