Tetramorium tantillum, Bolton, B., 1979

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 : 152-153

Tetramorium tantillum sp. n.

(Figs 30, 31)

Holotype worker. TL 4.5, HL 1.09, HW 0.92, CI 90, SL 0.74, SI 80, PW 0.70, AL 1.22.

Mandibles with faint and delicate longitudinal striation, the anterior clypeal margin arcuate and entire. Clypeus medially with only three longitudinal carinae. Eyes moderate, maximum diameter 0.21, about 0.23 x HW, not strongly protuberant. Frontal carinae long, almost reaching occipital region before merging with other cephalic sculpture, but not strong, no more strongly developed than the longitudinal rugae between them. The frontal carinae very weakly sinuate along their length, broadest at about level of eyes and converging slightly posteriorly, not diverging towards the occipital corners. Outline shape of lateral alitrunk as in Fig. 31. Propodeal spines straight and acute, metapleural lobes broad and bluntly triangular. Pedicel in profile as in Fig. 31, in dorsal view the petiole node roughly globular, very slightly broader than long and distinctly more voluminous than the postpetiole. Dorsum of head with irregular longitudinal rugae which are widely spaced, about 7 between the frontal carinae at the level of the eyes. Spaces between rugae with feeble ground-sculpture which amounts to little more than a slight roughening of the surface. Dorsal alitrunk with low, rounded, very weak rugae which form a feeble, almost effaced reticulum on the promesonotum. Dorsal surfaces of petiole and postpetiole smooth, with superficial faint markings which resemble an almost effaced fine reticulate-punctulation. Sides of petiole node with a few vestigial rugulae. Gaster unsculptured. All dorsal surfaces of head and body with numerous hairs, mostly erect or sub-erect. Colour uniform dark brown.

Paratype workers. TL 4.2 - 4.4, HL 1.00 - 1.02, HW 0.88 - 0.90, CI 88 - 90, SL 0.70 - 0.74, SI 79 - 82, PW 0.64 - 0.68, AL 1.12 - 1.88. Maximum diameter of eye 0.19 - 0.21 (3 measured).

Holotype worker, Madagascar: Mangabe Isl., Antongil Bay 19. ii. 1977, prim. rain forest, AB 42 litter (W. L. & D. E. Brown) (MCZ, Cambridge). Paratypes. 3 workers with same data as holotype (MCZ, Cambridge; BMNH).

Closely related to tosii but not as specialized as that species. The eyes in tantillum are much less prominent, the scapes and propodeal spines shorter, and the petiole node is constructed differently (Figs 30, 31 and 32, 33).