Modularity's Role in Cranial Disparification of the Loricarioidei - A Hyperdiverse Clade of Neotropical Catfishes

解决表型进化的驱动因素是进化生物学的中心目标。这项建议将以新热带叉尾叉叉亚目叉尾叉叉亚目为模型，测试生物力学脱钩--韧带连接的进化性丧失或松弛--如何影响骨学多样化。Loricariys Span&gt；1600种，具有奇怪的头部形状和独特的头骨修改，用于摄食、防御和移动，例如专门吃血、粘液鸟或木材的下巴，以及用于竞争和表面附着的可变颧齿。它们还显示出三种主要的颅内韧带的分支缺失：1)上颌骨至中筛，2)双侧下颌支相互连接，3)下颌骨至盖骨。1996年的一项有影响力的研究发现，在毛滴虫科中，颅骨差异最小，它保留了所有三个联系，而在缺乏所有三个联系的Loricariidae中，头骨差异最大，但很少有属被研究，系统发育的影响也没有被明确考虑。这项建议利用&gt；20年来在系统基因组学、解剖学可视化、比较方法和种群基因组学方面的最先进方法进行野外采集，以完善关于解剖分离和模块化如何影响生物多样性的理论。我将培训20名HQP(14名本科生，3名硕士，3名博士)进行创新和综合的生物多样性研究，并有机会获得野外、实验室和分类学方面的专业知识。我们将生成和分析：1)横跨&GT的Loricarioidei分类单元密集的系统发育假说；800个蛋白质编码基因座，439个物种(26%)，以及所有170个属；2)节点日期的系统发育年表，用于利用化石和地质替代年龄校准；以及3)一个3D数字解剖库，包括来自系统发育中所有分类群的高分辨率头颅CT扫描。基于CT的表面网格和基于地标的几何形态测量将划定贯穿Loricarioidei的可变相互关联的颅内特征套件的形态空间。我们将使用系统发育比较方法来估计多样性比率、形态空间中的谱系重叠和进化收敛到适应高峰，并将使用基于SNP的结构和高度混合的亚马逊3物种组合的人口学来研究物种形成和选择机制。据估计，Loricarioidei的起源于早白垩世，在南美洲北部和中美洲南部的淡水中形成了超过100 Ma的多样性。它们现在是无处不在的新热带食草动物、食害性食肉动物、逆食性食肉动物和寄生虫。因此，我的研究计划将有助于理解物种丰富的专业消费者分支如何在地球上生物多样性最丰富的进化剧场之一实现多样化，并将推动一场关于模块化作为多样化促进剂的作用的积极辩论，以及能够统一基因组和表型进化理论的主题。

Resolving drivers of phenotypic evolution is a central goal of Evolutionary Biology. This proposal will test how biomechanical decoupling - evolutionary loss or relaxation of ligamentous linkages - affects osteological diversification, using the Neotropical catfish suborder Loricarioidei as a model. Loricarioids span >1600 species having bizarre head shapes and unique skull modifications for feeding, defence, and locomotion, such as jaws specialized to eat blood, slimecoat, or wood, and evertible cheek-teeth for competition and surface attachment. They also exhibit the variable, clade-specific absence of three major intracranial ligaments linking: 1) premaxillae to the mesethmoid, 2) bilateral mandibular rami to each other, and 3) mandibles to the opercula. An influential 1996 study found cranial disparity to be lowest in family Trichomycteridae, which retains all three linkages, and highest in Loricariidae, which lacks all three linkages, but few genera were examined and phylogenetic influence was not explicitly considered. This proposal leverages >20 years of field collections with state-of-the-art methods in phylogenomics, anatomical visualization, comparative methods, and population genomics to refine theory regarding how anatomical decoupling and modularization affects biological diversification. I will train a diverse group of 20 HQP (14 undergrads, 3 MSc, 3PhD) in innovative and integrative biodiversity research with opportunities to gain field, laboratory, and taxonomic expertise. We will generate and analyze: 1) taxon-dense phylogenetic hypotheses for Loricarioidei spanning >800 protein-coding loci, 439 species (26%), and all 170 genera, 2) a node-dated phylogenetic chronogram for loricarioid diversification using fossil and geological vicariance age calibrations, and 3) a 3D digital anatomical library comprising high-resolution cranial CT-scans from all taxa in the phylogeny. CT-based surface meshes and landmark-based geometric morphometrics will delimit the morphospace of intracranial character suites that are variably interlinked across Loricarioidei. We will use phylogenetic comparative methods to estimate diversification rates, lineage overlap in morphospace, and evolutionary convergence to adaptive peaks, and will examine speciation and selection mechanisms using SNP-based structure and demography of a highly admixed 3-species Amazonian assemblage. With an estimated origin in the Early Cretaceous, Loricarioidei has diversified throughout freshwaters of northern South and southern Central America for more than 100 Ma. They are now ubiquitous Neotropical algivores, detritivores, invertivores, and parasites. Thus, my research program will help to understand how a species-rich clade of specialized consumers diversified in one of Earth's most biodiverse evolutionary theatres, and will inform an active debate on modularity's role as a diversification accelerant and a motif capable of unifying genomic and phenotypic evolutionary theory.