Abstract
Closely related taxa with dissimilar morphologies are often considered to have diverged via natural selection favoring different phenotypes. However, some studies have found these scenarios to be paired with limited or no genetic differentiation. Desmognathus quadramaculatus and D. marmoratus are sympatric salamander species thought to represent a case of ecological speciation based on distinct morphologies, but the results of previous studies have not resolved corresponding patterns of lineage divergence. Here, we use genome-wide data to test this hypothesis of ecological speciation. Population structure analyses partitioned individuals geographically, but not morphologically, into two adjacent regions of western North Carolina: Pisgah and Nantahala. Phylogenetic analyses confirmed the nominal species are nonmonophyletic and resolved deep divergence between the two geographic clusters. Model-testing overwhelmingly supported the hypothesis that lineage divergence followed geography. Finally, ecological niche modeling showed that Pisgah and Nantahala individuals occupy different climatic niches, and geographic boundaries for the two lineages correspond to differences in precipitation regimes across southern Appalachia. Overall, we reject the previous hypothesis of ecological speciation based on microhabitat partitioning. Instead, our results suggest that there are two cryptic lineages, each containing the same pair of morphotypes.
| Original language | English |
|---|---|
| Pages (from-to) | 2378-2393 |
| Number of pages | 16 |
| Journal | Evolution |
| Volume | 72 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 2018 |
Bibliographical note
Funding Information:We thank J.A. Wooten for contributing tissue samples; J.J. Apodaca for assistance with sample collection in the field; the Lemmon Lab at FSU for facilitating sequencing; the UK Information Technology Department and Center for Computational Sciences for computing time on the Lipscomb High Performance Computing Cluster; and M. Donohue, D.M. Filipek, D.K. Herrig, C.R. Linnen, Superlab, and three anonymous reviewers for providing helpful comments on the manuscript. This research was supported by a Highlands Biological Station Grant-in-aid of Research, Bruce Family Scholarship in Herpetology, Wimberly C. Royster Graduate Excellence Award of Special Distinction, Kentucky Opportunity Fellowship, Ribble Graduate Mini-Grant, Society for Systemic Biologists Graduate Student Research Award, Kentucky Academy of Sciences Marcia Athey Award, and NSF DEB-135500.
Funding Information:
K.S.J. and D.W.W. designed the study, K.S.J. conducted the study, K.S.J. and D.W.W. wrote the manuscript. We thank J.A. Wooten for contributing tissue samples; J.J. Apodaca for assistance with sample collection in the field; the Lemmon Lab at FSU for facilitating sequencing; the UK Information Technology Department and Center for Computational Sciences for computing time on the Lipscomb High Performance Computing Cluster; and M. Donohue, D.M. Filipek, D.K. Herrig, C.R. Linnen, Superlab, and three anonymous reviewers for providing helpful comments on the manuscript. This research was supported by a Highlands Biological Station Grant-in-aid of Research, Bruce Family Scholarship in Herpetology, Wimberly C. Royster Graduate Excellence Award of Special Distinction, Kentucky Opportunity Fellowship, Ribble Graduate Mini-Grant, Society for Systemic Biologists Graduate Student Research Award, Kentucky Academy of Sciences Marcia Athey Award, and NSF DEB-135500. Data and analysis files used in this study are available on Dryad: https://doi.org/10.5061/dryad.n0p44hn.
Publisher Copyright:
© 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.
Keywords
- Appalachia
- ddRAD sequencing
- ecological divergence
- niche modeling
- speciation
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Genetics
- Agricultural and Biological Sciences (all)