Myrmicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Above images are from Barva Transect, Braulio Carrillo National Park, 2000m site, Berlese sample of epiphytic material. Additional images are worker from 1830m, nest under epiphytes (face view, lateral view); and worker from 1070m, nest under epiphytes (face view, lateral view). Note dramatic difference in sculpture at lower elevation. Also notice weak development of mandible notch on 2000m specimen.
Discussion of schmidti complex (click here).
Range
Panama, Costa Rica. Costa Rica: Cordilleras above 1100m.
Identification
Basal margin of mandible flat, without a notch, or with very faint development of notch; anterior clypeal margin transverse, anteromedian portion not extending beyond rounded lateral lobes, downturned portion with small median notch; sculpture on face and mesosoma faint to strong; dorsal face of propodeum rounding into posterior face, not forming angle or tooth; WL about 1mm.
Similar species: Stenamma JTL-006.
Natural History
This species is an arboreal cloud forest specialist. It occurs at relatively high elevation, including the highest ridge crests of Monteverde, 2000m on Volcan Barba, and 2400m on Cerro Gemelo in the Cordillera de Talamanca.
The nests are relatively common under small epiphyte mats on small branches. It seems to prefer small isolated epiphyte patches on small-guage stems, rather than large contiguous mats. In Monteverde and on Volcan Barba, I have been able to predictably collect nests by searching under small epiphyte clumps out on smaller branches, rather than under the large mats on larger branches. This is in contrast to Stenamma JTL-006, for which I do not find nests but I do find workers if I sift crown humus from the larger mats.
Comments
The general habitus of this species if much like schmidti and JTL-006, and if the mandibles are closed it can be very difficult to distinguish from JTL-006. Its relationship to the schmidti complex is suggested not only by the general habitus but by the occasional presence of a very faintly developed mandibular notch. Unlike schmidti and JTL-006, the anteromedian clypeal margin is less protruding, and the downturned portion has a small median notch. The compound eyes are larger than the eyes of schmidti and JTL-006. Like JTL-006 it has weak to absent gastral pubescence, and the face may be completely punctatorugose or partially smooth and shiny. The mesosoma in lateral view is generally more gracile than other forms, with no propodeal tubercles.
Literature Cited
Page author:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu
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