Tetramorium ambatovy, 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 : 60-62

Tetramorium ambatovy sp. n.

(figs 69, 92, 93, 94)

Holotype worker, MADAGASCAR, Toamasina, Ambatovy , 12.4 km NE Moramanga, 18.84963 S, 48.2947 E, 1010 m, montane rainforest, sifted litter (leaf mold, rotten wood), collection code BLF16914, 3.–6.III.2007 (B.L. Fisher et al.) ( CASC: CASENT0124721 ) . Paratypes, six workers with same data as holotype ( BMNH: CASENT0124748 ; CASC: CASENT: CASENT0124729; CASENT0124730; CASENT0124737; CASENT0124759; MHNG: CASENT0124741 ); and four workers with same data as holotype except collected from pitfall trap and collection code BLF16915 ( CASC: CASENT0122307 ; CASENT0123371; CASENT0114807; MCZ: CASENT0122306 ) .

Diagnosis

Within its species group T. ambatovy can be easily differentiated from the other group members due to the fine and irregular rugulae on its mesosomal dorsum, which is never longitudinally organised, and the comparatively large eyes (OI 25–26).

Description

HL 0.66–0.72 (0.69); HW 0.65–0.71 (0.68); SL 0.48–0.52 (0.50); EL 0.17–0.18 (0.17); PH 0.32–0.38 (0.34); PW 0.47–0.52 (0.49); WL 0.80–0.87 (0.83); PSL 0.19–0.23 (0.21); PTL 0.11–0.13 (0.12); PTH 0.27–0.29 (0.28); PTW 0.20–0.23 (0.22); PPL 0.21–0.23 (0.22); PPH 0.26–0.28 (0.27); PPW 0.32–0.35 (0.33); CI 97–99 (98); SI 72–76 (74); OI 25–26 (26); DMI 58–61 (59); LMI 40–44 (41); PSLI 28–32 (30); PeNI 41–45 (44); LPeI 40–45 (43); DPeI 174–195 (181); PpNI 63–69 (67); LPpI 79–85 (82); DPpI 145–155 (150); PPI 148–163 (153) (12 measured).

Head weakly longer than wide (CI 97–99). Anterior clypeal margin with distinct median impression. Frontal carinae well-developed, ending at or shortly before posterior head margin. Antennal scrobes faint and shallow. Antennal scapes short, not reaching posterior head margin (SI 72–76). Eyes comparatively large (OI 25–26). Mesosomal outline in profile flat to weakly convex, weak to moderate margination from lateral to dorsal mesosoma; promesonotal suture and metanotal groove absent; mesosoma comparatively high, compact, and stout (LMI 40–44). Propodeal spines long, spinose, and acute (PSLI 28–32); propodeal lobes small and triangular. Petiolar node in profile squamiform, approximately 2.2 to 2.5 times higher than long (LPeI 40–45), anterior and posterior faces approximately parallel, anterodorsal and posterodorsal angles at about same height, dorsum not tapering backwards posteriorly; node in dorsal view 1.7. to 2 times longer than wide (DPeI 174–195). Postpetiole in profile rounded, approximately 1.2 times higher than long (LPpI 79–85), in dorsal view between 1.4 to 1.5 times wider than long (DPpI 145–155). Postpetiole in profile appearing a bit more voluminous than petiolar node, in dorsal view approximately 1.5 to 1.6 times wider than petiolar node (PPI 148–163). Mandibles longitudinally rugose or rugulose; clypeus distinctly striate, sometimes irregularly arranged; cephalic dorsum between frontal carinae reticulate-rugose but with including a portion with more pronounced longitudinal rugosity; lateral and ventral head reticulate-rugose. Ground sculpture on head often faint, sometimes moderately developed reticulatepunctate. Lateral mesosoma partly with irregular rugulae, partly completely unsculptured; dorsal mesosoma with fine and irregular rugulae; ground sculpture faint to absent. Both segments generally unsculptured, smooth, and shiny, postpetiole sometimes laterally with weak sculpture. All dorsal surfaces of body with abundant, long, erect pilosity. Body of uniform brownish colour, appendages often of lighter colour.

