Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
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Identification
Minor worker: head length 0.48mm, head width 0.46mm, scape length 0.38mm, Webers length 0.54mm (n=1). Head flattened to slightly excavate behind; mesonotal suture absent; humeri projecting as small tubercles, each bearing a long seta; propodeal spines short; pair of feeble, subparallel carinae on dorsum of propodeum, extending from metanotal groove to bases of spines; face largely smooth and shining, sculpture if present confined to anterior half; mesosoma foveolate with shiny patches on sides of pronotum and mesonotal dorsum; gaster smooth and shining; dorsal pilosity abundant, flexuous; color dirty yellow to brown.
Major worker: head length 0.85mm, head width 0.80mm, scape length 0.40mm (n=1). Anterior half of face with longitudinal, subparallel rugae, posterior half smooth and shining; clypeus with longitudinal median keel; hypostomal margin straight, with small, rounded median tooth, and pair of stout, sharp teeth about one third to half distance to recessed teeth flanking mandible bases; dorsal pilosity abundant; head with abundant, suberect setae projecting from sides of head in face view.
Range
Costa Rica, Mexico (type locality). Costa Rica: Atlantic and southern Pacific lowlands.
Natural History
This species occurs in mature wet forest. It is a relatively common arboreal ant, nesting in dead branches and under epiphytes. Colonies often appear large, with workers scattered over a wide area.
Selected Records
La Selva: mature wet forest; 4-day old treefall, Stryphnodendron and enormous Dipteryx.
La Selva: in thick dead snag, soft and rotten, extending from tree trunk.
Braulio Carrillo National Park (Carrillo).
10km ESE Moravia de Chirripo: 2nd growth patches surrounded by tall rainforest. Under epiphyte clump on tree trunk in forest patch.
Corcovado National Park (Sirena): mature wet forest; under epiphyte mats in canopy Sloanea.
Corcovado National Park (Sirena): mature wet forest; 20-28m high in Ficus; nesting in the root-mat of an orchid.
Corcovado National Park (Sirena): A dead branch had fallen in the center of a stream, on a bed of rocks. Attached to the side was a termite nest. At a broken end many Pheidole were milling about and recruiting to some dead beetle larvae that had been exposed and crushed by the branch fall. The Pheidole had a nest layered between the termite nest and the branch. The nest was full of males, but I never found any queens, winged or otherwise. When I began to point these specimens, I found them very oily, and it was difficult to make them stick. Could this be a defense against nasute attack?
Corcovado National Park (Sirena): in canopy Sloanea; 25m high; nesting under loose bark of a 2cm dia. dead branch.
Corcovado National Park (Sirena): A tall dead tree, largely barkless, recently fell. There were two pheidole species, I think, but they looked very similar. The darker species [umphreyi] was abundant on the surface, often entering small beetle holes. The lighter species [sagana] was found as a cluster of minors, soldiers, and brood beneath a scrap of bark that remained attached to the tree.
Corcovado National Park: Mangrove swamp at mouth of Rio Corcovado. Nesting in a 7cm dia. rotten branch suspended 1.5m high.
Corcovado National Park (Sirena): on a large, fresh branch fall from a canopy tree, Apeiba membranacea.
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
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