Monomorium firmum

A collection of this ant was made in miombo woodland. Monomorium firmum has only been collected a few times.

Identification
Bolton (1987) - This relatively large yellow species is a conspicuous member of the schultzei-complex. It is closest related to Monomorium vecte, also known from Zimbabwe, the two together being distinguished from the remaining schultzei-complex members which have relatively large propodeal spiracles by their dense pilosity. Of all schultzei-complex members in which the metanotal groove is broad and traversed by long conspicuous cross-ribs, and the propodeal spiracle is large, only firmum and vecte have 8 or more pairs of hairs on the promesonotal dorsum. Differences separating the two are noted under vecte.

Distribution based on Regional Taxon Lists
Afrotropical Region: Zimbabwe.

Nomenclature

 *  firmum. Monomorium firmum Santschi, 1926b: 231 (w.) ZIMBABWE. See also: Bolton, 1987: 389.

Worker
Bolton (1987) - TL 2.6-2.8, HL 0.58-0.66, HW 0.46-0.54, CI 79-83, SL 0.50-0.56, SI 100-109, PW 0.30-0.33, AL 0.70-0.76 (10 measured).

Clypeal carinae conspicuous, relatively close together, feebly divergent anteriorly and sometimes the carinae broken or interrupted at about their midlength. Space between the clypeal carinae shallowly transversely concave. Anterior margin of narrow prominent median section of clypeus weakly concave, the anterior and lateral margins of this section separated by blunt angles, without projecting denticles. Maximum diameter of eye 0.20-0.22 x HW and with 6-7 ommatidia in the longest row. With the head in full-face view the eyes close to the midlength of the sides, usually the posterior margins of the eyes at or even slightly behind the midlength of the sides. Antennal scapes, when laid straight back from their insertions, reaching or slightly surpassing the occipital margin. Sides of head evenly shallowly convex in full-face view and the occipital margin shallowly convex or the median area more or less flat. Promesonotum in profile a low convexity, descending behind to the broad impressed metanotal groove which is traversed by long strong cross-ribs. Propodeal spiracle large and conspicuous. Petiole node in profile relatively low, broadly subconical and with both anterior and posterior faces weakly convex. Subpetiolar process a conspicuous lobe. Postpetiole lower than petiole, smaller and more broadly rounded in profile. All dorsal surfaces of head and body with numerous standing hairs, the promesonotum with more than 8 pairs. Mostly unsculptured and shining except for scattered hair-pits, but the metanotal groove crossribbed and the mesopleuron in some with traces of weak reticulate sculpture. Colour yellow.

Type Material
Bolton (1987) - Syntype workers, Zimbabwe: Vumba Mts, 6000 ft (1830 m), Cloudlands 6-17.iv.1923 (G. Arnold)  [examined].