Runcinida is a small heterobranch order of sea slugs with 61 known species distributed worldwide across temperate and tropical latitudes with two established families (Ilbiidae and Runcinidae). Little is known about the phylogenetic relationships within Runcinida. Here, we present the first molecular phylogeny of the order with an emphasis on European species and we discuss the taxonomic status of the type species Runcina coronata. Molecular phylogenetics based on the mitochondrial genes cytochrome c oxidase subunit I and 16S rRNA and nuclear gene histone H3 is used to investigate relationships between species. Detailed morpho-anatomical worked was additionally employed to study Runcina coronata. Our results suggest the monophyly of Runcinida and showed that Runcina coronata is a complex of four species, namely: R. coronata proper, R. aurata and two new species here formally described (R. caletensis sp. nov. and R. tingensis sp. nov.).

中文翻译：

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欧洲 Runcinida (Gastropoda, Heterobranchia) 的分子系统发育：发现了一个意想不到的复杂物种库，特别是 Runcina coronata 的案例

Runcinida 是海蛞蝓的一个小型异分支目，有 61 种已知物种，分布在全球温带和热带纬度，有两个已建立的科（Ilbiidae 和 Runcinidae）。关于Runcinida内的系统发育关系知之甚少。在这里，我们介绍了该命令的第一个分子系统发育，重点是欧洲物种，我们讨论了模式物种 Runcina coronata 的分类地位。基于线粒体基因细胞色素 c 氧化酶亚基 I 和 16S rRNA 和核基因组蛋白 H3 的分子系统发育用于研究物种之间的关系。还采用了详细的形态解剖学研究来研究 Runcina coronata。我们的研究结果表明 Runcinida 的单系，并表明 Runcina coronata 是四个物种的复合体，即：R. coronata proper，R.