Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 0.55mm, head width 0.47mm, scape length 0.67mm, Webers length 0.66mm (n=1). Head rounded behind; mesonotal suture weakly impressed; short propodeal spines present; face and mesosoma foveolate except for smooth and shining areas on promesonotal dorsum and sides of pronotum; first gastral tergum smooth and shining; dorsal pilosity sparse, short, moderately stiff; color brown.
Major worker: head length 0.92mm, head width 0.89mm, scape length 0.66mm (n=1). Face punctatorugose throughout; hypostomal margin straight, with median tooth, and a pair of slightly larger teeth about one half distance from midline to recessed teeth flanking mandible bases (Figure); dorsal pilosity sparse; head with abundant, suberect setae projecting from sides of head in face view.
Contrast with rugiceps: minor worker with propodeal spines, and shiny patch on promesonotal dorsum equal to or greater than that on rugiceps; major worker with relatively longer, more erect setae on sides of head. These differences are slight, but the two forms are sympatric and distinct at La Selva and adjacent parts of Braulio Carrillo National Park.
Variation: minor workers from Monteverde are larger (head length 0.68mm, head width 0.57mm, scape length 0.85mm, Webers length 0.87mm [n=1]); major workers from Monteverde have variable face sculpture, often much shinier, with few or no puncta, rugae often becoming faint posteriorly, and often radiating fan-like from median area between frontal carinae.
Range
Costa Rica: Atlantic slope and montane areas.
Natural History
This species is very common in Winkler samples from mature wet forest, from 50m elevation at La Selva to cloud forest areas in the Talamancas and Monteverde. Workers have been observed on the ground at night, and at baits during the day. Nests have been observed in and under dead wood on the ground.
Selected Records
Winkler samples from Guanacaste Conservation Area (Pitilla), Volcan Arenal, Monteverde, Penas Blancas, La Selva, Braulio Carrillo to 900m, Hitoy Cerere, Cerro Pittier at 1600m, Fila Cruces near San Vito.
Page authors:
John T. Longino, The Evergreen State College, Olympia WA 98505 USA. longinoj@evergreen.edu
Stefan Cover, Museum of Comparative Zoology, Harvard University, Cambridge MA 02138 USA. scover@oeb.harvard.edu
Last modified: 2 September 2003.
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