Tetramorium hapale

Identification
Bolton (1980) - The four uniformly dark-coloured species of the camerunense-complex (Tetramorium camerunense, T. hapale, Tetramorium ictidum, Tetramorium ubangense) form a tetrad of closely related species. Tetramorium camerunense stands out fairly well from this collection as it lacks dorsal cephalic ground-sculpture and the petiole node in dorsal view either lacks the transverse anterior crest or at most has it very reduced and almost invisible. In the other three species the dorsal cephalic ground-sculpture is dense and conspicuous, either densely reticulate-punctate or punctulate-granular; also the transverse anterior crest on the petiole dorsum is present and usually very distinctive. T. ubangense is distinguished from both T. hapale and T. ictidum by being a larger species (HW 0.78 as opposed to HW 0.66 at maximum in the other two) and by having the petiole node broader than long in dorsal view, as opposed to its being longer than broad in the other two. Finally, T. ubangense retains delicate but fairly distinctive punctulate sculpture on the dorsal surfaces of both pedicel segments. The last two species, T. hapale and T. ictidum, separate well on measurable characters as T. hapale has a long, quite narrow head and relatively long scapes (CI 85, SI 84) whilst in T. ictidum the head is broader and the scapes relatively shorter (CI 88-92, SI 78-80).

Distribution based on Regional Taxon Lists
Afrotropical Region: Ivory Coast.

Nomenclature

 *  hapale. Tetramorium hapale Bolton, 1980: 339 (w.) IVORY COAST.

Worker
Holotype. TL 3.0, HL 0.75, HW 0.64, CI 85, SL 0.54, SI 84, PW 0.46, AL 0.82.

Mandibles smooth and shining with scattered small pits. Anterior clypeal margin with a shallow median impression. Median clypeal carina sharp and distinct, running the length of the clypeus and flanked on each side by 1-2 much feebler rugulae, without other sculpture. Frontal carinae fine but more strongly developed than other cephalic sculpture, running back well beyond the level of the posterior margins of the eyes but fading and merging with the rugular sculpture of the occipital region before reaching the margin. Maximum diameter of eye 0.14, about 0.22 x HW and with 7 ommatidia in the longest row. Dorsal alitrunk evenly convex, not impressed at the metanotal groove. Propodeum armed with a pair of short, straight spines which are slightly longer than the elongate-triangular metapleural lobes. Petiole in profile with a narrow, more or less straight anterior peduncle. Petiole node with dorsal surface about as long as the tergal portion is high, anterodorsal angle roughly right-angled, the posterodorsal angle blunter. In dorsal view the petiole node longer than broad and with a conspicuous transverse ridge or crest running across the anterior face; the crest is continuous with a lateral raised ridge which runs diagonally across each side of the node. Dorsum of head with very fine irregular weak longitudinal rugulae, the spaces between them with a dense and conspicuous punctulate-granular ground-sculpture. Occipital region of head with a few anastomoses or cross-meshes, especially laterally, but without a rugoreticulum. Sides of head between eye and frontal carinae as strongly punctulate-granular as dorsum but the rugulae in this area much weaker. Dorsal alitrunk with scattered, disorganized, very weak rugulae. Ground-sculpture almost effaced on pronotum, much weaker than on head, but posteriorly on alitrunk the ground-sculpture strengthening. Petiole dorsum with very scattered, virtually effaced vestiges of rugular sculpture, postpetiole and gaster smooth and shining. All dorsal surfaces of head and body with numerous standing hairs, the longest of those on the alitrunk about equal to the maximum diameter of the eye. Scapes and tibiae only with short appressed pubescence. Colour uniform mid-brown but the appendages yellow.

Type Material
Holotype worker, Ivory Coast: Banco Forest, nr Abidjan, 11.1.1963, no. ASO (W. L. Brown).