海洋生物分类与系统演化实验室知识库

 活额寄居蟹科Diogenidae Ortmann，1982隶属于异尾下目（Anomura）寄居蟹总科（Paguroidea），是寄居蟹总科的第二大科。细螯寄居蟹属Clibanarius Dana，1852是活额寄居蟹科多样性较高的属之一，然而，目前关于该属系统发育关系的研究却很少。本研究采用了2种线粒体基因（16S rRNA和COI）和2种核蛋白编码基因（NaK和PEPCK）联合数据集重建了细螯寄居蟹属的系统发育关系。研究共选取了来自印度–西太平洋海域的11种细螯寄居蟹，采用了最大似然法和贝叶斯推断法构建了系统进化树，得到结果如下：橙红细螯寄居蟹C. rutilus和下齿细螯寄居蟹C. infraspinatus聚为一支，亲缘关系较近，白刺细螯寄居蟹C. snelliusi独立于该分支之外；扁长细螯寄居蟹C. longitarsus和条纹细螯寄居蟹C. striolatus聚为一支，亲缘关系较近；墨吉细螯寄居蟹C. merguiensis，兰指细螯寄居蟹C. englaucus和微小细螯寄居蟹C. humilis聚为一支，亲缘关系较近，兰绿细螯寄居蟹C. virescens独立于该分支之外。研究结果不支持根据指节和掌节长度的不同对细螯寄居蟹属进行划分，推测尾节中缝这一形态特征对细螯寄居蟹属的物种划分可能更具有分类学意义。

目前关于活额寄居蟹科内部系统演化关系的研究很少。本研究通过采用2种线粒体基因（16S rRNA和COI）和2种核蛋白编码基因（NaK和PEPCK）联合数据集进行了活额寄居蟹科系统演化关系的研究。结果表明：研究所涉及的活额寄居蟹科14属52种可大致分为3大支；支持细螯寄居蟹属Clibanarius，硬壳寄居蟹属Calcinus，真寄居蟹属Dardanus，似寄居蟹属Paguropsina和活额寄居蟹属Diogenes的单系性；长眼寄居蟹属Paguristes和窝长眼寄居蟹属Areopaguristes为多系群，活额寄居蟹科则为并系发生。长眼寄居蟹属和窝长眼寄居蟹属的分类学地位可能存在问题，需要结合形态特征分析对二者及其下种分类单元进行重新修订。此外，分化时间分析显示活额寄居蟹科起源于侏罗纪中期（c. 169.59 Mya，95% HPD：189.29–148.13 Mya），并于白垩纪早期（c. 142.02 Mya，95% HPD：164.45–121.78 Mya）由浅海迁移到深海，但仍有部分物种留在浅海，具有多次入侵深海的演化历史。

本研究首次联合线粒体和核基因探究了细螯寄居蟹属的种间关系，并对活额寄居蟹科的系统发育关系进行了较为全面的研究，为活额寄居蟹科系统演化关系的研究和分类系统的修订提供了分子生物学的证据，也为异尾下目的系统演化研究提供了基础资料。

Diogenidae Ortmann, 1892 is the second-largest family of Paguroidea, Anomura. Clibanarius Dana, 1852 is one of the most diverse genera within Diogenidae. However, there are very limited studies on the phylogeny of Clibanarius. In this study, we reconstruct the molecular phylogeny of Clibanarius based on two mitochondrial (16S rRNA and COI) and two nuclear protein-coding (NaK and PEPCK) genes using a multigene phylogenetic approach. A total of 11 selected Clibanarius species from the Indo-West Pacific are analyzed, and the Bayesian and maximum likelihood analyses produced identical results in topology. The current research suggests that C. rutilus and C. infraspinatus are more closely related to each other than to C. snelliusi, and C. striolatus shows a close relationship to C. longitarsus. The close association of C. merguiensis with C. englaucus and C. humilis is strongly supported with C. virescens being divergent from them. Our phylogenetic results contradict the morphological classification scheme proposed for Clibanarius and indicate that the relative length of dactyls and propodi is not phylogenetically significant in Clibanarius. In addition, we speculate that the morphological characteristic of the median cleft of the telson may be phylogenetically important for Clibanarius.

The phylogenetic relationships of Diogenidae have been poorly documented in the previous studies. Here, we reconstruct the phylogeny and analyze divergence times of this family based on two mitochondrial (16S rRNA and COI) and two nuclear protein-coding (NaK and PEPCK) genes for 14 genera of Diogenidae including 52 species. It is suggested that the studied 52 Diogenid species can be divided into three clades. The genera Clibanarius, Calcinus, Dardanus, Paguropsina and Diogenes show to be monophyletic. However, Paguristes and Areopaguristes are recovered as polyphyletic, with Diogenidae paraphyletic. The taxonomic status of genera Paguristes and Areopaguristes is obscure, which requires further revision according to morphological characteristics. In addition, divergence time analysis dates the origin of Diogenidae to the Middle Jurassic (c. 169.59 Mya, 95% HPD: 189.29–148.13 Mya) and shows that species of Diogenidae may radiate from shallow water to deep sea during the Early Cretaceous (c. 142.02 Mya, 95% HPD: 164.45–121.78 Mya). However, some Diogenid species still remain in the shallow water. The present molecular phylogeny indicates that Diogenid hermit crabs have a history of multiple invasions into the deep sea.

In this study, the mitochondrial and nuclear protein-coding gene concatenated dataset are used to explore the interspecific relationships of Clibanarius for the first time. The most comprehensive molecular phylogenetic analysis of Diogenidae are provided, adding molecular evidences for taxonomy and phylogeny of this family. Meanwhile, this study also provides fundamental information for the systematic evolution of Anomura.