Abstract
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.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 302-314 |
| Number of pages | 13 |
| Journal | Molecular Phylogenetics and Evolution |
| Volume | 24 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2002 |
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Keywords
- Bufo americanus group
- Bufo systematics
- Call evolution
- Geographic variation
- Hybridization
- mtDNA
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Molecular Biology
- Genetics
Cite this
Molecular systematics, hybridization, and phylogeography of the Bufo americanus complex in Eastern North America. / Masta, Susan E.; Sullivan, Brian; Lamb, Trip; Routman, Eric J.
In: Molecular Phylogenetics and Evolution, Vol. 24, No. 2, 2002, p. 302-314.Research output: Contribution to journal › Article
}
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.
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
UR - http://www.scopus.com/inward/record.url?scp=0036036259&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036036259&partnerID=8YFLogxK
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 -