Pheidole susannae

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Pheidole susannae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Pheidole
Species: P. susannae
Binomial name
Pheidole susannae
Forel, 1886

Pheidole obscurior casent0178039 profile 1.jpg

Pheidole obscurior casent0178039 dorsal 1.jpg

Specimen labels


Pheidole susannae is a relatively common species in disturbed habitats throughout the Neotropics but occurs in numerous habitat types, including: highly disturbed areas such as city parks, seasonal dry forest, mature lowland rainforest, and second growth rainforest. It can occur on the ground or in the canopy. Workers readily recruit to baits, and major workers often recruit along with minor workers. Nests are in small cavities and appear to be somewhat opportunistically inhabited. (Longino 2009)


See the description in the nomenclature section.

Keys including this Species


Longino (2009) - Southern Mexico to southern Brazil.

Wilson (2003) - Ranging from Veracruz, Mexico, south to Colombia, Venezuela, and Trinidad. I have also verified a record from Cayo Congo, Puerto Rico, col. J. A. Torres. Kempf (1972b) cites the species from Rio Grande do Sul, a doubtful record I have not been able to check.

Distribution based on Regional Taxon Lists

Neotropical Region: Argentina, Barbados, Brazil, Colombia, Costa Rica, Dominican Republic, El Salvador, Guatemala (type locality), Honduras, Mexico, Netherlands Antilles, Nicaragua, Paraguay, Puerto Rico, Trinidad and Tobago, Venezuela.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


This widespread species is also very adaptable in habitat and nest site. In Colombia colonies have been found variously in forests and pastures. In Costa Rica, Longino (1997) reports susannae nesting under the bark and into an abandoned termite nest at the base of a large tree and in cracks in the floor of a housing unit near the La Selva Biological Station forest. I found it nesting behind a concrete curb inside a San José, Costa Rica, city park, foraging during the day. On Barro Colorado Island, Panama, I observed a nuptial flight in progress in tropical evergreen forest at 1600 hrs; males were emerging in the company of minors and majors from a crevice in the trunk of a tree 1–2 m from the ground. (Wilson 2003)


Minor Worker

Major Worker


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

  • obscurior. Pheidole susannae r. obscurior Forel, 1886b: xliv (s.w.) BRAZIL. Forel, 1893g: 410 (q.m.). Raised to species and senior synonym of partita: Wilson, 2003: 330. Junior synonym of susannae: Longino, 2009: 79.
  • susannae. Pheidole susannae Forel, 1886b: xliii (s.w.) GUATEMALA. Senior synonym of evoluta: Kempf, 1964e: 63; of atricolor: Wilson, 2003: 351; of obscurior (and its junior synonym partita): Longino, 2009: 79.
  • partita. Pheidole partita Mayr, 1887: 590 (s.), 604 (w.) BRAZIL. Junior synonym of obscurior: Wilson, 2003: 330; of susannae: Longino, 2009: 79.
  • atricolor. Pheidole susannae r. atricolor Forel, 1901e: 356 (s.w.q.m.) COLOMBIA. Junior synonym of susannae: Wilson, 2003: 351.
  • evoluta. Pheidole incisa subsp. evoluta Borgmeier, 1929: 204, pl. 6, fig. 3 (s.w.) BRAZIL. Junior synonym of susannae: Kempf, 1964e: 63.

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


From Wilson (2003): A member of the fallax group, most similar to Pheidole haskinsorum, Pheidole lattkei and Pheidole nubicola, and distinguished as follows.

Major: in both side and frontal views, head tapered conspicuously toward occiput; occipital cleft deep, antennal scape failing to reach the occipital corner by about 2X the maximum scape width; pilosity fringing side and frontal profiles posterior to eye level subrecumbent; rugoreticulum extensive all around the eye; anterior half of first gastral tergite shagreened and opaque; humerus in dorsal-oblique view low and smoothly rounded.

Minor: pronotum entirely smooth; occiput moderately narrowed, with nuchal crest; propodeal spines reduced to denticles.

A highly variable species that may in time prove to be a complex of sibling species.

MEASUREMENTS (mm) Lectotype major: HW 1.30, HL 1.44, SL 1.06, EL 0.20, PW 0.60. Paralectotype minor: HW 0.54, HL 0.82, SL 1.12, EL 0.14, PW 0.40.

COLOR Major: body reddish yellow, gaster a slightly contrasting light reddish brown.

Minor: concolorous medium yellow. Other series vary from reddish yellow to dark brown.

Pheidole susannae Wilson 2003.jpg

Figure. Upper: lectotype, major. Lower: paralectotype, minor. Scale bars = 1 mm.

Lectotype Specimen Labels

Type Material

GUATEMALA: Retalhuleu, Pacific slope. Museum of Comparative Zoology - as reported in Wilson (2003)

Longino (2009):

Syntype major, minor worker: Guatemala, Retalhuleu (Stoll) Musee d'Histoire Naturelle Genève (examined).

Pheidole susannae r. obscurior Lectotype major worker (here designated, labeled with unique pin code JTLC000015316) and associated paralectotype minor worker: Brazil, Rio de Janeiro (Naegeli) Musee d'Histoire Naturelle Genève (examined).

Pheidole partita Brazil, Rio de Janeiro (Naegeli).

Pheidole susannae r. atricolor Syntype major,minor worker, gyne, male: Colombia, Magdalena, San Antonio (Forel) Musee d'Histoire Naturelle Genève (examined).

Pheidole incisa subsp. evoluta Syntype major, minor worker: Brazil, Rio Grande do Sul, Porto Alegre, 30 Nov 1924 (Buck).


Eponymous, no attribution given. (Wilson 2003)


  • Forel, A. 1886b. Espèces nouvelles de fourmis américaines. Ann. Soc. Entomol. Belg. 30:xxxviii-xlix. (page xliii, soldier, worker described)
  • Kempf, W. W. 1964e. Miscellaneous studies on Neotropical ants. III. (Hymenoptera: Formicidae). Stud. Entomol. 7: 45-71 (page 63, senior synonym of evoluta)
  • Kempf, W. W. 1972b. Catálogo abreviado das formigas da região Neotropical. Stud. Entomol. 15: 3–344.
  • Longino, J.T. 2009. Additions to the taxonomy of New World Pheidole. Zootaxa 2181: 1-90. PDF
  • Wilson, E. O. 2003. Pheidole in the New World: A dominant, hyperdiverse ant genus. Harvard University Press, Cambridge, MA. (page 351, fig. major, minor described, Senior synonym of atricolor)