Speciation with gene flow in whiptail lizards from a Neotropical xeric biome.
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.
Pós-Graduação em Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, 59072-970, Brazil.
Eliana F
EF
Oliveira
Pós-Graduação em Sistemática e Evolução, Universidade Federal do Rio Grande do Norte, Natal, RN, 59072-970, Brazil.
Marcelo
M
Gehara
Pós-Graduação em Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, 59072-970, Brazil.
Vinícius A
VA
São-Pedro
Department of Biology, 6S-143, College of Staten Island, The City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA.|Department of Biology, The Graduate School, City University of New York, New York, NY, 10016, USA.
Xin
X
Chen
Department of Biology, 6S-143, College of Staten Island, The City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA.|Department of Biology, The Graduate School, City University of New York, New York, NY, 10016, USA.
Edward A
EA
Myers
Department of Biology, 6S-143, College of Staten Island, The City University of New York, 2800 Victory Boulevard, Staten Island, NY, 10314, USA.|Department of Biology, The Graduate School, City University of New York, New York, NY, 10016, USA.|Department of Herpetology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024-5192, USA.
Frank T
FT
Burbrink
Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, João Pessoa, PB, 58000-00, Brazil.
Daniel O
DO
Mesquita
Departamento de Botânica e Zoologia, Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, RN, 59072-970, Brazil.
Adrian A
AA
Garda
Departamento de Zoologia, Universidade de Brasília, Brasília, DF, 70910-900, Brazil.
Guarino R
GR
Colli
Departamento de Zoologia, Universidade de São Paulo, São Paulo, SP, 05422-970, Brazil.
Miguel T
MT
Rodrigues
Departamento de Zoologia, Universidade de São Paulo, São Paulo, SP, 05422-970, Brazil.
Federico J
FJ
Arias
Museu de Zoologia, Universidade de São Paulo, São Paulo, SP, 04263-000, Brazil.
Hussam
H
Zaher
Departamento de Zoologia, Universidade de São Paulo, São Paulo, SP, 05422-970, Brazil.
Rodrigo M L
RM
Santos
Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, 59072-970, Brazil.
Gabriel C
GC
Costa
D000818:Animals; D001499:Bayes Theorem; D001938:Brazil; D002467:Cell Nucleus / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D017753:Ecosystem; D051456:Gene Flow; D049810:Genetic Speciation; D014644:Genetic Variation; D006239:Haplotypes; D008116:Lizards / Q000145:classification / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D058974:Phylogeography; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial
Caatinga biome; Cnemidophorus; Miocene diversification; approximate Bayesian computation approach; coalescent methods; phylogeography