Pheidole heterothrix

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Pheidole heterothrix
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Pheidole
Species: P. heterothrix
Binomial name
Pheidole heterothrix
Santschi, 1923

Pheidole heterothrix casent0913375 p 1 high.jpg

Pheidole heterothrix casent0913375 d 1 high.jpg

Specimen Labels


One series, collected by W. L. Brown at Horco Molle, Tucumán, was found at 900–1150 m in myrtaceous forest. (Wilson 2003)


See the description in the nomenclature section.

Keys including this Species


In addition to the types, from Villaguay, Entre Rios, Argentina, I have seen series from the Argentine provinces of La Pampa, Misiones, and Tucumán. (Wilson 2003)

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina (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.

  • heterothrix. Pheidole obtusopilosa st. heterothrix Santschi, 1923d: 59 (s.w.) ARGENTINA. Raised to species and senior synonym of gavrilovi: Wilson, 2003: 436.
  • gavrilovi. Pheidole gavrilovi Kusnezov, 1952b: 80 (s.w.) ARGENTINA. Junior synonym of heterothrix: Wilson, 2003: 436.

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


From Wilson (2003): DIAGNOSIS Similar to Pheidole obtusopilosa in some traits but distinguished from it and other Pheidole species as follows.

Major: patch of rugoreticulum present between eye and antennal fossa on each side; entire remainder of dorsal surface of head, including occiput, carinulate; very faint antennal scrobe present; promesonotal profile smoothly rounded; mesonotal convexity low but with distinct anterior and posterior declivities; all of pronotum carinulate; humeri rugoreticulate; pilosity dense and short; postpetiole from above conulate.

Minor: humerus subangulate; propodeal spines robust, moderately long, and directed backward; all of body except gaster foveolate.

MEASUREMENTS (mm) Lectotype major (heterothrix, not “gavrilovi”): HW 1.12, HL 1.16, SL 0.54, EL 0.18, PW 0.62.

Paralectotype minor: HW 0.54, HL 0.54, SL 0.44, EL 0.10, PW 0.32.

COLOR Major: all of body light reddish brown except gaster, which is medium reddish brown.

Minor: body dark reddish brown, appendages medium reddish brown.

Pheidole heterothrix Wilson 2003.jpg

Figure. Upper: major (syntype of synonymous gavrilovi). Lower: minor (syntype of synonymous gavrilovi). Upper outlines of minor mesosoma and occiput are those of heterothrix syntype. ARGENTINA: Loreto, Misiones, Argentina. Compared with lectotype and paralectotype of heterothrix. Scale bars = 1 mm.

Type Material

Villaguay, Entre Rios, Argentina. Naturhistorisches Museum, Basel - as reported in Wilson (2003)


Gr heterothrix, different hair (from that of obtusopilosa). (Wilson 2003)


  • Santschi, F. 1923d. Pheidole et quelques autres fourmis néotropiques. Ann. Soc. Entomol. Belg. 63: 45-69 (page 59, soldier, worker described)
  • Wilson, E. O. 2003. Pheidole in the New World: A dominant, hyperdiverse ant genus. Harvard University Press, Cambridge, MA. (page 436, fig. major, minor described, Raised to species: new status)

References based on Global Ant Biodiversity Informatics

  • 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.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Kusnezov N. 1952. El género Pheidole en la Argentina (Hymenoptera, Formicidae). Acta Zoologica Lilloana 12: 5-88.
  • Kusnezov N. 1978. Hormigas argentinas: clave para su identificación. Miscelánea. Instituto Miguel Lillo 61:1-147 + 28 pl.
  • Vittar, F. 2008. Hormigas (Hymenoptera: Formicidae) de la Mesopotamia Argentina. INSUGEO Miscelania 17(2):447-466