TY - JOUR
T1 - Molecular systematics, hybridization, and phylogeography of the Bufo americanus complex in Eastern North America
AU - Masta, Susan E.
AU - Sullivan, Brian
AU - Lamb, Trip
AU - Routman, Eric J.
N1 - Funding Information:
We gratefully appreciate the help of many people who assisted in this study, either in collecting Bufo or providing valuable information as to when and where they could be found. Thanks to Jeff Davis, Matt Carll, Greg Lipps, Arthur Hulse, Dennis Buchanin, Joseph Mitchell, Kevin de Queiroz, Gordon Burghardt, Janalee Caldwell, Carla Cicero, David Wake, Craig Reading, Erik Gergus, Steve Beaupre, Paul Brunkow, John Himes, Chris Leary, and Robert Reed. Special thanks to Jay Withgott for assistance over many months of long days and even longer nights collecting toads across the country. The paper was improved by comments from three anonymous reviewers. This work was supported by a NIH-MBRS SCORE Grant #S06GM52588 to E.J.R.
PY - 2002
Y1 - 2002
N2 - We reconstruct phylogenetic relationships among a well-studied group of toads and find relationships that differ greatly from the current taxonomic understanding. We use mitochondrial sequences encoding ND1, tRNALeu(UUR), and part of 16S to infer relationships among members of the Bufo americanus complex. Focusing on the four taxa that historically have been most problematic due to morphological similarity and hybridization in sympatry, we sample 150 individuals from multiple populations across each species' geographic range. Our evidence conflicts with previous taxonomic hypotheses that were based on ability to hybridize, geographic distribution, and call variation. First, sequences from B. fowleri do not comprise the sister clade to sequences of B. woodhousii; therefore the previous classifications of B. fowleri as sister species to, or eastern subspecies of, B. woodhousii are both called into question. Second, sequences from B. americanus are more closely related to those of B. woodhousii than to those of B. terrestris, indicating that similar advertisement call characteristics evolved independently. Third, sequences of B. fowleri are paraphyletic, with sequences of B. terrestris embedded within. Lastly, sequences from B. fowleri cluster into three distinct mitochondrial clades, with some divergences corresponding to greater than 2 mya. These clades are somewhat geographically structured, suggesting divergence in allopatry during the Pleistocene. These mitochondrial divergences are not accompanied by known phenotypic differences, however, suggesting either evolutionary stasis in morphology and behavior, cryptic phenotypic evolution, or that hybridization in secondary contact has homogenized phenotypic differences that may have arisen in allopatry.
AB - We reconstruct phylogenetic relationships among a well-studied group of toads and find relationships that differ greatly from the current taxonomic understanding. We use mitochondrial sequences encoding ND1, tRNALeu(UUR), and part of 16S to infer relationships among members of the Bufo americanus complex. Focusing on the four taxa that historically have been most problematic due to morphological similarity and hybridization in sympatry, we sample 150 individuals from multiple populations across each species' geographic range. Our evidence conflicts with previous taxonomic hypotheses that were based on ability to hybridize, geographic distribution, and call variation. First, sequences from B. fowleri do not comprise the sister clade to sequences of B. woodhousii; therefore the previous classifications of B. fowleri as sister species to, or eastern subspecies of, B. woodhousii are both called into question. Second, sequences from B. americanus are more closely related to those of B. woodhousii than to those of B. terrestris, indicating that similar advertisement call characteristics evolved independently. Third, sequences of B. fowleri are paraphyletic, with sequences of B. terrestris embedded within. Lastly, sequences from B. fowleri cluster into three distinct mitochondrial clades, with some divergences corresponding to greater than 2 mya. These clades are somewhat geographically structured, suggesting divergence in allopatry during the Pleistocene. These mitochondrial divergences are not accompanied by known phenotypic differences, however, suggesting either evolutionary stasis in morphology and behavior, cryptic phenotypic evolution, or that hybridization in secondary contact has homogenized phenotypic differences that may have arisen in allopatry.
KW - Bufo americanus group
KW - Bufo systematics
KW - Call evolution
KW - Geographic variation
KW - Hybridization
KW - mtDNA
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U2 - 10.1016/S1055-7903(02)00216-6
DO - 10.1016/S1055-7903(02)00216-6
M3 - Article
C2 - 12144763
AN - SCOPUS:0036036259
VL - 24
SP - 302
EP - 314
JO - Molecular Phylogenetics and Evolution
JF - Molecular Phylogenetics and Evolution
SN - 1055-7903
IS - 2
ER -