Tetramorium nosybe 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 : 39-41

Tetramorium nosybe Hita Garcia & Fisher sp. n.

(figs 39, 41, 51, 52, 53)

Holotype worker, MADAGASCAR, Antsiranana, Nosy Be, Réserve Naturelle Intégrale de Lokobe , 6.3 km 112° ESE Hellville, 13.41933 S, 48.33117 E, 30 m, rainforest, beating low vegetation, collection code BLF3426, 19.– 24.III.2001 (B.L. Fisher, C. Griswold et al.) ( CASC: CASENT0422207 ) . Paratypes, five workers with same data as holotype ( CASC: CASENT0404427 ; CASENT0404429; CASENT0404430) ; four workers with same data as holotype except sampled from sifted litter and collection code BLF3422 ( CASC: CASENT0466777 ; CASENT0467021; CASENT0467100; CASENT0467118) ; eight workers with same data as holotype except sampled ex rotten stick on ground and collection code BLF3495 ( BMNH: CASENT0428029 ; CASC: CASENT0427995 ; CASENT0427996; CASENT0428028; CASENT0428080); and two workers with same data as holotype except sampled from low vegetation and collection code BLF3518 ( CASC: CASENT0428020 ; MHNG: CASENT0428021 ) .

Diagnosis

Tetramorium nosybe can be recognised within the T. bonibony group by the following character combination: anterior face of pronotum well developed but without a distinct anterodorsal protuberance; petiolar node triangular cuneiform, strongly anteroposteriorly compressed dorsally, and strongly transverse in dorsal view (LPeI 38–43; DPeI 232–279); body of uniform brown colour.

Description

HL 0.71–0.78 (0.76); HW 0.71–0.78 (0.76); SL 0.50–0.54 (0.53); EL 0.15–0.18 (0.16); PH 0.42–0.49 (0.46); PW 0.53–0.61 (0.57); WL 0.91–1.01 (0.96); PSL 0.28–0.33 (0.31); PTL 0.11–0.15 (0.13); PTH 0.29–0.34 (0.31); PTW 0.29–0.35 (0.32); PPL 0.22–0.25 (0.23); PPH 0.30–0.35 (0.33); PPW 0.29–0.35 (0.33); CI 99–101 (100); SI 68–71 (69); OI 21–23 (22); DMI 58–60 (59); LMI 46–50 (48); PSLI 39–44 (41); PeNI 54–58 (57); LPeI 38–43 (41); DPeI 232–279 (251); PpNI 54–59 (57); LPpI 68–73 (70); DPpI 132–146 (141); PPI 100–105 (102) (10 measured).

Head as long as wide (CI 99–101). Anterior clypeal margin with median impression. Frontal carinae moderately developed, fading out shortly before posterior head margin. Antennal scrobes absent. Antennal scapes short, not reaching posterior head margin (SI 68–71). Eyes small to moderate (OI 21–23). Mesosoma with welldeveloped anterior face of pronotum, but without a distinct anterodorsal median protuberance on pronotum, mesosoma weakly to moderately marginate from lateral to dorsal mesosoma; promesonotal suture and metanotal groove absent; mesosoma comparatively high, compact, and stout (LMI 46–50). Propodeal spines very long, spinose, and acute (PSLI 39–44); propodeal lobes small and triangular. Petiolar node in profile triangular cuneiform, strongly anteroposteriorly compressed dorsally, approximately 2.3 to 2.6 times higher than long (LPeI 38–43), anterior and posterior faces not parallel, node in dorsal view distinctly transverse and comparatively thin, between 2.3 to 2.8 times wider than long (DPeI 232–279). Postpetiole in profile approximately rounded, approximately 1.3 to 1.5 times higher than long (LPpI 68–73), in dorsal view approximately 1.3 to 1.5 times wider than long (DPpI 132–146). Postpetiole in profile more voluminous than petiolar node, in dorsal view as wide as petiolar node to slightly wider (PPI 100–105). Mandibles striate; clypeus with one distinct median longitudinal ruga and one or two often weaker rugae at each side; cephalic dorsum between frontal carinae anteriorly and centrally longitudinally rugose and posteriorly reticulate-rugose, dorsum with five to nine longitudinal rugae, rugae ending close to posterior head margin but often broken or with cross-meshes, always with one well-developed longitudinal median ruga, median ruga running from posterior head margin to posterior clypeal margin, approximately at eye level diverging into two rugae leading to posterior clypeal margin; lateral and ventral head mainly reticulate-rugose to longitudinally rugose. Ground sculpture on head weakly to moderately reticulatepunctate. Lateral mesosoma reticulate-rugose to irregularly longitudinally rugose; dorsal mesosoma anteriorly strongly reticulate-rugose, posteriorly reticulate-rugose to longitudinally rugose. Waist segments and gaster unsculptured, smooth, and shiny. All dorsal surfaces of body with abundant, long, fine, and erect pilosity. Body of uniform dark brown colour.

