Tetramorium xanthogaster Santschi

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 : 139

Tetramorium xanthogaster Santschi stat. n.

(Figs 3, 4)

Tetramorium (Xyphomyrmex) [sic] sikorae st. xantogaster [sic] Santschi , 1911: 124. Holotype worker, Madagascar {J. de Gaulle) (NM, Basle) [examined]. Xiphomyrmex sikorae subsp. xanthogaster Santschi ; Wheeler, 1922: 1032. Emery, 1922: 287 [justified emendation].

Worker. TL 3.2, HL 0.76, HW 0.66, CI 89, SL 0.54, SI 82, PW 0.50, AL 0.88.

Mandibles smooth with scattered small pits. Median clypeal carina very faint, almost effaced, much less distinct than the lateral carinae. Frontal carinae very reduced, their posterior extensions fine and no more distinct than the rugulae between them. Antennal scrobes absent. Metanotal groove not impressed. Propodeum armed with a pair of short, stout spines, the metapleural lobes roughly triangular. Dorsum of head with very fine, faint, irregular longitudinal rugulae and with a superficial reticulate ground sculpture between them. Dorsal alitrunk with scattered, weak, predominantly longitudinal rugulae. Pedicel and gaster unsculptured, smooth and polished. All dorsal surfaces of head and body with erect or suberect fine hairs. Head and alitrunk dark brown, pedicel and gaster clear pale yellow, the two strongly contrasting.

As Santschi pointed out in the original description, this small species is close to sikorae , but unlike that species it is bicoloured, has relatively longer antennal scapes, lacks scrobes and has much better developed propodeal spines. The presence of gastral pilosity places this species in the sikorae-complex of the schaufussi-group, but the characters given above will quickly separate xanthogaster from its allies.