DISSERTATION RESEARCH: Innovation and constraint: the evolution of power-amplified feeding in syngnathiform fishes

论文研究：创新与约束：合颌鱼类功率放大摄食的演化

• 批准号: 1500800
• 负责人: Peter Wainwright
• 金额: $ 2.03万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1500800&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Innovation; constraint; evolution

Syngnathiformes (seahorses, pipefishes, trumpetfish and relatives) are a group of fishes with unusual and novel modes of locomotion, reproduction, and feeding. Nearly all species are characterized by an elongated snout, which they rotate towards prey during feeding strikes. Recent research has shown that seahorses and pipefish are using power amplification to achieve extremely fast rotations, resulting in strikes that are among the fastest recorded for any fish (less than 2.5 milliseconds). This research will reconstruct the sequential evolutionary assembly of this mechanically extreme feeding mechanism and will investigate the consequences of this feeding mechanism on head shape diversity. The findings of this work will advance knowledge about how complex structure-function relationships evolve and influence subsequent structural evolution. The study will produce set of phylogenetic trees that reveal the evolutionary relationships among over 200 syngnathiform species. These will be a valuable resource and shared with other researchers to advance knowledge of the evolutionary history of this unique and unusual group of fishes. Other data and products from this research, including slow-motion videos, will engage a wide audience in the diversity of fish feeding strategies by incorporation into existing coursework at the University of California, Davis and through YouTube. In addition to forming an ambitious and integrative doctoral dissertation, this research will involve undergraduates interested in pursuing STEM related fields through hands-on training and experience. This research will investigate the evolution of a mechanically extreme and complex feeding mechanism in syngnathiform fishes, beginning with the inference of a phylogeny using modern hybrid-enrichment (ultraconserved elements, UCEs) and next-generation sequencing technologies (Objective #1). Previous research has shown that seahorses and pipefish use power amplification to rotate their head towards prey faster than would be possible by direct muscle activation, and it has been proposed that this mechanism relies on a unique pivot joint in the skull. A combination of morphological and functional approaches including high-speed video, biomechanical modeling, and micro-CT scanning will be used to characterize and compare the feeding functional morphology of lineages related to seahorses and pipefish (Objective #2). The phylogeny from Objective #1 will be used to reconstruct the evolutionary history of the structural and functional changes necessary for power-amplified feeding in syngnathiform fishes and to test hypotheses about how the possession of this specialized mechanism has influenced the evolution of head shape in syngnathiforms (Objective #3). Models of continuous character evolution will to be fit to craniofacial shape data and compared in the software program OUwie to test the hypothesis that the possession of power amplification exerts strong stabilizing selection on craniofacial morphology. While the literature focuses on innovations that increase diversity, this work incorporates a model-testing approach to determine whether this novel feeding mechanism may constrain morphological diversification at macroevolutionary timescales.

海马目（海马、海龙、喇叭鱼及其近亲）是一类具有不寻常且新颖的运动、繁殖和摄食模式的鱼类。几乎所有物种都有一个细长的口鼻部，它们在捕食时会向猎物旋转口鼻部。最近的研究表明，海马和海龙正在利用功率放大来实现极快的旋转，从而产生鱼类中最快的攻击速度（小于 2.5 毫秒）。这项研究将重建这种机械极端进食机制的顺序进化组装，并将研究这种进食机制对头部形状多样性的影响。这项工作的发现将增进人们对复杂结构-功能关系如何演化并影响后续结构演化的认识。该研究将生成一组系统发育树，揭示 200 多个合颌类物种之间的进化关系。这些将是宝贵的资源，并与其他研究人员共享，以增进对这一独特且不寻常的鱼类的进化历史的了解。这项研究的其他数据和产品，包括慢动作视频，将通过纳入加州大学戴维斯分校的现有课程并通过 YouTube 吸引广泛的受众了解鱼类喂养策略的多样性。除了形成一篇雄心勃勃的综合性博士论文外，这项研究还将让有兴趣通过实践培训和经验追求 STEM 相关领域的本科生参与。这项研究将研究合颌鱼类机械极端和复杂的摄食机制的进化，首先使用现代混合富集（超保守元件，UCE）和下一代测序技术（目标＃1）推断系统发育。先前的研究表明，海马和海龙利用功率放大将头部旋转到猎物的速度比直接肌肉激活的速度更快，并且有人提出这种机制依赖于头骨中独特的枢轴关节。形态学和功能方法的结合，包括高速视频、生物力学建模和微型 CT 扫描，将用于表征和比较与海马和海龙相关的谱系的摄食功能形态（目标#2）。目标#1的系统发育将用于重建合颌鱼类功率放大摄食所需的结构和功能变化的进化历史，并检验关于这种特殊机制的拥有如何影响合颌鱼类头部形状进化的假设（目标#3）。连续性格进化模型将与颅面形状数据进行拟合，并在软件程序OUwie中进行比较，以检验功率放大的拥有对颅面形态产生强稳定选择的假设。虽然文献关注的是增加多样性的创新，但这项工作采用了模型测试方法来确定这种新颖的喂养机制是否可以在宏观进化时间尺度上限制形态多样化。