Departamento de Biología (Botánica), Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain.
Departamento de Botánica, Ecología y Fisiología Vegetal, Universidad de La Laguna, La Laguna, Santa Cruz de Tenerife, Spain.
PLoS One. 2019 Feb 13;14(2):e0211017. doi: 10.1371/journal.pone.0211017. eCollection 2019.
Biogeography, systematics and taxonomy are complementary scientific disciplines. To understand a species' origin, migration routes, distribution and evolutionary history, it is first necessary to establish its taxonomic boundaries. Here, we use an integrative approach that takes advantage of complementary disciplines to resolve an intriguing scientific question. Populations of an unknown moss found in the Canary Islands (Tenerife Island) resembled two different Californian endemic species: Orthotrichum shevockii and O. kellmanii. To determine whether this moss belongs to either of these species and, if so, to explain its presence on this distant oceanic island, we combined the evaluation of morphological qualitative characters, statistical morphometric analyses of quantitative traits, and molecular phylogenetic inferences. Our results suggest that the two Californian mosses are conspecific, and that the Canarian populations belong to this putative species, with only one taxon thus involved. Orthotrichum shevockii (the priority name) is therefore recognized as a morphologically variable species that exhibits a transcontinental disjunction between western North America and the Canary Islands. Within its distribution range, the area of occupancy is limited, a notable feature among bryophytes at the intraspecific level. To explain this disjunction, divergence time and ancestral area estimation analyses are carried out and further support the hypothesis of a long-distance dispersal event from California to Tenerife Island.
生物地理学、系统学和分类学是互补的科学学科。为了了解一个物种的起源、迁移路线、分布和进化历史，首先有必要确定其分类学界限。在这里，我们采用综合方法，利用互补学科来解决一个有趣的科学问题。在加那利群岛（特内里费岛）发现的一种未知苔藓的种群类似于两种不同的加利福尼亚特有种：Orthotrichum shevockii 和 O. kellmanii。为了确定这种苔藓是否属于这两个物种之一，如果是，解释其在这个遥远的海洋岛屿上的存在，我们结合了形态定性特征的评估、定量性状的统计形态测量分析以及分子系统发育推断。我们的结果表明，这两种加利福尼亚苔藓是同一种，加那利群岛的种群属于这个假定的物种，只有一个分类单元涉及其中。因此，Orthotrichum shevockii（优先名）被认为是一种形态多变的物种，在北美西部和加那利群岛之间表现出跨大陆的不连续分布。在其分布范围内，占据面积有限，这是在种内水平上苔藓植物的一个显著特征。为了解释这种不连续性，进行了分歧时间和祖先区域估计分析，并进一步支持了从加利福尼亚远距离传播到特内里费岛的假设。
