a Department of Life Sciences , University of Trieste , via Giorgieri 10, 34127 Trieste , Italy.
b Department of Ecology, Faculty of Environmental Sciences , Czech University of Life Sciences Prague , Czech Republic, Kamýcká 129, 16500 Praha 6 , Czech Republic.
Mycologia. 2019 Jan-Feb;111(1):127-160. doi: 10.1080/00275514.2018.1543510. Epub 2019 Feb 6.
Rock-inhabiting fungi (RIF) are adapted to thrive in oligotrophic environments and to survive under conditions of abiotic stress. Under these circumstances, they form biocoenoses with other tolerant organisms, such as lichens, or with less specific phototrophic consortia of aerial algae or cyanobacteria. RIF are phylogenetically diverse, and their plastic morphological characters hamper the straightforward species delimitation of many taxa. Here, we present a phylogenetic study of two RIF genera, Lichenothelia and Saxomyces. Representatives of both genera inhabit rather similar niches on rocks, but their phylogenetic relationships are unknown so far. The cosmopolitan genus Lichenothelia is recognized by characters of fertile ascomata and includes species with different life strategies. In contrast, Saxomyces species were described exclusively by mycelial characters found in cultured isolates from rock samples collected at high alpine elevations. Here, we use an extended taxon sampling of Dothideomycetes to study the phylogenetic relationships of both Lichenothelia and Saxomyces. We consider environmental samples, type species, and cultured isolates of both genera and demonstrate their paraphyly, as well as the occurrence of teleomorphs in Saxomyces. We applied three species delimitation methods to improve species recognition based on molecular data. We show the distinctiveness of the two main lineages of Lichenothelia (Lichenotheliales s. str.) and Saxomyces and discuss differences in species delimitation depending on molecular markers or methods. We revise the taxonomy of the two genera and describe three new taxa, Lichenothelia papilliformis, L. muriformis, and Saxomyces americanus, and the teleomorph of S. penninicus.
石生真菌（RIF）适应在贫营养环境中茁壮成长，并能在非生物胁迫条件下生存。在这些情况下，它们与其他耐受生物形成生物群落，如地衣，或与不太特定的光养共生体的气生藻类或蓝细菌形成生物群落。RIF 在系统发育上是多样化的，其可塑性的形态特征阻碍了许多分类群的直接物种界定。在这里，我们对两个 RIF 属，Lichenothelia 和 Saxomyces 进行了系统发育研究。这两个属的代表都栖息在岩石上相当相似的小生境中，但它们的系统发育关系至今尚不清楚。世界性的属 Lichenothelia 的特征是可育子囊果，包括具有不同生活策略的物种。相比之下，Saxomyces 物种仅通过在高海拔岩石样本中分离出的培养物的菌丝体特征来描述。在这里，我们使用扩展的 Dothideomycetes 分类群采样来研究 Lichenothelia 和 Saxomyces 的系统发育关系。我们考虑了这两个属的环境样本、模式种和培养物分离物，并证明了它们的并系性，以及 Saxomyces 中存在的同形现象。我们应用了三种物种界定方法来基于分子数据提高物种识别。我们展示了 Lichenothelia（Lichenotheliales s. str.）和 Saxomyces 的两个主要谱系的独特性，并讨论了根据分子标记或方法在物种界定上的差异。我们修订了这两个属的分类法，并描述了三个新的分类群，Lichenothelia papilliformis、L. muriformis 和 Saxomyces americanus，以及 S. penninicus 的同形现象。
