Polyrhachis viscosa

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Polyrhachis viscosa
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Formicinae
Tribe: Camponotini
Genus: Polyrhachis
Subgenus: Myrma
Species group: viscosa
Species: P. viscosa
Binomial name
Polyrhachis viscosa
Smith, F., 1858

Polyrhachis viscosa casent0227561 p 1 high.jpg

Polyrhachis viscosa casent0227561 d 1 high.jpg

Specimen Labels


Nests directly into sandy soil, usually in open localities. Foragers occur mostly on the ground but also ascend low bushes, trees and grass stems. A savannah and arid-zone species, it is interesting to note its occurrence on the coastal plains of Ghana as well as inland in the savannah proper. Alate females were recorded from Sudan in August. (Bolton 1973)


Rigato (2016) - A viscosa-group species with a uniquely (among all African Polyrhachis) apically enlarged scape and proximally flattened first funicular joint.

I often found specimens of P. omissa labelled as P. viscosa and mixed with it, but omissa always lacks the distinctive antennal features that separate viscosa from all other African Polyrhachis. Polyrhachis viscosa has a strongly widened apex of the scape and a strongly depressed first funicular joint (see Fig. 22 in Bolton, 1973). This feature is unique to viscosa and seemingly constant. Although I found several gynes assignable to P. omissa collected in Yemen, Collingwood and Agosti (1996) in their survey of Arabian ants mentioned P. viscosa and Polyrhachis lacteipennis only. Polyrhachis lacteipennis superficially recalls viscosa and omissa, but belongs to the non-African subgenus Myrmhopla and has a slender and immarginate mesosoma and other very distinctive features.

The main features separating omissa from viscosa workers can be summarized as follows:

Polyrhachis omissa Polyrhachis viscosa
Scape and first funicular joint of usual shape. Scape strongly widened apically and first funicular joint strongly flattened proximally.
Head apperaring almost round, CI 88 or more. Head appearing somewhat elongate, CI 86 or less.
Anterior clypeal margin entire, medially crenulate and at most faintly notched. Anterior clypeal margin usually with a small, but distinct, median notch.
Frons narrower, FI 28 or less. Frons wider, FI 30 or more.
Mesosoma stouter: pronotum about twice as wide as propodeum; mesonotum in dorsal view about 2.5 times as wide as long. Mesosoma more slender: pronotum about 1.5 times as wide as propodeum; mesonotum in dorsal view about twice as wide as long.

Keys including this Species


Latitudinal Distribution Pattern

Latitudinal Range: 17.266667° to -25.69188°.

Tropical South

Distribution based on Regional Taxon Lists

Afrotropical Region: Burkina Faso, Democratic Republic of Congo, Eritrea (type locality), Ethiopia, Ghana, Kenya, Malawi, Nigeria, Saudi Arabia, Somalia, South Africa (type locality), Sudan, Uganda, United Republic of Tanzania, Zimbabwe, Zimbabwe.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.




Images from AntWeb

Polyrhachis viscosa casent0235675 h 1 high.jpgPolyrhachis viscosa casent0235675 p 1 high.jpgPolyrhachis viscosa casent0235675 d 1 high.jpgPolyrhachis viscosa casent0235675 l 1 high.jpg
Worker. Specimen code casent0235675. Photographer Will Ericson, uploaded by California Academy of Sciences. Owned by AFRC, Pretoria, South Africa.
Polyrhachis viscosa casent0903462 h 1 high.jpgPolyrhachis viscosa casent0903462 p 1 high.jpgPolyrhachis viscosa casent0903462 d 1 high.jpgPolyrhachis viscosa casent0903462 l 1 high.jpg
Syntype of Polyrhachis viscosaWorker. Specimen code casent0903462. Photographer Z. Lieberman, uploaded by California Academy of Sciences. Owned by NHMUK, London, UK.
Polyrhachis viscosa casent0905621 h 1 high.jpgPolyrhachis viscosa casent0905621 p 1 high.jpgPolyrhachis viscosa casent0905621 d 1 high.jpgPolyrhachis viscosa casent0905621 l 1 high.jpg
Syntype of Polyrhachis antinoriiWorker. Specimen code casent0905621. Photographer Will Ericson, uploaded by California Academy of Sciences. Owned by MSNG, Genoa, Italy.


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

  • viscosa. Polyrhachis viscosus Smith, F. 1858b: 71, pl. 4, fig. 41 (w.) SOUTH AFRICA. Combination in P. (Myrma): Santschi, 1914b: 143. Senior synonym of antinorii: Dalla Torre, 1893: 271; of imatongica, spretula: Bolton, 1973b: 330. See also: Arnold, 1924: 749.
  • antinorii. Polyrhachis antinorii Emery, 1877b: 365, fig. (w.) ETHIOPIA. Junior synonym of viscosa: Dalla Torre, 1893: 271.
  • spretula. Polyrhachis (Myrma) viscosa var. spretula Santschi, 1923e: 294 (w.q.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of viscosa: Bolton, 1973b: 330.
  • imatongica. Polyrhachis (Myrma) cubaensis subsp. imatongica Weber, 1943c: 388, pl. 16, fig. 22 (w.) SUDAN. Junior synonym of viscosa: Bolton, 1973b: 330.

Type Material

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



Bolton (1973) - TL 5.9-7.6, HL 1.56-1.96, HW 1.29-1.63, CI 80-86, SL 1.52-2.07, SI 119-135, PW 1.00-1.37, MTL 1.48-2.04. (30 measured.)

