Genetic variability in tropical and temperate populations of Trapeliopsis glaucolepidea: Evidence against long-range dispersal in a lichen with disjunct distribution

摘要

The squamulose lichen Trapeliopsis glaucolepidea displays a widely disjunct distribution in Europe, East Africa, tropical America, and New Guinea. Using ITS sequences from 38 European and 31 Latin American individuals, we compared the genetic variability within and among populations of this species. Specifically, we addressed the questions whether recur-rent genetic exchange occurs between Latin America and Europe, whether there are signs of historical long-range dispersal, whether genetic variability is higher in tropical than in temperate populations, and whether the separation of T. glaucolepidea and T percrenata is supported by genetic characters. Intercontinental gene flow seems to be absent and there are also no signs of historical long-range dispersal. Two deviating haplotypes from Europe might belong to an unrecognized species or indicate the presence of paralogous ITS sequences. But our dataset does not support separation of T. glaucolepidea and T percrenata based on morphological characters. More thorough sampling efforts and more sequences are necessary to make more detailed inferences on the phylogeography of T. glaucolepidea.