Amoebidae – Microworld

Family Amoebidae Ehrenberg, 1838

Diagnosis: Locomotive amoebae usually larger than 80 µm in length, with cylindrical pseudopodia bearing hyaline caps. Some species are monopodial, but most are polypodial. Cytoplasmic crystals are common. The nucleus often contains nuclear material in numerous small fragments.

Key to the genera:

1	Amoeba multinucleate	2
–	Amoeba usually with one nucleus	3
2	Amoeba usually polypodial, with longitudinal ridges	Chaos
–	Amoeba usually monopodial, without longitudinal ridges	Parachaos
3	Amoeba monopodial, branching only when changing direction	4
–	Amoeba usually polypodial	5
4	Amoeba free-living	Trichamoeba
–	Amoeba parasitic on freshwater coelenterates (Hydra)	Hydramoeba
5	Amoeba usually > 200 µm; nucleus granular	6
–	Amoeba usually < 200 µm; nucleus with few nucleolar pieces	Deuteramoeba
6	With longitudinal ridges	Amoeba
–	Without longitudinal ridges	Metachaos