From the river to the ocean: mitochondrial DNA analyses provide evidence of spectacled caimans (Caiman crocodilus Linnaeus 1758) mainland–insular dispersal

There are few studies that have investigated the evolutionary history of large vertebrates on islands off the Caribbean coast of South America. Here we use the spectacled caiman (Caiman crocodilus) to investigate among- and withinpopulation patterns of genetic diversity to understand connectivity between island and mainland populations. The spectacled caiman is naturally distributed across Central and South America including the islands of Trinidad and Tobago, which are considered to have the only natural insular populations of the species. Because of this apparent isolation, we sought to determine whether caimans on Trinidad and Tobago comprise a unique lineage and have reduced genetic diversity compared to mainland caimans. We test these hypotheses by using mitochondrial DNA variation to assess the phylogenetic and phylogeographical relationships of the C. crocodilus populations inhabiting these islands within the evolutionary context of the entire spectacled caiman complex. Phyloge