Monomorium dakarense

Nothing is known about the biology of .

Identification
Bolton (1987) - A member of the M. australe complex in the M. salomonis species group. Associated with bicolor until the present, dakarense is best regarded as a distinct species. Apparently it was linked to Monomorium bicolor by Santschi (1914c) purely on the grounds of their similar colour, but he separated them by saying that in dakarense the scape was shorter and the psammophore better developed. The scape is indeed shorter in dakarense (SI 95-100) than in bicolor (SI 104-115), but also the former is considerably smaller (compare the measurements above with bicolor HL 0.70-0.93, HW 0.52-0.75, SL 0.56-0.78). The cephalic sculpture of bicolor is composed of sharply defined reticulate-punctation everywhere, and the first gastral tergite is less densely hairy.

M. dakarense is separated from its immediate allies by combining the distinctive colour scheme of the bicolor-complex with a lack of the reticulate-punctate cephalic sculpture usually associated with that colour scheme, replacing it by the silky punctulate-shagreenate sculpture generally associated with Monomorium sutu and its close relatives in the australe-complex. It is thus difficult to decide if dakarense is a member of the bicolor-complex (because of its colour) which has independently acquired the cephalic sculpture typical of sutu and allies, or if it is a member of the australe-complex which has acquired the bicolor-complex colour scheme. For the present I incline towards the latter as dakarense seems closer morphologically to Monomorium opacior, Monomorium parvinode and Monomorium minor than it does to any member of the bicolor-complex.

Distribution based on Regional Taxon Lists
Afrotropical Region: Senegal.

Nomenclature

 * . Monomorium bicolor st. dakarensis Santschi, 1914d: 353 (diagnosis in key) (w.) SENEGAL.
 * Type-material: syntype workers (number not stated, “many”).
 * Type-locality: Senegal: Longa (Roubaud).
 * Type-depository: NHMB.
 * [Misspelled as dakariense by Santschi, 1927d: 245.]
 * Subspecies of bicolor: Wheeler, W.M. 1922a: 869; Emery, 1922e: 176; Ettershank, 1966: 88.
 * Subspecies of subopacum: Santschi, 1927d: 245.
 * Status as species: Bolton, 1987: 339 (redescription); Bolton, 1995b: 260.
 * Distribution: Senegal.

Worker
Bolton (1987) - TL 2.2-2.3, HL 0.57-0.59, HW 0.44-0.47, CI 77-80, SL 0.44-0.45, SI 95-100, PW 0.30-0.31, AL 0.66-0.70 (3 measured).

Maximum diameter of eye 0.23-0.24 x HW, with 7-8 ommatidia in the longest row. Distribution of pilosity as in bicolor but first gastral tergite with numerous standing hairs in front of the apical transverse row. Head under low magnification appearing uniformly finely granular; under higher magnification the entire dorsum opaque, very finely and densely punctulate-shagreenate and having a silky appearance. Alitrunk, petiole and postpetiole finely densely reticulate-punctate. First gastral tergite shagreenate. Head and alitrunk orange-yellow to dull orange-brown, the gaster blackish brown, the two colours strongly contrasting.

Type Material
Bolton (1987) - Syntype workers, Senegal: Longa (Roubaud) [examined].

References based on Global Ant Biodiversity Informatics

 * Diame L., B. Taylor, R. Blatrix, J. F. Vayssieres, J. Y. Rey, I. Grechi, and K. Diarra. 2017. A preliminary checklist of the ant (Hymenoptera, Formicidae) fauna of Senegal. Journal of Insect Biodiversity 5(15): 1-16.