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River Drainage Reorganization and Reticulate Evolution in the Two-Lined Salamander (Eurycea bislineata) Species
Todd W Pierson1, Kenneth H Kozak2, Travis C Glenn3
1Department of Ecology, Evolution, and Organismal Biology, Kennesaw State University, Kennesaw, GA 30144, USA.
Systematic Biology
|October 25, 2023
Summary
Reticulate evolution, not a simple tree, explains the complex history of the two-lined salamander species complex. River drainage changes led to gene flow and hybridization, challenging traditional taxonomy.
Area of Science:
- Evolutionary Biology
- Genetics
- Amphibian Systematics
Background:
- Biogeographic barriers and secondary contact drive complex evolutionary histories.
- The two-lined salamander (Eurycea bislineata) species complex presents a taxonomic challenge due to conflicting data.
- Previous mitochondrial DNA (mtDNA) studies suggested vicariance but couldn't assess gene flow.
Purpose of the Study:
- To investigate the reticulate evolutionary history of the Eurycea bislineata species complex.
- To resolve taxonomic discrepancies using multi-locus genetic data.
- To understand the role of paleodrainage reorganization in shaping salamander evolution.
Main Methods:
- Generated triple-enzyme restriction site-associated DNA sequencing (3RAD) data for over 100 individuals.
- Analyzed data using complementary phylogenetic and population genetic methods.
- Compared results with previous mitochondrial DNA (mtDNA) analyses.
Main Results:
- Discordance in previous datasets is explained by a reticulate evolutionary history.
- Evidence of significant gene flow and introgression among lineages.
- River drainage reorganization significantly influenced salamander population structure and gene flow.
Conclusions:
- The evolutionary history of the Eurycea bislineata complex is reticulate, not strictly bifurcating.
- Traditional phylogenetic methods are insufficient for groups with complex gene flow.
- Systematics should incorporate non-hierarchical evolutionary processes like hybridization and introgression.
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