Monomorium marshi

Little is known about this species. One of the few specimens of this ant was hand collected in the Namib desert.

Identification
Bolton (1987) - The long antennal scapes, distinctive colour pattern and presence of hairs on the dorsal alitrunk make this Namib Desert species immediately recognizable. Its closest relative within the viator-complex appears to be Monomorium vatranum, but this is a uniformly darkly coloured species with shorter scapes, and its alitrunk pilosity is restricted to a single pair of hairs at the pronotal humeri.

Distribution based on Regional Taxon Lists
Afrotropical Region: Namibia.

Nomenclature

 *  marshi. Monomorium marshi Bolton, 1987: 349, figs. 50, 53 (w.) NAMIBIA.

Worker
Holotype. TL 3.1, HL 0.76, HW 0.54, CI 71, SL 0.68, SI 126, PW 0.38, AL 0.94.

Anterior margin of median portion of clypeus shallowly convex. Head in full-face view with sides weakly divergent in front of eyes and weakly convergent behind them, the occipital margin broadly but shallowly concave. Maximum diameter of eye 0.30 x HW, with 12 ommatidia in the longest row. Head relatively long and narrow, scapes relatively very long (CI and SI, above). Alitrunk long and low in profile, with promesonotal dorsum evenly shallowly convex and sloping posteriorly to the unimpressed metanotal groove. Propodeal dorsum long and low, distinctly on a much lower level than the promesonotum. Node of petiole in profile small and quite low, the anterior peduncle of the petiole lacking a conspicuous anteroventral process, having instead merely a short very low ridge. Cephalic dorsum with 4-5 pairs of erect hairs straddling the midline behind the level of the frontal lobes, and with a transverse row of 6 standing hairs along the occipital margin, the outermost of which is close to the occipital corner on each side. Pronotal and mesonotal dorsa both with standing hairs present, the hairs longer and denser on the former than on the latter. Propodeal dorsum without hairs. There is variation in distribution of pilosity, see paratype discussion below. Nodes of petiole and postpetiole each with 2 pairs of backward directed hairs. First gastral tergite with numerous but widely spread hairs present in front of the apical transverse row, the hairs more or less evenly distributed over the entire sclerite. Dorsum of head finely reticulate to reticulate-shagreenate. Dorsal alitrunk more sharply reticulate to finely reticulate-punctate everywhere. Sides of alitrunk reticulate-punctate except for the pronotum, which is less strongly sculptured. First gastral tergite with fine superficial reticulate patterning only. Head and alitrunk dull orange-brown, gaster black and glossy.

Paratypes. TL 2.7-3.2, HL 0.68-0.76, HW 0.47-0.55, CI 70-74, SL 0.62-0.68, SI 120-130, PW 0.32-0.39, AL 0.80-0.98 (11 measured). Maximum diameter of eye 0.28-0.31 x HW, with 11-13 ommatidia in the longest row. Variation in pilosity shows the head with 3-5 pairs straddling the midline behind the level of the frontal lobes; occipital margin with a transverse row of 4 or 6 hairs; pronotum with 4-5 pairs of hairs; mesonotum with 0-2 pairs; propodeum usually hairless but with a single pair in one specimen; petiole node with 1-2 pairs; postpetiole with 2 pairs. Colour varies from light orange with a dark brown gaster, to dull orange-brown with a black gaster.

Type Material
Holotype worker, Namibia: Namib Desert, 15° 18' E, 23° 06' S, pitfall, sample P 11, 1984 (A. C. Marsh). Paratypes. 5 workers with same data as holotype; 3 workers with same data but 15° 36' E, 23° 04' S, sample P 10; 3 workers, Mirabeb, 8.iv.1982, sample M 12 (A. C. Marsh) (BMNH; ).