Proceratium micrommatum (Roger 1863)

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker face view

worker lateral view


Honduras, Costa Rica, Panama, Colombia, Venezuela. Costa Rica: Atlantic and southern Pacific lowlands.


Petiolar node "bun-shaped," broad at the base, with anterior and posterior faces converging to a rounded summit; mid-tibia lacking a pectinate apical spur; mesosoma relatively more elongate and less convex compared to convexiceps; size smaller than panamense (WL less than 0.95mm).

Similar species: convexiceps, panamense.

Natural History

The genus Proceratium comprises mostly rare and cryptic ants of leaf litter and soil, distributed throughout the world in both tropical and temperate zones (Baroni Urbani and de Andrade 2003). Some species of the genus are known to be specialized predators of spider eggs (Brown 1980).

In Costa Rica this species is known from lowland wet forest. The species is encountered as isolated workers in sifted leaf litter samples from the forest floor.


A much broader concept of micrommatum was adopted by Ward (1988). Baroni Urbani and de Andrade (2003) took a more fine scale view, splitting micrommatum into multiple species. The three Costa Rican species micrommatum, convexiceps, and panamense are very similar and key next to each other in Baroni Urbani and de Andrade.

Type data

Sysphingta micrommata Roger 1863:176. Syntype worker: South America.

Literature Cited

Baroni Urbani, C., and M. L. de Andrade. 2003. The ant genus Proceratium in the extant and fossil record (Hymenoptera: Formicidae). Museo Regionale di Scienze Naturali-Torino, Torino, Italy.

Brown, W. L., Jr. 1980 ("1979"). A remarkable new species of Proceratium, with dietary and other notes on the genus (Hymenoptera: Formicidae). Psyche (Camb.) 86:337-346.

Roger, J. 1863. Die neu aufgefuehrten Gattungen und Arten meines Formiciden-Verzeichnisses nebst Ergaenzung einiger frueher gegebenen Beschreibungen. Berl. Entomol. Z. 7:131-214.

Ward, P. S. 1988. Mesic elements in the western Nearctic ant fauna: taxonomic and biological notes on Amblyopone, Proceratium, and Smithistruma (Hymenoptera: Formicidae). J. Kansas Entomol. Soc. 61:102-124.

Page author:

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

Date of this version: 23 December 2005.
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