Tetramorium ictidum

Clearly a species that likes moist habitats, two of the relatively few collections of T. ictidum include habitat information. One is from a rainforest canopy sample (SY-311) and the other from the litter of a swamp forest (JTL7947-s).

Identification
Bolton (1980) - Of the four uniformly dark-coloured species which constitute a part of the camerunense-complex T. ictidum is isolated by its possession of conspicuous ground-sculpture on the dorsum of the head, relatively small size (HW 0.66 at maximum), petiole node which is as long as or slightly longer than broad dorsally, densely rugulose pronotum and relatively short broad head, CI 88-91.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Gabon, Ghana, Uganda.

Nomenclature

 *  ictidum. Tetramorium ictidum Bolton, 1980: 339 (w.) CAMEROUN.

Worker
Holotype: TL 2.8, HL 0.70, HW 0.64, CI 91, SL 0.50, SI 78, PW 0.42, AL 0.78. Paratypes (8 measured): TL 2.7-2.9, HL 0.68-0.72, HW 0.62-0.66, CI 88-91, SL 0.49-0.52, SI 78-80, PW 0.40-0.44, AL 0.76-0.81.

Mandibles smooth and shining, with scattered minute pits. Anterior clypeal margin with a small, shallow median impression. Median clypeal carina sharp and strong, flanked by a much weaker lateral pair which may fail to reach the anterior margin. Frontal carinae fine but sharp, reaching back well beyond the level of the eyes but fading out and merging with the remaining cephalic sculpture on the occiput, not reaching the margin. Maximum diameter of eye 0.13, about 0.2 x HW and with 8 ommatidia in the longest row. Propodeum armed with a pair of short, rapidly tapering acute spines which are very slightly downcurved along their length. Metapleural lobes short and broadly triangular, distinctly shorter than the propodeal spines. Petiole in profile with the node narrowing from base to apex, the dorsal length less than the height of the tergal portion. Node of petiole in dorsal view slightly longer than broad. Dorsum of head finely longitudinally rugulose, with about 11 rugulae between the frontal carinae at eye-level. Spaces between the rugulae with a conspicuous finely punctulate or granular ground-sculpture. Occipital region with a few faint cross-meshes or anastomoses but without a reticulum except on the corners where a weak meshwork is present. Sides of head between eye and frontal carinae with fine, dense granular ground-sculpture and with reticulate rugulae, especially immediately above and behind the eye, such rugular sculpture suppressed closer to the frontal carina. Dorsal alitrunk densely and finely irregularly rugulose everywhere, forming an irregular reticulum on the pronotum but more disorganized elsewhere. Ground sculpture a weak superficial punctulation, almost effaced on the pronotum, stronger posteriorly. Dorsal surfaces of petiole and postpetiole mostly smooth but with vestigial traces of very faint punctulae. Gaster unsculptured. All dorsal surfaces of head and body with numerous quite stout hairs, the longest of those on the dorsal alitrunk and first gastral tergite shorter than the maximum eye diameter. Colour uniform dark brown, the appendages lighter.

Paratypes: As holotype but maximum diameter of eye 0.13-0.14, about 0.20-0.21 x HW, and with 10-13 longitudinal rugulae between the frontal carinae at eye level. Petiole in dorsal view with the node about as broad as long in some, otherwise slightly longer than broad as in holotype.

Type Material
Holotype worker, Cameroun: 14 miles [23 km] E. of Douala, 80 m, 20.xi.1966 (E. S. Ross & K. Lorenzen). Paratypes. 8 workers with same data as holotype (CASC; ; ).

References based on Global Ant Biodiversity Informatics

 * Belshaw R., and B. Bolton. 1994. A survey of the leaf litter ant fauna in Ghana, West Africa (Hymenoptera: Formicidae). Journal of Hymenoptera Research. 3: 5-16.
 * Yanoviak S. P., B. L. Fisher, and A. Alonso. 2007. Arboreal ant diversity (Hymenoptera: Formicidae) in a central African forest. African Journal of Ecology. 46(1): 60-66.