Acanthostichus quadratus

AntWiki: The Ants --- Online
Acanthostichus quadratus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Acanthostichus
Species: A. quadratus
Binomial name
Acanthostichus quadratus
Emery, 1895

Acanthostichus quadratus casent0249286 p 1 high.jpg

Acanthostichus quadratus casent0249286 d 1 high.jpg

Specimen Labels


The type material was found in the stomach of a toad (Bufo crucifer).


A member of the serratulus species complex. Mackay (1996) - This species is closely related to Acanthostichus serratulus, but differs in the quadrate petiole (elongate in A. serratulus). It is similar to Acanthostichus kirbyi, but differs in that the clypeus is relatively wider (Fig. 13) and the two lateral teeth on the clypeus are almost always absent.

Keys including this Species


Latitudinal Distribution Pattern

Latitudinal Range: 25.68015° to -29.095278°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Bolivia (type locality), Brazil, Ecuador, Peru.

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

Acanthostichus quadratus casent0249286 p 2 high.jpgAcanthostichus quadratus casent0249286 p 3 high.jpg
Male (alate). Specimen code casent0249286. Photographer Estella Ortega, uploaded by California Academy of Sciences. Owned by PSWC, Philip S. Ward Collection.


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

  • quadratus. Acanthostichus quadratus Emery, 1895j: 750, fig. OO.A; pl. 16, figs. 5, 6; pl. 17, fig. 12 (w.q.) BOLIVIA, BRAZIL.
    • Type-material: lectotype worker (by designation of Mackay, 1996: 162), 1 paralectotype queen.
    • Type-locality: lectotype Brazil: Amazonas (Staudinger); paralectotype with same data.
    • [Note: other original syntype series, Bolivia: Misiones de Mosetenes, Rio Beni, is confirmed by Mackay, 1996: 162, in MSNG.]
    • Type-depository: MSNG.
    • Combination in A. (Acanthostichus): Emery, 1911d: 13.
    • Subspecies of serratulus: Forel, 1906d: 249.
    • Status as species: Emery, 1911d: 13; Borgmeier, 1923: 51; Wheeler, W.M. 1934g: 163 (in key); Kusnezov, 1962a: 132; Kempf, 1972a: 10; Brown, 1975: 42; Bolton, 1995b: 54; Mackay, 1996: 161 (redescription); Bezděčková, et al. 2015: 109.
    • Senior synonym of niger: Mackay, 1996: 162.
    • Distribution: Argentina, Bolivia, Brazil, Ecuador, Peru.
  • niger. Acanthostichus serratulus var. niger Santschi, 1933e: 105 (w.) ARGENTINA (Misiones).
    • Type-material: lectotype worker, 1 paralectotype worker.
    • Type-locality: lectotype Argentina: Misiones, Loreto, no. 1940 (A.A. Ogloblin); paralectotype with same data.
    • Type-depository: MACN.
    • Junior synonym of serratulus: Kusnezov, 1962a: 132; Kempf, 1972a: 10.
    • Status as species: Brown, 1975: 42; Brandão, 1991: 322; Bolton, 1995b: 54.
    • Junior synonym of quadratus: Mackay, 1996: 162.

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

Mackay (1996):



Mackay 1996. Figures 50-58.

HL 0.99-1.49, HL 0.88-1.46, SL 0.49-0.78, SW 0.19-0.24, WL 1.18-1.91, PW 0.40-0.73, PL 0.41-0.83, FL 0.68-0.94, FW 0.23-0.38, SI 49-52, CI 89-99, PI 93-120, FI 2.50-3.14, SL/SW 2.60-3.06.

Median and lateral clypeal teeth poorly developed (usually absent, except in larger workers); head slightly convex posteriorly; petiole subquadrate, subpetiolar process with posteriorly directed tooth; dorsum of petiole usually moderately smooth and shining with longitudinal troughs, especially well developed near the lateral borders.


The types of A. serratulus var. niger are identical to those of A. quadratus. My concept of the female is based on a paralectotype A. serratulus var. niger mounted on a piece of card next to the lectotype worker.

