The current taxonomic status of this species is as a subspecies of fuscoatra (Roger 1861), and a junior synonym of impressa; see Taxonomy.
Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Range
Costa Rica, Panama. Costa Rica: known from mid to upper elevation sites from Cordillera de Guanacaste to Cordillera Volcanica Central; also known from Bocas del Toro region of Panama, so probably continuous in montane sites throughout the country.
Identification
Mesosomal dorsum with erect hairs; opening of propodeal spiracle viewed perpendicularly slit-shaped, more than twice as long as wide; mandible with approximately 9 teeth; in side view, dorsal outline of mesosoma forms a continuous convexity including mesonotum, metanotum and propodeal dorsum; propodeal groove obsolete or nearly so, and not strongly impressed; cheeks without a distinct carina between lateral clypeal wing and eye margin; stridulatory file absent; arolia absent; head width greater than 2.0mm; mesosoma greater than 3.6mm long; dorsolateral margin of pronotum uniformly punctate, rounded; clypeus broad front to back, anterior margin truncate, flattened to weakly notched, but with medial margin well in front of frontal lobes.
Similar species: harpax is smaller, and usually has a dorsolateral carina on the pronotum; impressa has a shallower (front to back) clypeus.
Natural History
This species is a dramatically large ant which I occasionally see as individual workers on roads and trails. I have one nest observation from Cerro Cacao in the Guanacaste Conservation Area:
At the bottom of the forest patch below the station, along the trail back to Quebrada Grande, I observed a nest in the steep bank of the trail. A purpurascens worker captured a Gnamptogenys worker from a nest I was excavating. The purpurascens worker moved irregularly back and forth at first, but then went to a simple circular hole in the bank. I followed the hole, excavating horizontally into the bank, until I was a full arm's length plus trowel length into the bank. At this point I began scooping out a few workers at a time. I obtained about 16 workers this way, but then had to stop.
Pachycondyla purpurascens Forel 1899:12. Syntype worker: Costa Rica, Cache [MHNG] (examined). Proposed revised status.
Pachycondyla fuscoatra subsp. purpurascens Forel: Emery 1901:48.
Pachycondyla impressa (Roger) (part): Kempf (1961), Bolton (1995).
Emery (1901, 1911) considered transversa and purpurascens to be distinct species in Costa Rica. Kempf (1961) synonymized transversa under impressa, but his treatment of purpurascens was ambiguous. He placed it in the list of synonymy beneath impressa, but he listed it as "? Pachycondyla purpurascens," and did not follow it with "NOV. SYN." Other names in the list were followed by "NOV. SYN." In his discussion of synonyms, he stated that he exempted purpurascens from formal synonymy because of its larger than normal size, and that further study was warranted. He did not examine any material of purpurascens, relying on published records. Bolton (1995) listed purpurascens as a synonym of impressa, attributing the synonymy to Kempf (1961). I follow Emery in considering purpurascens a distinct species, and propose a revived status to full and valid species.
Specimens examined
COSTA RICA: Cartago: Juan Vinas, 9¡54'N, 83¡45'W (A. Alfaro); Cachi, 9¡50'N, 83¡48'W [purpurascens syntype]; Guanacaste: Cerro Cacao, 10¡56'N, 85¡28'W, 1500m (J. Longino); Puntarenas: Monteverde, 10¡18'N, 84¡48'W, 1500m (J. Longino); San Jose: Bajo La Hondura, Braulio Carrillo Nat. Park, 10¡04'N, 83¡59'W, 1100m (J. Longino).
PANAMA: Bocas del Toro, Fortuna-Chiriqui Grande Road, 8¡47'N, 82¡11'W, 800m (D. M. Olson).
Literature Cited
Bolton, B. 1995. A New General Catalogue of the Ants of the World. Harvard University Press, Cambridge, Mass.
Emery, C. 1901. Notes sur les sous-familles des Dorylines et Ponerines (Famille des Formicides). Annales de la Societe Entomologique de Belgique 45:32-54.
Emery, C. 1911. Hymenoptera. Fam. Formicidae. Subfam. Ponerinae. Genera Insectorum 1181-125.
Forel, A. 1899. Formicidae. Biologia-Centrali Americana 3:1-169.
Kempf, W. W. 1961. As formigas do genero Pachycondyla Fr. Smith no Brasil (Hymenoptera: Formicidae). Revta Bras. Entomol. 10:189-204.
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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