Milioliida

Milioliida is an order of foraminifera, which are single-celled organisms belonging to the Rhizaria supergroup. They are characterized by their imperforate calcareous shells, often referred to as tests. These tests are typically composed of calcium carbonate and are built in a variety of complex coiling patterns, most commonly planispiral, streptospiral, or quinqueloculine. The chambers within the test are interconnected, allowing for the extension of pseudopodia, which are used for locomotion and feeding.

The Milioliida are predominantly marine organisms, found in a wide range of oceanic environments from shallow coastal waters to the deep sea. They are particularly abundant in warm, tropical and subtropical seas, often inhabiting coral reefs and seagrass beds. Many species are benthic, living attached to substrates like algae or sediment, while others are planktonic. Their diet consists of small planktonic organisms, diatoms, and bacteria, which they capture using their pseudopodia.

Fossil records indicate that Milioliida have a long evolutionary history, with evidence dating back to the Devonian period. They have played a role in the formation of sedimentary rocks throughout geological time. Due to their distinctive test morphologies and widespread distribution, fossilized milioliids are valuable indicators for paleoenvironmental and paleoceanographic reconstructions. Modern Milioliida are studied for their ecological roles, particularly as components of benthic communities and as indicators of water quality.