Tetramorium intonsum

Samples have been collected from leaf litter or rotten wood, the majority from rotting logs. The state of the wood does not seem to matter much to this species as it has been found in dry dead wood as well as in wet-rotten stumps. (Bolton 1980)

Identification
Bolton (1980) - Tetramorium intonsum belongs to a complex of four small yellow species in this group, the other members being Tetramorium jugatum, Tetramorium shilohense and Tetramorium termitobium. Together they are characterized by their moderately developed frontal carinae, coarse sculpture, small (as opposed to minute) eyes with 3-5 ommatidia in the greatest diameter, and vestigial or very feeble antennal scrobes. Tetramorium intonsum is easily isolated from this assemblage by its possession of dense fine pilosity, suberect to subdecumbent long pubescence on the hind tibiae and relatively long antennal scapes in which SI range is 93-99 as opposed to a range of 78-93 in the other 3 species combined. The upper portion of this range is seen only in T. jugatum (SI 86-93) and specimens in which the SI matches are quickly separable on the pilosity characters, as indicated in the key.

Distribution based on Regional Taxon Lists
Afrotropical Region: Ghana, Ivory Coast, Nigeria, United Republic of Tanzania.

Nomenclature

 *  intonsum. Tetramorium intonsum Bolton, 1980: 288, fig. 68 (w.) GHANA.

Worker
Holotype: TL 2.9, HL 0.70, HW 0.59, CI 84, SL 0.56, SI 95, PW 0.42, AL 0.80. Paratypes (20 measured): TL 2.8-3.1, HL 0.64-0.70, HW 0.54-0.59, CI 81-85, SL 0.52-0.56, SI 93-99, PW 0.38-0.50, AL 0.76-0.90. As holotype, with maximum diameter of eye 0.07-0.08, about — 0.12-0.15 x HW and with 4-5 ommatidia in the greatest diameter.

Mandibles longitudinally striate. Anterior clypeal margin entire, without a notch or impression medially; median clypeal carina running from anterior margin to posterior suture. Frontal carinae moderately developed, running back beyond the level of the posterior margins of the eyes but fading out behind that level, not approaching the occipital region. Antennal scrobes vestigial, the area of the side of the head below the frontal carinae only slightly concave, evenly sculptured. Antennal scapes relatively long, SI > 90. Eyes small, with only 4 ommatidia in the greatest diameter; maximum diameter of eye 0.08, about 0.14 x HW, smaller than the maximum width of the scape. With the alitrunk in profile the propodeum armed with a pair of moderately long, stout spines. Metapleural lobes low and triangular. Petiole in profile with a stout anterior peduncle, the node with the anterodorsal angle blunt but conspicuous, almost a right-angle; posterodorsal angle represented by a short convex surface where the dorsum grades into the posterior face. In dorsal view the node very slightly longer than broad. Dorsum of head irregularly longitudinally rugulose, the occipital region and sides of the head reticulate-rugulose, all of the cephalic sculpture fine but dense. Dorsal alitrunk densely rugulose, predominantly longitudinally so but with scattered cross-meshes and - reticular patches, especially visible on dorsum of pronotal shoulders. Dorsum of petiole with fine rugular sculpture but the postpetiole virtually unsculptured dorsally, only with some light shagreening. First gastral tergite unsculptured. All dorsal surfaces of head and body covered in a dense pelt of fine soft hairs. With the head in full-face view the sides between the posterior margins of the eyes and the occipital corners with - abundant projecting hairs, usually too dense to be counted easily. Dorsal (outer) surfaces of hind tibiae with - dense long pubescence which is suberect to subdecumbent and very conspicuous. Colour uniform yellow.

Paratypes: Some paratypes with ruguloreticulum on occiput more sharply defined than in holotype and also with the dorsal alitrunk predominantly reticulate-rugulose. On the dorsum of the postpetiole some individuals show vestiges of rugular sculpture but in others this area is smooth. A majority of specimens have the propodeal spines either slightly downcurved or very feebly sinuate along their length; even in the holotype the spines are not absolutely straight. Degree of elevation of the standing pubescence on the dorsal (outer) surfaces of the middle and hind tibiae is variable from suberect to subdecumbent, but is always very dense and easily discernible. With the alitrunk in profile the metanotal groove is commonly weakly impressed, but this is not the case in scattered individuals in each series.

Type Material
Holotype worker, Ghana: Tafo, 15.i.1971, rotten wood (B. Bolton). Paratypes. 8 workers with same data as holotype; 2 workers, Tafo, 9.ii.1971, litter sample (B. Bolton); 6 workers, Tafo, 20.x.1970, rotten log (B. Bolton); 6 workers, Tafo, 10.ix.1970, rotten log (B. Bolton) - (BMNH;, ).

References based on Global Ant Biodiversity Informatics

 * 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.
 * Kone M., S. Konate, K. Yeo, P. K. Kouassi, K. E. Linsemair. 2010. Diversity and abundance of terrrestrial ants along a gradient of land use intensification in a transitional forest-savannah zone of Cote d'Ivoire. Journal of Applied Biosciences 29: 1809-1827.
 * Kone M., S. Konate, K. Yeo, P. K. Kouassi, and K. E. Linsenmair. 2012. Changes in ant communities along an age gradient of cocoa cultivation in the Oumé region, central Côte dIvoire. Entomological Science 15: 324339.
 * Stephens S. S., P. B. Bosu, and M. R. Wager. 2016. Effect of overstory tree species diversity and composition on ground foraging ants (Hymenoptera: Formicidae) in timber plantations in Ghana. International Journal of Biodiversity Science, Ecosystem Services & management 12(1-2): 96-107.
 * Yeo K., T. Delsinne, S. Komate, L. L. Alonso, D. Aidara, and C. Peeters. 2016. Diversity and distribution of ant assemblages above and below ground in a West African forest–savannah mosaic (Lamto, Cote d’Ivoire). Insectes Sociaux DOI 10.1007/s00040-016-0527-6