Cariridris

Known from a single species, which is the oldest known fossil ant.

Note that Dlussky & Rasnitsyn (2003) treated this genus (and its sole species) as belonging to the family Sphecidae rather than Formicidae. They state: C. bipetiolata as described and figured by Brandão et al. (1989) looks very similar to an unnamed Santana fossil kept at the American Museum Natural History (New York, New York, USA) and described as belonging to either Sphecidae (Ampulicinae) or Dryinidae (Darling, Sharkey, 1990). One of us (APR) jointly with W.J. Pulawski of the California Academy of Sciences (San Francisco, California, USA) have studied that fossil (AMNH 44108) and found it belonging to Sphecidae (probably to subfamily Ampulicinae) rather than to Formicidae. That is why we maintain here our earlier conclusion that Cariridris is a genus of Sphecidae (Rasnitsyn, 1990; Dlussky, 1998).

Dlussky (2012) followed the treatment of Dlussky and Rasnitsyn (2003) and considered this genus to be incertae sedis in Ampulicidae. However, it appears he was unaware of the specimens examined by Osten (2007) (as he does not cite this paper). Osten's taxonomic placement is followed here, with the genus placed back within the Formicidae and in the subfamily Myrmeciinae (see Cariridris bipetiolata for details).

Distribution
This taxon is known from.

Nomenclature

 * † [Myrmeciinae]
 * †Cariridris Brandão & Martins-Neto, 1990: 201. Type-species: †Cariridris bipetiolata, by original designation.

Taxonomic history

 * †Cariridris incertae sedis in Myrmeciinae: Brandão & Martins-Neto, 1990: 203; Brandão, 1991: 336; Bolton, 1994: 73; Bolton, 1995b: 23.
 * †Cariridris incertae sedis in Formicidae: Bolton, 2003: 263.
 * †Cariridris as genus: all authors.
 * †Cariridris excluded from Formicidae, incertae sedis in Hymenoptera, Aculeata: Grimaldi, et al. 1997: 7; Ward & Brady, 2003: 362.
 * †Cariridris excluded from Formicidae, transferred to Sphecidae: Verhaagh, 1996: 11.
 * †Cariridris excluded from Formicidae, incertae sedis in Ampulicidae: Rasnitsyn, 2002: 249; Dlussky & Rasnitsyn, 2002: 418; Dlussky, 2012: 288 (in text).
 * †Cariridris in Myrmeciinae: Osten, 2007: 353.