Odontomachus ruginodis M. R. Smith 1937

Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia

worker petiole, lateral view

worker lateral view

Face view (small, large). Alternate lateral view (small, large).


West Indies, USA (Florida), Costa Rica. Costa Rica: coastal lowlands of the Atlantic coast and Osa Peninsula; La Selva; Hitoy Cerere (100m).


Face to near margin of vertex striate; first gastral tergite smooth and shining; head length 2.2-2.4mm (n=4); color variable, often in a gradient from legs to head to mesosoma to gaster, with legs light red orange, and gaster dark brown; petiolar node as seen from the side with posterior face convex to base of well differentiated dorsal spine; anterior face relatively less convex than bauri; anterior face of petiole largely smooth and shining; lateral face of petiole with feeble transverse rugae near base; posterior face of petiole weakly to more often strongly transversely rugose, usually over much of face; pronotal dorsum with striae curving mesad, becoming transverse at posterior border; pubescence on first gastral tergum suberect and relatively uniform, not wooley.

Natural History

O. ruginodis is known to occupy coastal areas in South Florida (Deyrup et al. 1985). I have made the following collections of ruginodis in Costa Rica:

Heredia: La Selva: Collected under epiphyte mat in treefall. Tree down, long-since leafless, but trunk and branches still above surrounding veg., scattered moss/epiphyte clumps still intact.

Limon: Hitoy Cerere: Primary wet forest. Nesting in rotten log.

Limon: 25km NW Cahuita: Coconut strand along beach edge.

Puntarenas: Corcovado, San Pedrillo: foragers on ground at beach edge.

Puntarenas: Corcovado, Sirena: clearing near beach. A colony was in a bed of closely-packed plant cuttings. There were wide, flat-bottomed chambers 2cm below the soil surface in a plastic bag full of potting soil. There was a short cone built on the surface of the soil. Cavities between the bases of adjacent bags contained pupae and tending adults.

Puntarenas: Corcovado, Llorona: collecting on one of the rock islands offshore, separated from land even at low tide, vegetated on top.


Brown (1976) had a very broad concept of brunneus, and considered Wheeler's (1905) ruginodis a junior synonym. Deyrup et al. (1985) recognized brunneus and ruginodis as distinct sympatric species in Florida, with brunneus being the clearly native species widespread in the southeastern USA, and ruginodis being restricted to coastal areas of southern Florida, and a possible introduction from the West Indies. With the separation of brunneus and ruginodis, the ranges of both species is now uncertain, because Brown's range for brunneus was a conflation of the two.

In Costa Rica, a similar separation of brunneus and ruginodis appears to occur. I have seen nine different collections of ruginodis from Costa Rica, which closely match specimens I have seen from coastal Florida and Jamaica. The Costa Rican specimens are often from coastal sites, and from open or disturbed inland sites. Thus, it follows a pattern in which species widespread in the caribbean are also found in coastal and anthropogenic habitats on both sides of Costa Rica. Curiously, I have seen a single specimen from Costa Rica that closely matches material of brunneus from the southern USA. This specimen was from a campsite in cleared pasture at the edge of primary rainforest, at 500m elevation in Braulio Carrillo National Park. A possible scenario, consistent with the situation in the southern USA, is that brunneus is a biogeographically older resident adapted to disturbances and to habitats otherwise marginal for most Odontomachus, and ruginodis is a newer and even weedier equivalent, originating in the caribbean, and expanding its range and abundance due to the activities of man (perhaps to the detriment of brunneus).

In Costa Rica, the two collections from more inland sites (La Selva, Hitoy Cerere) are larger and have darker heads than the remaining collections from coastal sites.

Type Data

Odontomachus haematodus var. ruginodis M. R. Smith 1937:828. Syntype worker, queen: Bahamas. First available use of Odontomachus haematodes subsp. insularis var. ruginodis Wheeler 1905:82.

Literature Cited

Brown, W. L., Jr. 1976. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section A. Introduction, subtribal characters. Genus Odontomachus. Studia Entomol. 19:67-171.

Deyrup, M., J. Trager, N. Carlin 1985. The genus Odontomachus in the southeastern United States (Hymenoptera: Formicidae). Entomological News 96:188-195.

Smith, M. R. 1937(1936). The ants of Puerto Rico. Journal of Agriculture of the University of Puerto Rico 20:819-875.

Wheeler, W. M. 1905. The ants of the Bahamas, with a list of the known West Indian species. Bull. Am. Mus. Nat. Hist. 21:79-135.

Page author:

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

Date of this version: 7 January 1999
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