Tetramorium nify 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 : 42-43

Tetramorium nify Hita Garcia & Fisher sp. n.

(Figs. 61, 68, 69, 96, 97, 98)

Holotype worker, MADAGASCAR, Toamasina, Réserve Spéciale Ambatovaky, Sandrangato River, 16.81753 S, 49.29498 E, 360 m, rainforest, ex rotten log, collection code BLF24814, 25.II.2010 (B.L. Fisher et al.) (CASC: CASENT0163155). Paratype, one worker with same data as holotype (CASC: CASENT0163345).

Diagnosis

Tetramorium nify can be clearly distinguished from the other species of the T. andrei complex by the following character combination: small eyes (OI 16-17); long propodeal spines (PSLI 29-30); posterodorsal corner of petiolar node not strongly protruding posteriorly; body very dark brown to black in colour.

Description

HL 0.83-0.95 (0.87); HW 0.82-0.93 (0.86); SL 0.60-0.66 (0.63); EL 0.14-0.15 (0.14); PH 0.41-0.51 (0.44); PW 0.61-0.72 (0.65); WL 1.02-1.21 (1.08); PSL 0.25-0.28 (0.26); PTL 0.30-0.37 (0.33); PTH 0.32-0.38 (0.35); PTW 0.26-0.31 (0.28); PPL 0.29-0.33 (0.31); PPH 0.32-0.37 (0.34); PPW 0.33-0.38 (0.35); CI 98-100 (99); SI 69-74 (73); OI 16-17 (17); DMI 59-63 (60); LMI 39-42 (41); PSLI 29-30 (30); PeNI 43-44 (43); LPeI 91-100 (96); DPeI 82-88 (84); PpNI 52-54 (53); LPpI 88-91 (90); DPpI 112-116 (113); PPI 121-125 (124) (five measured).

Head weakly longer than wider to as long as wide (CI 98-100). Posterior had margin weakly concave. Anterior clypeal margin weakly medially impressed. Frontal carinae strongly developed, diverging posteriorly, and ending at corners of posterior head margin. Antennal scrobes moderately developed, but shallow, narrow, and without defined posterior and ventral margins. Antennal scapes comparatively short, not reaching posterior head margin (SI 69-74). Eyes very small (OI 16-17). Mesosomal outline in profile flat, moderately marginate from lateral to dorsal mesosoma; promesonotal suture and metanotal groove absent; mesosoma comparatively stout and high (LMI 39-42). Propodeal spines with very broad base, up-curved, elongate-triangular, and moderately long (PSLI 29-30); propodeal lobes well-developed, triangular and acute. Petiolar node in profile rectangular nodiform with well-defined angles, around 1.0 to 1.1 times higher than long (LPeI 91-100), anterior and posterior faces approximately parallel, anterodorsal and posterodorsal margins approximately at same height, dorsum straight; node in dorsal view approximately 1.2 times longer than wide (DPeI 82-88). Postpetiole in profile globular, approximately 1.1 times higher than long (LPpI 88-91); in dorsal view around 1.1 to 1.2 times wider than long (112-116). Postpetiole in profile appearing less voluminous than petiolar node, in dorsal view approximately 1.2 times wider than petiolar node (PPI 121-125). Mandibles distinctly longitudinally rugose; clypeus longitudinally rugose, with three to five rugae; cephalic dorsum between frontal carinae with 8 to 11 longitudinal rugae, most rugae running unbroken from posterior head margin to posterior clypeus, few rugae interrupted or with cross-meshes; lateral and ventral head longitudinally rugose, rarely with cross-meshes. Mesosoma laterally and dorsally distinctly longitudinally rugose. Forecoxae unsculptured. Waist segments strongly irregularly longitudinally rugose. Gaster completely unsculptured, smooth and shining. Ground sculpture generally faint to absent everywhere on body. All dorsal surfaces of head, mesosoma, waist segments, and gaster with abundant, long, and fine standing hairs. First gastral tergite without appressed pubescence. Anterior edges of antennal scapes with erect, standing hairs. Body uniform dark brown to black in colour.

Notes

Tetramorium nify is only known from five specimens from Ambatovaky, Befingotra, and Isle Saint Marie.

Within the species complex, T. nify is another species with fairly small eyes (OI 16-17). The other species with comparatively small eyes are T. elf, T. electrum, T. isoelectrum, and T. isectum. The first three have very long to extremely long propodeal pines (PSLI 46-64), short and blunted propodeal lobes, and differently shaped petiolar nodes. Tetramorium isectum has even smaller eyes (OI 15-16) than T. nify, a petiolar node with the anterodorsal margin situated higher than the posterodorsal and the dorsum weakly tapering backwards, and bright orange body colour, whereas T. nify is very dark brown to black in colour and has anterodorsal and posterodorsal margins of the petiolar node at about the same height. Disregarding eye size, T. nify also cannot be confused with T. ala, T. andohahela , or T. voasary. Tetramorium andohahela has the posterodorsal corner of the petiolar node strongly protruding posteriorly, T. ala has the posterior corners of the head weakly angular and marginate, and T. voasary has a petiolar node with the anterodorsal and posterodorsal angles fairly rounded. The defining characters of the first two are absent in T. nify, and the petiole of the latter has a node with well-defined anterodorsal and posterodorsal angles, which separates it from T. voasary.

The last species of the complex, T. andrei, is morphologically very close to T. nify, and we have treated the material as conspecific for a while during this revision. The only good diagnostic character that divides them is eye size, which is much larger in T. andrei (OI 19-25, usually above 20). However, we observed both in sympatry in Ambatovaky and Befingotra and specimens of T. nify are easily separable from sympatric T. andrei due to their fairly small eyes and a petiolar node with sharper defined antero- and posterodorsal margins. The mesosoma of T. nify is also a bit shorter (DMI 59-63) than the one of T. andrei (DMI 50-60). As noted in its description, T. andrei is a remarkably variable species, which very likely includes several cryptic species. However, especially on the basis of the co-occurrence without intermediate forms, we treat T. nify as its own species distinct from T. andrei.

Etymology

The species epithet is an arbitrary combination of letters.

Material examined

MADAGASCAR: Antsiranana, Rés. Anjanaharibe-Sud, 6.5 km SSW Befingotra, 14.75 S, 49.5 E, 875 m, rainforest, 18.-22.X.1994 (B.L. Fisher); Toamasina, Ile Sainte Marie, Forêt Kalalao, 9.9 km 34° Ambodifotatra, 16.9225 S, 49.88733 E, 100 m, rainforest, 24.-27.XI.2005 (B.L. Fisher et al.); Toamasina, Réserve Spéciale Ambatovaky, Sandrangato River, 16.81753 S, 49.29498 E, 360 m, rainforest, 25.II.2010 (B.L. Fisher et al.).