RESUMEN
This study surveyed the mitochondrial haplotype diversity of nine freshwater fish species and two estuarine-marine species from the coastal basins and drainages of the highland plateaus of Paraná, Brazil. Portions of the cytochrome b gene or the control region were sequenced. The demographic history of each species was inferred using the Bayesian skyline method, mismatch distribution analysis and statistical neutrality tests. Demographic reconstruction analyses revealed a single pattern of variation in the effective population size (Ne ) among species. No dramatic changes in Ne were detected in upland species. By contrast, evidence of population expansion over the past 200 000 years was detected in all coastal plain and estuarine species. These findings correspond to periods of low sea-level (regressions) followed by a rapid increase in the sea-level by >100 m. The resulting reconnections and subsequent fragmentation and isolation between the estuarine and freshwater bodies were putatively relevant to the historical demography of the fish species in these areas.
Asunto(s)
Estuarios , Peces/genética , Variación Genética , Filogeografía , Animales , Océano Atlántico , Secuencia de Bases , Teorema de Bayes , Brasil , Citocromos b/genética , ADN Mitocondrial/genética , Agua Dulce , Haplotipos , Dinámica PoblacionalRESUMEN
Astyanax is among the most speciose genera in the Characidae. In this study, molecular markers were used to assess the extent to which some of the commonly recognized Astyanax species of the upper Iguaçu River correspond to natural groups. These results indicate that the diversity of Astyanax has been severely underestimated with several potential cryptic species.