Tetramorium sada 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 : 47-49

Tetramorium sada Hita Garcia & Fisher sp. n.

(figs 30, 37, 38, 60, 61, 62)

Holotype worker, MADAGASCAR, Mahajanga, Parc National Tsingy de Bemaraha, 3.4 km 93° E Bekopaka, Tombeau Vazimba , 19.14194 S, 44.828 E, 50 m, tropical dry forest, beating low vegetation, collection code BLF4234, 6.–10.XI.2001 (B.L. Fisher, C. Griswold et al.) ( CASC: CASENT0443274 ) . Paratypes, 49 workers with same data as holotype ( BMNH: CASENT0443394 ; CASC: CASENT0443271 ; CASENT0443273; CASENT0443277; CASENT0443280; CASENT0443330; CASENT0443304; CASENT0443311; CASENT0443312; CASENT0443313; CASENT0443342; CASENT0443345; CASENT0443362; CASENT0443363; CASENT0443377; CASENT0443382; CASENT0443383; CASENT0443384; CASENT0443385; CASENT0443398; CASENT0443399; CASENT0443422; CASENT0443433; CASENT0443438; MCZ: CASENT0443364 ; MHNG: CASENT0443439 ; NHMB: CASENT0443381 ) .

Diagnosis

The following character set separates T. sada from all other species in the T. bonibony group: mesosoma with well developed anterior face of pronotum but without an anterodorsal median protuberance; petiolar node in profile triangular nodiform, strongly anteroposteriorly compressed dorsally, and highly transverse in dorsal view (LPeI 25–30; DPeI 400–463); postpetiole distinctly narrower than petiolar node (PPI 89–95); distinct bicolouration with dark brown head and mesosoma contrasting with yellow waist segments and gaster.

Description

HL 0.70–0.84 (0.79); HW 0.70–0.86 (0.80); SL 0.46–0.58 (0.54); EL 0.16–0.19 (0.18); PH 0.41–0.52 (0.48); PW 0.50–0.64 (0.59); WL 0.85–1.09 (1.01); PSL 0.30–0.37 (0.34); PTL 0.07–0.09 (0.08); PTH 0.26–0.34 (0.30); PTW 0.30–0.39 (0.36); PPL 0.21–0.25 (0.23); PPH 0.27–0.37 (0.33); PPW 0.27–0.37 (0.33); CI 100–103 (102); SI 65– 70 (68); OI 21–22 (22); DMI 56–60 (58); LMI 46–49 (48); PSLI 42–45 (43); PeNI 59–63 (61); LPeI 25–30 (28); DPeI 400–463 (425); PpNI 54–60 (56); LPpI 67–76 (70); DPpI 132–152 (142); PPI 89–95 (92) (12 measured).

Head as wide as long to weakly wider (CI 100–103). Anterior clypeal margin with median impression. Frontal carinae moderately developed, ending between posterior eye margin and posterior head margin. Antennal scrobes absent. Antennal scapes short, not reaching posterior head margin (SI 65–70). Eyes comparatively small (OI 21– 22). Mesosoma with well developed anterior face of pronotum but without an anterodorsal median protuberance, mesosoma weakly to moderately marginate from lateral to dorsal mesosoma; promesonotal suture and metanotal groove absent; mesosoma very high, compact, and stout (LMI 46–49). Propodeal spines very long, spinose, and acute (PSLI 42–45); propodeal lobes small and triangular. Petiolar node in profile triangular cuneiform and strongly anteroposteriorly compressed dorsally, approximately 3.3 to 3.9 times higher than long (LPeI 25–30), anterior and posterior faces not parallel, node in dorsal view highly transverse and very thin, between 4.0 to 4.6 times wider than long (DPeI 400–463). Postpetiole in profile approximately rounded, approximately 1.3 to 1.5 times higher than long (LPpI 67–76), in dorsal view approximately 1.3 to 1.5 times wider than long (DPpI 132– 152). Postpetiole in profile more voluminous than petiolar node, in dorsal view distinctly less broad than petiolar node, only approximately 0.9 times width of petiolar node (PPI 89–95). 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, moderately long, fine, and erect pilosity. Body distinctly bicoloured, head and mesosoma brown to dark brown, waist segments and gaster yellow, appendages of lighter brown than head and mesosoma.

