Adaptive radiation and the role of ecology in neotropical cichlid fish divergence

南美洲和中美洲的河流中有6000多种淡水鱼，这是地球上最多样化的鱼类动物群。值得注意的是，人们对这种惊人多样性的起源知之甚少。由这项提议资助的研究将以慈鱼科作为模型来研究新热带鱼类的进化。我们之前和正在进行的工作表明，至少有一类美国丽鱼，地龙亚科，通过一种被称为适应性辐射的过程实现了多样化。这种快速的多样性可能与血统入侵以前未被占领的生态位有关，这些血统后来成为新热带食地动物的现代属。根据这些结果，我们推测南美洲和中美洲的其他种群也可能通过适应性辐射实现了多样化。我们将通过描述所有新热带慈济鱼的进化史，重建它们进化过程中的过去事件，并揭示推动它们多样化的力量来检验这一假设。此外，我们还将通过研究南美洲慈鱼属的现代生态学和遗传学来评估生态压力在新热带慈鱼物种形成中的重要性。了解南美洲和中美洲鱼类的多样性是如何起源的，将有助于阐明热带淡水鱼起源的过程，特别是热带淡水鱼的起源，以及整个生物多样性。这项研究应该为未来理解新热带淡水鱼进化的努力铺平道路。该项目还将产生大量关于新热带慈济鱼生态的数据。这些信息应有助于养护工作，并揭示热带鱼类及其环境面对日益严重的威胁的潜在脆弱性，这些威胁形式包括无管制渔业、农业和水电开发的生境改变以及对水资源的日益增长的需求。

Rivers of South and Central America harbor more than 6000 species of freshwater fishes, the most diverse fish fauna on Earth. Remarkably, little is known about the origin of this astonishing diversity. Research funded by this proposal will study the evolution of Neotropical fishes using the family Cichlidae as a model. Our previous and ongoing work indicates that at least one group of American cichlids, the Geophaginae, diversified through a process known as adaptive radiation. This rapid diversification was probably associated with invasion of previously unoccupied ecological niches by lineages that would become the modern genera of Neotropical geophagines. Based on these results, we hypothesize that other groups of South and Central American cichlids may have also diversified by adaptive radiation. We will test this hypothesis by describing the evolutionary history of all Neotropical cichlids, reconstructing past events in their evolution and uncovering the forces that drove their diversification. Additionally, we will assess the importance of ecological pressures in Neotropical cichlid speciation by studying the modern ecology and genetics of the cichlid genus Geophagus from South America. Understanding how the diversity of South and Central American cichlids originated will shed light on the processes responsible for the origin of tropical freshwater fish in particular and biodiversity in general. This study should pave the way for future efforts to understand Neotropical freshwater fish evolution. The project also will generate extensive data on the ecology of Neotropical cichlids. This information should help conservation efforts and reveal potential vulnerabilities of tropical fishes and their environment to mounting threats in the form of unregulated fisheries, habitat modification for agriculture and hydroelectric development, and increasing demand on water resources.