Didemnidae

Didemnidae is a family of ascidians, commonly known as tunicates, belonging to the order Pleurogona. These marine invertebrates are colonial organisms, meaning a single individual is composed of many zooids working together. Didemnids are characterized by their calcareous tunic, a tough outer layer that often incorporates foreign particles like sand and spicules. This tunic can be thin and transparent or thick and opaque, providing protection and support to the colony. The zooids within a didemnid colony are typically small and arranged in a specific pattern, often with a central atrial opening from which water is expelled.

These ascidians are found in marine environments worldwide, from tropical to temperate waters, and are frequently observed attached to hard substrates such as rocks, coral reefs, and artificial structures. Many species are sessile, remaining in one place throughout their adult lives. Didemnids play important ecological roles, including filtration of water, providing habitat for other small organisms, and serving as a food source for some predators. Their ability to form extensive colonies can significantly influence the benthic environment. Reproduction in didemnids can be both sexual, involving the release of gametes into the water column, and asexual, through budding or fragmentation of existing colonies. The larval stage is free-swimming, allowing for dispersal to new locations. Some didemnid species have also been noted for their potential in biochemical research due to the unique compounds produced in their tissues.