Acanthostichus quadratus

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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


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






The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • quadratus. Acanthostichus quadratus Emery, 1895j: 750, fig. OO.A; pl. 16, figs. 5, 6; pl. 17, fig. 12 (w.q.) BOLIVIA. Senior synonym of niger: Mackay, 1996: 162.
  • niger. Acanthostichus serratulus var. niger Santschi, 1933e: 105 (q.) ARGENTINA. Junior synonym of serratulus: Kusnezov, 1962a: 132. Revived from synonymy and raised to species: Brown, 1975: 42. 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].


  • Emery, C. 1895l. Die Gattung Dorylus Fab. und die systematische Eintheilung der Formiciden. Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 685-778 (page 750, 00.A pl. 16, fig. 12 worker, queen described)
  • MacKay, W. P. 1996. A revision of the ant genus Acanthostichus (Hymenoptera: Formicidae). Sociobiology 27: 129-179 (page 162, Senior synonym of niger)
  • Morini, M. S. de C.; Yashima, M.; Zene, F. Y.; Silva, R. R. da; Jahyny, B. 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 43:573-578. [2004]