Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Costa Rica, tropical South America (Lattke 1995). Costa Rica: widespread and common in moist to wet forest, to 800m.
Promesonotal suture very faintly impressed, not breaking sculpture; scapes fail to reach margin of vertex when laid back; dorsal surface of mandible smooth and shiny; propodeal dorsum transversely striate; HL less than 1.5mm; when head is seen in perfect full-face view, vertex margin straight or feebly concave in the middle; propodeum unarmed.
Gnamptogenys annulata is an arboreal ant relatively common in lowland moist to wet forest. Nests are in dead wood and under loose bark, from just above ground level to the canopy. There are few observations of foraging, but nests contain abundant chitin fragments of diverse insects, including aradid bugs, Coleoptera, and ants. I have observed workers investigating boreholes in dead logs, and I observed workers at Estacion Maritza, in the Guanacaste Conservation Area, carrying adult scolytids as prey.
I observed a nest in Corcovado National Park. It was in a rotten log, 1.5m high. I first observed a worker carrying an aradid bug nymph toward the nest. Numerous chambers in soft, rotten wood were filled with workers, teneral workers, and brood. When exposed, the ants remained motionless until I began to collect them. There was abundant chitinous debris in the nest. One of the chambers contained a dead Pheidole (cephalica?) queen. She looked fresh, recently killed. The chitinous debris included Coleoptera, aradid bug nymphs, a male ant, and a Camponotus worker.
Ectatomma (Gnamptogenys) rimulosa var. annulata Mayr 1887:543.
Lattke, J. E. 1995. Revision of the ant genus Gnamptogenys in the New World (Hymenoptera: Formicidae). Journal of Hymenoptera Research 4:137-193.
Mayr, G. 1887. Sudamerikanische Formiciden. Verhandlungen der zoologische-botanische Gesellschaft Wien 37:511-632.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.email@example.com
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