Subfamily PONERINAE
Tribe PONERINI
Odontomachus ruginodis M. R. Smith

Odontomachus ruginodis, dorsal view of a worker (click image to enlarge).
Photo courtesy of http://www.antweb.org/

Introduction
Ants in this genus differ from other ponerine ants found in the United States by the unique head shape; peculiar mandibles, which are elongate and inserted near the center of the clypeus (see photo above); the large tapering petiole; and the large size of the workers. Members of this genus are commonly called trap-jaw ants due to their elongate mandibles, which can be opened to 180°, then snapped rapidly together on prey. These ants are amazing in their ability to control and time the mandibular movement. When necessary, an ant can forcibly close the mandibles against a surface or other organism and actually propel itself away for up to several inches! Remarkable behavior. Additionally, they can use the mandibles for much more sensitive movements such as caring for larvae or nest building.

Odontomachus ruginodis is a large, ponerine ant that occurs in southern Florida.

Taxonomic History (from Barry Bolton, 2012)
Described as Odontomachus haematodus var. ruginodis Smith, 1937; raised to species by Wilson (1964); treated as a junior synonym of O. brunneus by Brown (1976); and revived from synonymy by Deyrup et al. 1985.

Identification
Worker: (Deyrup and Cover 2004; and Deyrup et al. 1985). Color, reddish-brown to piceus to slightly bicolored with reddish-brown head and mesosoma and blackish gaster; appendages usually paler. Length approximately 7 mm. Pronotum with transverse striae posteriorly. Petiole with transverse striae on sides and posteriorly. Inner side of hind femur glabrous at base. Metasternum lacking paired, slender, acute spines between metacoxae (present in O. haematodus). Gaster with fine appressed pubescence separated by at least one-fourth the length of each hair.

Males: (from Deyrup et al. 1985)
Head and thorax yellow to yellowish-brown, gaster brownish, propodeum and lateral spot on pronotum brownish black, and antennae and legs pale yellowish-brown. Ocelli not on a conspicuous turret (as in some species), with each ocellus less than two-thirds as wide as the ocelllo-ocular space. Petiole strongly rugose laterally.

This species is small to medium sized for the genus. Workers have conspicuous transverse striae covering the entire petiole and reduced gastral pubescence. Males are yellowish with a dark spot on pronotum, dark brown propodeum, and brownish gaster. This species is similar to O. haematodus, which is larger, has paired metasternal spines, and has reduced striae on posterior portion of petiole. Males of O. haematodus are concolorous yellow.

Biology and Economic Importance
Similar to other members of this subfamily, Odontomachus workers have a prominent sting(er), and have the ability to inflict a relatively painful sting.

Distribution
West Indies, USA (southern Florida), Costa Rica. Costa Rica: coastal lowlands of the Atlantic coast and Osa Peninsula; La Selva; Hitoy Cerere (100m) (from AntWeb). According to Mark Deyrup (pers. com), this species is confined to the US to central and south Florida (Brevard, Broward, Charlotte, Collier, Dade, Glades, Hendrey, Highlands, Hillsborough, Indian River, Lee, Manatee, Martin, Monroe, Orange, Polk, Sarasoto, St. Lucie, and Volusia Counties).

Literature Cited
Bolton, B. 2012. Bolton World Catalog Ants. accessed on October 2012. [Available online: http://www.antweb.org/world.jsp]

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. and S. Cover. 2004.  A new species of Odontomachus ant (Hymenoptera:  Formicidae) from inland ridges of Florida, with a key to Odontomachus of the United States.  Florida Entomologist 87: 136-144.

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.

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