Monomorium opacior

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Monomorium opacior
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Monomorium
Species: M. opacior
Binomial name
Monomorium opacior
Forel, 1913

Monomorium opacior casent0902215 p 1 high.jpg

Monomorium opacior casent0902215 d 1 high.jpg

Specimen Labels


Specimen records show this to be a species that lives in semi-open areas such as acacia woodland and Bushveld.


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

Keys including this Species


Distribution based on Regional Taxon Lists

Afrotropical Region: Botswana, Namibia, South Africa, Zimbabwe (type locality).

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb




The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • opacior. Monomorium salomonis var. opacior Forel, 1913j: 216 (in text) (w.) ZIMBABWE. [First available use of Monomorium salomonis r. junodi var. opacior Forel, 1913a: 136; unavailable name.] Arnold, 1916: 220 (q.). Subspecies of salomonis: Arnold, 1916: 220; Stitz, 1923: 156. Raised to species and senior synonym of opacior Bolton: Bolton, 1995b: 265.
  • opacior. Monomorium opacior Bolton, 1987: 352 (w.) ZIMBABWE. Material of the unavailable name serenum referred here by Bolton, 1987: 352. Junior synonym of opacior Forel: Bolton, 1995b: 265.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Bolton (1987) - The species is described from a syntypic series as Arnold's original series are mounted flat on card and all individuals have suffered some damage and abrasion. For this reason it has not proved possible to select a holotype from the original material which exhibits all the diagnostics of the species.



Bolton (1987) - Syntype. TL 2.2-2.4, HL 0.60-0.66, HW 0.47-0.50, CI 75-78, SL 0.48-0.52, SI 100-108, PW 0.32-0.34, AL 0.68-0.74 (6 measured).

Median portion of clypeus with anterior margin transverse, sometimes appearing very slightly convex. Sides of head in full-face view almost straight, only extremely feebly convex and somewhat convergent posteriorly. Occipital margin very shallowly concave. Eyes slightly in front of the midlength of the sides of the head, the maximum eye diameter 0·24-0·26 x HW, with 8-9 ommatidia in the longest row. Metanotal groove very feebly impressed . Dorsum of head with two pairs of standing hairs behind the level of the frontal lobes, the first situated just behind the level of the eyes, the second at the occipital margin. Dorsal alitrunk without standing hairs. Petiole node without hairs, the postpetiole with a single pair which projects backward. First gastral tergite with 1-2 pairs of hairs in front of the apical transverse row, situated on the basal half of the sc1erite. Dorsum of head opaque, blanketed by fine and dense reticulate-shagreenate to punctate-shagreenate sculpture; mid-dorsally the sculpture with very fine dense longitudinal scratch-like striolae, giving the surface in this area a silky appearance. Pronotal dorsum finely reticulate to reticulate-shagreenate; posteriorly on the dorsal alitrunk the sculpture becoming more sharply reticulate or even weakly reticulate-punctate. First gastral tergite with superficial reticular patterning at least near the base, but this may fade out apically, leaving the sclerite featureless. Colour dull light brown, the gaster much darker brown and shining.

Non-partypic material. TL 2.3-2.7, HL 0.56-0.68, HW 0.43-0.52, CI 74-78, SL 0.44-0.57, SI 102-110, PW 0.30-0.35, AL 0.64-0.80 (8 measured). Maximum diameter of eye 0.25-0.27 x HW and with 8-9 ommatidia in the longest row. As syntypes but in some the first gastral tergite with 3 pairs of hairs on the basal half. Development of fine striolate component of cephalic sculpture is variable; in some individuals it is conspicuous, in others virtually absent. Also variable is the extent of the superficial reticular patterning on the first gastral tergite and the colour, which ranges from dull yellowish brown to pale medium brown . The gaster is sometimes only marginally darker than the head and alitrunk in shade.

Type Material

Bolton (1987) - Syntype workers, Zimbabwe: Bulawayo, 3.xi. 1912, no. 130 (G. Arnold) (The Natural History Museum; Musee d'Histoire Naturelle Genève) [examined].


  • 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. (page 352, worker described, material of the unavailable name serenum referred here: )
  • Arnold, G. 1916. A monograph of the Formicidae of South Africa. Part II. Ponerinae, Dorylinae. Ann. S. Afr. Mus. 14: 159-270 (page 220, queen describedm, variety of salomonis)
  • Forel, A. 1913a. Fourmis de Rhodesia, etc. récoltées par M. G. Arnold, le Dr. H. Brauns et K. Fikendey. Ann. Soc. Entomol. Belg. 57: 108-147 (page 136, [First available use of Monomorium salomonis r. junodi var. opacior Forel, 1913a: 136; unavailable name.] )
  • Forel, A. 1913k. Ameisen aus Rhodesia, Kapland usw. (Hym.) gesammelt von Herrn G. Arnold, Dr. H. Brauns und Anderen. Dtsch. Entomol. Z. 1913(Su Suppl: 203-225 (page 216, (in text) worker described)
  • Stitz, H. 1923. Hymenoptera, VII. Formicidae. Beitr. Kennt. Land- Süsswasserfauna Dtsch.-Südwestafr. 2: 143-167 (page 156, Variety of salomonis)

References based on Global Ant Biodiversity Informatics

  • IZIKO South Africa Museum Collection
  • Santschi, F. "Résultats de la Mission scientifique suisse en Angola, 1928-1929. Formicides de l'Angola." Revue Suisse de Zoologie 37 (1930): 53-81.
  • Stitz H. 1923. Hymenoptera, VII. Formicidae. Beiträge zur Kenntnis der Land- und Süsswasserfauna Deutsch-Südwestafrikas 2: 143-167.