Tetramorium petersi

Identification
Bolton (1980) - In the sericeiventre-complex of this group, characterized by their lack of short standing hairs on the scapes and tibiae, three species may be isolated by their possession of relatively dense pilosity on the head and body. These are Tetramorium sepositum, T. petersi and Tetramorium asetyum, all of which have hairs projecting from the sides of the head behind the eyes and have more than one pair of hairs on the propodeal dorsum. Also in these species the hairs on the alitrunk and gaster tend to be long, slender and fine, broadest basally and tapering along their length to an acute apex. Of these three species T. sepositum has only 1-2 long fine hairs breaking the outline of the head on each side whereas the other two species have numerous short projecting hairs in this region, usually more than 10 on each side and sometimes too numerous to count easily. These two remaining species, T. asetyum and T. petersi, are separated as follows.

T. asetyum
 * Dorsum of head with fine dense longitudinal rugulae; ground-sculpture reticulate-punctulate and distinct.
 * Eyes relatively slightly smaller, maximum diameter 0.24-0.26 x HW.
 * Dorsal alitrunk coarsely longitudinally rugose.
 * Petiole dorsum coarsely rugulose with punctulate spaces.
 * First gastral tergite coarsely sculptured everywhere.

T. petersi
 * Dorsum of head with scattered feeble longitudinal rugulae; ground sculpture faint and inconspicuous.
 * Eyes relatively slightly larger, maximum diameter 0.27-0.28 x HW.
 * Dorsal alitrunk smooth or with vestigial sparse rugular traces.
 * Petiole dorsum mostly or entirely smooth, not punctulate.
 * First gastral tergite smooth except for very feeble shagreening at extreme base.

Distribution based on Regional Taxon Lists
Afrotropical Region: Namibia.

Nomenclature

 *  petersi. Tetramorium blochmanni subsp. petersi Forel, 1910f: 19 (w.) NAMIBIA. Subspecies of sericeiventre: Wheeler, W.M. 1922a: 902. Raised to species: Bolton, 1980: 329.

Worker
Bolton (1980) - TL 3.6-3.7, HL 0.84-0.86, HW 0.68-0.72, CI 81-84, SL 0.78-0.82, SI 114-115, PW 0.50-0.54, AL 1.00-1.06 (3 measured).

Mandibles longitudinally striate. Anterior clypeal margin entire, without trace of a median notch or impression. Median clypeal carina strongly defined, remainder of clypeus unsculptured or at most with a pair of very feeble rugulae. Frontal carinae short and very feebly defined behind the frontal lobes, ending at the level of the eyes and scarcely stronger than the weak cephalic rugulae. Antennal scrobes absent. Maximum diameter of eye 0.19-0.20, about 0.27-0.28 x HW and with 12-13 ommatidia in the longest row. Alitrunk in profile long and low, weakly and shallowly depressed at the level of the metanotal groove. Propodeum armed with a pair of acute spines. Metapleural lobes long and narrowly triangular, parallel to and as long as the propodeal spines but somewhat stouter than the latter. Petiole in profile long and low, the dorsal length greater than the height of the tergal portion. In dorsal view the petiole node slightly longer than broad. Dorsum of head with scattered fine irregular longitudinal rugulae, the spaces between them with faint superficial ground-sculpture which is inconspicuous. Dorsal alitrunk with pronotum unsculptured, or at most with a few vestigial longitudinal rugulae. Mesonotum similar but the propodeum with fine transverse rugulae. Sides of petiole and postpetiole with sparse fine rugular sculpture which may also be present on the dorsum of the latter, but the dorsum of the petiole with an unsculptured median strip or area. Extreme base of first gastral tergite with exceptionally faint shagreening, the pits from which hairs arise conspicuous. Pilosity dense and distinctive, all dorsal surfaces of head and body with numerous long fine hairs which are acute apically, the longest of those on the pronotum about equal to the maximum diameter of the eye. With the head in full-face view the sides behind the eyes with numerous (usually > 10 on each side) short hairs breaking the outline of the sides. Hairs as densely present on propodeum as elsewhere on dorsal alitrunk. Hairs on first gastral tergite elongate, fine and acute apically. Dorsal (outer) surfaces of hind tibiae with long fine pubescence which is decumbent to appressed. Colour light brown with a slight reddish tint, the gaster darker in shade than the alitrunk.

Type Material
Bolton (1980) - Syntype workers, South West AFRICA: Okahandja (Peters) [examined].

References based on Global Ant Biodiversity Informatics

 * Arnold G. 1917. A monograph of the Formicidae of South Africa. Part III. Myrmicinae. Annals of the South African Museum. 14: 271-402.
 * 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
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004