Stolidobranchia
Stolidobranchia is an order of sea squirts, commonly known as tunicates, within the subphylum Tunicata. This group encompasses a diverse range of filter-feeding marine invertebrates that exhibit a wide array of body forms and life histories. Their defining characteristic is their possession of a stolidobranch, a specialized structure in their pharynx responsible for filtering food particles from the surrounding water.
Common Names
Stolidobranchs are often referred to as "sea squirts" or "tunicates," terms that broadly encompass all members of the subphylum Tunicata. However, within this broader grouping, no specific common names are typically associated with the order Stolidobranchia.
Characteristics
Stolidobranchs share several key characteristics that distinguish them from other tunicate orders:
- Stolidobranch: As their name suggests, they possess a specialized filtering apparatus in their pharynx known as the stolidobranch. This structure is composed of a series of folds and slits that effectively trap food particles from the water current.
- Body Form: Stolidobranchs exhibit a variety of body forms, ranging from solitary, cylindrical individuals to colonial forms with complex branching systems.
- Life Cycle: Most stolidobranchs undergo a distinct life cycle that includes a free-swimming larval stage, often resembling a tadpole, which eventually settles and transforms into a sessile adult form.
- Filter Feeding: They are filter feeders, meaning they extract food particles from the surrounding water.
Environments
Stolidobranchs are found in a wide range of marine environments, including:
- Coastal waters: They are common in shallow coastal waters, often attached to rocks, seaweeds, or other marine substrates.
- Deep sea: Some stolidobranch species have adapted to life in the deep sea, inhabiting environments with low light levels and extreme pressure.
- Polar regions: Certain species are found in polar regions, demonstrating remarkable adaptability to cold temperatures.