Clypeus usually with the anterior margin narrowly notched medially. Apex of scape greatly swollen in dorsal view, three or more times the width just distal of the basal neck and forming a hood which hides the base of the first funicular segment in dorsal view. First segment of funiculus dorsoventrally flattened basally. Eyes flat to weakly convex. Alitrunk marginate throughout its length. Promesonotal suture distinct; metanotal groove absent from or only very faintly present on the dorsal alitrunk, its location usually marked only by a weak indentation of the lateral margination or by a break in the sculpturation. Pronotal spines long and acute; propodeal teeth short, upcurved, connected by a transverse ridge running across the posterior margin of the propodeum, the ridge raised into a blunt tubercle medially. The size of this median propodeal tubercle is variable, being almost absent in small individuals, but occasionally as large as the propodeal teeth. Node of petiole with the lateral pair of spines long and directed upwards and backwards. Between them is a pair of shorter, acute spines of variable length. Anterior face of the first gastral segment concave medially.

Dorsum of alitrunk and gaster without erect hairs; all surfaces of body with a very sparse short, greyish pubescence, which may be absent.

Clypeus with a fine, longitudinal striation, loosely overlaid by fine shallow punctures. Head and alitrunk loosely and finely reticulate-rugose with the interspaces reticulate-punctate. Gaster finely and densely reticulate-punctate.

Rigato (2016) - (n=16): HL 1.58–1.87, HW 1.30–1.59, CI 79–86, SL 1.70–2.15, SI 125–142, FW 0.40–0.50, FI 30–35, PW 1.11–1.47, WL 1.97–2.50, HTL 1.66–2.20.


Bolton (1973) - As worker, with the usual differences associated with the caste. Pronotal spines and propodeal teeth reduced, but often the median tubercle on the posterior propodeal margin is enlarged or double.


References based on Global Ant Biodiversity Informatics

  • André E. 1887. Description de quelques fourmis nouvelles ou imparfaitement connues. Rev. Entomol. (Caen) 6: 280-298.
  • Bolton B. 1973. The ant genus Polyrhachis F. Smith in the Ethiopian region (Hymenoptera: Formicidae). Bulletin of the British Museum (Natural History). Entomology 28: 283-369.
  • Borowiec L. 2014. Catalogue of ants of Europe, the Mediterranean Basin and adjacent regions (Hymenoptera: Formicidae). Genus (Wroclaw) 25(1-2): 1-340.
  • Collingwood, C. A. and D. Agosti. 1996. Formicidae (Insects: Hymenoptera) of Saudi Arabia (Part 2) Fauna of Saudi Arabia 15: 300-385.
  • Dieng M. M., A. B. Ndiaye, C. T. Ba, and B. Taylor. 2016. Les fourmis (Hymenoptera, Formicidae) de l’enclos d’acclimatation de Katane de la reserve de faune du Ferlo nord (Senegal). Int. J. Biol. Chem. Sci. 10(4): 1626-1636.
  • Emery, C. "Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte prima. Formiche provenienti dal Viaggio dei signori Antinori, Beccari e Issel nel Mar Rosso e nel paese dei Bogos. [concl.]." Annali del Museo Civico di Storia Naturale 9 (1877): 363-381.
  • Finzi B. 1939. Materiali zoologici dell'Eritrea raccolti da G. Müller durante la spedizione dell'Istituto Sieroterapico Milanese e conservati al Museo di Trieste. Parte III. Hymenoptera: Formicidae. Atti del Museo Civico di Storia Naturale di Trieste 14: 153-168.
  • Forel A. 1907. Ameisen von Madagaskar, den Comoren und Ostafrika. Wissenschaftliche Ergebnisse. Reise in Ostafrika 2: 75-92.
  • Forel A. 1910. Ameisen aus der Kolonie Erythräa. Gesammelt von Prof. Dr. K. Escherich (nebst einigen in West-Abessinien von Herrn A. Ilg gesammelten Ameisen). Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 29: 243-274.
  • IZIKO South Africa Museum Collection
  • Kone M., S. Konate, K. Yeo, P. K. Kouassi, K. E. Linsemair. 2010. Diversity and abundance of terrrestrial ants along a gradient of land use intensification in a transitional forest-savannah zone of Cote d'Ivoire. Journal of Applied Biosciences 29: 1809-1827.
  • Levieux J. 1972. Etude du peuplement en fourmis terricoles d'une savane preforestiere de Cote d'Ivoire. Revue d'Ecologie et de Biologie du Sol 10(3): 381-428.
  • Lévieux J. 1972. Les fourmis de la savane de Lamto (Côte d'Ivoire): éléments de taxonomie. Bulletin de l'Institut Fondamental d'Afrique Noire. Série A. Sciences Naturelles 34: 611-654.
  • Lévieux J. 1977. La nutrition des fourmis tropicales: V- Elements de synthèse. Les modes d'exploitation de la biocenose. Insectes Sociaux 24(3): 235-260.
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  • Medler J. T. 1980: Insects of Nigeria - Check list and bibliography. Mem. Amer. Ent. Inst. 30: i-vii, 1-919.
  • Menozzi C. 1930. Formiche della Somalia italiana meridionale. Memorie della Società Entomologica Italiana. 9: 76-130.
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  • Rigato F. 2016. The ant genus Polyrhachis F. Smith in sub-Saharan Africa, with descriptions of ten new species. (Hymenoptera: Formicidae). Zootaxa 4088: 1-50.
  • Robson Simon Database Polyrhachis -05 Sept 2014
  • 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
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