The ring species concept revisited
(English)Manuscript (preprint) (Other academic)
Ring species may offer important insights into the role of isolation by distance in speciation. In recent years, the study of ring species has been revigorated by the application of phylogeographic methods. The concept of ring species, however, has received little attention since its original formulation in the first half of the twentieth century. A review of the two best-documented cases of putative ring species suggests that different evolutionary patterns have been referred to by the term ‘ring species’. These putative ring species share a circular colonization pattern but have fundamentally different evolutionary histories and patterns of geographic variation. Because these patterns cannot be explained by a single evolutionary model, a terminological distinction is warranted. It is suggested that the term ‘ring species’ be restricted to taxa which form a single evolutionary unit and in which the end-points have diverged as a result of isolation by distance. The new evolutionary term ‘taxon chain’ is suggested for a clade consisting of multiple evolutionary units separated by secondary contact zones. The study of ring species and taxon chains requires an integrative approach, including the description of geographic variation, phylogeographic study of historical divergence, assessment of gene flow, and study of interactions in contact zones.
circular overlaps, Ensatina, isolation by distance, Phylloscopus, speciation, taxon chain
IdentifiersURN: urn:nbn:se:su:diva-95972OAI: oai:DiVA.org:su-95972DiVA: diva2:662616