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Misleading phylogenetic inferences based on single-exemplar sampling in the turtle genus Pseudemys
Phillip Q Spinks1, Robert C Thomson, Gregory B Pauly
1Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA. pqspinks@ucla.edu
Molecular Phylogenetics and Evolution
|April 16, 2013
Summary
Phylogenetic analyses of North American turtles (Pseudemys) suggest species boundaries are unclear and the genus may be oversplit. Single-exemplar sampling can yield conflicting evolutionary trees, highlighting the need for caution in phylogenetic interpretations.
Area of Science:
- Systematics and evolutionary biology
- Molecular phylogenetics
- Herpetology
Background:
- Reconstructing species trees is challenging with poorly defined taxa.
- Single-exemplar sampling is common but its reliability is questioned.
- The North American turtle genus Pseudemys presents long-standing phylogenetic challenges.
Purpose of the Study:
- To investigate species boundaries and phylogenetic relationships within the genus Pseudemys.
- To evaluate the impact of single-exemplar sampling on phylogenetic reconstruction.
- To assess the current species delimitation within Pseudemys.
Main Methods:
- Sequencing of 10 nuclear and 3 mitochondrial genes from 86 Pseudemys individuals.
- Population-genetic and phylogenetic analyses of molecular data.
- 100 replicated single-exemplar phylogenetic analyses to test tree robustness.
Main Results:
- Little evidence supports current species and subspecies divisions in Pseudemys, suggesting oversplitting.
- Single-exemplar phylogenetic analyses, despite high support, produced conflicting evolutionary trees.
- Phylogenetic tree topology may depend on individual sampling rather than the true species tree.
Conclusions:
- The genus Pseudemys may contain fewer species than currently recognized.
- Single-exemplar phylogenies require cautious interpretation, especially for shallowly diverged or poorly delimited species.
- Further research integrating morphology, biogeography, and extensive molecular data is needed for Pseudemys taxonomy.
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