Atta (Trachymyrmex) cornetzi Forel 1912:183. Worker, queen: Colombia. Combination in Trachymyrmex: Gallardo, 1916:242. Senior synonym of annulatus, bivittatus, brevispinosus, gatun, naranjo and uncifer: Weber, 1958:49.
Trachymyrmex cornetzi inhabits wet and dry forest habitats. It seems to prefer relatively open areas with a thin litter layer. Nests are in the soil.
This species is relatively common at La Selva Biological Station. Nests have been excavated by attine specialists in the laboratory clearing, it has been collected at honey/crisco baits in the forest, and the ALAS project has collected it in Winkler and Berlese samples.
One nest I excavated at La Selva was 10cm deep, with a 4cm diameter spherical chamber containing a fungus garden. The nest entrance was completely unadorned and led straight down to the chamber. The nest was collected on 1 July 1992 and contained abundant alate queens and a few adult males.
Another nest I excavated was in Manuel Antonio National Park. A nest was in clay soil in the middle of a trail. There was an asymmetrical pile of soil at the nest entrance, and a 3-4cm diameter fungus nest in a chamber about 5cm deep. A small Mycocepurus nest, with a small turret of clay soil, was within 5cm of the nest entrance of the Trachymyrmex.
I have also collected the species as ground foragers in Corcovado and Santa Rosa National Parks.