Olivera-Hyde Miluska, Jones Jess W, Hallerman Eric M
Department of Fish and Wildlife Conservation Virginia Polytecnic Institute and State University Blacksburg Virginia USA.
Present address: U.S. Geological Survey Eastern Ecological Science Center at the Leetown Research Laboratory Kearneysville West Virginia USA.
Ecol Evol. 2023 Jan 24;13(1):e9717. doi: 10.1002/ece3.9717. eCollection 2023 Jan.
The Green River in Kentucky in the eastern United States is a freshwater mussel biodiversity hotspot, with 71 known species. Among them, the endangered coexists with other morphologically similar species in the genera and , known colloquially as "pigtoes." Identification of species in these genera is challenging even for mussel experts familiar with them. In our study, the correct identification of these species by experts ranged from 57% to 83%. We delineated taxonomic boundaries among seven species and tested for cryptic biodiversity among these look-alike mussels utilizing mitochondrial and nuclear DNA sequence variation. Phylogenetic analysis of combined (1215 bp) mitochondrial DNA cytochrome oxidase I () and NADH dehydrogenase 1 () genes showed five well-diverged groups that included , , , and as distinct clades, with and grouped into a single clade. While our mitochondrial DNA analyses did not distinguish and as phylogenetically distinct species, the typical shell forms of these two nominal taxa are very distinct. Further phylogenetic analysis using nuclear ribosomal transcribed spacer region subunit I () DNA sequences also showed that and were not distinct lineages. No cryptic species were detected in the and samples analyzed from the Green River. The highest haplotype diversity (), average number of nucleotide differences (), and nucleotide diversity () were observed for at both the ( = 0.896, = 3.805, = 0.00808) and ( = 0.984, = 6.595, 0.00886) markers, with similarly high genetic diversity in the other taxa. Our results give managers confidence that cryptic taxa do not occur within or among these morphologically similar species in the Green River, and populations appear genetically diverse, indicative of large and healthy populations.
美国东部肯塔基州的格林河是淡水贻贝生物多样性热点地区，有71种已知物种。其中，濒危的[物种名称未给出]与[属名未给出]属和[属名未给出]属中其他形态相似的物种共存，这些物种俗称“猪趾蚌”。即使对于熟悉这些属的贻贝专家来说，识别这些属中的物种也具有挑战性。在我们的研究中，专家对这些物种的正确识别率在57%至83%之间。我们划定了七个物种之间的分类界限，并利用线粒体和核DNA序列变异测试了这些相似贻贝中的隐秘生物多样性。对线粒体DNA细胞色素氧化酶I（COI）和NADH脱氢酶1（ND1）基因组合（1215bp）进行系统发育分析，结果显示有五个分化明显的类群，其中[属名未给出]、[属名未给出]、[属名未给出]和[属名未给出]为不同的分支，而[属名未给出]和[属名未给出]归为一个分支。虽然我们的线粒体DNA分析没有将[物种名称未给出]和[物种名称未给出]区分成系统发育上不同的物种，但这两个标称分类单元的典型壳形非常不同。使用核糖体转录间隔区亚基I（ITS1）DNA序列进行的进一步系统发育分析也表明，[物种名称未给出]和[物种名称未给出]不是不同的谱系。在从格林河采集并分析的[物种名称未给出]和[物种名称未给出]样本中未检测到隐秘物种。在COI（Hd = 0.896，k = 3.805，π = 0.00808）和ITS1（Hd = 0.984，k = 6.595，π = 0.00886）标记中，[物种名称未给出]的单倍型多样性（Hd）、平均核苷酸差异数（k）和核苷酸多样性（π）最高，其他分类单元也具有相似的高遗传多样性。我们的结果让管理者相信，在格林河这些形态相似的物种内部或之间不存在隐秘分类单元，而且种群在基因上似乎具有多样性，这表明种群数量大且健康。
