Tetractinellids

Tetractinellids are a family of marine sponges belonging to the class Demospongiae. These sponges are characterized by their distinctive skeletal structure, which is composed of tetractine spicules. Tetractines are siliceous spicules that have four rays or axes radiating from a central point. This arrangement gives the tetractinellids their name. They are found in oceans worldwide, inhabiting a range of depths from shallow coastal waters to the deep sea. Tetractinellids exhibit a variety of body shapes, including massive, encrusting, and globular forms. Their large size and porous structure allow them to filter large volumes of seawater, extracting microscopic food particles. The skeletal framework, formed by the spicules, provides support and protection. Some species of tetractinellids are commercially important, particularly the species known as "bath sponges," which have a soft, compressible skeleton suitable for cleaning purposes. Reproduction in tetractinellids can be both sexual and asexual. Larval stages are typically planktonic before settling to the seabed to develop into new sponges. Their ecological role includes contributing to biodiversity and acting as habitat for other marine organisms.