Tetramorium pleganon, 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 : 146

Tetramorium pleganon sp. n.

Holotype worker. TL 3.8, HL 0.92, HW 0.87, CI 97, SL 0.64, SI 74, PW 0.68, AL 1.10.

Mandibles with very faint, delicate longitudinal striation. Anterior clypeal margin with a very small median impression. Maximum diameter of eye 0.20. Frontal carinae strong, surmounted for most of their length by a narrow rim or flange, occipitally becoming indistinguishable from the surrounding sculpture. Antennal scrobes shallow but broad. Dorsal alitrunk transversely flattened, in dorsolateral view appearing only very weakly convex. Sides of alitrunk bluntly marginate. Propodeal spines elongate and strong, somewhat downcurved along their length. Metapleural lobes short-triangular, acute apically. Node of petiole in profile slightly higher than long, the anterolateral angle roughly a right-angle and the dorsum sloping posteriorly to the much more rounded posterodorsal angle. Postpetiole evenly convex. Dorsum of head regularly longitudinally rugulose, without occipital reticulation; about 11 rugulae between the frontal carinae at the level of the eyes, the spaces between them with very feeble ground-sculpture. Middle of dorsal alitrunk longitudinally rugose, with four roughly parallel strong rugae running from anterior pronotum to propodeum. Outside of these the rugae are more disorganized and meandering, with traces of a broken reticulum in places, especially on the pronotum. Petiole and postpetiole strongly rugose dorsally, the two about equally strongly sculptured. Basal third of first gastral tergite finely and densely reticulate-punctate. All dorsal surfaces of head and body with abundant fine hairs, dorsal surfaces of hind tibiae with suberect to subdecumbent short pilosity. Colour blackish brown, the appendages lighter.

Paratype workers. As holotype, but with dimensions TL 3.7 - 4.0, HL 0.92 - 0.96, HW 0.88 - 0.92, CI 96, SL 0.66 - 0.70, SI 75 - 76, PW 0.66 - 0.69, AL 1.10 - 1.12. Eye diameter 0.18 - 0.20 (2 measured).

Holotype worker, Madagascar: 84 km SW. Sambava on road to Andapa, 70 - 160 m, 17. ii. 1977 degraded for. AB 43, strays on path (W. L. & D. E. Brown) (MCZ, Cambridge).

Paratypes. Three workers with same data as holotype (MCZ, Cambridge; BMNH).

This is the only known Malagasy species with 11 - merous antennae which has the first gastral tergite sculptured.