Pheidole ajax

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Pheidole ajax
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Pheidole
Species: P. ajax
Binomial name
Pheidole ajax
Forel, 1899



Specimen Label

A nest was found by Longino (1997). beneath the bark of a rotten stump in mature wet forest.


See the description in the nomenclature section.

Keys including this Species


Atlantic slope to 600 m (Longino 1997).

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia, Costa Rica (type locality), Nicaragua.

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.

  • ajax. Pheidole ajax Forel, 1899c: 71 (s.w.) COSTA RICA. See also: Wilson, 2003: 263.

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 large brown member of the fallax group immediately recognizable in the major by the extremely long propodeal spines; by the completely carinulate center of the head and frontal lobes, which is flanked by a rugoreticulum on either side in full-face view; and by the striate first gastral tergite.

Minor: extremely long propodeal spines and mostly smooth and shiny head and body.

Similar to Pheidole fiorii, Pheidole hector, Pheidole jaculifera and Pheidole lourothi, differing in many details of body form, sculpturing, and pilosity, as depicted.

MEASUREMENTS (mm) Major (Rio Toro Amarillo, Costa Rica): HW 1.28, HL 1.36, SL 1.16, EL 0.22, PW 0.66.

Minor (Rio Toro Amarillo, Costa Rica): HW 0.56, HL 0.82, SL 1.12, EL 0.14, PW 0.40.

COLOR Major: body dark brown, appendages medium brown.

Minor: body and most appendages medium to light brown, except for yellowish brown tarsi.

Pheidole ajax Wilson 2003.jpg

Figure. Upper: major. Lower: minor. COSTA RICA: Rio Toro Amarillo, near Guapiles, col. William L. Brown. Minor compared with syntype in Museum d’Histoire Naturelle, Genève, by W. O. Brown. Scale bars = 1 mm.

Syntype Specimen Labels

Type Material

San José, Costa Rica. Musee d'Histoire Naturelle Genève - as reported in Wilson (2003)


Gr Ajax, legendary Greek hero of the Trojan war. (Wilson 2003)