Tetramorium ankarana Hita, 2012

Hita Garcia, F. & B. L. Fisher, 2012, The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region - taxonomic revision of the T. kelleri and T. tortuosum species groups., Zootaxa 3592, pp. 1-85 : 9-11

Tetramorium ankarana Hita Garcia & Fisher sp. n.

(Figs. 1, 2, 5, 6, 7, 141)

Holotype worker, MADAGASCAR, Antsiranana, Réserve Ankarana, 7 km SE Matsaborimanga, 12° 54' S, 49° 07' E, 150 m, rainforest, ground foragers, collection code PSW11043, 30.XI.1990 (P.S. Ward) (CASC: CASENT0247543). Paratypes, one worker with same data as holotype (BMNH: CASENT0247311); and two workers from Antsiranana, Réserve Spéciale de l'Ankarana, 22.9 km 224° SW Anivorano Nord, 12.90889 S, 49.10983 E, 80 m, tropical dry forest, on low vegetation, collection code BLF03007, 10.-16.II.2001 (B.L. Fisher, C. Griswold et al.) (CASC: CASENT0404423; CASENT0427943).

Diagnosis

Tetramorium ankarana can be easily distinguished from T. kelleri by the following character combination: much smaller eyes (OI 20); relatively longer antennal scapes (SI 101-104); and long propodeal spines (PSLI 35-38).

Description

HL 0.97-1.02 (0.99); HW 0.85-0.89 (0.86); SL 0.88-0.90 (0.88); EL 0.17-0.18 (0.17); PH 0.47-0.50 (0.49); PW 0.66-0.72 (0.69); WL 1.21-1.31 (1.26); PSL 0.34-0.37 (0.36); PTL 0.33-0.36 (0.35); PTH 0.34-0.36 (0.35); PTW 0.26-0.29 (0.28); PPL 0.28-0.31 (0.29); PPH 0.34-0.37 (0.35); PPW 0.33-0.37 (0.35); CI 87-88 (87); SI 101-104 (102); OI 20 (20); DMI 54-56 (55); LMI 37-40 (39); PSLI 35-38 (36); PeNI 39-42 (41); LPeI 97-100 (99); DPeI 79-84 (81); PpNI 50-52 (51); LPpI 81-85 (83); DPpI 116-125 (120); PPI 122-128 (125) (four measured).

Head much longer than wide (CI 87-88); posterior head margin very weakly concave. Anterior clypeal margin medially impressed, often weakly so. Frontal carinae strongly developed, approaching corners of posterior head margin. Antennal scrobes well-developed, moderately deep, narrow, and without defined posterior margin; ventral margin moderately defined. Antennal scapes long, reaching posterior head margin (SI 101-104). Eyes small (OI 20). Mesosomal outline in profile flat to weakly convex, very weakly marginate from lateral to dorsal mesosoma, sides rounding smoothly onto the dorsum; promesonotal suture and metanotal groove absent; mesosoma comparatively stout and high (LMI 37-40). Propodeal spines long, spinose and acute (PSLI 35-38); propodeal lobes short, triangular, and rounded. Petiolar node in profile clublike with fairly rounded margins, approximately as long as high (LPeI 97-100), anterodorsal margin situated lower than posterodorsal margin, dorsum noticeably convex; node in dorsal view approximately 1.2 to 1.3 times longer than wide (DPeI 79-84). Postpetiole in profile globular, approximately 1.2 times higher than long (LPpI 81-85); in dorsal view around 1.1 to 1.3 times wider than long (DPpI 116-125). Postpetiole in profile appearing less voluminous than petiolar node, in dorsal view 1.2 to 1.3 times wider than petiolar node (PPI 122-128). Mandibles strongly striate; clypeus longitudinally rugose/rugulose, with three to four rugae/rugulae, median ruga always present and distinct, remaining rugae weaker; cephalic dorsum between frontal carinae reticulate-rugose to longitudinally rugose, posteriorly more reticulate-rugose and anteriorly more longitudinally rugose; lateral and ventral head mostly reticulate-rugose. Mesosoma dorsally mainly reticulate-rugose, laterally reticulate-rugose to longitudinally rugose. Forecoxae usually with weak to moderately developed longitudinal rugae/rugulae. Waist segments mainly longitudinally rugulose, less reticulate-rugulose. First gastral tergite unsculptured, smooth, and shining. Whole body covered with numerous, very long, fine standing hairs. Body of uniform dark reddish brown colour.

Notes

The new species is currently only known from the type locality Ankarana where it was collected in tropical dry forest and rainforest at elevations of 80 to 150 m.

Tetramorium ankarana is the second species known from the species group, and it is easily distinguishable from T. kelleri. The latter species has much larger eyes (OI 24-26), relatively shorter antennal scapes (SI 89-99), and extremely long propodeal spines (PSLI 49-68), whereas T. ankarana possesses significantly smaller eyes (OI 20), slightly longer antennal scapes (SI 101-104), and much shorter propodeal spines (PSLI 35-38). Furthermore, T. ankarana is also much darker in colour than most of the material of T. kelleri, which ranges from whitish-yellowish to brown. However, some series were almost the same colour as T. ankarana , and we do not consider colouration a good diagnostic character in this case.

Etymology

The name of the new species refers to the type locality, the Réserve Spéciale de l'Ankarana. The reserve is of high importance for the conservation of animal biodiversity, and the dedication of this new species accounts for its importance. The species epithet is a noun in apposition, and thus invariant.

Material examined

MADAGASCAR: Antsiranana, Réserve Ankarana, 7 km SE Matsaborimanga, 12° 54' S, 49° 07' E, 150 m, rainforest, 30.XI.1990 (P.S. Ward); Antsiranana, Réserve Spéciale de l'Ankarana, 22.9 km 224° SW Anivorano Nord, 12.90889 S, 49.10983 E, 80 m, tropical dry forest, 10.-16.II.2001 (B.L. Fisher, C. Griswold et al.).