Trachymyrmex JTL-003

Attini, Myrmicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view


Costa Rica: throughout country in mid-elevation sites (above 500m).


Preorbital carina sinuous or straight, extending past eye and directed toward posterolateral vertex margin; in face view lateral and posterolateral tubercles weak to absent, such that sides of head appear evenly rounded; relative to JTL-006 anterolateral pronotal tubercles relatively longer and thinner, posterolateral vertex margins with more developed tubercle, generally "spikier" in appearance.

Similar species: JTL-006.

Natural History

This species is relatively common in mid-elevation sites, in mature forest habitats. I have found it at the 1070m and 1500m sites on the Barva Transect in Braulio Carrillo National Park, at Refugio Eladio in the Penas Blancas Valley east of Monteverde, at Estacion Cacao in the Guanacaste Conservation Area, and in the small cloud forest on the highest ridges of the Osa Peninsula in Corcovado National Park.

The quantitative sampling on the Barva Transect by the ALAS project yielded workers in Winkler samples, flight intercept traps, Malaise traps, and sweep net samples. At Penas Blancas I have found foragers on the trails. At Cacao I excavated an entire nest. It was in a clay bank along the trail, at the edge of the mature forest below the station building. There were two chambers, an upper one relatively near the surface, and a lower one about 20cm deep. The upper chamber contained only small fungus masses; the lower chamber contained the colony queen and a much larger fungus mass. I scooped the contents into a plastic bag, and a few minutes later observed an adult diapriid male in the bag (I gave the specimen to Lubomir Masner that evening).

Images of a nest excavated at 1500m site (Finca Murillo) of Barva Transect, near Braulio Carrillo National Park. (12 March 2005, J. Longino collection code JTL5515)

Workers near inconspicuous nest entrance beneath leaf litter on forest floor.

Nest entrance exposed after removing leaf that partially covered entrance.

Vertical cutaway showing nest chamber. Pen is 13cm long.

Close-up of nest chamber and fungus garden.

Page author:

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

Date of this version: 25 November 2005.
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