Pyramica trieces (Brown 1960)

Dacetini, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

Line drawing of face view of worker and, at lower right, anterior view of apical fork of mandible (image).


Full Range: Nicaragua to Panama.

Costa Rican Range: Atlantic slope from sea level to 1000m, extending over Cordillera de Tilaran and Guanacaste in wet to moist forest.


Mandibles in full-face view linear, elongate and narrow; ventral surface of petiole without spongiform tissue; leading edge of scape with freely projecting hairs; inner margin of mandible without a tooth or distinctly enlarged denticle at or near the midlength; labral lobes short, trigger hairs at apices of lobes long; outer margins of mandibles relatively straight; mandibles short and thick, with inner margin convex; mandible with exactly 3 small preapical teeth; ground pilosity of head nearly or quite obsolete. Also see Bolton (2000:194).

Head length 0.57-0.62mm, mandible length 0.27-0.30, CI 77-82, MI 46-52 (n=10 workers, Bolton 2000).

Similar species: gundlachi, subedentata, eggersi.

Natural History

Members of the genus are all predaceous, with a static pressure mode of attack (Bolton 1999).

This species occurs in mature wet forest habitats. It nests in dead wood on the forest floor. Workers forage in the leaf litter.

Selected Records

Winkler samples from La Selva, Braulio Carrillo National Park to 1000m, Rara Avis, Hitoy Cerere, Turrialba, Penas Blancas Valley.

La Selva: Chris Thompson study, numerous colonies in dead wood on ground.

Original Description

Strumigenys trieces Brown 1960:50, fig. 8. Holotype worker: Costa Rica, no locality data, 18.vii.1931 (F. Nevermann) [MCZC].

Later moved to Pyramica. See Bolton (2000) for complete synonymy.

Literature Cited

Bolton, B. 1999. Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae). J. Nat. Hist. 33:1639-1689.

Bolton, B. 2000. The ant tribe Dacetini, with a revision of the Strumigenys species of the Malagasy Region by Brian L. Fisher, and a revision of the Austral epopostrumiform genera by Steven O. Shattuck. Memoirs of the American Entomological Institute 65:1-1028.

Brown, W. L., Jr. 1960 (1959). The neotropical species of the ant genus Strumigenys Fr. Smith: Group of gundlachi (Roger). Psyche 66:37-52.

Page author:

John T. Longino, The Evergreen State College, Olympia WA 98505

Date of this version: 7 May 2001
Previous versions of this page: 16 April 1997
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