Eirenidae
The Eirenidae are a family of hydrozoans, commonly known as veil jellyfish, flower hat jellyfish, or crown jellyfish. They are found in all oceans, with the highest species diversity occurring in tropical and subtropical waters. Eirenidae are characterized by their unique bell shape, which resembles a flower or crown, and their lack of tentacles, instead possessing a complex network of stinging filaments that extend from the bell margin. These filaments are arranged in a circular pattern and are used to capture prey, which primarily consists of small crustaceans and plankton.
Characteristics
Eirenidae are distinguished by their bell-shaped medusae, which can range in size from a few millimeters to several centimeters. They lack true tentacles, instead possessing a network of stinging filaments known as cnidocysts that extend from the bell margin. These filaments are arranged in a circular pattern, resembling a crown or flower, giving rise to the common names "crown jellyfish" and "flower hat jellyfish." The bell is often translucent and can be colored white, pink, orange, or purple. Some species have a distinctive pattern of radial stripes on their bell.
Like all hydrozoans, eirenidae possess a polyp stage in their life cycle. These polyps are typically small and inconspicuous and are often found attached to rocks, seaweeds, or other substrates. The polyps are responsible for asexual reproduction, producing medusae through a process called budding.
Environment
Eirenidae are found in all oceans, from the tropics to the poles. They are most diverse in tropical and subtropical waters, where they are common components of plankton communities. Eirenidae can be found in a variety of habitats, including open ocean, coastal waters, estuaries, and even freshwater environments. They are often seen near the surface, where they feed on zooplankton. Some species are known to migrate vertically, moving up to the surface at night to feed and sinking deeper during the day.
Species
The Eirenidae family includes approximately 20 described species, with new species being discovered regularly. Some of the most common and well-known species include:
- Eirene viridula: The green crown jellyfish, found in the Atlantic Ocean.
- Liriope tetraphylla: The flower hat jellyfish, found in the Indo-Pacific region.
- Phialidium hemisphaericum: The hemisphere jellyfish, found in the Atlantic Ocean.
References