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.

海龙形目（海马，海龙，喇叭鱼和亲戚）是一组具有不寻常和新颖的运动，繁殖和进食模式的鱼类。几乎所有的物种都有一个细长的吻，它们在觅食时会旋转着吻向猎物。最近的研究表明，海马和海龙正在使用功率放大来实现极快的旋转，从而导致任何鱼类记录中最快的罢工（不到2.5毫秒）。本研究将重建这种机械极端的喂养机制的顺序进化组装，并将调查这种喂养机制对头部形状多样性的后果。这项工作的发现将推进关于复杂的结构-功能关系如何演变并影响随后的结构演变的知识。这项研究将产生一套系统发育树，揭示200多个海龙类物种之间的进化关系。这将是一个宝贵的资源，并与其他研究人员分享，以促进对这一独特和不寻常的鱼类群体的进化历史的了解。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现有的课程和YouTube，吸引广大观众参与鱼类饲养策略的多样性。除了形成一个雄心勃勃的和综合的博士论文，这项研究将涉及有兴趣通过实践培训和经验追求干相关领域的本科生。这项研究将调查一个机械极端和复杂的摄食机制在海龙类鱼类的演变，开始与使用现代杂交富集（ultraconserved元素，UCEs）和下一代测序技术（目标#1）的遗传推断。先前的研究表明，海马和海龙使用功率放大来旋转它们的头部朝向猎物，比直接肌肉激活更快，并且已经提出这种机制依赖于头骨中独特的枢轴关节。形态和功能方法的组合，包括高速视频，生物力学建模和显微CT扫描将用于表征和比较海马和海龙相关谱系的摄食功能形态（目标#2）。目标#1的进化史将用于重建海龙形目鱼类功率放大摄食所需的结构和功能变化的进化历史，并测试关于拥有这种专门机制如何影响海龙形目鱼类头部形状进化的假设（目标#3）。将连续特征进化模型拟合到颅面形状数据中，并在软件程序OUwie中进行比较，以检验功率放大对颅面形态施加强稳定选择的假设。虽然文献的重点是创新，增加多样性，这项工作采用了模型测试的方法，以确定这种新的喂养机制是否可能限制形态多样化的宏观进化时间尺度。