Monomorium musicum

This species has been collected in grasslands.

Identification
Bolton (1987) - A member of the M. boerorum complex in the M. monomorium species group. This minute species is superficially similar to Monomorium braunsi, but in the latter the petiole node is very low and broadly convex dorsally, and the anterior peduncle of the node lacks a prominent anteroventral process. Monomorium torvicte, a close relative of musicum, is uniformly dark brown and has shorter scapes and smaller eyes but is otherwise very similar indeed. I have treated these as separate species for the present but suspect that further collecting may nullify the apparent differences between them.

Distribution based on Regional Taxon Lists
Afrotropical Region: South Africa.

Nomenclature

 *  musicum. Monomorium oscaris subsp. musicum Forel, 1910e: 442 (w.q.) SOUTH AFRICA. Raised to species: Emery, 1922e: 173; Bolton, 1987: 402.

Worker
Bolton (1987) - TL 1.6-1.7, HL 0.42-0.44, HW 0.32-0.33, CI 73-76, SL 0.26-0.27, SI 81-84, PW 0.20-0. 22, AL 0.40-0.42 (3 measured).

Clypeal carinae narrow but sharply defined posteriorly, divergent anteriorly and tending to fade out before reaching the anterior margin. Prominent median portion of clypeus transverse on its anterior margin and with an obtuse angle separating the anterior and lateral margins, but without projecting teeth or denticles. Maximum diameter of eye 0.22-0.24 x HW and with 6 ommatidia in the longest row. With the head in full-face view the eyes very obviously far in front of the midlength of the sides. Antennal scapes, when laid straight back from their insertions, falling far short of the occipital margin. Sides of head shallowly convex and divergent posteriorly, so that the width of the head at the occipital margin is greater than its width immediately in front of the eyes. Occipital margin broad and weakly concave medially. Promesonotum in profile low, scarcely higher than the highest point of the propodeum. Dorsum of promesonotum more or less flat in profile, downcurved anteriorly to the cervix and posteriorly to the narrow and weakly impressed metanotal groove; the latter with few short inconspicuous cross-ribs. Propodeal dorsum highest immediately behind the metanotal groove, the dorsum then rounding evenly into the declivity through a broad smooth curve. Propodeal spiracle small. Petiole node low subconical in profile, with a short anterior peduncle which is subtended by a small subtriangular and flange-like anteroventral process. Postpetiole much smaller than petiole, its dorsum low and evenly convex. All dorsal surfaces of head and body with standing hairs, 3-4 pairs present on the promesonotum. Sculpture absent except for minute hair-pits and metanotal cross-ribs. Colour yellow, the head and gaster of some individuals with a faint brownish tint.

Type Material
Bolton (1987) - Syntype workers, female, South Africa: Natal no. 156 (Haviland) [examined].