Pentameras are a group of protozoans found mainly in freshwater habitats. They are an important part of the microbial ecosystem and are essential for decomposition and nitrogen cycle processes. Pentameras are easily identifiable by the characteristic five-lobed scales that form their outer shell. The scales are arranged in a plate-like or polygonal pattern, giving them the common name “pentamerate”. Pentameras feed by scraping off organic material off surfaces or by engulfing bacteria and organic debris. They use a modified oral groove to obtain nutrition, and are able to contract this groove to capture their food. They can also ingest bacteria and other particles directly through their body wall. They excrete waste and other small suspended particles as colorful clouds. Pentameras reproduce by binary fission, where a single cell divides in two. The two new organisms will have identical genetic material and will bear the same characteristics that their parent had. Due to their role in the environment, particularly in regards to water quality and nutrient cycling, pentameras have been studied by scientists as part of environmental management and river sciences. Research has shown that polluted environments have a decrease in the number of these animals, indicating that they are able to detect pollutants and respond accordingly.