海洋生物分类与系统演化实验室知识库

金柳珊瑚科隶属刺胞动物门、珊瑚虫纲、八放珊瑚亚纲、软珊瑚目、钙轴珊瑚亚目，分布在全球海域，目前包含14属112种。除少数物种生活于浅水外，大多数金柳珊瑚生长在海山、陆坡等深水硬底生境。目前，在西太平洋仅记录冠柳珊瑚属Stephanogorgia、侧柳珊瑚属Pleurogorgia、根柳珊瑚属Radicipes、金相柳珊瑚属Metallogorgia、金柳珊瑚属Chrysogorgia 和假金柳珊瑚属Pseudochrysogorgia 6个属。在我国，尚未开展金柳珊瑚的分类学研究。

海山是大洋中独特的生境，成为深海生物多样性研究与保护的热点区域。热带西太平洋海山众多，但真正开展探索的却很少。自2016年以来，通过“科学号”科考船及其搭载的“发现号”无人深潜器在西太平洋采样，从热带西太平洋三座海山共获取了23号金柳珊瑚标本。基于该样品，本论文开展了系统的分类学与系统发育研究。本研究在总结金柳珊瑚科各个类群研究背景和大量文献资料的基础上，对所有种类进行了详细的形态学描述，包括外部形态、分枝、珊瑚虫和不同部位的骨片等，同时提供了各属种的分类检索表和地理分布信息。共鉴定了4属（金柳珊瑚属、金相柳珊瑚属、虹柳珊瑚属Iridogorgia、波柳珊瑚属Rhodaniridogorgia）16种，发现了9个金柳珊瑚新种（簇生金柳珊瑚Chrysogorgia fascicularis n. sp.、双列金柳珊瑚Chrysogorgia binata n. sp.、叉状金柳珊瑚Chrysogorgia ramificans n. sp.、枝状金柳珊瑚Chrysogorgia stipitiformis n. sp.、脆弱金柳珊瑚Chrysogorgia fragilis n. sp.、纤柔金柳珊瑚Chrysogorgia gracilis n. sp.、致密虹柳珊瑚Iridogorgia densispicula n. sp.、粗糙虹柳珊瑚Iridogorgia squarrosa n. sp.、长枝波柳珊瑚Rhodaniridogorgia macroclada n. sp.）。

MtMutS基因是八放珊瑚里的一种线粒体错配修复蛋白基因。通过采用mtMutS基因进行测序分析，构建了4种金柳珊瑚的系统发育树。经分析显示，Iridogorgia densispicula n. sp.和其它种的mtMutS基因遗传距离比同类其它种之间的明显要高，且在系统发育树中以单一的演化枝最先分化出来，支持该新种的有效性。对于I. squarrosa n. sp.、C. ramificans n. sp.和C. binata n. sp.等，基于遗传距离和进化树数据很难与相近种进行区分，它们均有着高的置信度，显示出较近的间亲缘关系。

本研究揭示和描述了热带西太海山地区金柳珊瑚的多样性及多个深海新物种，为海山生物多样性分布假说的准确性判定提供了参考。通过探索金柳珊瑚的进化关系，丰富了海洋生物的基因库和物种信息，对我国探索和利用深海生物资源具有十分重要的意义。

The family Chrysogorgiidae (Cnidaria, Anthozoa, Octocorallia, Alcyonacea, Calcaxonia) is distributed in the global ocean, including 14 genera and 112 recorded species at present. Except a few species growing in the coastal waters, most chrysogorgiids are living in the deep water and hard bottom of the seamounts or continental slopes. At present, there are only six genera including Pleurogorgia, Radicipes, Metallogorgia, Stephanogorgia, Chrysogorgia and Pseudochrysogorgia found in the Western Pacific. In China, systematic classification of chrysogorgiids have not yet been carried out, and only two unidefined species were recorded in the East China Sea.

