Pheidole exarata Emery 1896

= Pheidole JTL-119

Suggested synonym:
= Pheidole grantae Forel 1908

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

major face view

major lateral view


Minor worker: head length 0.77mm, head width 0.72mm, scape length 0.73mm, Webers length 0.98mm (n=1). Differing from excubitor in the following respects: face densely foveolate throughout; clypeus with a median keel; metanotal groove less impressed, with less distinct step at anterior border of propodeal dorsum; setae less appressed on scapes; mesosoma more densely foveolate and occasionally with rugae; anterior portion of gaster faintly shagreened; a pair of setae on propodeal dorsum.

Major worker: head length 1.82mm, head width 1.66mm, scape length 0.84mm (n=1). Differing from excubitor in the following respects: clypeus with prominent median keel; more abundant pilosity on mesosomal dorsum and sparse short setae projecting from sides of head.


Costa Rica (type locality), Colombia. Costa Rica: Atlantic slope to 1600m.

Natural History

Occurs in mature wet forest habitats (including cloud forest); arboreal, forming large polygynous(?) nests beneath epiphytes in high canopy.

Selected Records

Braulio Carrillo National Park at 950m: mature wet forest gap; incipient colony in 1.5cm dia live melastome vine stem.

Penas Blancas Valley: edge between primary forest and large area of low secondgrowth; nest in a few internodes of Cecropia insignis sapling.

Penas Blancas Valley: mature wet forest; crown and trunk of canopy Guarea; colony under moss on small canopy branch; about 20m high; near end of branch.

Monteverde: mature leeward cloud forest; freshly cut canopy tree, Eugenia cf. acapulcensis (det. B. Haber); column on branch; another group under moss mat.

Monteverde: forest edge; in crowns of recently felled trees, Nectandra(?) and Citharexylum(?); populous colony under epiphyte mat on Nectandra; multiple dealate queens, many alate queens.

Monteverde: cloud forest; fresh treefall, a large Ficus; nest under thick epiphyte clump.


The morphospecies we called JTL-119 is probably Emery's exarata, based on the line drawings in Wilson (2003) and the type locality.

Pheidole grantae Forel was described from Costa del Tablazo, Costa Rica, a montane site near Cartago. It appears to be a more heavily sculptured version of P. exarata, with the first gastral tergite fully shagreened and the foveolate sculpture extending more posteriorly on the face of the major. We consider these differences to be intraspecific variation.

There is a complex of Pheidole species showing a geographic mosaic of differentiated forms. Members of this complex include excubitor Wilson 2003, exarata Emery 1896, and stulta Forel 1886. Wilson (2003) synonymized two forms, championi Forel 1899 and championi sima Forel 1912, under stulta. The type locality of stulta is Bahia, Brazil. Pheidole championi was described from Panama, Volcan de Chiriqui. Pheidole championi var. sima was described from Costa Rica, "Canas Gudas" [probably Puntarenas Province, Canas Gordas, a site very near Volcan Chiriqui]. Thus technically stulta occurs in Costa Rica. Pheidole stulta appears to be a shinier version of excubitor. The minor has a completely shiny face and pronotum, and more of the face of the major is smooth and shining. No cases are known where any of these forms are sympatric. It remains to be seen whether this "stulta complex" is multiple species or one geographically variable species.

See excubitor.

Literature Cited

Wilson, E. O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus. Harvard University Press, Cambridge, Mass

Page authors:

John T. Longino, The Evergreen State College, Olympia WA 98505 USA.

Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA.

Date of this version: 2 September 2003.
Previous versions of this page: 27 December 1997
Go back to top

Go to Ants of Costa Rica Homepage