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

模块化在 Loricarioidei 颅骨差异中的作用 - 新热带鲶鱼的高度多样化分支

• 批准号: RGPIN-2022-05006
• 负责人: Lujan, Nathan
• 金额: $ 2.11万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751448
• 关键词: Modularity; Role; Cranial; Disparification; Loricarioidei

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.

解决表型进化的驱动因素是进化生物学的中心目标。这项建议将测试生物力学脱钩-进化的损失或放松韧带联系-影响骨骼的多样化，使用新热带鲶鱼亚目Loricarioidei作为模型。甲鲶科动物涵盖超过1600个物种，它们具有奇异的头部形状和独特的头骨修饰，用于进食、防御和运动，例如专门吃血、薄外套或木材的颌骨，以及用于竞争和表面附着的可翻转的颊齿。它们还表现出可变的、分支特异性的三个主要颅内韧带的缺失：1）前颌骨到筛中，2）双侧下颌支彼此连接，3）下颌骨到鳃盖。1996年的一项有影响力的研究发现，颅骨差异在毛鼻蝠科中最低，保留了所有三个联系，而在甲鲶科中最高，缺乏所有三个联系，但很少有属被检查，系统发育的影响没有被明确考虑。该提案利用了超过20年的实地收集与最先进的方法在生物基因组学，解剖可视化，比较方法，和人口基因组学，以完善理论关于解剖解耦和模块化如何影响生物多样性。我将在创新和综合生物多样性研究方面培训20名HQP（14名本科生，3名硕士，3名博士），并有机会获得实地，实验室和分类学专业知识。我们将生成并分析：1）分类密集的系统发育假说，涵盖800蛋白编码位点，439种（26%），所有170属，2）node-dated系统发育年表的甲类多样化使用化石和地质地理距离年龄校准，和3）三维数字解剖库，包括高分辨率的头颅CT扫描，从所有分类群的甲类。基于CT的表面网格和基于地标的几何形态测量学将划定颅内字符套件的形态空间，这些字符套件在整个甲鲶亚目中相互连接。我们将使用系统发育比较方法来估计多样化率，谱系重叠的形态空间，和进化收敛到适应性高峰，并将研究物种形成和选择机制，使用基于SNP的结构和人口高度混合的3种亚马逊组合。估计起源于早白垩世，Loricarioidei已经在北方南部和中美洲南部的淡水中多样化超过100 Ma。它们现在是无处不在的新热带区食藻动物、反食藻动物、反食虫动物和寄生虫。因此，我的研究计划将有助于了解一个物种丰富的分支的专门消费者多样化在地球上最具生物多样性的进化剧院之一，并将告知积极辩论模块化的作用作为多样化的促进剂和一个主题能够统一的基因组和表型进化理论。