Species boundaries in the messy middle – testing the hypothesis of micro-endemism in a recently diverged lineage of coastal fog desert lichen fungi

Species delimitation among closely related species is challenging because traditional phenotype-based approaches, e.g., morphology, ecological, or chemical characteristics, often produce conflicting results. With the advent of high-throughput sequencing, it has become increasingly cost-effective to acquire genome-scale data which can resolve previously ambiguous species boundaries. As the availability of genome-scale data has increased, numerous species delimitation analyses, such as BPP and SNAPP+Bayes factor delimitation (BFD*), have been developed to delimit species boundaries. However, even empirical molecular species delimitation approaches can be biased by confounding evolutionary factors, e.g., hybridization/introgression and incomplete lineage sorting, and computational limitations. Here we investigate species boundaries and the potential for micro-endemism in a lineage of lichen-forming fungi, Niebla Rundel & Bowler in the family Ramalinaceae. The species delimitation model...

近缘物种间的物种界定（species delimitation）颇具挑战，因为传统基于表型的研究方法——例如形态学、生态学或化学特征分析——往往会得到相互矛盾的结果。随着高通量测序（high-throughput sequencing）技术的发展，获取全基因组规模数据的成本效益比不断提升，这类数据可用于厘清此前模糊不清的物种边界。随着全基因组规模数据的可获取性持续提升，学界已开发出多种物种界定分析方法，例如BPP、SNAPP+贝叶斯因子界定（Bayes factor delimitation，缩写为BFD*），用于划定物种边界。然而，即便实证分子物种界定方法，也可能受到混杂进化因素（例如杂交/渐渗与不完全谱系分选（incomplete lineage sorting））以及计算限制的干扰而产生偏倚。本研究针对扁枝衣科（Ramalinaceae）下的一个地衣型真菌演化支——Niebla属（Niebla Rundel & Bowler），探究其物种边界以及微特有性（micro-endemism）的潜在可能性。本研究采用的物种界定模型……