Pheidole exarata occurs in mature wet forest habitats from 800–1600m elevation. It is arboreal, forming large colonies beneath epiphytes and in live stems. An incipient colony was found in a cavity in a live, 1.5cm diameter stem of a melastomataceous vine; a colony was found in several internodes of a Cecropia insignis sapling, another in an internode of Cecropia angustifolia; a large aggregation of minor and major workers, but no sexuals or brood, was found in a clean hollow stem of Neomirandea angularis (Asteraceae). One colony under epiphytes was observed with multiple dealate queens, evidence of polygyny. (Longino 2009)
See the description in the nomenclature section.
Keys including this Species
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
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The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- exarata. Pheidole exarata Emery, 1896g: 68 (s.w.) COSTA RICA. Senior synonym of grantae: Longino, 2009: 31. See also: Wilson, 2003: 686.
- grantae. Pheidole crassipes r. grantae Forel, 1908b: 53 (s.w.) COSTA RICA. Raised to species: Wheeler, 2003: 700. Junior synonym of exarata: Longino, 2009: 31.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
The types of P. grantae closely match the drawings of P. exarata in Wilson (2003), the type localities are relatively close, and there is no evidence of distinct sympatric forms of this moderately common species in the central highlands of Costa Rica. Pheidole exarata is an upland version of the closely related lowland species, Pheidole excubitor. A third member of this complex is Pheidole stulta (the oldest name in the complex). Pheidole stulta is similar to P. exubitor but with less sculpture on the face of the major and pronotum of the minor (Wilson 2003). Geographic variation is not well understood in these forms and the distinctness of P. exarata, P. exubitor and P. stulta should be further evaluated. (Longino 2009)
From Wilson (2003): DIAGNOSIS A large, medium brown (major) or plain light brown (minor) member of the tristis group with small propodeal spines, possessing as well a subpostpetiolar process and bell-shaped postpetiolar node.
Major: all of dorsal head surface covered by parallel longitudinal carinulae; and pronotal dorsum by transverse carinulae.
Minor: occiput broad, lacking a nuchal collar; all of dorsal surface of head and mesosoma foveolate and opaque.
Similar to Pheidole alpinensis, Pheidole excubitor, Pheidole germaini, Pheidole grandinodus, Pheidole obrima, Pheidole rogeri, Pheidole stulta, Pheidole tristis and Pheidole zoster, differing in many details of body form, sculpturing, and pilosity, as illustrated, and in color, as described.
MEASUREMENTS (mm) Lectotype major: HW 1.60, HL l.78, SL 0.86, EL 0.20, PW 0.80. Paralectotype minor: HW 0.80, HL 0.86, SL 0.78, EL 0.14, PW 0.50.
COLOR Major: concolorous medium reddish brown.
Minor: concolorous plain light brown.
Figure. Upper: lectotype, major. Lower: paralectotype, minor. Scale bars = 1 mm.
Syntype major, minor worker: Costa Rica, San José: San José Museo Civico di Storia Naturale, Genoa (not examined). See also: Wilson, 2003: 686.
Pheidole crassipes r. grantae Syntype major, minor worker: Costa Rica, Cartago: Cote Tablazo [a montane site near Cartago] (Biolley) Musee d'Histoire Naturelle Genève (examined).
- Emery, C. 1896g. Studi sulle formiche della fauna neotropica. XVII-XXV. Bull. Soc. Entomol. Ital. 28: 33-107 (page 68, soldier, worker described)
- 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 686, fig. major, minor described)