Tetramorium perlongum

Identification
Bolton (1980) - Of the 13 species included in the setigerum-group T. perlongum and Tetramorium dolichosum are distinguished by their possession of exceptionally long legs and antennal scapes, the latter always with SI exceeding 150. These two species are best separated by their relative lengths of scape as SI is 154-162 in T. dolichosum and 174-180 in perlongum. Besides this T. dolichosum is much more strongly sculptured, the head having coarse rugular sculpture the spaces between which are coarsely reticulate-punctate. The strong puncturation is conspicuous everywhere on the body including the sides of the alitrunk and both pedicel segments. A narrow, raised flange bordering the occiput is present in both species but is much stronger in T. dolichosum and has a series of short ribs radiating forward from it on the dorsum of the head. Finally the median clypeal carina is complete in T. dolichosum and usually continuous with the median cephalic carina which runs back about the same distance as the frontal carinae. In T. perlongum the median clypeal carina is feeble or absent posteriorly and the median cephalic carina is vestigial or absent.

Distribution based on Regional Taxon Lists
Afrotropical Region: Angola.

Nomenclature

 *  perlongum. Tetramorium perlongum Santschi, 1923e: 284 (w.) ANGOLA. [Also described as new by Santschi, 1925h: 165.] See also: Bolton, 1980: 281.

Worker
Bolton (1980) - TL 4-8-5-4, HL 1-08-1-20, HW 0-78-0-86, CI 70-74, SL 1-38-1-50, SI 174-180, PW 0-58-0-68, AL 1:28-1:44 (20 measured).

Mandibles longitudinally striate. Anterior clypeal margin entire, without a median notch or impression. Median clypeal carina distinct on anterior half but fading out or absent posteriorly. Frontal carinae close together, straight and more or less parallel, running back approximately to the level of the posterior margins of the eyes, behind which they are absent or indistinguishable from the other cephalic sculpture. Antennal scrobes absent. Scapes exceptionally long, SI as above. Maximum diameter of eye 0-22-0-27, about 0:29-0:32 x HW. Head in full-face view long and narrow with gently convex sides and an evenly but shallowly concave occipital margin. In profile the head with a narrow lug posteriorly, the posteroventral portion of which forms a sharp angle where it meets the ventral surface. Alitrunk in profile with the promesonotum convex and sloping posteriorly to the feebly impressed metanotal groove. Behind the metanotal groove the propodeum usually with a raised tumulus, more distinct in some workers than in others; the dorsum behind this tumulus more or less flat. Propodeal spines long, narrow and acute, with a tendency to be slightly downcurved along their length. Metapleural lobes low and rounded. Legs very long, the metathoracic (hind) leg with the femur about 1:65-1:90 at maximum. Petiole in profile with a long anterior peduncle, the node with a blunt or narrowly rounded anterodorsal angle and a feebly convex dorsum which rounds smoothly into the posterior face, the two not separated by an angle. Postpetiole evenly convex. Dorsum of head with a few weak, spaced-out, irregular rugulae, much effaced in some specimens, especially between the frontal carinae. Ground-sculpture an inconspicuous shagreening or fine punctulation. Dorsal alitrunk weakly sculptured with a few feeble rugulae, usually with extensive clear patches. Dorsal surfaces of petiole and postpetiole, and base of first gastral tergite with dense, fine granulation or punctulation, weaker in some individuals than in others. All dorsal surfaces of head and body with scattered strong hairs, the majority of which are blunt apically. Scapes and tibiae only with fine appressed pubescence. Colour dark brown.

Type Material
Bolton (1980) - Holotype worker, ANGOLA: Benguela, Capelongo-Dongo (Rohan-Chabot) [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.
 * IZIKO South Africa Museum Collection
 * Santschi F. 1923. Descriptions de nouveaux Formicides éthiopiens et notes diverses. I. Revue Zoologique Africaine (Brussels) 11: 259-295.
 * Santschi F. 1937. Résultats de la Mission scientifique suisse en Angola (2me voyage) 1932-1933. Fourmis angolaises. Revue Suisse de Zoologie. 44: 211-250.