Tetramorium marginatum Forel

Bolton, B., 1979, The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Malagasy region and in the New World., Bulletin of the British Museum (Natural History) Entomology 38, pp. 129-181 : 142-143

Tetramorium marginatum Forel

(Figs 10, 11)

Tetramorium {Xiphomyrmex) marginatum Forel, 1895 b: 485 . Syntype workers, Madagascar: central Madagascar {Sikora) (MHN, Geneva) [examined].

Worker. TL 3.8 - 3.9, HL 0.84 - 0.86, HW 0.78, CI 90 - 93, SL 0.68 - 0.70, SI 87 - 90, PW 0.60, AL 1.00 - 1.02 (2 measured).

Mandible with a few faint and feeble striae but with extensive smooth areas. Clypeus with a sharp, fine median carina. Frontal carinae short, ending just posterior to the level of the eyes. Antennal scrobes very weak, merely short, shallow impressions below the frontal carinae and not as long as the antennal scapes. Pronotal corners rounded in dorsal view, the sides of the pronotum bluntly marginate. Dorsum of mesonotum and propodeum separated from the sides by an acute, very distinct margination which runs to the bases of the long, acute propodeal spines. Dorsal alitrunk between the margination transversely flat, longitudinally feebly convex. Metapleural lobes short and rounded. Petiole in profile anteroposteriorly compressed, the node tapering from base to apex as shown in Fig. 11. Dorsum of head with sparse, scattered, fine longitudinal rugulae which peter out posteriorly. Dorsal alitrunk unsculptured but with superficial patterning, the pedicel and gaster unsculptured. All dorsal surfaces of head and body with erect or suberect fine hairs. Head and alitrunk black or blackish brown, the pedicel and gaster dark brown.

Rendered highly conspicuous among the Malagasy tetramoriines by its lack of sculpture, sharply margined mesonotum and propodeum and compressed petiole, marginatum is unlikely to be confused with any other member of the genus from Madagascar or Africa.

Material examined

Madagascar: Rte d'Anosibe (W. L. & D. E. Brown); Beforona (A. Peyrieras).