säteiläiset

Säteiläiset are a large group of amoeboid protists. They are characterized by their intricate, often radially arranged pseudopods, which are used for locomotion and feeding. Many säteiläiset have a hard outer shell called a test, which is made of various materials including calcium carbonate, silica, or chitin. The morphology of these tests is highly diverse and often used for species identification.

Säteiläiset are found in a wide range of environments, from freshwater and marine habitats to soil. They are particularly abundant in marine plankton, where some species form vast blooms. Their diet consists mainly of bacteria, algae, and other small protists, which they capture using their pseudopods.

Reproduction in säteiläiset can be both asexual and sexual. Asexual reproduction typically occurs through budding or fission, while sexual reproduction involves the fusion of gametes. The life cycles of many species are complex and may include different stages and forms.

Fossilized tests of säteiläiset are common in the geological record, providing valuable information about past marine ecosystems and ocean conditions. Their diversity and abundance in certain fossil assemblages have made them important index fossils for stratigraphy. Some groups of säteiläiset have also been studied for their potential roles in nutrient cycling within aquatic ecosystems.