Global diversity of polychaetes (Polychaeta; Annelida) in freshwater

Abstract

Species that are dependant on, or adapted to, freshwater environments are found in almost all mammalian orders, and two orders,\r the Cetacea and the Sirenia, are strictly aquatic and include some freshwater-dependant species. Overall, the aquatic and\r freshwater-dependant species represent around 70 of the more than 1,200 living or recent genera of mammals, and occur in all\r continents except Antarctica. They include some of the most endangered species of mammals, and several have gone extinct or\r become critically endangered in recent decades. One of the main threats is habitat loss or degradation. This chapter provides\r an overview of the freshwater species within each order of mammals, their evolutionary history, their relations to humans\r and their conservation status.