Pheidole bilimeki Mayr, 1870

Pheidole bilimeki is a member of the Neotropical P. punctatissima clade, together with P. anastasii and P. punctatissima (Economo et al. 2015). Among species treated here, it is easily confused with the aforementioned and members of the P. flavens complex. Minor workers can also be confused with those of P. parva. See section under P. anastasii for identification notes. In the southeastern United States, P. bilimeki is often confused with P. floridana Emery, which is discussed in more detail below. In the Neotropics, there are many native species that closely resemble P. bilimeki (Wilson 2003).

            We propose the synonymy of P. lauta Wheeler to be transferred from P. floridana to P. bilimeki. In his original description Wheeler (1908c) wrote, “…the worker has the base of the gaster opaque whereas this is shining in the specimen of floridana given me by Prof. Emery.” The description and the photographs we have examined of the type specimens all agree with the concept of P. bilimeki used here and in Longino and Cox (2009).

Should P. floridana therefore be synonymized under P. bilimeki? Wilson (2003) offered that the former might represent the northernmost population of the latter, and recent phylogenetic analyses (Economo et al. 2015; Moreau 2008) show these two as sibling taxa. Based on the results of her analysis, Moreau (2008) found that her samples of P. bilimeki (Costa Rica, RA0162) and putative P. floridana (Florida, RA0331) were each other’s closest relatives, and that this pair was sister to P. anastasii (Costa Rica). The result is also supported by Economo et al. (2015), which found a shallow divergence separating P. bilimeki from putative P. floridana, especially compared to the deep divergence separating these sister taxa from P. anastasii. Moreau (2008) concluded that in order for P. anastasii to be a valid member of P. bilimeki, as proposed by Wilson (2003), P. floridana would also have to be accepted as a synonym of P. bilimeki.

We suggest that this conundrum stems from the common misapplication of the name P. floridana (a shiny gaster species) to collections of what are in fact the North American population of P. bilimeki (a matte gaster species). Naves (1985) came to a similar conclusion in his revision of the Pheidole of Florida, “P. floridana seems to be confined to southeast Florida in the Miami area. This is the only place where I was able to locate this species. Due to its close relationship to P. anastasii the latter has been misidentified as P. floridana many times, thus, mistakenly extending the supposed range of P. floridana. P. anastasii is actually the species widely distributed in Florida, while floridana is absent or at least must be rare in most of the state.”

One explanation for the confusing phylogenetic results is that RA0331 actually refers to P. bilimeki Mayr, and that true members of P. floridana Emery from the Miami area were not included in the aforementioned phylogenetic analyses. The samples of RA0331 were collected in central Florida from Polk County, well outside the Miami area from which the P. floridana Emery is known (Naves 1985). Deyrup, who collected and identified the specimens of RA0331, has previously (2003; 1988; 1989) applied the name P. floridana to matte gaster specimens that earlier authors (Naves 1985; Smith 1933; Wheeler 1932) would have considered P. anastasii Emery, and that we consider P. bilimeki Mayr.

To properly ascertain the taxonomic status of P. floridana Mayr we suggest a future phylogenetic analysis that includes specimens matching the type material of P. floridana, preferably from the Miami area. If there is evidence supporting the conspecificity of samples matching our concept of P. bilimeki, then the validity of P. floridana Emery must be revaluated. If, rather, the P. floridana samples are heterospecific with respect to P. bilimeki, then there are at least two hypotheses that could explain this result. One is that P. floridana is endemic to Florida. The second, perhaps more compelling albeit ironic explanation, would propose the Miami population of P. floridana is conspecific with a Neotropical species inadvertently introduced to Florida. Miami is a major shipping port and was the gateway for many introduced ants over the past two centuries (Deyrup et al. 2000).