Monomorium rosae

This species has been found in savanna forest and a tea field.

Identification
Heterick (2006) - A member of the M. exiguum complex in the M. monomorium species group.

Bolton (1987) - A widely distributed species which shows variation in size and pilosity over its range. Analysis of rosae when more material is available may well show that 2-3 sibling species are involved here. For the present all samples are treated as a single species, easily identified by its 11-segmented antennae, dark colour, moderately long scapes and distinctively shaped postpetiole node. The shape of the postpetiole is shared only with Monomorium pulchrum and Monomorium bequaerti among species with 11 antennal segments, but both of these are lighter in colour. Apart from this the petiole and postpetiole nodes are broader than long in dorsal view in rosae and pulchrum, but longer than broad in bequaerti. M. pulchrum has the propodeal dorsum quite evenly and continuously convex in profile, which is not the case in rosae where a flattened or depressed mid-dorsal section is conspicuous.

The two syntype workers of rosae are lighter in colour than all the remaining material examined, but I strongly suspect that they had not attained full adult colour when captured, and have faded somewhat since then.

Distribution based on Regional Taxon Lists
Afrotropical Region: Democratic Republic of Congo, Ghana, Kenya, Nigeria, Senegal.

Nomenclature

 *  rosae. Monomorium (Lampromyrmex) rosae Santschi, 1920b: 13, fig. 2 (w.) DEMOCRATIC REPUBLIC OF CONGO. Senior synonym of cotterelli: Bolton, 1987: 408.
 * cotterelli. Diplomorium cotterelli Donisthorpe, 1942f: 217 (w.) GHANA. Junior synonym of rosae: Bolton, 1987: 408.

Worker
Bolton (1987) - TL 1.6-2.0, HL 0.42-0.50, HW 0.33-0.40, CI 76-82, SL 0.28-0.35, SI 85-94, PW 0.21-0.25, AL 0.42-0.56 (12 measured).

Clypeal carinae only feebly developed but quite distinct, widely separated and divergent anteriorly. Median portion of clypeus with anterior margin transverse or even weakly convex, the anterior and lateral borders of the prominent median section of the clypeus meeting in an obtuse angle, without projecting angles or denticles. Basal (fourth) tooth of mandible much smaller than the third, reduced to a denticle. Maximum diameter of eye 0.19-0.23 x HW and with 5-6 ommatidia in the longest row. Outer ring of ommatidia encircling more than one longitudinal row. Eyes in full-face view distinctly in front of midlength of sides of head. Antennae with 11 segments, the scapes when directed straight back from their insertions failing to reach the occipital margin. Promesonotum in profile shallowly convex, the metanotal groove shallowly impressed and traversed by short but conspicuous cross-ribs. Propodeal spiracle small and pinhole-like. Propodeal dorsum in profile convex immediately behind the metanotal groove; this followed by a posteriorly sloping section which is feebly convex or almost flat, and which rounds posteriorly into the much more steeply sloping declivity. Petiole in profile with the node subconical, broad basally and rapidly tapering to a narrowly rounded apex; the node bluntly wedge-shaped. Subpetiolar process a narrow, sometimes vestigial, longitudinal strip; ventral outline of petiole node behind the process feebly convex but not strongly bulging ventrally. Node of postpetiole in profile about equal in volume to that of the petiole, or slightly less; much more broadly rounded dorsally than the petiole. Anterior face of postpetiole in profile shorter and conspicuously steeper than the long gradually sloping posterior face. In dorsal view both nodes broader than long. Standing hairs present on all dorsal surfaces of head and body, with 4-6 pairs on the promesonotum and 2-3 pairs on the propodeum. Sculpture absent except for metanotal cross-ribs and some shagreening or reticulation on the pleurae. Colour glossy blackish brown to black.

Type Material
Bolton (1987) - Syntype workers, Zaire: Boma, 7.ix.1913, No. 36 (Bequaert) [examined].