Eurhopalothrix floridana
Eurhopalothrix floridana is a small (~2.5 mm) brownish red ant with a triangular head, 7-segmented antennae, deep antennal scrobes, small eyes, triangular mandibles, distinctive appressed spatulate hairs and no spongiform. Although described from Florida relatively recently, there is broad speculation that it is not native to Florida or any other part of North America north of Mexico (Brown & Kempf, 1960; Deyrup, 1991; Deyrup et al., 2000; Deyrup et al., 1997). Eurhopalothrix species are predatory, and observations of one species suggest that these ants may be somewhat specialized predators of termites (Wilson & Brown, 1985).
Deyrup et al. (1997) argued that E. floridana is actually fairly common in Florida, and are skeptical that it could have remained undetected for so long if the species was native. They point out that the species is unknown from the West Indies, from where almost all of Florida’s tropical ant fauna is derived. The authors also present arguments for its status as a native species, including its cryptic nature, low tolerance for disturbed habitats and capacity for surviving in xeric conditions. The discovery of a specimen from Key West collected in 1887 makes for inconclusive evidence of native status, as Key West was a thriving commercial port during that time which received many shipments of exotic horticultural plants from Mexico.
Diagnosis of worker among Antkey species. Head shape triangular. Antenna 7-segmented. Antennal club 2-segmented. Antennal scapes not conspicuously short; easily extended beyond eye level. Antennal scrobe present and deeply excavated. Eyes small (less than 5 facets), situated on upper margin of scrobe. Frontal lobes do not obscure face outline between mandible and eye. Posterolateral corners of head unarmed, without spines. Mandibles triangular. Pronotal spines absent. Propodeum armed with spines. Waist 2-segmented. Spongiform not attached to any portion of waist. Color brownish red. Abundant ground pilosity characterized by small whitish appressed spatulate hairs.
Among Antkey species, Eurhopalothrix floridana is most likely to be confused with Strumigenys species that have triangular mandibles, such as S. margaritae and S. membranifera. However, E. floridana is easily separated from these by its 7-segmented antennae ( versus 6-segmented in Strumigenys), eye that is situated on the upper margin of the antennal scrobe (versus lower margin in Strumigenys), and lack of spongiform on either waist segment.
Native range. Unknown, but likely includes Mexico (Deyrup et al., 1997).
Introduced range. Florida population is likely introduced (Deyrup et al., 1997).