Anthoathecata
Anthoathecata is a subclass within the class Hydrozoa, which belongs to the phylum Cnidaria. This subclass includes a diverse group of marine invertebrates, characterized by their polyp-based life cycle and the presence of stinging cells called nematocysts. They are typically found in a variety of marine environments, ranging from shallow coastal waters to the deep sea.
Common Names
Anthoathecata are commonly referred to as "hydroids" or "hydrozoans." These terms are often used interchangeably, but it's important to note that "hydrozoan" refers to the entire class, while "hydroid" can be a more general term used for both Anthoathecata and Leptomedusae (another subclass within Hydrozoa).
Characteristics
Anthoathecata share several key characteristics:
- Polyp-based life cycle: They typically exhibit a polyp-based life cycle, with a dominant polyp stage. Polyps are cylindrical, stalk-like structures with a mouth surrounded by tentacles.
- Nematocysts: Anthoathecata possess nematocysts, specialized stinging cells used for defense and capturing prey. These cells are located on their tentacles and can inject venom.
- Medusa stage (optional): Some species within Anthoathecata exhibit a medusa stage, which is a free-swimming, bell-shaped form. This stage is usually less prominent compared to the polyp stage.
- Colonial lifestyle: Many species of Anthoathecata live in colonies, with individual polyps connected by a shared body wall. The colony can take various forms, including branching structures, encrusting mats, or even free-floating colonies.
- Diversity: The subclass Anthoathecata exhibits considerable diversity in terms of morphology, feeding habits, and ecological roles.
Environments
Anthoathecata are widespread in marine environments, from the intertidal zone to the deep sea. They can be found on a variety of substrates, including rocks, seaweed, corals, and even other marine invertebrates. Some species are even known to form symbiotic relationships with other organisms.
Examples of Anthoathecata
Some well-known examples of Anthoathecata include:
- Hydra: A common freshwater genus known for its regenerative abilities.
- Tubularia: A genus of colonial hydroids with large, polyp-like structures.
- Physalia: The Portuguese Man-of-War, a highly venomous siphonophore that is a type of Anthoathecata.
References
For further information on Anthoathecata, consult these reliable sources: