Tetramorium khyarum

Tetramorium khyarum is widely distributed in savannah and grassland in the western half of the continent but does not seem to be very common.

Identification
Bolton (1980) - In the sericeiventre-complex of this group T. khyarum is characterized by its lack of projecting hairs behind the eyes and its possession of a single pair of hairs on the propodeal dorsum. It is most closely allied to Tetramorium sepositum but here the sides of the head have projecting hairs and the propodeum has numerous pairs of standing hairs. As in most other species of this complex there is considerable variation in sculpture between different populations, and in the non-paratypic material the main features are as follows. Sculpture of the first gastral tergite may be reduced to a basal band covering the basal quarter of the sclerite, the remainder being smooth and shining. The punctulate ground-sculpture of the head and alitrunk may be enhanced in some populations and reduced in others, and the same applies to the rugular intensity on the alitrunk and pedicel segments. Measurements of nonparatypic material give the range TL 3.9-4.4, HL 0.88-1.00, HW 0.72-0.80, CI 79.84, SL 0.82-0.90, SI 111-118, PW and AL within paratype range (20 measured).

Distribution based on Regional Taxon Lists
Afrotropical Region: Botswana, Ivory Coast, Nigeria, Saudi Arabia.

Nomenclature

 *  khyarum. Tetramorium khyarum Bolton, 1980: 327, fig. 111 (w.) NIGERIA.

Worker
Holotype: TL 4.0, HL 0.96, HW 0.77, CI 80, SL 0.87, SI 113, PW 0.58, AL 1.18. Paratypes (4 measured): TL 4.0-4.3, HL 0.96-1.00, HW 0.76-0.80, CI 79-81, SL 0.87-0.90, SI 113-118, PW 0.56-0.62, AL 1.16-1.22. Maximum diameter of eye 0.18-0.20, about 0.24-0.26 x HW.

Mandibles coarsely longitudinally striate. Anterior clypeal margin entire, without trace of a median impression but the median carina sharp and distinct. Frontal carinae short, extending back approximately to level of midlengths of eyes. Antennal scrobes absent. Scapes long, SI > 100. Maximum diameter of eye 0.20, about 0.26 x HW. Propodeum armed with a pair of spines which are paralleled below by the elongate metapleural lobes, which are narrowly triangular. Petiole with an elongate node in profile, the dorsal length of which is greater than the height of the tergal portion. In dorsal view the node is longer than broad. Dorsum of head finely longitudinally rugulose, the spaces between rugulae with superficial punctulate ground-sculpture. Occipital region with a feeble reticulum towards the corners but centrally this disappears and is replaced by a few feeble longitudinal rugulae with 1-2 faint anastomoses. Dorsal alitrunk longitudinally rugose with conspicuous fine punctulate ground-sculpture, the rugae strongest on the pronotum. Petiole and postpetiole finely and irregularly rugose, with fine punctulate ground-sculpture. First gastral tergite blanketed by dense minute punctulation or shagreening and with dense, extremely fine striolae so that the surface is completely opaque and has a silky appearance. All dorsal surfaces of head and body with stout standing hairs, the propodeal dorsum with only a single pair, situated above the spiracles or slightly forward from this position. Scapes and tibiae only with short decumbent or appressed pubescence. Sides of head behind eyes without projecting hairs. Colour dull red, the gaster blackish brown.

Paratypes: As holotype but some with the occipital sculpture more pronounced.

Type Material
Holotype worker, Nigeria: Zaria, 11.iii.1969 (D. Simpson). Paratypes. 4 workers with same data as holotype.

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.
 * El-Hawagry M. S., M. R. Sharaf, H. M. Al Dhafer, H. H. Fadl, and A. S. Aldawood. 2015. Addenda to the insect fauna of Al-Baha Province, Kingdom of Saudi Arabia with zoogeographical notes. Journal of Natural History http://dx.doi.org/10.1080/00222933.2015.1103913
 * IZIKO South Africa Museum Collection
 * Robertson H. G. 2000. Formicidae (Hymenoptera: Vespoidea). Cimbebasia Memoir 9: 371-382.
 * Sharaf M. R., H. M. Al Dhafer, and S. A. Aldawood. 2014. First record of the myrmicine ant genus Meranoplus Smith, 1853 (Hymenoptera: Formicidae) from the Arabian Peninsula with description of a new species and notes on the zoogeography of Southwestern Kingdom Saudi Arabia. PLoS ONE 9(11): e111298 (doi:10.1371/journal.pone.0111298).
 * Sharaf M.R., and K. Al-Zailaie. 2006. Ant fauna (Hymenoptera: Formicidae) of Farasan islands protectorate (Saudi Arabia). Bulletin of the Entomological Society of Egypt 83: 61-68.