【作者】 甘志彬；

【导师】 李新正；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋生物学， 2014， 博士

【摘要】 隶属于长臂虾总科Palaemonoidea的拟贝隐虾科Anchistioididae、叶颚虾科Gnathophyllidae、膜角虾科Hymenoceridae以及长臂虾科Palaemonidae当中的隐虾亚科Pontoniinae，四个类群在总体形态特征以及生活环境等方面非常相似；他们之间的系统演化关系以及分类地位等问题一直存在争议。本研究中采用1种线粒体基因（16S rRNA）和3种细胞核基因（histone3，NaK和enolase）构建包括所属这四个类群的28个属43个物种的系统进化树。系统进化树显示叶颚虾科和膜角虾科的物种嵌合到隐虾亚科物种的分支当中。这一结果与以往的分子系统学研究以及幼体形态学研究的结果一致。叶颚虾科和膜角虾科区别于长臂虾总科中其他科的形态特征为退化或消失的大颚切齿突和增宽的第三颚足内肢。与此相同或相似的特征状态同样发现于隐虾亚科中的部分类群。根据一系列文献对叶颚虾科和膜角虾科中种属的描述，发现除了第三颚足内肢形态特化之外，这些种属的其他形态特征都可以很好地符合隐虾亚科的定义特征。在隐虾亚科的类群当中，因共栖宿主的不同第三颚足内肢同样存在着各式各样的特化形式。推测叶颚虾和膜角虾第三颚足内肢形态是为了适应不同的生活方式（共栖或取食于海星或海胆），而发生特化的一种性状变异；这一性状变异可以被包含于隐虾亚科各式各样的第三颚足内肢性状变异之中。根据系统发育分析，拟贝隐虾科与隐虾亚科亲缘关系较远，这与两者在幼体形态和成体腹肢形态特征的显著差异相印证。分析中获得的系统进化树将隐虾亚科及叶颚虾科和膜角虾科的种属分为两个主要类群：其中之一形态特征比较原始，与长臂虾亚科部分种属的特征状态相似；另一个类群则表现出更多的特化特征。隐虾亚科是长臂虾总科中种类最多、生物多样性最高、生活方式最多样的科级分类单元，主要分布于印度-西太平洋热带亚热带珊瑚礁海域。对隐虾亚科内部种属之间的系统演化以及物种多样化与共栖生活方式的关系研究基本处于空白，但又是极具吸引力的课题。本研究采用2种线粒体基因（12S rRNA和16SrRNA）和2种细胞核基因（histone3和NaK）探索分布于印度-西太平洋海域的隐虾亚科及其邻近类群内部的系统演化关系，推测隐虾亚科生物多样性与共栖生活方式之间的联系。构建的系统进化树包括了45个属104个物种。与之前的系统发育分析研究相比，新增10个属被显示为单系类群，而Dactylonia属和小岩虾属Periclimenaeus被显示为并系群。根据系统发育分析结果，分布于浅水水域的海百合共栖隐虾类群可以分为不同的支系，这与通过形态特征相似性分析得出的结果基本相同。于此相似，与双壳类软体动物共栖的隐虾类也明显分为两个支系：近隐虾属Anchiopontonia+江瑶虾属Conchodytes和贝隐虾属Anchistus；两者在形态上也具有明显差别。同样的，与海胆共栖的隐虾类也分为不同的支系，散布于不同的分支当中。这种现象说明与相同宿主共栖的隐虾类可以通过不同的途径进化而来，即隐虾类在演化过程中存在着多重入侵。隐虾亚科中呈现出数量繁多的独特形态特征以及性状状态的不稳定性可以通过两个推测得到解释：1)隐虾类当中的性状特异性是其为了适应不同的生态位或者宿主而在自然选择的压力下发展而成；2)隐虾类的性状具有较强的形态可塑性，而共栖生活方式促进了这一过程并提供了“模具”，换言之，隐虾类的系统演化受到其共栖宿主的强烈影响。采用所属长臂虾科两亚科31属39种长臂虾的线粒体基因16S rRNA和核基因H3序列片段，以鼓虾科细足鼓虾(Alpheus gracilipes)为外群初步分析长臂虾亚科和隐虾亚科之间的系统发育关系。构建的三种系统进化树均不支持将长臂虾科分为两个亚科的分类安排。并且在形态特征上兼具两亚科特征的大部分长臂虾类群在通过不同方式构建的系统进化树中位置并不稳定，而且分支置信度均很低，即目前仅采用少数分子标记和少数类群单元的系统发育分析没能很好地解决这些类群的系统演化地位。未来应该综合更多的分子标记和分类单元，以求获得比较清晰的长臂虾科系统演化关系。更多还原

