DNA barcoding reveals species level divergence between populations of the microhylid frog genus Arcovomer (Anura: Microhylidae) in the Atlantic Rainforest of southeastern Brazil

Abstract

The microhylid frogs belonging to the genus Arcovomer have been reported from lowland Atlantic Rainforest in the Brazilian states of Espírito Santo, Rio de Janeiro, and São Paulo. Here, we use DNA barcoding to assess levels of genetic divergence between apparently isolated populations in Espírito Santo and Rio de Janeiro. Our mtDNA data consisting of cytochrome oxidase subunit I (COI) nucleotide sequences reveals 13.2% uncorrected and 30.4% TIM2 + I + Γ corrected genetic divergences between these two populations. This level of divergence exceeds the suggested 10% uncorrected divergence threshold for elevating amphibian populations to candidate species using this marker, which implies that the Espírito Santo population is a species distinct from Arcovomer passarellii. Calibration of our model-corrected sequence divergence estimates suggests that the time of population divergence falls between 12 and 29 million years ago.

• Candidate species
• COI calibration
• cryptic species
• Mitochondrial DNA
• molecular clock
• phylogeography

Acknowledgements

José Pombal, Jr. (MN/UFRJ) provided helpful comments on the manuscript. We are grateful to Marcelo Weksler (UNIRIO and MN/UFRJ) for considerable help with laboratory maintenance. We also thank Piero Ruschi (MNRJ/UFRJ) for his laboratory assistance and to Nadjha Vieira (Ecotrópica Ambiental) for providing administrative assistance to this project.

Declaration of interest

Funding for this study was provided by PETROBRAS (Contract 0802.0081462.13.3). W. Bryan Jennings’ research is funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Grant numbers 311755/2011-9 and 564940/2010-0) and by Fundação de Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ, Grant number E-26/111.404/2012). Paulo A. Buckup’s research is supported by CNPq (Grant numbers 564940/2010-0, 476822/2012-2, and 307610/2013-6) and FAPERJ (E-26/111.404/2012). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.