Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Mountains of Honduras south to Bolivia, east to Venezuela. Costa Rica: generally above 1300m elevation in all the cordilleras from Guanacaste to Talamanca.
Mesosomal dorsum with erect hairs; opening of propodeal spiracle viewed perpendicularly slit-shaped, more than twice as long as wide; mandible with ten or more teeth; dorsal outline of mesosoma interrupted by a distinct, impressed propodeal groove, so that the mesonotum forms a convexity separate from the more or less convex propodeal dorsum; eyes situated anteriorly on head, such that a line drawn through the centers of the eyes crosses the frontal carinae near their greatest constriction; cheeks without a distinct carina reaching from clypeal wing to eye margin.
This species is a common inhabitant of cloud forest habitats, where it is usually the only large, conspicuous Pachycondyla. I have often observed foraging workers on roads and trails. Workers may be seen foraging day or night. Most of my collections are from sifted litter samples from the forest floor leaf litter. I once observed an alate queen high in the canopy of a large oak tree in Monteverde. Mackay and Mackay (2010) report a nest under a stone, and three delalate queens collected from a rotten log, suggesting pleometrosis.
Montane species such as this one are interesting because they now occur as isolated populations on mountaintops, almost certainly with no or very limited gene flow among them. During full-glacial periods of the Pleistocene, they probably formed more continuous populations, because montane conditions would have extended much farther down the mountain slopes. The current separate populations probably formed 10-15 thousand years ago.
Pachycondyla aenescens Mayr 1870:396. Syntype worker: Colombia.
Mackay, W. P., and E. E. Mackay 2010. The Systematics and Biology of the New World Ants of the Genus Pachycondyla (Hymenoptera: Formicidae). Edwin Mellon Press, Lewiston.
Mayr, G. 1870. Formicidae novogranadenses. Sitzungsberichte der k. Akademie der Wissenschaften. Mathematisch-Naturwissenschaftliche Classe 61:370-417.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.firstname.lastname@example.org
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