Formicinae, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Additional images: minor worker, lateral view of petiole (reduced, original), dorsal view of mesosoma (reduced, original).
Guatemala, Costa Rica. Costa Rica: throughout the country to about 1000m elevation.
Minor worker: propodeum with distinct pair of posteriorly projecting subtriangular spines; dorsal face of propodeum subrectangular, longer than wide in dorsal view; propodeal spines widely spaced; first gastral tergite with dense layer of appressed pubescence beneath erect setae, pubescence nearly covering integument; petiole subquadrate, not scale-like; petiole with posteriorly projecting medial spine.
This species seems to be most abundant in very open, insolated, relatively dessicating environments. It seems to be very common along coastlines; most of my collections are from beach margins and coastal strand vegetation, from both coasts. For example, during extensive collections in Corcovado National Park I found mucronatus almost exclusively along the beach, and not further inland in nearby secondgrowth vegetation. However, the species is not restricted to beach margins. I have collected it several times along the dry, dusty road to Monteverde, up to 900m elevation. At La Selva Biological Station, far from the coast, it is only moderately abundant. It is collected occasionally in canopy fogging samples, and I have collected nests in dead twigs from the high canopy and from low, open second growth vegetation.
Foragers are diurnal, and often visit extrafloral nectaries.
Nests are in dead wood, usually narrow-guage dead stems, but I have found nests in old fenceposts and in a Rhizophora stump. Along the road to Monteverde, I once found nests in two large, dead, woody nodes of Cordia alliodora. The entrance holes looked like they were originally made by Cephalotes setulifer (an obligate Cordia alliodora specialist that makes circular entrance holes in nodes) but by then were slightly irregular and elliptical. One node contained 12 workers, 2 alate queens, 7 males, and no brood. The second node contained 25 workers, 4 alate queens, 2 males, 1 dealate queen, and brood.
Emery, C. 1890. Studii sulle formiche della fauna neotropica. Bull. Soc. Entomol. Ital. 22:38-80.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.email@example.com
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