| Epiactis | |
|---|---|
 | |
| Epiactis prolifera with young | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Anthozoa |
| Order: | Actiniaria |
| Family: | Actiniidae |
| Genus: | Epiactis Verrill, 1869 [1] |
| Species | |
Epiactis is a genus of sea anemones in the family Actiniidae. There are about nineteen recognised species and the type species is Epiactis prolifera .
A revision in 1989 determined that the genus Cnidopus was a synonym of Epiactis. At this time, two new species, E. lisbethae and E. fernaldi were described and E. ritteri was restored to the genus in which it was originally placed. Four species of Epiactis are known from the Pacific coast of North America, the external brooders E. prolifera and E. lisbethae which differ in sexuality and brooding periodicity, and the internal brooders E. ritteri and E. fernaldi, which differ in their cnidocyte armoury, sexuality and histology. [2]
These sea anemones have a substantial base and a smooth column. The margin and fosse are distinct and the sphincter well developed. The tentacles that surround the oral disc are short and unbranched and not narrower at the base. The longitudinal muscles of the tentacles and the radial muscles of the oral disc are usually ectodermal. The mesenteries in the gastroventicular cavity are arranged hexagonally and are greater in number at the base than at the margin. Twelve or more pairs of mesenteries are perfect and the gonads develop on these. The retractors are often very strong and are diffuse or restricted. The cnidocytes include spirocysts, basitriches and microbasic p-mastigophors. Juveniles develop in brood pouches or attached to the column. [3]
Tube-dwelling anemones or ceriantharians look very similar to sea anemones but belong to an entirely different subclass of anthozoans. They are solitary, living buried in soft sediments. Tube anemones live inside and can withdraw into tubes, which are composed of a fibrous material made from secreted mucus and threads of nematocyst-like organelles known as ptychocysts. Within the tubes of these ceriantharians, more than one polyp is present, which is an exceptional trait because species that create tube systems usually contain only one polyp per tube. Ceriantharians were formerly classified in the taxon Ceriantipatharia along with the black corals but have since been moved to their own subclass, Ceriantharia.
Cribrinopsis fernaldi, also known as the crimson anemone, snakelock anemone, chevron-tentacle anemone and Fernald brooding anemone, is a sea anemone native to the Pacific Ocean off northwestern North America.
Sea anemones are the marine, predatory animals of the order Actiniaria. They are named after the anemone, a terrestrial flowering plant, because of the colourful appearance of many. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra. Unlike jellyfish, sea anemones do not have a medusa stage in their life cycle.
Diadumene lineata, the orange-striped green sea anemone, has several morphotypes which have been described multiple times.
Hormathiidae is a family of sea anemones in the class Anthozoa.
Epiactis prolifera, the brooding, proliferating or small green anemone, is a species of marine invertebrate in the family Actiniidae. It is found in the north-eastern Pacific. It has a feature rare among animals in that all individuals start life as females but develop testes later in their lives to become hermaphrodites.
Liponema is a genus of sea anemones, in the family Liponematidae.
Haloclavidae is a family of sea anemones. Members of the family are found worldwide and many live largely buried in soft substrates with only their oral disc and tentacles protruding.
Peachia is a genus of sea anemone in the family Haloclavidae. Members of this genus typically burrow into soft substrates. The only part of the animal that is normally visible is the oral disc and tentacles which lie flat on the sand in a star shape. The type species is Peachia cylindrica.
Actinodendron arboreum, commonly known as tree anemone or hell's fire anemone, is a species of sea anemone in the family Actinodendronidae. It is native to the Indo-Pacific where it grows at depths of down to 28 metres (92 ft). Most sea anemone species are harmless to humans, but A. arboreum is highly venomous and its sting can cause severe skin ulcers.
Phlyctenanthus australis, commonly known as red anemone and southern anemone, is a species of sea anemone in the family Actiniidae. It grows to a maximum size of 10 cm in diameter. The column is red-brown in colour with blue vesicles covering it. The tentacles are reddish-brown and short, and number up to around 100. This species is found in south Australia, New South Wales, down to Tasmania. This species lives on exposed reefs at depths of between 1 and 35 metres.
Arachnactidae is a family of tube-dwelling anemones in the order Ceriantharia. It is the only family in the monotypic order Penicillaria and comprises around 38 species. They differ from other ceriantharians in the makeup of their cnidome, the relative sizes of the oral discs and the shape and structure of the mesenteries. These tube anemones dwell in parchment-like tubes immersed in soft sediment, and have two whorls of tentacles, the outer ones being much longer than the inner ones.
Epiactis thompsoni, the red-striped anemone, is a species of marine invertebrate in the family Actiniidae, found in New Zealand and South Australia. They are commonly found in the rocky intertidal zone.
Spirularia is an order of marine Cnidarians, tube-dwelling anemones, in the subclass Ceriantharia. It is one of the two orders making up Ceriantharia and includes two families, Botrucnidiferidae and Cerianthidae, and around 99 species. The two orders differ in the makeup of their cnidome, the relative sizes of the oral discs and the shape and structure of the mesenteries.
Gonactinia is a monotypic genus of sea anemones, and G. prolifera is the only species in the genus. It is sometimes called the storey anemone and is found on either side of the northern Atlantic Ocean.
Diadumene is a genus of sea anemones. It is the only genus in the monotypic family Diadumenidae.
Epiactis ritteri, the sandy anemone or Ritter's brooding anemone, is a species of sea anemone in the family Actiniidae. It is found in the Pacific Ocean on the western coast of North America in the shallow sub-littoral zone.
Epiactis lisbethae, commonly known as Lisbeth's brooding anemone, is a species of sea anemone in the family Actiniidae. It is similar in appearance to the common brooding anemone, and like it is native to shallow waters on the western coast of North America.
Epiactis fernaldi, commonly known as the Fernald brooding anemone, is a species of sea anemone in the family Actiniidae. It is native to shallow waters around the San Juan Islands off the western coast of North America.
Mesacmaea mitchellii is a species of sea anemone in the family Haloclavidae. It is found in the northeastern Atlantic Ocean and the Mediterranean Sea where it burrows in soft sediment.