Tetractinellida
Tetractinellida is an order of sponges belonging to the class Demospongiae. They are commonly known as tetractinid sponges and are characterized by their spicules, which are needle-like structures that provide support to the sponge. Tetractinid sponges are diverse and widespread, inhabiting various marine environments around the world.
Characteristics
Tetractinellida sponges are distinguished by their tetractine spicules, which are four-rayed spicules with a central point. These spicules are made of silica and can be smooth or ornamented with spines. Some tetractinid sponges also possess other types of spicules, such as monaxons (one-rayed) or triaxons (three-rayed). The spicules can be arranged in various patterns, forming a complex skeletal framework within the sponge.
Environments
Tetractinellida sponges are found in a wide range of marine habitats, including:
- Shallow coastal waters
- Deep-sea environments
- Coral reefs
- Rocky shores
- Seagrass beds
Diversity
The order Tetractinellida is a diverse group of sponges, with over 1,000 species described. They exhibit a wide range of colors, shapes, and sizes. Some tetractinid sponges are small and inconspicuous, while others can grow to be quite large. Some species are encrusting, forming thin layers on surfaces, while others are erect and branched.
References
For further information, please refer to the following references: