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 New General Catalogue, a catalogue of the world's ants.

  • 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)