The Class Euglenophyceae is a group of unicellular, photosynthetic eukaryotes that are mainly found in freshwater ecosystems. This class is characterized by its unique form of movement called euglenoid movement, which is achieved through the action of a flagellum. Some synonyms for Euglenophyceae include euglenoids, euglenids, and euglenales. A distinguishing feature of the Euglenophyceae is the presence of a proteinaceous, pellicle or outer layer, which is believed to be involved in regulating the organism's shape and motility. Members of this class exhibit a wide range of morphological diversity, with some species resembling animal cells more than plant cells. Euglenophyceae is an important class of algae that plays a role in nutrient cycling and also serves as a food source for other aquatic organisms.