Suggested synonym:
= Pheidole sagana Wheeler 1934
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 (Figure); dorsal pilosity abundant; head with abundant, suberect setae projecting from sides of head in face view.
Range
Costa Rica, Mexico. 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.
Comments
Wilson (2003) examined the lectotype major of this species. For locality he put "Puerto Jimenez, Osa Peninsula," but this is probably an error. We are not certain if that town existed in the late 1800's, and it was not one of Alfaro's standard collecting localities. In contrast, Jimenez, near present day Guapiles on the Atlantic slope, was an Alfaro collecting site. It is the type locality for many Neotropical ants, probably including nitidicollis.
Based on Wilson's illustrations and text, we are not convinced there is a difference between Emery's nitidicollis and Wheeler's sagana.
Literature Cited
Wilson, E. O. 2003. Pheidole in the New World: A Dominant, Hyperdiverse Ant Genus. Harvard University Press, Cambridge, Mass
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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