Seamounts with their unique habitat have been the hotspot of deep-sea biodiversity research and protection. There are numerous seamounts in the tropical Western Pacific, where only a few have been explored. Since 2016, we have collected 23 chrysogorgiid specimens from three seamounts by ROV Faxian (Discovery) during the cruises of the R/V Kexue (Science) in the tropical Western Pacific. Based on these specimens, we carried out a systematic study about taxonomy and phylogeny. Based on the summaries about the research backgrounds for each taxon and a large number of literatures, this study made detailed morphological descriptions for all species, including the external morphology, branches, polyps and sclerites in different parts. And it also provided identification keys to each genus and species, and the information on their geographical distribution. A total of 24 specimens of chrysogorgiids were identified as 4 genera (Chrysogorgia, Metallogorgia, Iridogorgia and Rhodaniridogorgia) and 16 species, including 9 new species (Chrysogorgia fascicularis n. sp., Chrysogorgia binata n. sp., Chrysogorgia ramificans n. sp., Chrysogorgia stipitiformis n. sp., Chrysogorgia fragilis n. sp., Chrysogorgia gracilis n. sp., Iridogorgia densispicula n. sp., Iridogorgia squarrosa n. sp. and Rhodaniridogorgia macroclada n. sp.)

The octocoral mtMutS gene codes for a protein with all the necessary components for DNA mismatch repair. The phylogenetic trees of four species were constructed in this study by using mtMutS gene sequencing. Based on the phylogenetic analysis, the genetic distances of mtMutS between I. densispicula n. sp. and congeners are much higher than those among the rest congeners. And I. densispicula n. sp. branched early with a single basal clade within Iridogorgia with full node support in the phylogenetic trees, supporting the effectiveness of the new species. Molecular phylogenetic analysis indicates that I. squarrosa n. sp., C. ramificans n. sp. and C. binata n. sp.  are clustered with some species with high support, and difficult to separate with them by genetic distances and phylogenetic tree, indicating their close relationships. 

In this study, the diversities of chrysogorgiids in seamounts of the tropical Western Pacific and a few unknown deep-sea new species are revealed and described, which provides a reference for the hypothesis about seamount biodiversity distribution pattern. It is of great significance to explore and ultilize the deep-sea biological resources by exploring the evolutionary relationship of chrysogorgiids, enriching the sequences of the GenBank and the species information.

第1章 绪论...............................................................................................................1

1.1 金柳珊瑚科分类学特征及分布习性................................................................ 1

1.1.1 金柳珊瑚科的分类学特征..........................................................................1

1.1.2 形态学术语..................................................................................................4

1.1.3 金柳珊瑚科的分布和习性......................................................................... 9

1.2 金柳珊瑚科分类系统.......................................................................................11

1.3 国内外研究进展...............................................................................................12

1.4 本研究背景和意义...........................................................................................13

1.5 实验材料和方法...............................................................................................14

1.5.1材料来源…………….................................................................................14

1.5.2形态学方法.................................................................................................15

1.5.3测序及系统发育分析.................................................................................15

第2章 金柳珊瑚科种类描述............................................................................17

2.1 金柳珊瑚科各属分类检索...............................................................................17

2.2 金柳珊瑚属Chrysogorgia Duchassaing & Michelotti, 1864..........................18

2.3 虹柳珊瑚属Iridogorgia Verrill, 1883............................................................. 58

2.4 金相柳珊瑚属Metallogorgia Versluys, 1902..................................................71

2.5 波柳珊瑚属Rhodaniridogorgia Watling, 2007...............................................78

第3章 四种金柳珊瑚的系统发育研究..........................................................83

3.1 虹柳珊瑚属两物种的系统发育分析...............................................................83

3.2 金柳珊瑚属两物种的系统发育分析...............................................................86

第4章 金柳珊瑚的地理分布初探...................................................................91

4.1 各大洋中的物种组成与分布...........................................................................91

4.2 海山金柳珊瑚种类组成及共有种………………….………………………..94

第5章 结论.............................................................................................................95

参考文献...................................................................................................................97

致谢...........................................................................................................................103

作者简历及攻读学位期间发表的学术论文与研究成果........................ 105