Tetramorium geminatum

Identification
Bolton (1980) - This species is most closely related to Tetramorium ataxium, from which it differs by its longer pilosity and reduced ground-sculpture. In T. ataxium the hairs on the dorsum of the head (discounting those on the clypeus and the occipital margin) and on the first gastral tergite are predominantly, and in most series obviously, shorter than the maximum diameter of the eye. Some specimens of T. ataxium have hairs which approach this length but none have them obviously longer, which is the case in T. geminatum. Besides this, the punctulate ground-sculpture which is conspicuous in T. ataxium is very reduced in T. geminatum and not at all obvious.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Gabon.

Nomenclature

 *  geminatum. Tetramorium geminatum Bolton, 1980: 298 (w.) GABON.

Worker
Holotype: TL 3.4, HL 0.80, HW 0.70, CI 88, SL 0.67, SI 96, PW 0.52, AL 0.96. Paratypes (9 measured): TL 3.0-3.4, HL 0.72-0.80, HW 0.62-0.70, CI 85-89, SL 0.62-0.68, SI 96-100, PW 0.42-0.52, AL 0.82-0.96. Maximum diameter of eye 0.12-0.14, about 0.19-0.21 x HW.

Mandibles longitudinally striate. Anterior clypeal margin entire, without a notch or impression. Median clypeal carina strongly developed, much stronger than the pair of ridges which arise at the apices of the frontal lobes and run anteromedially on the clypeus towards the median carina. Frontal carinae strongly developed, running back onto the occipital surface but ending abruptly before reaching the occipital margin; distance from ends of carinae to occipital margin slightly greater than maximum diameter of eye. Scapes long, SI > 90 (range 96-100); antennal scrobes shallow and broad but conspicuous. Maximum diameter of eye 0.14, about 0.20 x HW. Propodeal spines long and strong, feebly sinuate and acute apically. Metapleural lobes broadly triangular. Petiole node in profile rectangular, 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 widely spaced longitudinal rugae to the level of the posterior margins of the eyes: Between this level and the ends of the frontal carinae a few cross-meshes are present; occipital area reticulate-rugose. Dorsal surfaces of alitrunk and petiole reticulate-rugose but the sculpture of the propodeal dorsum weaker and — predominantly longitudinal. Ground-sculpture between the rugulae everywhere very feeble so that the face surfaces are glossy. First gastral tergite unsculptured. All dorsal surfaces of body with numerous long, stout hairs which are blunted apically; longest hairs on dorsal alitrunk and first gastral tergite longer than maximum diameter of eye. Colour reddish brown, dark and glossy.

Paratypes: As holotype but length and shape of propodeal spines variable, being slightly upcurved, slightly downcurved or feebly sinuate.

Type Material
Holotype worker, Gabon: Plateau d’Ipassa, 9 IPA, AN6 (J. 4. Barra). Paratypes. 7 workers with same data as holotype; 1 worker same locality but AMC2, IPA (J. A. Barra); 1 worker same locality but 9 IPA, AN4 (J. 4. Barra) (MCZ; ).

References based on Global Ant Biodiversity Informatics

 * 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.