Testate amoebas are like the snails of the microworld. The word "testate" refers to the amoeba's shell, which is also called a "test". They live in this shell just like a snail does; carrying it around and reaching out to collect food. Testate amoebas can either grow their shell, as in this illustration, or they can build one using particles from the environment, like Difflugia does. In soil, the shells are typically simple, smooth and somewhat flattened to help them travel through tight spaces. In more lush environments like moss, leaf litter or freshwater the shell can be much larger and can even have spikes and other fancy features.
Testate amoebas are very common in forest soils, but they can also be easy to find in compost or garden soils with plenty of organic material. They regularly show up in agricultural soil too, but tend to be smaller and less abundant there due to frequent disturbance and poor habitat.
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