River drainage reorganization and reticulate evolution in the Two-Lined Salamander (Eurycea bislineata) species complex

Todd W Pierson; Kenneth H Kozak; Travis C Glenn; Benjamin M Fitzpatrick

doi:10.1093/sysbio/syad064

River drainage reorganization and reticulate evolution in the Two-Lined Salamander (Eurycea bislineata) species complex

Syst Biol. 2023 Oct 25:syad064. doi: 10.1093/sysbio/syad064. Online ahead of print.

Authors

Todd W Pierson¹, Kenneth H Kozak², Travis C Glenn³, Benjamin M Fitzpatrick⁴

Affiliations

¹ Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, Kennesaw, GA 30144, USA.
² Bell Museum and Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, Saint Paul, MN 55108, USA.
³ Department of Environmental Health Science and Institute of Bioinformatics, University of Georgia, Athens, GA 30609, USA.
⁴ Department of Ecology and Evolutionary Biology, University of Tennessee Knoxville, Knoxville, TN 37996, USA.

PMID: 37879625
DOI: 10.1093/sysbio/syad064

Abstract

The origin and eventual loss of biogeographic barriers can create alternating periods of allopatry and secondary contact, facilitating gene flow among distinct metapopulations and generating reticulate evolutionary histories that are not adequately described by a bifurcating evolutionary tree. One such example may exist in the two-lined salamander (Eurycea bislineata) species complex, where discordance among morphological and molecular datasets has created a "vexing taxonomic challenge". Previous phylogeographic analyses of mitochondrial DNA (mtDNA) suggested that the reorganization of Miocene paleodrainages drove vicariance and dispersal, but the inherent limitations of a single-locus dataset precluded the evaluation of subsequent gene flow. Here, we generate triple-enzyme restriction site-associated DNA sequencing (3RAD) data for >100 individuals representing all major mtDNA lineages and use a suite of complementary methods to demonstrate that discordance among earlier datasets is best explained by a reticulate evolutionary history influenced by river drainage reorganization. Systematics of such groups should acknowledge these complex histories and relationships that are not strictly hierarchical.

Keywords: Plethodontidae; amphibian; hybridization; introgression; stream capture.