Morphological homoplasy, life history evolution, and historical biogeography of plethodontid salamanders inferred from complete mitochondrial genomes
The evolutionary history of the largest salamander family (Plethodontidae) is characterized by extreme morphological homoplasy. Analysis of the mechanisms generating such homoplasy requires an independent, molecular phylogeny. To this end, we sequenced 24 complete mitochondrial genomes (22 plethodontids and two outgroup taxa), added data for three species from GenBank, and performed partitioned and unpartitioned Bayesian, ML, and MP phylogenetic analyses. We explored four dataset partitioning strategies to account for evolutionary process heterogeneity among genes and codon positions, all of which yielded increased model likelihoods and decreased numbers of supported nodes in the topologies (PP > 0.95) relative to the unpartitioned analysis. Our phylogenetic analyses yielded congruent trees that contrast with the traditional morphology-based taxonomy; the monophyly of three out of four major groups is rejected. Reanalysis of current hypotheses in light of these new evolutionary relationships suggests that (1) a larval life history stage re-evolved from a direct-developing ancestor multiple times, (2) there is no phylogenetic support for the ''Out of Appalachia'' hypothesis of plethodontid origins, and (3) novel scenarios must be reconstructed for the convergent evolution of projectile tongues, reduction in toe number, and specialization for defensive tail loss. Some of these novel scenarios imply morphological transformation series that proceed in the opposite direction than was previously thought. In addition, they suggest surprising evolutionary lability in traits previously interpreted to be conservative.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Biological and Environmental Research; National Science Foundation Postdoctoral Fellowship, AmphibiaTree Project NSF EF-0334939, National Institutes of Health Training Grant (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 840044
- Report Number(s):
- LBNL-55249; R&D Project: 626849; TRN: US200509%%773
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 101, Issue 384; Other Information: Submitted to Proceedings of the National Academy of Sciences of the United States of America: Volume 101, No.384; Journal Publication Date: 09/21/2004; PBD: 1 Aug 2004
- Country of Publication:
- United States
- Language:
- English
Similar Records
Molecular mechanisms of extensive mitochondrial gene rearrangementin plethodontid salamanders
Homoplasy in genome-wide analysis of rare amino acid replacements: the molecular-evolutionary basis for Vavilov's law of homologous series