Pheidole fiorii

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Pheidole fiorii
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Pheidole
Species: P. fiorii
Binomial name
Pheidole fiorii
Emery, 1890

Pheidole fiorii casent0281749 p 1 high.jpg

Pheidole fiorii casent0281749 d 1 high.jpg

Specimen Labels

Longino (1997) observes, as I have, that fiorii “inhabits mature wet forest understory. It makes hemispherical carton nests under individual leaves of palms, aroids, and other large-leaved plants. The nests are on the order of 10 cm across, and usually at head height or lower. Colonies appear to be monogynous and with a single nest.” Longino notes also that fiorii has varied greatly in abundance at La Selva and Peñas Blancas from one season or year to the next, for unknown reasons. At Peñas Blancas he observed a nest being raided by a colony of the army-ant-like ponerine genus Simopelta. (Wilson 2003)


See the description in the nomenclature section.

Keys including this Species


Atlantic slope and montane Costa Rica to 950 m. (Wilson 2003)

Distribution based on Regional Taxon Lists

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

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


Nest described in Black (1987).

A colony (nest pictured below) included one dealate queen, 646 workers, 67 soldiers, 6 gynes, larvae and over 400 pupae (workers 414, soldiers 5, gynes 17) (C. Peeters unpublished).

Partly opened carton nest of P. fiorii, showing inhabited chambers with workers, soldiers and brood. The single dealate queen is seen on upper right. Many seeds (all the same size and shape) are scattered throughout. From El Ceibo, Costa Rica. Photo by Christian Peeters






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

  • fiorii. Pheidole fiorii Emery, 1890b: 51 (s.) COSTA RICA. Forel, 1899c: 70 (q.); Forel, 1908b: 52 (w.m.). [Also described as new by Emery, 1894k: 56.] See also: Wilson, 2003: 291.

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 medium-sized member of the fallax group with extremely long propodeal spines and scapes in both castes.

Major: occiput, lateral sections of the head, and posterior strip of pronotum rugoreticulate.

Minor: dorsal surface of head and almost all of mesosoma foveolate to some degree and opaque to subopaque, although the degree of foveolation is variable and parts of the head and promesonotum are often nearly smooth and shiny.

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

On variation, John T. Longino (1997). writes: “This species (or species complex) shows a common pattern of being darker at higher elevations . . . It also exhibits spatial variation in the pilosity of the major worker head. Collections from sea level to about 600 m on the Atlantic slope are yellow, and the major worker has the sides of head with abundant erect setae. Collections from higher elevations in Braulio Carrillo National Park are dark brown, and the major worker continues to have the sides of head with abundant erect setae. Collections from the Peñas Blancas Valley are dark brown, and the major worker has the sides of head with sparse, appressed setae.”

MEASUREMENTS (mm) Major (Lago Hula, Costa Rica): HW 1.48, HL 1.52, SL 1.24, EL 0.24, PW 0.68. Minor: HW 0.64, HL 0.92, SL 1.40, EL 0.18, PW 0.48.

COLOR Yellow to dark brown, with increasing elevation.

Pheidole fiorii Wilson 2003.jpg

Figure. Upper: major. Lower: minor. COSTA RICA: Lago Hula, Heredia (E. O. Wilson). (The minor was compared with a syntype in the Museum of Comparative Zoology, Harvard University) Scale bars = 1 mm.

Type Material

Jimenez, Costa Rica; collected by Anastasio Alfaro. Museo Civico di Storia Naturale, Genoa and Museum of Comparative Zoology - as reported in Wilson (2003)


Named after Andrea Fiori. (Wilson 2003)