Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, USA; Institute of Evolutionary Biology and Animal Ecology, University of Bonn, Germany.
Department of Electrical and Computer Engineering, UC San Diego, La Jolla, CA, USA.
Mol Phylogenet Evol. 2020 Oct;151:106892. doi: 10.1016/j.ympev.2020.106892. Epub 2020 Jun 18.
Sabellida is a well-known clade containing tube-dwelling annelid worms with a radiolar crown. Iterative phylogenetic analyses over three decades have resulted in three main clades being recognized; Fabriciidae, Serpulidae and Sabellidae, with Fabriciidae proposed as the sister group to Serpulidae. However, relationships within Sabellidae have remained poorly understood, with a proliferation of genera. In order to obtain a robust phylogeny with optimal support, we conducted a large-scale phylogenomic analysis with 19 new sabellid transcriptomes for a total of 21 species. In contrast to earlier findings based on limited DNA data, our results support the position of Fabriciidae as sister taxon to a Sabellidae + Serpulidae clade. Our large sampling within Sabellidae also allows us to establish a stable phylogeny within this clade. We restrict Sabellinae to a subclade of Sabellidae and broaden the previously monotypic Myxicolinae to include Amphicorina and Chone. We tested the robustness of species tree reconstruction by subsampling increasing numbers of genes to uncover hidden support of alternative topologies. Our results show that inclusion of more genes leads to a more stable topology with higher support, and also that including higher divergence genes leads to stronger resolution.
沙蚕目是一个广为人知的类群，包含有放射冠的栖管环节动物。三十年来的反复系统发育分析已识别出三个主要的类群；矶沙蚕科、盘管虫科和沙蚕科，矶沙蚕科被提议为盘管虫科的姊妹群。然而，沙蚕科内的关系仍然知之甚少，分类群数量不断增加。为了获得具有最佳支持的稳健系统发育，我们对 19 种新的沙蚕转录组进行了大规模的系统基因组分析，共涉及 21 个物种。与基于有限 DNA 数据的早期发现相比，我们的结果支持矶沙蚕科作为沙蚕科+盘管虫科类群的姊妹分类群的位置。我们在沙蚕科内的大量采样还使我们能够在这个类群内建立一个稳定的系统发育。我们将沙蚕亚科限制在沙蚕科的一个亚科内，并将以前单型的沙蚕亚科扩展到包括 Amphicorina 和 Chone。我们通过逐步增加基因数量来测试物种树重建的稳健性，以揭示替代拓扑结构的隐藏支持。我们的结果表明，包含更多的基因会导致更稳定的拓扑结构和更高的支持，并且包含更高分歧的基因会导致更强的分辨率。
