PosterMGS.pdf

<p>Neotropical freshwater systems are extraordinarily diverse, yet little is known about the small scale evolutionary processes that shape and maintain this diversity. A large portion of these ecosystems is currently in peril due to the presence of invasive species, fishing exploitation, climate change impacts, and habitat loss related to river impoundments, deforestation, and mining. The Xingu River, a tributary of the Amazon River, is undergoing major changes with the construction of the Belo Monte hydroelectric megadam. This study focuses on <i>Hypancistrus </i>sp., an undescribed armored catfish species endemic to the lower and middle Xingu River that presents remarkable color variation and is abundant across its distribution. These fishes are highly sought after in the aquarium trade, however scientific studies investigating their ecology, taxonomy, and evolution are still lacking. We will use population genetics, phylogeography, and landscape genetics approaches to investigate the genetic diversity and structure of <i>H</i>. sp.. We obtained 133 tissue samples from 20 sampling sites covering the entire species distribution, and will construct ddRAD libraries to generate genomic SNP data. We will investigate three non-exclusive hypotheses: 1) existence of a general pattern of downstream increase in genetic diversity; 2) waterfalls act as barriers to gene flow; 3) environmental variables associated with rapids habitat (e.g. water velocity and substrate) are important selective agents for this species. Our results will be invaluable to monitor the impacts of the Belo Monte dam and to better understand diversification processes in the Neotropical freshwaters.</p