''Urticina eques'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of sea anemone in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Actiniidae Actiniidae is the largest family of sea anemones, to which most common, temperate, shore species belong. Most members of this family do not participate in symbioses with fishes. Three exceptions are the bubble-tip anemone (with anemonefish and ...

. It is commonly known as the white-spotted rose anemone or strawberry anemone.

Taxonomy

According to one authority, the populations of ''Urticina eques'' found in the Pacific Ocean are not the same species as those in the Atlantic Ocean and should instead be considered to be conspecific with '' Cribrinopsis albopunctata'', a new species from

Kamchatka The Kamchatka Peninsula (russian: полуостров Камчатка, Poluostrov Kamchatka, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and west ...

Description

''Urticina eques'' has a smooth, red column with vertical rows of white tubercles. In contrast to other similar species, the tubercles are not adhesive and do not normally attract gravel and shell fragments. There are no acontia with stinging nematocysts protruding through the body wall. The oral disk is plain red and the tapering tentacles are red and have no transverse striations. This is a large sea anemone with a diameter of up to and length.''Urticina lofotensis'' (Danielssen, 1890)
Walla Walla University. Retrieved 2011-10-29.

Distribution and habitat

''Urticina eques'' is found in the North Atlantic Ocean and the Pacific coast of North America. It occurs between low water mark and a depth of about . It is found on rocks and pilings, in crevices and gullies and favours exposed habitats with fast moving water.

Biology

''Urticina eques'' is dioecious. In California, female ripeness occurs in December as the sea temperature begins to fall. The large eggs, in diameter, are produced at intervals, and the release of sperm by the males follows shortly afterwards. In some females, large

oocyte An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The femal ...

s also release eggs at other times of year. The

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s emerge through the mouth of the anemone and fertilisation is external. The eggs develop into

planula A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores. Some groups of Nemerteans also produce larvae that are very similar to the planula, which ...

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e which drift with the current before settling and growing into new individuals.

Ecology

Juveniles of the painted greenling, a species of fish, have a facultative association with ''Urticina eques''. They are often found among the tentacles or close to the column, especially when resting and inactive at night. According to researcher Joel Elliot, these associations occurred mainly in moderately exposed locations where the sea anemones and fish were both numerous; the large anemone offers the fish protection from

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

and provides a safe environment for it to feed on copepods and other small

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s that are also associated with the anemone. The research indicated that the fish seemed to be unharmed by the anemone's nematocysts. The anemones themselves were thought not to derive any benefits from the arrangement.

References

{{Taxonbar, from1=Q10711119, from2=Q1990723 Actiniidae Animals described in 1858