Tetramorium shilohense

Identification
Bolton (1980) - Tetramorium intonsum belongs to a complex of four small yellow species in this group, the other members being Tetramorium jugatum, T. 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. T. shilohense is distinguished from its immediate allies (T. intonsum, T. jugatum, T. termitobium) by its lack of standing pubescence on the tibiae, relatively short scapes and regular longitudinal sculpture on the pronotum. The related T. intonsum is a much more densely hairy species with standing tibial pubescence and longer scapes, whilst T. jugatum and T. termitobium both lack the characteristic pronotal sculpture which defines T. shilohense. Beside this T. termitobium has a more massively constructed head with more strongly convex sides so that its CI is higher (92-94) than in T. shilohense (85-89).

Distribution based on Regional Taxon Lists
Afrotropical Region: Kenya, Malawi, Zimbabwe.

Nomenclature

 *  shilohense. Tetramorium simillimum var. shilohensis Forel, 1913j: 218 (w.) ZIMBABWE. Raised to species: Bernard, 1953b: 248. See also: Bolton, 1980: 290.

Worker
Bolton (1980) - TL 2.4.2.8, HL 0.58-0.74, HW 0.50-0.65, CI 85-89, SL 0.42-0.52, SI 78-85, PW 0.36-0.44, AL 0.66-0.80 (20 measured).

Mandibles longitudinally striate. Anterior clypeal margin entire or at most with a very feeble, shallow median impression which is restricted to the anterior apron and does not intrude upon the body of the clypeus. Frontal carinae moderately developed, surmounted by a low raised rim or flange, reaching back beyond the level of the eyes but merging with the remaining cephalic sculpture on the occiput. Antennal scrobes broad and very shallow, reduced, represented only by a slight concavity of the side of the head below the frontal carinae. Eyes small, smaller than the maximum width of the scape, with only 3-5 ommatidia across the greatest diameter. Maximum diameter of eye 0.06-0.10, about 0.12-0.15 x HW. With the alitrunk in profile the metanotal groove usually weakly impressed, rarely absent. Propodeal spines elongate triangular, broad basally. Metapleural lobes broadly triangular. Petiole in profile with an elongate and fairly stout anterior peduncle, the node with the anterodorsal angle roughly right-angular and usually quite sharply developed; posterodorsal angle blunter and more broadly rounded, often the dorsal and posterior faces meeting in a narrow curve. Petiole in dorsal view with the node varying from slightly broader than long to slightly longer than broad, the former condition apparently predominant. Dorsum of head irregularly longitudinally rugulose, the occipital area usually with a ruguloreticulum, at least with numerous cross-meshes and anastomoses. Dorsal pronotum strongly ‘and quite regularly longitudinally rugose, the components spaced out and usually without trace of cross-meshes although one or two may be present. Dorsal surfaces of petiole and postpetiole commonly with traces of rugular sculpture which may be very faint; in some the postpetiole merely feebly punctulate. First gastral tergite smooth and shining. All dorsal surfaces of head and body with numerous standing hairs, the tibiae of the middle and hind legs only with short decumbent to appressed pubescence. Colour uniform yellow to light brownish yellow.

Type Material
Bolton (1980) - Syntype workers, RHODESIA: Shiloh, 10.v.1913 (G. Arnold), and Bembesi, 12.i.1913 (G. Arnold) ({{{AMGS}}) [examined].

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.
 * Garcia F.H., Wiesel E. and Fischer G. 2013.The Ants of Kenya (Hymenoptera: Formicidae)Faunal Overview, First Species Checklist, Bibliography, Accounts for All Genera, and Discussion on Taxonomy and Zoogeography. Journal of East African Natural History, 101(2): 127-222
 * IZIKO South Africa Museum Collection