Pyramica microthrix (Kempf 1975)

Dacetini, Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view

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


Full Range: Costa Rica, Colombia.

Costa Rican Range: Atlantic slope from sea level to 1600m.


Mandibles in side view straight, not broadly curved ventrally; mandibles relatively short, subtriangular, much of the apical portion meeting along a serially toothed masticatory margin when closed (former Smithistruma); head relatively broad, CI 77-83; color red-brown to black; leading edge of the scape with entirely anteriorly directed short spatulate hairs; face punctate; sides of posterior half of mesosoma completely and densely punctulate; disc of postpetiole reticulate-punctate; ventral petiolar appendages entirely obsolete or present as very fine cariniform vestiges; infradental lamellae of propodeum vestigial or narrow and concave; gaster with 0-4 filiform (not spoon-shaped) erect setae; face lacking erect setae or with extremely inconspicous, short, subdecumbent setae. There is complex character variation. Also see Bolton (2000:222).

Very similar to two other species: cassicuspis and stauroma. Both of these have a stubble of short setae covering the face.

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. Workers are found in leaf litter on the forest floor. Most collections are from Winkler samples of sifted leaf litter, but one collection is of two workers in a rotten stick in the leaf litter.

Original Description

Smithistruma microthrix Kempf 1975:422, figs. 11, 12. Holotype worker: Costa Rica, Rio Toro Amarillo vic. Guapiles, 26 Feb. - 9 Mar. 1966 (W. L. Brown) [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.

Kempf, W. W. 1975 ("1974"). Report on Neotropical Dacetine ant studies (Hymenoptera: Formicidae). Rev. Bras. Biol. 34:411-424.

Page author:

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

Date of this version: 7 May 2001
Previous versions of this page: 4 March 1997, 13 August 1997
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