Speciation with gene flow in whiptail lizards from a Neotropical xeric biome |
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Authors: | Eliana F. Oliveira Marcelo Gehara Vinícius A. São‐Pedro Xin Chen Edward A. Myers Frank T. Burbrink Daniel O. Mesquita Adrian A. Garda Guarino R. Colli Miguel T. Rodrigues Federico J. Arias Hussam Zaher Rodrigo M. L. Santos Gabriel C. Costa |
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Affiliation: | 1. Pós‐Gradua??o em Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil;2. Pós‐Gradua??o em Sistemática e Evolu??o, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil;3. Department of Biology, 6S‐143, College of Staten Island, The City University of New York, Staten Island, NY, USA;4. Department of Biology, The Graduate School, City University of New York, New York, NY, USA;5. Department of Herpetology, American Museum of Natural History, New York, NY, USA;6. Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, Jo?o Pessoa, PB, Brazil;7. Departamento de Botanica e Zoologia, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil;8. Departamento de Zoologia, Universidade de Brasília, Brasília, DF, Brazil;9. Departamento de Zoologia, Universidade de S?o Paulo, S?o Paulo, SP, Brazil;10. Museu de Zoologia, Universidade de S?o Paulo, S?o Paulo, SP, Brazil;11. Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil |
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Abstract: | Two main hypotheses have been proposed to explain the diversification of the Caatinga biota. The riverine barrier hypothesis (RBH) claims that the São Francisco River (SFR) is a major biogeographic barrier to gene flow. The Pleistocene climatic fluctuation hypothesis (PCH) states that gene flow, geographic genetic structure and demographic signatures on endemic Caatinga taxa were influenced by Quaternary climate fluctuation cycles. Herein, we analyse genetic diversity and structure, phylogeographic history, and diversification of a widespread Caatinga lizard (Cnemidophorus ocellifer) based on large geographical sampling for multiple loci to test the predictions derived from the RBH and PCH. We inferred two well‐delimited lineages (Northeast and Southwest) that have diverged along the Cerrado–Caatinga border during the Mid‐Late Miocene (6–14 Ma) despite the presence of gene flow. We reject both major hypotheses proposed to explain diversification in the Caatinga. Surprisingly, our results revealed a striking complex diversification pattern where the Northeast lineage originated as a founder effect from a few individuals located along the edge of the Southwest lineage that eventually expanded throughout the Caatinga. The Southwest lineage is more diverse, older and associated with the Cerrado–Caatinga boundaries. Finally, we suggest that C. ocellifer from the Caatinga is composed of two distinct species. Our data support speciation in the presence of gene flow and highlight the role of environmental gradients in the diversification process. |
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Keywords: | approximate Bayesian computation approach Caatinga biome
Cnemidophorus
coalescent methods Miocene diversification phylogeography |
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