Stenamma JTL-006 Longino ms.

Myrmicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker lateral view

worker face view

Above images are from Barva Transect, Braulio Carrillo National Park, 1070m site, Winkler sample from forest floor. Additional images are worker from the same site, but from a nest under epiphytes (face view, lateral view); and a worker from 2000m site, hand collected from humus on a rotten log (face view, lateral view). Note that the two collections from the 1070m site appear radically different, like two different species, and they were in different microhabitats, yet the specimen from the 2000m site is precisely intermediate in characters.

Discussion of schmidti complex (click here).


Panama, Costa Rica. Costa Rica: throughout country in wet forest, sea level to 1500m.


Basal margin of mandible usually with notch, formed by sinuous indentation of basal margin and small denticle on proximal edge of notch (notch absent in Osa population); anterior clypeal margin with convex median lobe that extends to or beyond lateral clypeal teeth, downturned portion of anterior clypeus straight between lateral teeth, without indentation or median teeth; size small (WL less than 1mm); face with faint to strong sculpture over most of surface; erect setae on mesomal dorsum and first gastral tergite moderately to strongly stiffened; first gastral tergite lacking abundant appressed pubescence beneath erect setae.

Similar species: Stenamma schmidti, Stenamma JTL-017.

Natural History

This species inhabits a variety of forest types from lowland rainforest to upland cloud forest. It is widespread, occurring in both Atlantic and Pacific slope lowland rainforest. Workers and queens are most often collected in Winkler samples of sifted leaf litter and Berlese samples. At La Selva, Chris Thompson found a small nest in a dead stick in the leaf litter. In the Monteverde cloud forest It is common in Winkler samples of canopy humus and in canopy fogging samples. There seems to be a microhabitat shift across elevation. It occurs on the ground at low elevation, arboreally in cloud forest, and then back on the ground again in the narrow strip of moist forest on the Pacific side of the Monteverde cloud forest.


Literature Cited

Page author:

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

Date of this version: 29 September 2004.
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