Lituolida

Lituolida is an informal group of foraminifera, which are single-celled organisms belonging to the amoeboid protists. They are characterized by their coiled or labyrinthic shell structures, known as tests, which are typically made of agglutinated particles. These particles, such as sand grains or shell fragments, are cemented together with an organic secretion. The name "Lituolida" itself refers to the ancestral and characteristic lituus (spiral trumpet) shape of some of its members.

These organisms are exclusively marine, inhabiting a wide range of environments from shallow coastal waters to the deep sea. Their fossil record extends back to the Devonian period, making them an ancient lineage of shelled protists. Lituolid foraminifera play roles in marine ecosystems, contributing to sediment composition and serving as a food source for other organisms. Due to their agglutinated test and often microscopic size, their identification and classification can be challenging, relying on detailed examination of test morphology and internal structures. While not a formal taxonomic rank, the term Lituolida is useful for grouping together foraminifera with similar test construction strategies.