Nigeria is an Afrotropical region with considerable ecological heterogeneity and levels of biotic endemism.Among its vertebrate fauna,reptiles have broad distributions,thus,they constitute a compelling system for asse...Nigeria is an Afrotropical region with considerable ecological heterogeneity and levels of biotic endemism.Among its vertebrate fauna,reptiles have broad distributions,thus,they constitute a compelling system for assessing the impact of ecological variation and geographic isolation on species diversification.The red-headed rock agama,Agama agama,lives in a wide range of habitats and,thus,it may show genetic structuring and diversification.Herein,we tested the hypothesis that ecology affects its genetic structure and population divergence.Bayesian inference phylogenetic analysis of a mitochondrial DNA(mtDNA)gene recovered four well-supported matrilines with strong evidence of genetic structuring consistent with eco-geographic regions.Genetic differences among populations based on the mtDNA also correlated with geographic distance. The ecologicalniche model for the matrilines had a good fit and robust performance. Population divergence alongthe environmental axes was associated with climatic conditions, and temperature ranked highestamong all environmental variables for forest specialists, while precipitation ranked highest for theforest/derived savanna, and savanna specialists. Our results cannot reject the hypothesis that nicheconservatism promotes geographic isolation of the western populations of Nigerian A. agama.Thus, ecological gradients and geographic isolation impact the genetic structure and population divergenceof the lizards. This species might be facing threats due to recent habitat fragmentation,especially in western Nigeria. Conservation actions appear necessary.展开更多
文摘Nigeria is an Afrotropical region with considerable ecological heterogeneity and levels of biotic endemism.Among its vertebrate fauna,reptiles have broad distributions,thus,they constitute a compelling system for assessing the impact of ecological variation and geographic isolation on species diversification.The red-headed rock agama,Agama agama,lives in a wide range of habitats and,thus,it may show genetic structuring and diversification.Herein,we tested the hypothesis that ecology affects its genetic structure and population divergence.Bayesian inference phylogenetic analysis of a mitochondrial DNA(mtDNA)gene recovered four well-supported matrilines with strong evidence of genetic structuring consistent with eco-geographic regions.Genetic differences among populations based on the mtDNA also correlated with geographic distance. The ecologicalniche model for the matrilines had a good fit and robust performance. Population divergence alongthe environmental axes was associated with climatic conditions, and temperature ranked highestamong all environmental variables for forest specialists, while precipitation ranked highest for theforest/derived savanna, and savanna specialists. Our results cannot reject the hypothesis that nicheconservatism promotes geographic isolation of the western populations of Nigerian A. agama.Thus, ecological gradients and geographic isolation impact the genetic structure and population divergenceof the lizards. This species might be facing threats due to recent habitat fragmentation,especially in western Nigeria. Conservation actions appear necessary.