HL 1.83, HW 2.10, SL 0.79, SW 0.30, EL 0.23, WL 2.63, PW 1.85, PL 0.96, FL 1.35, FW 0.50, SI 43, CI 115, PI 52, FI 2.70, SL/SW 2.63. Subdichthadiiform (Fig. 50); mandibles without teeth (except apex); frontal carinae widely separated; eyes large; malar groove apparently absent; eyes large; ocelli absent; occiput slightly concave; dorsum of mesosoma with promesonotal suture poorly developed, metanotal suture somewhat more developed; propodeal angles in form of epilaut-like carinae; petiole much wider than long (Fig. 52); posterior femur not incrassate. Mostly smooth and shining throughout, with few scattered punctures, except sides of mesosoma and petiole, (which are more heavily and deeply punctate with a few longitudinal striae), and postpetiole and gaster (which are densely and evenly punctate). Long, flexuous hairs on all surfaces, gaster with dense, short, erect pubescence. Concolorous medium brown to dark reddish brown.

Type Material

Worker, female, BOLIVIA: Misiones de Mosetenes, Rio Beni (Museo Civico di Storia Naturale, Genoa) [seen]. Acanthostichus quadratus, lectotype worker ({MCSN) and paralectotype subdichthadiiform female (MCSN) (here designated); Amazonas, Staudinger and (followed by illegible name]; Acanthostichus quadratus Em.; Typus (MCSN) [all seen]; Acanthostichus serratulus var. niger, lectotype (here designated) and 1 paralectotype, both workers. Est[acion] Exp[erimental] Loreto (Misiones – Arg[entina]). Dr. A. A. Oglobin. # 1940. TIPUS. Acanthostichus serratulus Sm. V. niger Snts. [both seen].


References based on Global Ant Biodiversity Informatics

  • Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
  • Cuezzo, F. 1998. Formicidae. Chapter 42 in Morrone J.J., and S. Coscaron (dirs) Biodiversidad de artropodos argentinos: una perspectiva biotaxonomica Ediciones Sur, La Plata. Pages 452-462.
  • Emery C. 1895. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 8: 685-778.
  • Emery C. 1911. Hymenoptera. Fam. Formicidae. Subfam. Ponerinae. Genera Insectorum 118: 1-125.
  • Favretto M. A., E. Bortolon dos Santos, and C. J. Geuster. 2013. Entomofauna from West of Santa Catarina State, South of Brazil. EntomoBrasilis 6 (1): 42-63.
  • Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
  • Figueiredo C. J. de, R. R. da Silva, C. de Bortoli Munhae, and M. S. de Castro Morini. 2013. Ant fauna (Hymenoptera: Formicidae) attracted to underground traps in Atlantic Forest. Biota Neotrop 13(1): 176-182
  • Forel A. 1906. Fourmis néotropiques nouvelles ou peu connues. Annales de la Société Entomologique de Belgique 50: 225-249.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Kusnezov N. 1962. El género Acanthostichus Mayr (Hymenoptera, Formicidae). Acta Zoologica Lilloana 18: 121-138.
  • MacKay W. P. 1996. A revision of the ant genus Acanthostichus (Hymenoptera: Formicidae). Sociobiology 27: 129-179
  • Medeiros Macedo L. P., E. B. Filho, amd J. H. C. Delabie. 2011. Epigean ant communities in Atlantic Forest remnants of São Paulo: a comparative study using the guild concept. Revista Brasileira de Entomologia 55(1): 75–78.
  • Morini M. S. de C., M. Yashima, F. Y. Zene, R. R. da Silva, and B. Jahyny. 2004. Observations on the Acanthostichus quadratus (Hymenoptera: Formicidae: Cerapachyinae) visiting underground bait and fruits of the Syagrus romanzoffiana, in an area of the Atlantic forest, Brazil. Sociobiology 43(3): 573-578.
  • Santschi F. 1933. Fourmis de la République Argentine en particulier du territoire de Misiones. Anales de la Sociedad Cientifica Argentina. 116: 105-124.
  • Suguituru S. S., M. Santina de Castro Morini, R. M. Feitosa, and R. Rosa da Silva. 2015. Formigas do Alto Tiete. Canal 6 Editora 458 pages
  • Vittar, F. 2008. Hormigas (Hymenoptera: Formicidae) de la Mesopotamia Argentina. INSUGEO Miscelania 17(2):447-466