Tetramorium coillum, 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 : 147-148

Tetramorium coillum sp. n.

(Fig. 21)

Holotype worker. TL 2.8, HL 0.72, HW 0.67, CI 93, SL 0.46, SI 69, PW 0.48, AL 0.78.

Mandibles coarsely longitudinally striate, anterior clypeal margin with a distinct notch or impression. Maximum diameter of eye 0.12, about 0.18 x HW. Frontal carinae strong to behind level of eyes, but fading out before they reach the occipital area and becoming confused with the remaining sculpture. Antennal scrobes very feeble, all of the scrobal area sculptured. Propodeal spines strong, feebly upcurved along their length, metapleural lobes triangular and acute. Petiole in profile strongly nodiform, with a sharp anterodorsal angle and with a minute peak at the angle due to the presence of a transverse dorsal carina. Posterodorsal angle of petiole rounded. Node of petiole in dorsal view as broad as long. Dorsum of head finely and irregularly longitudinally rugulose, with a conspicuous punctulate ground-sculpture between them, the rugulae forming a weak reticulum occipitally. Dorsal alitrunk reticulate-rugulose, the sculpture more strongly developed than on the head, the individual rugulae low and rounded, with a beaded appearance dorsally due to the presence of fine aligned punctulation. Spaces between reticular meshes mostly smooth. Petiole dorsum finely and densely rugulose, the postpetiolar dorsum with extensive shining areas but with some rugulae present, especially posterolaterally. Gaster unsculptured. Short, fine acute hairs present on all dorsal surfaces of head and body. Colour dark brown.

Paratype workers. As holotype, TL 2.7 - 2.8, HL 0.66 - 0.72, HW 0.62 - 0.66, CI 91 - 94, SL 0.44 - 0.47, SI 69 - 72, PW 0.45 - 0.47, AL 0.72 - 0.78. Maximum diameter of eye 0.11 - 0.12, about 0.17 - 0.19 x HW.

Holotype worker, Madagascar: Bemanevika, Souspref. de Bealanana, 20. x. 1975, forest humus and litter, AB 46 (A. Peyrieras) (MCZ, Cambridge). Paratypes. 12 workers and 2 dealate females with same data as holotype (MCZ, Cambridge; BMNH).

This small species is closest related to ranarum and quasirum but differs from both of these by retaining rugular sculpture on the postpetiole and by having the anterodorsal angle of the petiole node sharp.