Department of Invertebrate Zoology and Geology, California Academy of Sciences, San Francisco, California, United States of America.
PLoS One. 2012;7(4):e33479. doi: 10.1371/journal.pone.0033479. Epub 2012 Apr 10.
Chromodorid nudibranchs (16 genera, 300+ species) are beautiful, brightly colored sea slugs found primarily in tropical coral reef habitats and subtropical coastal waters. The chromodorids are the most speciose family of opisthobranchs and one of the most diverse heterobranch clades. Chromodorids have the potential to be a model group with which to study diversification, color pattern evolution, are important source organisms in natural products chemistry and represent a stunning and widely compelling example of marine biodiversity. Here, we present the most complete molecular phylogeny of the chromodorid nudibranchs to date, with a broad sample of 244 specimens (142 new), representing 157 (106 new) chromodorid species, four actinocylcid species and four additional dorid species utilizing two mitochondrial markers (16s and COI). We confirmed the monophyly of the Chromodorididae and its sister group relationship with the Actinocyclidae. We were also able to, for the first time, test generic monophyly by including more than one member of all 14 of the non-monotypic chromodorid genera. Every one of these 14 traditional chromodorid genera are either non-monophyletic, or render another genus paraphyletic. Additionally, both the monotypic genera Verconia and Diversidoris are nested within clades. Based on data shown here, there are three individual species and five clades limited to the eastern Pacific and Atlantic Oceans (or just one of these ocean regions), while the majority of chromodorid clades and species are strictly Indo-Pacific in distribution. We present a new classification of the chromodorid nudibranchs. We use molecular data to untangle evolutionary relationships and retain a historical connection to traditional systematics by using generic names attached to type species as clade names.
双色海牛（16 属，300 多种）是一种美丽的、颜色鲜艳的海蛞蝓，主要生活在热带珊瑚礁栖息地和亚热带沿海水域。双色海牛是后鳃类中物种最丰富的一科，也是最具多样性的异鳃类群之一。双色海牛有可能成为一个研究多样化、颜色模式进化的模式群体，是天然产物化学中重要的生源生物体，也是海洋生物多样性的一个引人注目的、广泛吸引人的例子。在这里，我们展示了迄今为止双色海牛最完整的分子系统发育，样本广泛，共有 244 个标本（142 个新标本），代表了 157 个（106 个新标本）双色海牛物种、4 个 Actinocylcid 物种和另外 4 个利用两个线粒体标记（16s 和 COI）的多利德物种。我们证实了 Chromodorididae 的单系性及其与 Actinocyclidae 的姊妹群关系。我们还首次通过包括 14 个非单型双色海牛属中的一个以上成员来测试属的单系性。这 14 个传统的双色海牛属中的每一个都不是单系的，或者使另一个属成为并系的。此外，单型属 Verconia 和 Diversidoris 都嵌套在分支中。根据这里显示的数据，有三个单独的物种和五个局限于东太平洋和大西洋的分支（或这两个海洋区域中的一个），而大多数双色海牛分支和物种的分布范围严格局限于印度-太平洋地区。我们提出了一种新的双色海牛分类法。我们利用分子数据来理清进化关系，并通过使用与模式种相关联的属名作为分支名称，保留与传统系统学的历史联系。
