Actinozoa -

: Includes soft corals, sea pens, and sea fans. They strictly possess eight branched (pinnate) tentacles and eight mesenteries. Ecological Importance

: They use tentacles armed with specialized stinging cells called nematocysts to capture prey, ranging from plankton to small fish.

Historically, Actinozoa was divided into two main groups based on their symmetry and tentacle count: actinozoa

: Unlike many other cnidarians (such as jellyfish), Actinozoans do not have a medusa (free-swimming) stage in their life cycle. They remain as polyps throughout their lives.

: The body consists of a central gastrovascular cavity divided by vertical partitions called mesenteries or septa. These mesenteries increase the surface area for digestion and support the gonads. : Includes soft corals, sea pens, and sea fans

(now more commonly known as the class Anthozoa ) is a major group of marine invertebrates within the phylum Cnidaria . This class includes well-known sea creatures like sea anemones, stony corals, soft corals, and sea fans. Key Characteristics

: Includes sea anemones and stony corals. They typically have tentacles and mesenteries in multiples of six. Historically, Actinozoa was divided into two main groups

Actinozoans are the primary architects of , which are among the most biodiverse ecosystems on Earth. Stony corals secrete calcium carbonate skeletons that form the structural foundation of these reefs, providing habitat for thousands of other marine species.