Population structure of the American crocodile (crocodylus acutus) in Coiba Island, Panama, inferred from morphometric measurement and microsatellite markers



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The purpose of this project was to characterize the genetic and morphological composition of Crocodylus acutus in Coiba Island, Panama, and to infer the population structure derived from the genetic variability between the North and South region of the Island as influenced by geographic barriers and proximity to continental Panama. Multivariate analysis of variance (MANOVA) was performed to analyze the morphometric measurements. The MANOVA for the effect of sample site indicate differences between locations (P = 0.010). Regarding morphometric variables, North and South of Coiba Island overlapped in the discriminant space, but individuals in Mainland were slightly separated from the South of Coiba Island. The analysis of molecular variance (AMOVA) reported a variation among populations of 17.04%, and within populations of 82.96% with an Fst of 0.17 (P < 0.01) implying genetic structure between the populations sampled. The Bayesian analysis based on a clustering method for inferring population structure confirmed the subdivision identifying the maximum likelihood in a K = 3. Geographic barriers influenced the genetic and morphometric variation in the populations of C. acutus in Coiba Island, as confirmed by the presence of three subdivisions, the absence of immigrants and the landscape heterogeneity in the Island. This genetic structure should be considered in conservation programs.



Crocodylus acutus, Coiba Island, Microsatellites, Morphology, Population structure