Monomorium willowmorense

Identification
Bolton (1987) - A member of the M. subopacum complex in the M. salomonis species group.

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

Nomenclature

 *  willowmorense. Monomorium willowmorense Bolton, 1987: 364, fig. 54 (w.) SOUTH AFRICA. Material of the unavailable names willowmorensis, belli referred here by Bolton, 1987: 364. See also: Heterick, 2006: 107.

Worker
Heterick (2006) - Lectotype: HML 1.54, HL 0.60, 0.49, CeI 82, SL 0.46, SI 94, PW 0.32. HML 1.50 HL 0.60 HW 0.47 CeI 78 SL 0.45 SI 96 PW 0.31 (n=1).

HEAD: Head rectangular; vertex planar or weakly concave; frons shining and finely striolate and microreticulate; pilosity of frons consisting of abundant, incurved, appressed setulae only. Eye large, eye width 1.5× greater than greatest width of antennal scape; (in full-face view) eyes set above midpoint of head capsule; (viewed in profile) eyes set around midline of head capsule; eye elliptical, curvature of inner eye margin may be more pronounced than that of its outer margin. Antennal segments 12; antennal club three-segmented. Clypeal carinae weakly to strongly defined; anteromedian clypeal margin broadly convex; paraclypeal setae moderately long and fine, curved; posteromedian clypeal margin extending slightly beyond level of posterior margin of antennal fossae. Anterior tentorial pits situated nearer antennal fossae than mandibular insertions. Frontal lobes sinuate, divergent posteriad. Psammophore absent. Palp for mula 2,2. Mandibular teeth four; mandibles with sub-parallel inner and outer margins, striate; masticatory margin of mandibles strongly oblique; basal tooth a small to minute denticle or angle, much smaller than t3 (four teeth present).

MESOSOMA: Promesonotum shining and microreticulate, microreticulation reduced on humeri; (viewed in profile) promesonotum broadly convex anteriad, convexity reduced posteriad; promesonotal setae absent; standing promesonotal setae consisting of three pairs of longer, incurved, erect or semi-erect setae with occasionally a shorter seta between first anterior pair; appressed promesonotal setulae well-spaced over entire promesonotum. Metanotal groove strongly impressed, with distinct transverse costulae. Propodeum shining and densely microreticulate, distinct striolae present on metapleuron; propodeal dorsum slightly elevated anteriad and sloping away posteriad, propodeal angles not raised; propodeum angulate, propodeal angle blunt; standing propodeal setae absent; appressed propodeal setulae very sparse or absent; propodeal spiracle equidistant from metanotal groove and declivitous face of propodeum. Vestibule of propodeal spiracle absent or not visible. Propodeal lobes present as vestigial flanges or small strips of cuticle only.

PETIOLE AND POSTPETIOLE: Petiolar spiracle lateral and situated within anterior sector of petiolar node; node (viewed in profile) conical, vertex rounded; appearance of node shining and faintly microreticulate; ratio of greatest node breadth (viewed from front) to greatest node width (viewed in profile) about 1:1; anteroventral petiolar process present as a thin flange tapering posteriad; ventral petiolar lobe present; height ratio of petiole to postpetiole about 4:3; height–length ratio of postpetiole about 1:1; postpetiole shining and microreticulate; postpetiolar sternite not depressed at midpoint, its anterior end an inconspicuous lip or small carina.

GASTER: Pilosity of first gastral tergite consisting mainly of short, appressed setulae, together with a few erect and semi-erect setae.

GENERAL CHARACTERS: Color reddish- brown, gaster chocolate. Worker caste monomorphic.

MISC One worker of this otherwise South African species is known from Toamasina Province.

Type Material
Lectotype: worker (unavailable name belli), South Africa, Cape Province, Willowmore, 8.1.1914 [G.] Arnold. A lectotype has been chosen to fix the name, ‘Monomorium willowmorense’ for the taxon, which is morphologically similar to Monomorium subopacum. The specimen, originally on a pin holding three pointed specimens, has been transferred to a single pin and the original labels and a lectotype label have been appended to that pin. Paralectotypes: (i) Two workers (“belli”), data the same as for the lectotype (MHNG). Repinned with photocopies of the original labels. (ii) Two workers (“belli”) on separate pin, data as for lectotype (MHNG). (iii) Five workers (unavailable name “willowmorensis”), on two separate pins (i.e., 12 (both damaged) + 13) coll. 1.1.1914, otherwise data same as for lectotype (MHNG). (NB. The measurements of twelve workers from the then syntype series are provided in Bolton 1987).

References based on Global Ant Biodiversity Informatics

 * Arnold G. 1916. A monograph of the Formicidae of South Africa. Part II. Ponerinae, Dorylinae. Annals of the South African Museum. 14: 159-270.
 * Bolton B. 1987. A review of the Solenopsis genus-group and revision of Afrotropical Monomorium Mayr (Hymenoptera: Formicidae). Bulletin of the British Museum (Natural History). Entomology 54: 263-452.
 * Forel A. 1914. Formicides d'Afrique et d'Amérique nouveaux ou peu connus. Bulletin de la Société Vaudoise des Sciences Naturelles 50: 211-288.
 * Heterick B. 2006. A Revision of the Malagasy Ants Belonging to Genus Monomorium Mayr, 1855 (Hymenoptera: Formicidae). Proceeding of the California Academy of Sciences (PCAS) 57: 69-202
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004