Data from: What have been and what can be delimited as species using molecular data under the multi-species coalescent model? A case study using Hercules beetles (Dynastes; Dynastidae)

Molecular species delimitation using the multi-species coalescent model has become common for statistically and objectively determining species limits. Empirical examples of how consistently different molecular data sets delimit the same level of divergence as species using coalescent-based methods are still lacking. I applied the method of molecular species delimitation in the Bayesian Phylogenetics and Phylogeography (BPP) program to study species delimitation in the divergence between populations and between putative species across four species of Hercules beetles. The quantity and variability of the molecular data affected species delimitation. A divergence that represented a late stage along the speciation continuum, e.g. between sympatric biological species, could be delimited by BPP by fewer and less variable loci than a recent divergence, e.g. between geographic populations. My results further indicated that the use of genomic data could even over-split geographically continuously distributed populations into species. I compared my results with those from other empirical studies and argue for the need of a thorough review of the kind of evolutionary entities, e.g. geographic populations versus morphologically distinct taxa, that have been designated as species and whether such designations are consistent among studies.