Dimeroida

Dimeroida is a subclass of the class Demospongiae, which includes the majority of known sponge species. Demosponges are characterized by their porous, collagenous skeleton and lack of siliceous spicules. Dimeroida is distinguished by its dimeric structure, meaning that the sponge body is composed of two distinct layers: the pinacoderm and the choanoderm.

The pinacoderm is the outer layer of the sponge, which is composed of flattened cells called pinacocytes. This layer provides structural support and protection for the sponge. The choanoderm is the inner layer, which is composed of flagellated cells called choanocytes. These cells are responsible for filtering water and capturing food particles.

Dimeroida sponges are typically found in marine environments, where they attach to hard substrates such as rocks or coral. They are often found in shallow waters, but some species can be found at greater depths. Dimeroida sponges play an important role in marine ecosystems, as they help to filter water and recycle nutrients.

Dimeroida is a diverse subclass, with over 1,000 known species. These sponges exhibit a wide range of morphologies and ecological roles, making them an important group for study in marine biology.