Temporal range: Late Eocene Florissant, Colorado, United States
When describing this species Carpenter (1930) commented that it “is one of the most obscure of the Florissant ants, since nothing but the more general features are known”. Unfortunately little has changed over the past 90 years and this species remains essentially unknown. While there is little rigorous data to suggest it belongs in Iridomyrmex, placement in another genus would be just as tenuous and therefore Heterick and Shattuck (2011) retained it in Iridomyrmex as incertae sedis.
This taxon was described from the United States.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- †obscurans. †Iridomyrmex obscurans Carpenter, 1930: 51 (q.) U.S.A. (Oligocene). Provisionally retained in Iridomyrmex: Shattuck, 1992a: 16. Unidentifiable taxon, incertae sedis in Iridomyrmex: Heterick & Shattuck, 2011: 168.
- Carpenter, F. M. 1930. The fossil ants of North America. Bull. Mus. Comp. Zool. 70: 1-66 PDF (page 51, queen described)
- Shattuck, S. O. 1992a. Review of the dolichoderine ant genus Iridomyrmex Mayr with descriptions of three new genera (Hymenoptera: Formicidae). J. Aust. Entomol. Soc. 31: 13-18 (page 16, Provisionally retained in Iridomyrmex)