Microdaceton tibialis

Identification
Bolton (2000) - A number of features vary in this species. In Ghanaian material alone colour of the legs shows notable variation. They may be entirely ivory to dull yellow or the femora may show differing degrees of infuscation. The extreme femoral apices may be pale to medium brown, or this colour may extend through the distal third to two-thirds of the segment. In a few workers the entire femur is brown. When most of the femur is darkly coloured the pale tibia contrasts strongly.

The postpetiole disc may be entirely smooth, or have scattered minute punctures, or be superficially granulate; in a few there are vestigial traces of costulae on the central third. The first gastral tergite may be smooth and shining with widely scattered minute punctulae, or finely reticulate-punctate over part, most, or all of the sclerite; usually in these cases the tergite is more strongly sculptured basally than apically. Rarely there may be extremely fine scratch-like costular vestiges at the extreme base, among the reticulate-punctate sculpture.

All of these features are considered to represent variation within a single species.

Distribution based on Regional Taxon Lists
Afrotropical Region: Central African Republic, Democratic Republic of Congo, Gabon, Ghana, Ivory Coast, Kenya, Sudan, Uganda.

Nomenclature

 *  tibialis. Microdaceton tibialis Weber, 1952a: 30, fig. 25 (w.) DEMOCRATIC REPUBLIC OF CONGO. See also: Bolton, 1983: 403; Bolton, 2000: 29.

Worker
Bolton (1983) - TL 3.2-3.8, HL 0.88-0.98, HW 0.80-0.90, CI 88-92, ML 0.56-0.66, MI 63-69, SL 0.62-0.72, SI 75-81, PW 0.38-0.47, AL 0.78-0.90 (10 measured).

Answering to the description of Microdaceton exornatum in all major features, Microdaceton tibialis is distinguished as follows.

Bolton (2000) - TL 3.2-4.0, HL 0. 82-0.98, HW 0.71-0.90, CI 86-92, ML 0.54-0.66, MI 63-73, SL 0.56-0.72, SI 75-82, PW 0.33-0.47, AL 0.74-0.90 (20 measured).

Anterior clypeal margin with a small median impression. Eyes anterolateral, large and conspicuous. Occipital lobe with 2 tubercles of variable size, the first laterodorsal, the second at the posteriormost point of the dorsum and conspicuous in profile. Head without specialised or standing hairs of any description. Pronotum unarmed, humeri rounded. Mesonotum with a pair of acute conical teeth or tubercles. Propodeum with a pair of strong spines that are of moderate length, not exceptionally long and needle-like. Propodeal lobes long and stout, slightly upcurved. Posteroventral face of metapleuron, below propodeal lobe and above posterior margin of hind coxa, with a posteriorly directed patch of ivory or pale yellow cuticle that is much lighter in colour than the surrounding cuticle. Short simple hairs that arise from centres of foveolate sculpture usually appressed but may be slightly elevated; elongate specialised standing pilosity entirely absent from body and appendages. Petiole node in profile large when compared to postpetiole but not grossly inflated. Basigastral costulae vestigial to absent; base of gaster smooth or shagreenate. First gastral sternite usually smooth basally, but with weak superficial reticulation in some. Head, alitrunk and gaster blackish brown to black.

Type Material
Bolton (1983) - Holotype worker, ZAIRE: 37 km N. of Stanleyville (=Kisangani), lat. 0045'N, long. 25°15'E, 15.iii.1948, rain forest, no. 2218 (N. A. Weber) [examined].