Notes

The distribution of T. sada is limited to western Madagascar. It seems to be common from Tsingy de Bemaraha to Namoroka, but further north it is only known from Ankarafantsika. Furthermore, it lives in tropical dry forests, sometimes on tsingy, and was mainly collected from the leaf litter or lower vegetation.

Tetramorium sada cannot be mistaken for any other group member due to a few important diagnostic characters. The lack of a distinct anterodorsal median protuberance on the pronotum separates it from T. bonibony , T. popell , and T. trafo , while the conspicuous bicolouration distinguishes it from the remaining species of the group. Nonetheless, T. bonibony shares the same bicolouration and both could be confused with each other since their distribution ranges are comparatively similar and they co-occur in some localities. In addition to the difference in the development of the median protuberance on the pronotum, T. sada has shorter antennal scapes (SI 65–70) than T. bonibony (SI 69–74), although the variation is not highly significant. A better supporting character is the relationship between the widths of the petiolar node and the postpetiole. In T. sada the postpetiole is distinctly narrower than the petiolar node (PPI 89–95), whereas the postpetiole is as wide as to weakly wider than the petiolar node in T. bonibony (PPI 100–106).

If one does not consider the evident difference in colouration, T. sada also resembles T. vony and T. nosybe in general morphology. However, the latter two species also have a postpetiole which is as wide as to weakly wider than the petiolar node (PPI 100–107). The remaining two species, T. kali and T. olana , both have a much less anteroposteriorly compressed and transverse petiolar node (LPeI 45–57; DPeI 135–200), and are thus not likely to be misidentified with T. sada (LPeI 25–30; DPeI 400–463).

Etymology

The name of the new species is Malagasy and means "mixture of colour". It refers to the distinctive bicolouration of the new species. The species name is a noun in apposition, and thus invariant.

Material examined

MADAGASCAR: Mahajanga, Parc National d'Ankarafantsika, Forêt de Tsimaloto, 18.3 km 46° NE de Tsaramandroso, 16.22806 S, 47.14361 E, 135 m, tropical dry forest, 2.–8.IV.2001 (B.L. Fisher, C. Griswold et al.); Mahajanga, Parc National de Namoroka, 16.9 km 317° NW Vilanandro, 16.40667 E, 45.31 E, 100 m, tropical dry forest, 12.–16.XI.2002 (B.L. Fisher, C. Griswold et al.); Mahajanga, Parc National Tsingy de Bemaraha, 3.4 km 93° E Bekopaka, Tombeau Vazimba, 19.14194 S, 44.828 E, 50 m, tropical dry forest, 6.–10.XI.2001 (B.L. Fisher, C. Griswold et al.); Mahajanga, Parc National Tsingy de Bemaraha, 10.6 km ESE 123° Antsalova, 18.70944 S, 44.71817 E, 150 m, tropical dry forest on tsingy, 26.–20.XI.2001 (B.L. Fisher, C. Griswold et al.); Mahajanga, Réserve forestière Beanka, 54.3 km E Maintirano, 18.06009 S, 44.54086 E, 262 m, tropical dry forest on tsingy, 18.X.2009 (B.L. Fisher et al.); Mahajanga, Réserve forestière Beanka, 50.2 km E Maintirano, 18.02649 S, 44.05051 E, 250 m, tropical dry forest on tsingy, 19.–20.X.2009 (B.L. Fisher et al.); Mahajanga, Réserve forestière Beanka, 53.6 km E Maintirano, 18.04014 S, 44.53394 E, 272 m, tropical dry forest on tsingy, 25.X.2009 (B.L. Fisher et al.); Mahajanga, Réserve Spéciale de Bemarivo, 23.8 km 223° SW Besalampy, 16.925 S, 44.36833 E, 30 m, tropical dry forest, 19.–23.XI.2002 (B.L. Fisher, C. Griswold et al.).