Ichthyofauna associated with sandy beaches of the rio Machado, tributary of the rio Madeira, northern Brazil

The rio Machado is an large tributary of the rio Madeira, and investigations of the ichthyofauna are urgent given the current high threat of habitat loss on account of a hydroelectric plant under construction. Our inventory quantified 9,544 specimens, representing four orders and 38 species. Our study provides an unprecedented list of fish species from a poorly studied South American basin. This basin, which is considered one of the world’s biodiversity hotspots, presents high endemism, few cases of co-existence of phylogenetically related lineages, low species diversity, and few species occurrences with wide distribution