Cephalotes alfaroi (Emery 1890)

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker lateral view

worker face view

Images of major worker: lateral view (reduced, original), face view (reduced, original).


Panama, Costa Rica. Costa Rica: in lowland rainforest sites throughout the country, to 500m elevation.


Minor worker: eyes situated beneath the antennal scrobe, which extends above it to the vertex margin; frontal carinae not completely covering the genae; the entire border of the frontal carinae distinctly crenulated, with short, thick, somewhat clubbed setae projecting from the notches; the outer vertex spine, if present, with a laterally projecting denticule from its base, or without an outer spine, and the lateral denticule projecting from the sides of the head; CI less than or equal to 122 (CI = 100 x head width/head length. Head width = maximum head width behind the eyes, including the vertexal spines or lamellae if present. Head length = head length measured dorsally on the sagittal plane).

Major worker: eyes situated beneath the antennal scrobe, which extends above it to the vertex margin; anterior face of pronotum and remaining dorsal surface of mesosoma separated by a row of 4 stout spines, the two surfaces each flat and meeting at an obtuse angle.

Similar species: atratus.

Natural History

This species is found in mature lowland rainforest, where it is a resident of the high canopy. It is not common, but when workers are encountered they are conspicuous because of their large size and distinctive appearance. I most often encounter workers in treefalls.

I have seen one nest of this species. It was at Sirena in Corcovado National Park, in a 1-day old treefall. The tree was large, an Inga species with blood-red sap. Cephalotes workers were scattered thinly over the tree. Many workers were clustered around a nest entrance in a 30cm diameter branch, about half-way up the tree. I cut the branch open and collected the entire contents (alive) except for very small brood. This included minors, majors, a single dealate queen, an alate queen, and many males. The nest was a baseball-sized cavity in the center of a live branch. The entrance was through a rotten knot-hole. The entrance channel was plugged by a solid mass of ants, and the inside walls of the cavity were covered with a solid layer of ants. Water had collected in the bottom of the cavity, and it looked like there was much drowning brood in the bottom. I kept the colony alive for a while, in a plastic dish. The workers moved the brood into a petri dish covered with aluminum foil. They seemed to keep a lot of liquid around the brood.

The biology of alfaroi is probably similar to that of atratus, for which there are more published observations. See under atratus for additional natural history information.

Type Data

Cryptocerus alfaroi Emery 1890:76. Syntype worker and soldier: Costa Rica, Alajuela (Alfaro) [MCSN, MHNG].

Kempf (1963) synonymized alfaroi under serraticeps. Andrade and Baroni Urbani (1999) considered serraticeps a distinct species, endemic to Brazil and Peru, and removed alfaroi from synonymy.


As of Andrade and Baroni Urbani's 1999 revision, this species was still known only from workers. I have in my collection queens and males from the Sirena collection, and an alate queen from La Selva Biological Station. Thus sexuals are available for description, should the time and opportunity present themselves. The La Selva queen is smaller than the Sirena queens, and differs in numerous other details, raising the possibility of significant geographic variation within Costa Rica.

Literature Cited

Andrade, M. L. de, and C. Baroni Urbani. 1999. Diversity and adaptation in the ant genus Cephalotes, past and present (Hymenoptera, Formicidae). Stuttgarter Beitrage zur Naturkunde Serie B (Geologie und Palaontologie) 271:1-889.

Emery, C. 1890. Studii sulle formiche della fauna neotropica. Bull. Soc. Entomol. Ital. 22:38-80.

Kempf, W. W. 1963. Nota sinonimica acerca de formigas da tribo Cephalotini (Hymenoptera, Formicidae). Rev. Bras. Biol. 23:435-438.

Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505 USA.longinoj@evergreen.edu

Date of this version: 27 June 2000
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