Notes

The distribution of T. ambatovy is somewhat disjunctive. Most specimens are known from a strip that extends from the area around Ambatovy, Andasibe-Mantadia, and Torotorofotsy to Sahafina and then north to Ambatovaky, but one specimen was also collected from Andohahela in the southwest. The species appears to prefer montane or lowland rainforests at elevations from 140 to 1088 m, and was always collected from the leaf litter stratum.

As noted above, the unique sculpture on the mesosoma and the comparatively large eyes (OI 25–26) make it very difficult to confuse T. ambatovy with any other species of the T. dysalum group. It is very likely that T. ambatovy does not belong to the group, and instead represents a different lineage within Malagasy Tetramorium . The shape of the petiolar node resembles the one observed in some species of the mainly Afrotropical T. weitzeckeri group, but as discussed in Hita Garcia and Fisher (2011) and in the T. weitzeckeri group section of this study, within the Malagasy region, we consider only T. humbloti to be an introduced member of that group, whereas similarities observed in other Malagasy groups are very probably convergent developments.

Etymology

The name of the new species refers to the type locality. The species epithet is a noun in apposition and thus invariant.

Material examined

MADAGASCAR: Toamasina, Ambatovy, 12.4 km NE Moramanga, 18.84963 S, 48.2947 E, 1010 m, montane rainforest, 3.–6.III.2007 (B.L. Fisher et al.); Toamasina, Ambatovy, 12.4 km NE Moramanga, 18.83937 S, 48.30842 E, 1080 m, montane rainforest, 4.–7.III.2007 (B.L. Fisher et al.); Toamasina, Ambatovy, 12.4 km NE Moramanga, 18.84773 S, 48.29568 E, 1000 m, montane rainforest and grassland, 5.–8.III.2007 (B.L. Fisher et al.); Toamasina, Ambatovy, 12.4 km NE Moramanga, 18.85813 S, 48.28488 E, 1040 m, montane rainforest, 5.– 8.III.2007 (B.L. Fisher et al.); Toamasina, Forêt Ambatovy, 14.3 km 57° Moramanga, 18.85083 S, 48.32 E, 1075 m, montane rainforest, 21.–23.III.2004 (B.L. Fisher et al.); Toamasina, Parc National d´ Andasibe-Mantadia, Forêt de Mantadia, 25.7 km 248° Moramanga, 18.81402 S, 48.43028 E, 1040 m, rainforest, 7.XI.2005 (F.N. Raharimalala & B. Blaimer); Toamasina, Parc National de Zahamena, Tetezambatana forest, near junction of Nosivola and Manakambahiny Rivers, 17.74298 S, 48.72936 E, 860 m, rainforest, 18.–19.II.2009 (B.L. Fisher et al.); Toamasina, Reserve Betampona, Camp Rendrirendry 34.1 km 332° Toamasina, 17.924 S, 49.19967 E, 390 m, rainforest, 28.–29.XI.2005 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato river, 16.77274 S, 49.26551 E, 450 m, rainforest, 20.–22.II.2010 (B.L. Fisher et al.); Toamasina, Sahafina forest 11.4 km W Brickaville, 18.81445 S, 48.96205 E, 140 m, rainforest, 13.–14.II.2007 (B.L. Fisher et al.); Toamasina, Station forestière Analamazaotra, Analamazaotra 1.3km S Andasibe, 18.38466 S, 48.41271 E, 980 m, montane rainforest, 11.–13.XII.2007 (B.L. Fisher et al.); Toamasina, Torotorofotsy, 18.87082 S, 48.34737 E, 1070 m, montane rainforest, marsh edge, 24.III.2004 (B.L. Fisher et al.); Toliara, Parc National Andohahela, Col de Tanatana, 33.3km NW Tolagnaro, 24.7585 S, 46.85367 E, 275 m, rainforest, 24.XI.2006 (B.L. Fisher et al.).