Miliolidids

Miliolidids are a diverse superfamily of benthic foraminifera, single-celled organisms characterized by their calcium carbonate shells, known as tests. These microorganisms are found globally in marine environments, from shallow coastal waters to the deep sea, and are particularly abundant in tropical and subtropical regions. A defining feature of miliolidids is their distinctive shell morphology, which is typically composed of chambers that are added in a curved, non-reentrant, or planispiral arrangement. This can result in a variety of overall shapes, including oval, fusiform, or even flattened forms. The shell material is usually imperforate and can be porcellaneous, meaning it has a smooth, opaque, and often white appearance. Reproduction in miliolidids is primarily asexual, occurring through binary fission. Their feeding strategy is typically heterotrophic, with individuals consuming small organic particles or engaging in symbiosis with photosynthetic algae. Fossilized miliolidid tests are common in marine sedimentary rocks and are valuable indicators of past environmental conditions, particularly water depth and salinity, making them important for paleoceanographic studies. The superfamily encompasses several families, each with further variations in shell structure and chamber arrangement.