Polychaos dubium

Polychaos dubium is a freshwater amoeboid and one of the larger species of single-celled eukaryote. Like other amoebozoans, P. dubium moves by means of temporary projections called pseudopods. P. dubium reportedly has one of the largest genome size of any organism known, though the authors of a 2004 study suggest treating that measurement with caution.

Polychaos dubium was previously known as Amoeba dubia. The author who named the species later recognized it as different from species of Amoeba, and so designated it the type species of the genus Polychaos. Unlike species of Amoeba, P. dubium lacks longitudinal ridges on its pseudopods.