Speciation rates vary substantially over the tree of life. These rates should be linked to the rate at which population structure forms if a continuum between micro and macroevolutionary processes exists. Previous studies examining the link between speciation rates and the degree of population formation in clades have shown both correlation and no correlation. No study has examined the relationship between speciation rates and population structure in a young group endemic to an island. We examine this correlation in 109 Gemsnakes (Pseudoxyrhophiidae) endemic to Madagascar originating in the early Miocene, thus controlling for extinction associated with time and area. We find no relationship between rates of speciation and the formation rates of population structure over space in 33 species of Gemsnakes. Rates of speciation show low variation, and population structure varying widely across species indicates that speciation rates and population structure disconnection are largely due to persistence of lineages not susceptible to extinction. Extinction can be due to many factors all of which can prevent long-term persistence of species. We discuss how delimiting populations versus species may contribute to problems understanding the continuum between shallow and deep evolutionary processes.

GBS and AHE genomic data processed for tree anf population structure inference. All data and scripts to run analyses in this paper are provided (excluding BAMM and CLaDS runs, which are run as standalones).

Need R.