The genus Thuridilla Bergh, 1872 comprises mostly tropical sap-sucking sea slugs species with flamboyantly coloured forms. However, the potential for cryptic or pseudocryptic species masked by convergent or polymorphic colour patterns has not been tested using molecular characters. In this study, we sampled 20 of the 23 recognized worldwide species and performed the most comprehensive molecular phylogenetic analysis of the genus to date using a multi-locus approach combining two mitochondrial (cytochrome c oxidase subunit I, 16S rRNA) and two nuclear (Histone H3, 28S rRNA) genes using maximum likelihood, maximum-parsimony and Bayesian criteria. Three molecular species delimitation methods (ABGD, GMYC, bPTP) and the morphology of radular teeth were additionally used to aid in species delimitation. Our analyses supported 35 species within Thuridilla, of which more than one-third (13) are part of a single radiation here named the Thuridilla gracilis (Risbec, 1928) species-complex. This complex includes T. gracilis, T. splendens (Baba, 1949), T. bayeri (Er. Marcus, 1965), and T. ratna (Er. Marcus, 1965), plus nine additional undescribed species. All 13 species are distinguishable by radular characters, external morphology and their DNA. The detection of this radiation led diversity of Thuridilla to be underestimated by about 25% and provides a new comparative system for studying the role of colour patterns in marine diversification.

中文翻译：

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Thuridilla Bergh 的分子系统发育，1872 年海蛞蝓（腹足纲，Sacoglossa）揭示了海洋领域华丽而神秘的辐射案例

Thuridilla Bergh属，1872 年，主要包括热带吸食汁液的海蛞蝓物种，颜色艳丽。然而，尚未使用分子特征测试被收敛或多态颜色图案掩盖的隐蔽或伪隐蔽物种的潜力。在这项研究中，我们对全球 23 个公认的物种中的 20 个进行了采样，并使用结合两种线粒体（细胞色素c氧化酶亚基 I，16S rRNA）和两个核（组蛋白 H3，28S rRNA）基因使用最大似然、最大简约和贝叶斯标准。此外，还使用了三种分子物种界定方法（ABGD、GMYC、bPTP）和齿状齿的形态来帮助物种界定。我们的分析支持Thuridilla中的 35 个物种，其中超过三分之一 (13) 是这里称为Thuridilla gracilis (Risbec, 1928) 物种复合体的单一辐射的一部分。这个复合体包括T。 股 薄_ _ 芨芨草（巴巴，1949 年），T。 bayeri (Er. Marcus, 1965), 和T. ratna(Er. Marcus, 1965)，以及另外九个未描述的物种。所有 13 个物种都可以通过辐射特征、外部形态和它们的 DNA 来区分。这种辐射的检测导致Thuridilla的多样性被低估了约 25%，并为研究颜色模式在海洋多样化中的作用提供了一个新的比较系统。