Euglena variabilis is a species of biota in the family Euglenaceae. They are associated with freshwater habitat. They are native to Rio De Janeiro and Amazônia.
Definition: Living in the fluid medium (water or air) but unable to maintain their position or distribution independently of the movement of the water/air mass (adapted from Lincoln et al., 1998).
Definition: A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
