Terebellida
Terebellida is an order of marine polychaete worms, commonly known as “Terebellids.” They are a diverse group with over 800 known species found in various marine habitats worldwide. Terebellids are characterized by their distinctive body shape, which is typically long and cylindrical, with a prominent head and a segmented body.
Characteristics
Terebellids possess several distinguishing features that differentiate them from other polychaete orders. They typically have a pair of long, retractable tentacles called "tentacles" that are used for sensing and feeding. Terebellids also have a unique structure called a "branchial plume," which is a cluster of gill filaments that helps them breathe. Their bodies are covered in bristles called "chaetae," which aid in locomotion and burrowing. The most prominent feature of Terebellids is their well-developed "branchial crown" consisting of numerous branching filaments.
Environments
Terebellids are found in a wide variety of marine environments, including intertidal zones, subtidal zones, and deep sea habitats. They prefer soft-bottom sediments, such as sand, mud, and gravel, where they burrow and create tubes for protection and feeding. Some species are even found in association with coral reefs and other benthic communities.
Feeding
Terebellids are primarily deposit feeders, meaning they obtain their food by ingesting sediment and extracting organic matter. Their long tentacles are used to collect sediment and bring it to their mouths. Some species are also suspension feeders, using their branchial plumes to filter food particles out of the water column.
Reproduction
Terebellids are sexually reproducing animals, with separate sexes. They release sperm and eggs into the water column, where fertilization occurs. The fertilized eggs develop into free-swimming larvae that eventually settle to the bottom and metamorphose into juveniles.
Ecological Role
Terebellids play an important role in marine ecosystems by breaking down organic matter and cycling nutrients through the sediment. They also serve as a food source for other marine organisms, such as fish, crustaceans, and seabirds.
Examples of Terebellida
There are many examples of Terebellids, including:
- Terebella lapidosa
- Pectinaria belgica
- Amphitrite ornata