Acontiophoridae
Acontiophoridae is a family of cnidarians belonging to the order Actinulida. They are small, free-swimming, and are commonly referred to as “actinulae.” They are characterized by their bell-shaped bodies with tentacles, often bearing stinging cells called nematocysts. Acontiophoridae are generally considered a relatively small and understudied group of cnidarians.
Common Names
Acontiophoridae do not have a common name in English. The term "actinula" is sometimes used to refer to members of this family, but it is also a broader term encompassing the larval stage of many cnidarians.
Characteristics
Acontiophoridae exhibit several distinctive characteristics that distinguish them from other cnidarians:
- They are typically less than 1 mm in length.
- Their bodies are bell-shaped, with a single opening at the apex that serves as both a mouth and anus.
- They possess a single, central ring of tentacles around the bell margin.
- They have a characteristic, elongated, club-shaped body, sometimes with a distinct constriction.
- Their tentacles are typically covered in nematocysts, which they use for capturing prey and defense.
- They lack a polyp stage, which is characteristic of many other cnidarians.
Environments
Acontiophoridae are primarily found in marine environments worldwide. They are often associated with benthic (bottom dwelling) habitats, particularly in shallow coastal waters. However, some species have been found in deeper waters, such as the mesopelagic zone (200-1,000 meters).
References
World Register of Marine Species (WoRMS)
A molecular phylogeny of the cnidarian order Actinulida (Cnidaria, Hydrozoa)