Tetramorium anxium

There are collection records from forest, woodland, and shrubland. In Benin, Taylor et al. (2018) report this species from mango (Mangifera indica) orchards, where it is ground nesting.

Identification
A member of the Tetramorium simillimum species group.

Bolton (1980) - Among the species of the simillimum species-group in which the frontal carinae are strongly developed and which have conspicuous antennal scrobes only two species, Tetramorium buthrum and T. anxium, lack blanketing reticulate-punctate sculpture on the dorsum of the head. Of these two T. buthrum has the cephalic sculpture reduced to 5 weak longitudinal rugulae as opposed to 8-10 even more feeble rugulae in T. anxium. Coupled with this the ground-sculpture of the dorsum of the head is virtually absent in T. buthrum and it looks much more smooth and shiny than does the head of T. anxium.

Distribution based on Regional Taxon Lists
Afrotropical Region: Benin, Cameroun, Gabon, Ghana, Guinea, Ivory Coast, Togo, United Republic of Tanzania.

Nomenclature

 *  anxium. Tetramorium pusillum var. anxia Santschi, 1914d: 365, fig. 28 (w.q.) GUINEA. Raised to species: Bolton, 1980: 305.

Worker
Bolton (1980) - TL 2-0-2:2, HL 0:53-0:55, HW 0:46-0:49, CI 88-90, SL 0-39-0-40, SI 82-83, PW 0:34-0:36, AL 0:60-0:64 (3 measured).

Mandibles finely shagreened or punctulate, not longitudinally striate. Anterior clypeal margin entire, the median clypeal carina strong. Eyes moderate, maximum diameter c. 0-12, about 0.25 x HW, with 7-8 ommatidia in the greatest diameter. Frontal carinae strong, weakly sinuate, extending unbroken almost to occipital margin and markedly more strongly developed than any other longitudinal cephalic sculpture. Antennal scrobes broad and shallow, very distinct, less strongly sculptured than dorsum of head. Propodeal spines in profile a pair of short triangular teeth which are distinctly much shorter and narrower than the metapleural lobes, the latter broadly triangular. Petiole in profile with the dorsum of the node shorter than the height of the tergal portion, the anterior and posterior faces of the node slightly convergent dorsally. In dorsal view the node broader than long. Dorsum of head with feeble, scattered longitudinal rugulae. After the strong frontal carinae the most strongly developed component is the median cephalic carina which is stronger than any other longitudinal rugula. Surface of head with a very weak ground-sculpture, feebly shining. Dorsum of alitrunk with weak rugulae on the pronotum, the spaces between them smooth, virtually unsculptured. Posterior to this the rugulae becoming less conspicuous and the ground-sculpture more distinctly punctulate. Petiole and postpetiole punctulate, the first gastral tergite smooth, unsculptured. Hairs present on all dorsal surfaces of head and body, universally short, stout and blunt. Appendages without hairs but with fairly dense short pubescence. Colour uniform blackish brown, the appendages yellowish brown.

Type Material
Bolton (1980) - Syntype workers, female, GUINEA: Camayenne near Conakry (F. Silvestri) [examined].

References based on Global Ant Biodiversity Informatics

 * Bernard F. 1953. La réserve naturelle intégrale du Mt Nimba. XI. Hyménoptères Formicidae. Mémoires de l'Institut Français d'Afrique Noire 19: 165-270.
 * Braet Y., and B. Taylor. 2008. Mission entomologique au Parc National de Pongara (Gabon). Bilan des Formicidae (Hymenoptera) recoltes. Bulletin S. R. B. E./K.B.V.E. 144: 157-169.
 * IZIKO South Africa Museum Collection
 * Santschi F. 1914. Formicides de l'Afrique occidentale et australe du voyage de Mr. le Professeur F. Silvestri. Bollettino del Laboratorio di Zoologia Generale e Agraria della Reale Scuola Superiore d'Agricoltura. Portici 8: 309-385.
 * Taylor B., N. Agoinon, A. Sinzogan, A. Adandonon, Y. N'Da Kouagou, S. Bello, R. Wargui, F. Anato, I. Ouagoussounon, H. Houngbo, S. Tchibozo, R. Todjhounde, and J. F. Vayssieres. 2018. Records of ants (Hymenoptera: Formicidae) from the Republic of Benin, with particular reference to the mango farm ecosystem. Journal of Insect Biodiversity 8(1): 006–029.
 * Yeo K., L. M. M. Kouakou, W. Dekoninck, K. Ouattara, and S. Konate. 2016. Detecting intruders: assessment of the anthropophilic ant fauna (Hymenoptera: Formicidae) in the city of Abidjan and along access roads in Banco National Park (Côte d’Ivoire). Journal of Entomology and Zoological Studies 4(4): 351-359.
 * Yeo K., S. Konate, S. Tiho, and S. K. Camara. 2011. Impacts of land use types on ant communities in a tropical forest margin (Oumé - Cote d'Ivoire). African Journal of Agricultural Research 6(2): 260-274.