【Abstract】 The four palaemonoid (sub)families Anchistioididae, Gnathophyllidae,Hymenoceridae, and Pontoniinae are similar in morphology and all living in marinehabitats. Their systematic relationships are controversial. In this study, we usedsequences from four genes, including one mitochondrial ribosomal gene (16S rRNA)and three nuclear genes (H3, Nak and Enolase) to explore the phylogeneticrelationships among these four taxa. Our tree based on43species belonging to28genera shows that Gnathophyllidae, Hymenoceridae are nested within Pontoniinae.This result is consistent with evidence from larval morphology. The definingcharacteristics of Gnathophyllidae and Hymenoceridae, vestigial or missing mandibleincisor and broadened third maxilliped, same or similar forms could be found inPontoniinae as well; vice versa, based on description of species in literatures,gnathophyllids and hymenocerids meet the mainly diagnostic characteristics ofPontoniinae. The peculiar forms of third maxilliped presenting in gnathophyllids andhymenocerids might be the result of adaptive evolution, as well as the particularfeatures present in pontoniines. Anchistioididae is remoted to Pontoniinae based onphylogenetic tree, consistenting with the distinct morphological difference inpleopods. The pontoniine genera analyzed (together with Gnathophyllidae andHymenoceridae) are separated into two clades. The members of Clade I exhibitprimordial characters similar to that of Palaemoninae might be direct descendants ofancestor of Pontoniinae; and members of Clade II are relatively specialized.The phylogenetic relationships and evolutionary processes within the subfamilyPontoniinae, a speciose group of caridean shrimp with diverse lifestyles associatedwith coral reefs, are an interesting subject of study. In the present work, twomitochondrial ribosomal genes (12S and16S rRNA) and two protein-coding nucleargenes (histone3(H3) and the sodium–potassium ATPase α-subunit (Nak)) wereemployed to construct a phylogenetic tree including42genera and101species ofIndo-Pacific pontoniine shrimps. Compared to previous studies, ten additional generawere shown to be monophyletic groups, and the genera Dactylonia and Periclimenaeus were shown to be paraphyletic. The shallow-water crinoid-associatedpontoniines were divided into several groups according to the phylogenetic tree.These groups were mostly consistent with the morphological analysis conducted byprevious works. The studied bivalve-associated taxa exhibited ancestries that weretraceable to different lineages, and two groups could be distinguished:Anchiopontonia+Conchodytes and Anchistus. A similar situation occurred in the seaurchin-associated pontoniines. It is logical to speculate that pontoniines sharing thesame hosts may present different evolutionary pathways resulting from parallelintrusions of their hosts by morphologically plastic ancestral groups. Two hypotheseswere generated to account for the unique features observed in pontoniines:1) variousspecial ecological niches have been the major selective force molding the current highdiversity of pontoniines, and2) The transition of symbiosis in Pontoniinae results inthe morphological plasticity of pontoniines. In other words, the phylogeny of thePontoniinae is affectted by their hosts.The present study utilized a mitochondria gene (16S rRNA) and a nuclear gene(H3) to explore the phylogenetic relationships of subfamilies Palaemoninae andPontoniinae. The inner group contains31genera and39species, with specie ofAlpheidae (Alpheus gracilipes) as out group. The phylogenetic trees were constructedusing different methods and softwares. The scheme of two subfamiles withinPalaemonidae was denied by all the trees. And most of the genera which present bothmorphological characteristics of Palaemoninae and Pontoniinae were unresolved bythe phylogenetic trees. This work is just a preliminary study, if more molecularmarker and taxa can be involved, more precious and comprehensive phylogeneticrelationships within Palaemonidae could be figured out in the future.更多还原