LBNL-58663 A Molecular Assessment of Phylogenetic Relationships and Lineage Diversification Within the Family Salamandridae (Amphibia, Caudata) A Molecular Assessment of Phylogenetic Relationships and Lineage Diversification Within the Family Salamandrida

Abstract Phylogenetic relationships among species of the salamander family Salamandridae are investigated using nearly 3000 nucleotide bases of newly reported mitochondrial DNA sequence data from the mtDNA genic region spanning the genes tRNA Leu -COI. This study uses nearly comprehensive species-level sampling to provide the first complete phylogeny for the Salamandridae. Deep phylogenetic relationships among the three most divergent lineages in the family -Salamandrina terdigitata, a clade comprising the "True" salamanders, and a clade comprising all newts except S. terdigitata -are difficult to resolve

A Molecular Assessment of Phylogenetic Relationships and Lineage Diversification Within the Family Salamandridae (Amphibia, Caudata)

Phylogenetic relationships among species of the salamander family Salamandridae are investigated using nearly 3000 nucleotide bases of newly reported mitochondrial DNA sequence data from the mtDNA genic region spanning the genes tRNALeu-COI. This study uses nearly comprehensive species-level sampling to provide the first complete phylogeny for the Salamandridae. Deep phylogenetic relationships among the three most divergent lineages in the family Salamandrina terdigitata, a clade comprising the "True" salamanders, and a clade comprising all newts except S. terdigitata are difficult to resolve. However, most relationships within the latter two lineages are resolved with robust levels of branch support. The genera Euproctus and Triturus are statistically shown to be nonmonophyletic, instead each contains a diverse set of lineages positioned within the large newt clade. The genus Paramesotriton is also resolve as a nonmonophyletic group, with the newly described species P. laoensis constituting a divergent lineage placed in a sister position to clade containing all Pachytriton species and all remaining Paramesotriton species. Sequence divergences between P. laoensis and other Paramesotriton species are as great as those comparing P. laoensis and species of the genera Cynops and Pachytriton. Analyses of lineage diversification across the Salamandridae indicate that, despite its exceptional diversity, lineage accumulation appears to have been constant across time, indicating that it does not represent a true species radiation

A molecular assessment of phylogenetic relationships and lineage accumulation rates within the family Salamandridae (Amphibia, Caudata)

We examine phylogenetic relationships among salamanders of the family Salamandridae using approximately 2700 bases of new mtDNA sequence data (the tRNA(Leu), ND1, tRNA(Gln), tRNA(Gln), tRNA(Met), ND2, tRNA(Trp), tRNA(Ala), tRNA(Asn), tRNA(Cys), tRNA(Tyr), and Cot genes and the origin for light-strand replication) collected from 96 individuals representing 61 of the 66 recognized salamandrid species and outgroups. Phylogenetic analyses using maximum parsimony and Bayesian analysis are performed on the new data alone and combined with previously reported sequences from other parts of the mitochondrial genome. The basal phylogenetic split is a polytomy of lineages ancestral to (1) the Italian newt Salamandrina terdigitata, (2) a strongly supported clade comprising the “true” salamanders (genera Chioglossa, Mertensiella, Lyciasalamandra, and Salamandra), and (3) a strongly supported clade comprising all newts except S. terdigitata. Strongly supported clades within the true salamanders include monophyly of each genus and grouping Chioglossa and Mertensiella as the sister taxon to a clade comprising Lyciasalamandra and Salamandra. Among newts, genera Echinotriton, Pleurodeles, and Tylototriton form a strongly supported clade whose sister taxon comprises the genera Calotriton, Cynops, Euproctus, Neurergus, Notophthalmus, Pachytriton, Paramesotriton, Taricha, and Triturus. Our results strongly support monophyly of all polytypic newt genera except Paramesotriton and Triturus, which appear paraphyletic, and Calotriton, for which only one of the two species is sampled. Other well-supported clades within newts include (1) Asian genera Cynops, Pachytriton, and Paramesotriton, (2) North American genera Notophthalmus and Taricha, (3) the Triturus vulgaris species group, and (4) the Triturus cristatus species group; some additional groupings appear strong in Bayesian but not parsimony analyses. Rates of lineage accumulation through time are evaluated using this nearly comprehensive sampling of salamandrid species-level lineages. Rate of lineage accumulation appears constant throughout salamandrid evolutionary history with no obvious fluctuations associated with origins of morphological or ecological novelties. (c) 2006 Elsevier Inc. All rights reserved