Carim Kellie J, Auringer Grace, Docker Margaret F, Renaud Claude B, Clemens Benjamin J, Blanchard Monica R, Parker Christina, Young Michael K
Aldo Leopold Wilderness Research Institute, Rocky Mountain Research Station, U.S. Forest Service, Missoula, Montana, United States of America.
Department of Animal Science, University of California, Davis, California, United States of America.
PLoS One. 2024 Dec 19;19(12):e0313911. doi: 10.1371/journal.pone.0313911. eCollection 2024.
Accurate taxonomy is fundamental to the study and conservation of biodiversity. Because of their morphological similarities, most brook and river lampreys in western North America have been placed in the genus Lampetra along with lampreys from Eurasia and eastern North America. However, molecular-based phylogenetic studies dating back several decades indicate that lampreys from Pacific drainages are genetically distinct from Atlantic Lampetra. Reviewing previous phylogenetic analysis of two mitochondrial and two nuclear genes for Northern Hemisphere lampreys, we assign these western North American brook and river lampreys to a new genus, Occidentis. To assess species diversity within Occidentis, we performed a species delimitation analysis using all publicly available cytochrome b sequences of the genus. Similar to previous studies, O. ayresii and O. richardsoni were not reciprocally monophyletic and are best categorized as life history variants of a single species. In addition to O. pacifica, O. hubbsi, and the diverse O. ayresii species complex, as many as seven undescribed candidate species from Oregon and California were identified, supporting results from previous studies with more geographically limited datasets. One specimen from Paynes Creek, California, was identified as a candidate species, although this single individual showed minimal interspecific divergence (1.34%) with O. hubbsi. Further genetic assessment along with information on morphology and phylogeography is needed to determine whether the variation observed between groups of candidate species represents distinct species or divergent lineages within a species complex. Additional sampling will inform whether there are additional species not currently represented in this dataset. Thus, the number of species formally recognized under Occidentis is subject to change with new information. Systematic assessment of the distribution and phylogenetic complexity within Occidentis will enhance our understanding of its evolutionary history and taxonomic diversity, which will guide efforts to conserve the biodiversity of lampreys.
准确的分类学对于生物多样性的研究和保护至关重要。由于形态相似，北美洲西部的大多数溪鳗和河鳗与来自欧亚大陆和北美洲东部的鳗鲡一同被归入七鳃鳗属。然而，追溯到几十年前基于分子的系统发育研究表明，来自太平洋流域的七鳃鳗在基因上与大西洋七鳃鳗属不同。回顾先前对北半球七鳃鳗的两个线粒体基因和两个核基因的系统发育分析，我们将这些北美洲西部的溪鳗和河鳗归入一个新属，即西方七鳃鳗属。为了评估西方七鳃鳗属内的物种多样性，我们使用该属所有公开可用的细胞色素b序列进行了物种界定分析。与先前的研究类似，艾氏西方七鳃鳗和李氏西方七鳃鳗并非相互单系的，最好归类为单一物种的生活史变体。除了太平洋西方七鳃鳗、哈氏西方七鳃鳗以及多样的艾氏西方七鳃鳗物种复合体之外，还从俄勒冈州和加利福尼亚州鉴定出多达七个未描述的候选物种，这支持了先前使用地理范围更有限的数据集得出的结果。来自加利福尼亚州佩恩斯溪的一个标本被鉴定为候选物种，尽管这个个体与哈氏西方七鳃鳗的种间差异极小（1.34%）。需要进一步的基因评估以及形态学和系统地理学信息，以确定候选物种组之间观察到的变异是代表不同的物种还是物种复合体内的不同谱系。额外的采样将有助于了解该数据集中目前是否未涵盖其他物种。因此，西方七鳃鳗属正式认可的物种数量可能会随着新信息而改变。对西方七鳃鳗属内的分布和系统发育复杂性进行系统评估，将增进我们对其进化历史和分类多样性的理解，从而指导七鳃鳗生物多样性的保护工作。
