Hexacorallia
Hexacorallia is a subclass of the Anthozoa class of cnidarians, which are marine animals possessing stinging cells called nematocysts. Hexacorals are characterized by having polyps with six or a multiple of six tentacles, unlike the Octocorallia which have eight tentacles. This subclass includes familiar groups like sea anemones, hard corals, and soft corals. Hexacorals are found in a variety of marine environments, from shallow tropical reefs to the deep sea, and play important roles in marine ecosystems.
Characteristics
Hexacorals share a number of key characteristics that distinguish them from other cnidarians. These include:
- Six-fold symmetry: Their polyps exhibit radial symmetry, usually with six or multiples of six tentacles.
- Mesenteries: They have internal partitions called mesenteries that divide the gastrovascular cavity.
- Cnidocytes: These stinging cells are located in the tentacles and are used for defense and prey capture.
- Polyp form: Most hexacorals exist as solitary polyps, while some form colonies.
Environments
Hexacorals are found in a diverse range of marine environments, from shallow water to the deep sea. They can be found in:
- Coral reefs: Many hexacorals, particularly stony corals, build the complex structures of coral reefs.
- Intertidal zones: Sea anemones are common inhabitants of rocky shores and tide pools.
- Deep sea: Certain hexacorals thrive in the deep sea, contributing to the biodiversity of these environments.
Common Names
Hexacorals are often referred to by their common names, which vary depending on the specific group. Some common names include:
- Sea anemones: Solitary polyps with a columnar body and a ring of tentacles.
- Stony corals: Colonial polyps that secrete a hard calcium carbonate skeleton, forming reefs.
- Soft corals: Colonial polyps with flexible skeletons, often with colorful tentacles.