Bufo spinulosus has a wide and fragmented distribution range in Chile (18° to 33° S) along altitudinal and latitudinal gradients. Genetic variation was estimated using RAPD (Random Amplified Polymorphic DNA) markers in 10 populations from northern and central Chile. Morphometric and genetic information was analyzed as a function of geographical origin. The correlation between genetic and morphometric differentiation was analyzed by the Mantel test. An increase in body size as a function of latitude was observed. Specimens from El Tatio had the smallest body size and the greatest morphometric divergence. The AMOVA applied to genetic data indicated that 57.85 % of the variance is explained by interregional differences and that 30.12 % of the variance is found within populations. Low levels of within-regions genetic differentiation was observed in northern populations while higher levels of genetic differentiation was found in populations from central Chile. Mantel tests revealed a significant, positive correlation between genetic variation and geographic distance. When we excluded El Tatio population, Mantel test analyses showed significant correlations between morphological distance and genetic and geographic distances. We discuss whether water temperature could explain the morphological divergence observed in individuals from El Tatio.
We analyze the geographic distribution pattern of Chilean amphibian and reptile species between 18°20′S (Arica) to 56°S (Magellanic Area) by the identification of centers of higher richness and endemism and we infer the biological processes that could have promoted these patterns from a biogeographic point of view, comparing our results with the present location of National Parks found in the National System of State Wildlife Protected Areas. Our results provide evidence that richness and endemism shows clear latitudinal trends along Chile, with highest values at mid-latitudes (31°S to 44°S). Five areas of endemism for phenetic analysis and six for PAE (Parsimony analysis of endemism) were found that agree with bioclimatic boundaries. We suggest that the richness and endemism patterns registered for Chilean herpetological taxa may be explained by an historical mechanism, in accordance with previous biogeographical proposals. To improve the conservation efforts for amphibians and reptiles we suggest inclusion of new protected areas at the regional level for the Mediterranean region of south-central Chile and for local northern and southern quadrats with high species richness and endemism.
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