Tetramorium jugatum

A small rotten-wood inhabiting species widely distributed in West and Central Africa (Bolton 1980). A number of contemporary collections (2019: KG40207, KGCOL00141) were taken from ground nests.

Identification
Bolton (1980) - Tetramorium jugatum is closely related to Tetramorium intonsum, Tetramorium shilohense and Tetramorium termitobium. The characters common to these species are discussed under T. intonsum. Of these four species T. intonsum is separated by its possession of long, very dense pubescence on the middle and hind tibiae which is suberect or subdecumbent and by its dense body pilosity and elongate antennal scapes, as noted in the discussion of that species. The remaining three lack such conspicuous pilosity and in general have shorter scapes. Of the remainder, T. shilohense is separated from T. jugatum by the regular longitudinal sculpture of the dorsal alitrunk which it possesses whilst termitobium is characterized by its more massively constructed head, in which CI is in the range 92-94 (as opposed to 83-88 in T. jugatum and 85-90 in T. shilohense).

Distribution based on Regional Taxon Lists
Afrotropical Region: Angola, Cameroun, Ghana, Ivory Coast, Nigeria.

Nomenclature

 *  jugatum. Tetramorium jugatum Bolton, 1980: 289, fig. 75 (w.) IVORY COAST.

Worker
Holotype: TL 2.5, HL 0.62, HW 0.54, CI 87, SL 0.48, SI 89, PW 0.39, AL 0.70. Paratypes (20 measured): TL 2.2-2.6, HL 0.56-0.68, HW 0.48-0.60, CI 83-88, SL 0.42-0.50, SI 86-93, PW 0.32-0.42, AL 0.60-0.72. Maximum diameter of the eye 0.06-0.08, about 0.12-0.14 x HW

Mandibles longitudinally striate. Anterior clypeal margin entire, without a notch or impression. Median carina sharp and running the length of the clypeus. Frontal carinae moderately developed and surmounted by a low rim or flange, running back beyond the level of the eyes but fading out and merging with the remaining cephalic sculpture well before approaching the occipital margin. Antennal scrobes vestigial, indicated by a very feeble concavity below the frontal carinae. Eyes small, with only 3 ommatidia in the greatest diameter, much smaller than the maximum width of the scape; maximum diameter of eye 0.07, about 0.13 x HW. With the alitrunk in profile the metanotal groove feebly impressed. Propodeal spines long and quite stout, the metapleural lobes low and triangular. Petiole in profile with a long, stout anterior peduncle and a short node, the anterodorsal angle of which is more sharply developed than the posterodorsal. In dorsal view the petiole node is very slightly broader than long. Dorsum of head irregularly longitudinally rugulose, the occipital area and the sides of the head reticulate-rugulose. Dorsal alitrunk predominantly longitudinally rugose but with numerous cross-meshes and irregularities. Petiole dorsum with faint rugulae but the postpetiole only with vestiges of sculpture present. First gastral tergite smooth. All dorsal surfaces of head and body with numerous standing hairs but these not so dense as to form a pelt. Dorsal (outer) surfaces of hind tibiae with short pubescence which is decumbent to appressed. Colour yellow but tinged with brown.

Paratypes: As holotype but eye with 3-5 ommatidia in its greatest diameter. Sculpture in some paratypes more sharply marked than in holotype, a few with three strong rugulae between the frontal carinae which run back beyond the level of the eye. Dorsal alitrunk distinctly reticulate-rugulose in some and many having traces of rugular sculpture on the postpetiolar dorsum.

Type Material
Holotype worker, Ivory Coast: Anyama, no. 8, Teke Forest, 1.ii.1974 (7. Diomande). Paratypes. 20 workers with same data as holotype; 21 workers, Tai Forest, 11.iii.1976, no. 12 (T. Diomande); 6 workers, Tai Forest, 11.iii.1976, no. 5 (7. Diomande) (BMNH; ; ).

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.
 * 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.
 * Bolton B. 1980. The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Ethiopian zoogeographical region. Bulletin of the British Museum (Natural History). Entomology 40: 193-384.
 * IZIKO South Africa Museum Collection
 * Levieux J., and T. Diomande. 1985. Evolution des peuplements de fourmis terricoles selon l'age de la végétation dans une foret de Cote d'Ivoire intacte ou soumise à l'action humaine. Insectes Sociaux 32(2): 128-139.