Cardiocondyla obscurior , full face view of a worker (click image to enlarge).
Photo courtesy of http://www.antweb.org/

Cardiocondyla obscurior full face view of a worker (click image to enlarge).
Photo courtesy of http://www.antweb.org/

Introduction
Cardiocondyla is an old world genus of omnivorous ants native to Africa and Asia.  This genus includes several common tramp species that have spread globally with human commerce.  Because of their small size, Cardiocondyla species are often overlooked.  Colonies of most species are small (<500 workers) and are typically located in soil, especially in disturbed, open habitats near rivers, roads, forest margins, or other similar areas (Seifert 2003).  However, some species also nest above ground in plant structures.  Members of this genus are not generally considered to be a pest species.

Identification
Cardiocondyla workers are small to medium in size (1.5 to 3.5 mm) and yellow to dark brown. The antenna is 11 or 12-segmented and terminates in a 3-segmented club. The clypeus is flattened with lateral portions projecting outward. The promesonotal suture is lacking. Propodeal spines may be distinct or absent. For their small size, workers have a relatively large sting. Pilosity is sparse to entirely absent on the dorsum of body.  In the southeastern United States, Temnothorax is the only genus that would be likely confused with Cardiocondyla.  Temnothorax species in this region differ by having distinct pilosity present on the dorsum of the body.  Cardiocondyla obscurior can be differentiated from the other four species of Cardiocondyla reported from the southeastern United States by its color, which is predominately yellowish brown except for the gaster, which is dark brown; its having a distinct metanotal groove, relatively short antennal scapes; and relatively long propodeal spines. It differs from the similar C. wroughtonii by its gaster being entirely dark and the spines tending to be somewhat shorter.

Original Description
Link to paper with original description by Wheeler: http://antbase.org/ants/publications/3409/3409.pdf

Biology and Economic Importance
Habitat/Nesting: Cardiocondyla obscurior has been reported to nest in cavities of trees, bushes, in dead twigs, in coconuts, and galls (Seifert, 2003).

Life Cycle: This species, similar to others in the genus, produces ergatoid males in addition to alate males.

Native Range: Asia?

Distribution
Worldwide: Canary Islands, Germany, Israel, Kenya, India, Nepal, Japan, Taiwan, Mariana Islands, Brazil, Puerto Rico, Virgin Islands (Seifert, 2003).

United States: Hawaii and Florida (Seifert, 2003). Recently, an alate female was collected in Mississippi.

Literature Cited

Seifert, B. 2003. The ant genus Cardiocondyla (Insecta: Hymenoptera: Formicidae) - a taxonomic revision of the C. elegans, C. bulgarica, C. batesii, C. nuda, C. shuckardi, C. stambuloffii, C. wroughtonii, C. emeryi, and C. minutior species groups. Ann. Naturhist. Mus. Wien. B. Bot. Zool. 104(B): 203-338.

Links

AntWeb Images
Ants of Costa Rica: Cardiocondyla obscurior Wheeler 1929
Identification Guide to Invasive Ants of the Pacific Islands: Cardiocondyla obscurior