Phylogenetic and phylogeographic insights on Trans-Andean spectacled caiman populations in Colombia

Context. Spectacled caiman (Caiman crocodilus) is a species complex with at least eight phylogenetic lineages distributed across Central and South America. However, several populations remain unstudied, which limits a clear understanding of the relationship among lineages as well as whether all hidden diversity has been unveiled. Aim. We analysed the molecular variation of spectacled caiman populations inhabiting the Colombian Trans-Andean range based on cytochrome oxidase I (COI) and cytochrome B (CytB) mitochondrial markers. Methods. We performed phylogenetic and population genetic analysis to identify phylogeographic patterns and verify genetic variation across Trans-Andean spectacled caiman by using a dataset of 78 individuals from 15 localities across Colombia. Results. Haplotype accumulation curve estimated that our sample sizes recovered 82.68% of all unique haplotypes. Analysis of molecular variance showed that most of the genetic variation across the Trans-Andean samples collected can be explained by macro basins (49.85%), 32.45% by localities and 17.70% by intra-specific variation within populations. Conclusions. Our study confirmed that high nucleotide diversity is present in Colombian Trans-Andean spectacled caiman populations, the absence of a genetically distinguished lineage in the Choco region, as suggested by morphologic analysis, and the presence of only one molecularly well distinguished group (C. c. fuscus sensu stricto) in the in the Colombian Trans-Andean region.