Synallactida
Synallactida is an order of marine worms belonging to the phylum Annelida. They are commonly known as “spoon worms” due to their distinctive spoon-shaped head. Synallactida includes a wide range of species, with over 100 described species. They are characterized by their unique feeding apparatus, which is adapted for scavenging or deposit feeding.
Characteristics
Synallactids possess a number of unique characteristics that distinguish them from other annelids. These include:
- A spoon-shaped head, called a "prostomium," which is often adorned with sensory tentacles.
- A distinctive "pharyngeal apparatus," which is a complex, muscular structure used for feeding. It is located in the anterior region of the body and can be everted to capture food particles.
- A body divided into numerous segments, with each segment typically bearing a pair of parapodia, which are fleshy appendages that aid in locomotion.
- A lack of a true circulatory system, with blood circulating through the body cavity.
- A simple nervous system, with a brain located in the head and a ventral nerve cord extending along the body.
Environments
Synallactids are found in a variety of marine habitats worldwide, including:
- Intertidal zones
- Subtidal sediments
- Deep-sea trenches
- Coral reefs
They play an important role in marine ecosystems, as they contribute to the decomposition of organic matter and the cycling of nutrients.
References
For further information on Synallactida, you can refer to the following reliable sources: