Population structure and phylogeography of tucuxi dolphins (sotalia fluviatilis)

Here we consider the phylogeography and population structure of the tucuxi dolphin Sotalia fluviatilis, based on samples (n = 26) collected across the Peruvian, Colombian and Brazilian Amazon Regions. Fourteen control region (CR) and two cytochrome b (Cyt-b) haplotypes were identified among these samples. The Amazonian population units identified showed high mitochondrial haplotype diversity and relatively high female mediated gene flow when compared to Sotalia guianensis and another Amazonian dolphin species, Inia geoffrensis throughout the sampled regions of the main river and its tributaries. A Union of Maximum Parsimonious Trees analysis generated a CR haplotype genealogy reflecting connectivity among sampled regions and identified divergent haplotypes found in the extremes of the species distribution. These results indicate the need to maintain connectivity between populations along the Amazon River and its tributaries as a main objective of management and conservation programs for Sotalia fluviatilis.