German Center for Marine Biodiversity Research (DZMB), Senckenberg am Meer, Südstrand 44, 26382 Wilhelmshaven, Germany.
Laboratory of Marine Research, Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, 199034 St. Petersburg, Russia.
Mol Phylogenet Evol. 2019 Jan;130:330-345. doi: 10.1016/j.ympev.2018.10.028. Epub 2018 Oct 23.
Among the most derived calanoid copepod superfamily Clausocalanoidea about half of the genera belong to the so-called "Bradfordian" families that are defined by the presence of sensory setae at the maxilla and maxilliped. Many of these "Bradfordian" taxa are insufficiently well described, because their taxonomy is complicated and phylogenetic relationships are not completely resolved. We therefore aimed to unravel their phylogenetic relationships using molecular multi-gene analyses. We conducted molecular multi-gene analysis on 26 species from 15 genera representing all seven "Bradfordian" families using five gene fragments, the nuclear ribosomal 18S, 28S and internal transcribed spacer 2 DNA, and mitochondrial cytochrome c oxidase subunit I and cytochrome b. The monophyly of "Bradfordians" as one lineage in the superfamily Clausocalanoidea was supported by Maximum Likelihood and Bayesian Inference multi-gene analyses. Except for the support of species belonging to the same genus and specimens belonging to the same species, no phylogenetic relationships among genera and families were supported. The impossibility of resolving phylogenetic relationships among "Bradfordian" genera and families may be due to the young age or fast radiation of "Bradfordians" within the mostly derived calanoid superfamily Clausocalanoidea. Therefore, mutation rates might be not sufficient to track phylogenetic relationships. Evidence on phylogenetic relationships between genera and families remain unresolved after implementing integrated morphological and molecular taxonomic approaches.
在最衍生的哲水蚤超科 Clausocalanoidea 中，大约一半的属属于所谓的“Bradfordian”科，这些科的定义是在大颚和大颚足上有感觉刚毛。这些“Bradfordian”类群中有许多描述不充分，因为它们的分类学很复杂，系统发育关系也不完全清楚。因此，我们旨在使用分子多基因分析来揭示它们的系统发育关系。我们使用五个基因片段（核核糖体 18S、28S 和内部转录间隔区 2 DNA 以及线粒体细胞色素 c 氧化酶亚基 I 和细胞色素 b）对代表七个“Bradfordian”科的 15 属的 26 种进行了分子多基因分析。最大似然法和贝叶斯推断多基因分析支持“Bradfordian”作为哲水蚤超科中一个谱系的单系性。除了支持属于同一属的物种和属于同一物种的标本外，没有支持属和科之间的系统发育关系。“Bradfordian”属和科之间的系统发育关系无法解决可能是由于“Bradfordian”在大部分衍生的哲水蚤超科 Clausocalanoidea 中年龄较轻或快速辐射。因此，突变率可能不足以追踪系统发育关系。在实施综合形态和分子分类学方法后，属和科之间的系统发育关系的证据仍然没有解决。
