Evolutionary significant units within populations of neotropical broad-snouted caimans (Caiman latirostris, Daudin, 1802).

Abstract

Evolutionary significant units are an important level of biodiversity in management and conservation programs. Molecular data are considered a high priority for efficient Broad-Snouted Caiman (Caiman latirostris) conservation. In this study, we used two mitochondrial (COI and 16sRNA) and one nuclear (RAG1) molecular markers to test the hypothesis of independent evolution of geographic lineages across Brazilian river basins. We captured caimans at night and cut one or more scales from the tail for genetic analyses. We obtained genetic data from 37 C. latirostris captured between September 2012 and June 2013 from 13 locations throughout four river basins: Doce, Jequitinhonha, Paraná, and São Francisco. Clades were closely associated to river basins, supporting the presence of three distinct phylogenetic lineages within the 1) São Francisco and Jequitinhonha, 2) Doce, and 3) Paraná river basins. These lineages have been isolated probably since the rise of Pleistocene low sea levels and do not have recent gene flow. They have mtDNA reciprocal monophyly and, therefore, present compelling evidence to be considered as evolutionary significant units. Considering the hidden genetic diversity within this species, we recommend conservation efforts for all three independent units within C. latirostris.