Tetramorium berbiculum

Identification
A member of the Tetramorium simillimum species group.

Bolton (1980) - Of the three yellow species in the oculatum-complex of this group two, Tetramorium arnoldi and T. berbiculum, have the propodeum unarmed. The third species, Tetramorium luteolum, has small but well-developed propodeal teeth. The differences separating T. arnoldi and T. berbiculum are tabulated as follows.

T. arnoldi
 * Hairs absent from dorsal alitrunk.
 * Antennal scapes shorter, SI 68-72.
 * Petiole node less massive in profile
 * Petiole node in dorsal view broader than long.
 * Head somewhat broader, CI 89-94.

T. berbiculum
 * Hairs present on dorsal alitrunk.
 * Antennal scapes longer, SI 77-80.
 * Petiole node more massive in profile
 * Petiole node in dorsal view about as long as broad.
 * Head somewhat narrower, CI 86-87.

Distribution based on Regional Taxon Lists
Afrotropical Region: Zimbabwe.

Nomenclature

 *  berbiculum. Tetramorium berbiculum Bolton, 1980: 307, fig. 92 (w.) ZIMBABWE.

Worker
Holotype. TL 2.9, HL 0.68, HW 0.59, CI 87, SL 0.46, SI. 78, PW 0.44, AL 0.78. Paratypes (2 measured): TL 2.8-2.9, HL 0.70, HW 0.60, CI 86, SL 0.46-0.48, SI 77-80, PW 0.46, AL 0.80-0.82. Maximum diameter of eye 0.18-0.19, about 0.30-0.32 x HW.

Mandibles finely longitudinally striate. Anterior clypeal margin entire, without a median notch or impression. Frontal carinae very feebly developed, ending close to level of posterior margins of eyes where they fade out or are broken. (In paratypes extending beyond level of eyes but in entire type-series the carinae no more strongly developed than the remaining cephalic rugulae.) Antennal scrobes vestigial, merely a very weak shallow impression in the sides of the head. Eyes situated very slightly behind the midlength of the sides, maximum diameter 0.18, about 0.30 x HW and with 11-12 ommatidia in the longest row. Metanotal groove slightly impressed in profile. Propodeum unarmed, the dorsum meeting the declivity in a blunt angle or very low blunt prominence, without differentiated teeth. Metapleural lobes prominent but low and rounded apically. Petiole node in profile with the dorsal surface sloping downwards posteriorly so that the anterior face of the node is distinctly longer than the posterior. Dorsal length of node equal to or slightly greater than the height of the tergal portion. In dorsal view the petiole node about as broad as long, rounded, without sharp margins or angles. Dorsum of head finely and irregularly longitudinally rugulose, with a dense blanketing reticulate-punctate ground-sculpture which is very conspicuous. Dorsal alitrunk finely reticulate-punctate with the faintest vestiges of rugular sculpture on the pronotum, almost effaced. Petiole and postpetiole exceedingly finely and shallowly punctulate, with a granular appearance. Base of first gastral tergite superficially shagreened. Stout, blunt, short hairs conspicuous on first gastral tergite and postpetiole, more sparse and shorter on head, promesonotum and petiole, absent from propodeum. Ventral surface of head with several elongate finer hairs situated just posterior to the buccal cavity which are hooked or J-shaped. Middle and hind tibiae with minute decumbent pubescence. Colour uniform pale yellow.

Paratypes as holotype.

Type Material
Holotype worker, Rhodesia: Nyamandhlovu, 27.xi.1960, Nat. Mus. S. Rhodesia (G. Arnold . Paratypes. 3 workers with same data as holotype (one with head missing) (NMBZ; ).

References based on Global Ant Biodiversity Informatics

 * IZIKO South Africa Museum Collection