Chaos (genus)

Chaos is a genus of single-celled amoeboid organisms in the family Amoebidae. The largest and most-known species, the so-called "giant amoeba" (Chaos carolinensis), can reach lengths up to 5 mm, although most specimens fall between 1 and 3 mm.

Members of this genus closely resemble those of the genus Amoeba and share the same general morphology, producing numerous cylindrical pseudopods, each of which is rounded at the tip. However, while Amoeba have a single nucleus, Chaos can have as many as a thousand. Because of this attribute, C. carolinensis was once placed in the genus Pelomyxa alongside the giant multinucleate amoeba Pelomyxa palustris. Recently, molecular phylogenetic studies of this species have confirmed the view of some earlier researchers that it is more closely related to Amoeba than to Pelomyxa. The species is now placed in the independent genus Chaos, a sister group to Amoeba.