Notes

The new species is mainly found on the island of Nosy Be, but a few specimens were sampled from two localities in western Madagascar. These localities, Ampasindava and Manongarivo, are less than 100 km away from Nosy Be. In addition, T. nosybe was only collected from rainforest habitats at elevations from 30 to 600 m, and seems to live in leaf litter, on the ground, or in lower vegetation.

Tetramorium nosybe is the only species within the group with a uniform dark brown colouration, and is thus easily recognisable. However, colour is not always a reliable character. Even so, it should not be confused with the three species with a conspicuous protuberance on the pronotum, T. bonibony , T. popell , and T. trafo . Also, it can be distinguished from T. kali and T. olana since they possess a less dorsally anteroposteriorly compressed petiolar node (DPeI 136–200). Again, not considering the colour, T. vony (yellow colouration) and T. sada (dark brown and yellow bicolouration) are superficially close to T. nosybe . Tetramorium sada , however, has a more transverse and broader petiolar node in dorsal view (DPeI 400–463; PPI 89–95) than T. nosybe (DPeI 232–279; PPI 100–105), whereas the latter shares much of its morphometric range and general morphology with T. vony . As noted in the description of T. vony though, both differ in their respective habitat preferences, which together with the colouration supports their separation as different species.

Etymology

The name of the new species refers to the island of Nosy Be where the type series was collected. It is a noun in apposition, and thus invariant.

Material examined

MADAGASCAR: Antsiranana, Ampasindava, Forêt d'Ambilanivy, 3.9 km 181° S Ambaliha, 13.79861 S, 48.16167 E, 600 m, rainforest, 4.–9.III.2001 (B.L. Fisher, C. Griswold et al.); Antsiranana, Nosy Be, Ambatoloaka, 13° 24' 59'' S, 48° 18' 26'' E, 100 m, lowland forest, 12.VIII.1992 (G.D. Alpert); Antsiranana, Nosy Be, 4km ESE Andoany (=Hellville), 13.41667 S, 48.3 E, 200 m, rainforest, 1.–2.V.1989 (P.S. Ward); Antsiranana, Nosy Be, Rés. Lokobe, 24° 59' S, 46° 18' E, 0–400 m, humid forest, 29.VIII.1989 (D.M. Olson); Antsiranana, Nosy Be, Lokobe Forest, 13° 24' 59'' S, 48° 18' 26'' E, 50 m, lowland forest, 11.VIII.1992 (G.D. Alpert); Antsiranana, Nosy Be, Réserve Naturelle Intégrale de Lokobe, 6.3 km 112° ESE Hellville, 13.41933 S, 48.33117 E, 30 m, rainforest, 19.– 24.III.2001 (B.L. Fisher, C. Griswold et al.); Antsiranana, Nosy Be, 3 km E Marodokana, 13° 27' 52.2'' S, 48° 18' 48.3'' E, 50 m, 18.II.1992 (G.D. Alpert); Antsiranana, R.S. Manongarivo, 10.8 km 229° SW Antanambao, 13.96167 S, 48.43333 E, 400 m, rainforest, 8.XI.2008 (B.L. Fisher).