Urticina crassicornis
Encyclopedia
Urticina crassicornis is a large and common intertidal and subtidal sea anemone
formerly known as Tealia crassicornis and commonly referred to as the Christmas Anemone. Its habitat includes a large portion of global coastal areas and it lives a solitary life for up to 80 years of age.
, Urticina crassicornis ranges from intertidal and subtidal zones of the Pribilof Islands
, Alaska to Monterey, California. In the Atlantic Ocean
, it is found in intertidal and subtidal zones ranging from the Arctic Ocean
above Newfoundland, Canada to Cape Cod
, Massachusetts and also along the coasts of Western Europe. In the state of Washington this sea anemone more commonly frequents the Puget Sound
compared to the Pacific Ocean front. It is found in a lower intertidal, upper subtidal zone - 30 m deep, inhabiting well protected and shaded areas. Urticina crassicornis is a benthic and sessile organism, firmly attached only to hard substrata. This sea anemone is frequently found on docks, wood pilings, and under large rock outcroppings.
s, sea urchin
s, mussel
s, gastropods, chiton
s, barnacle
s, fish
, and sometimes sea star
s and stranded jellies. A peculiar prey, the sun star, Pycnopodia helianthoides commonly known as the "Sunflower Star", is found in Washington state and has a size much greater than U. crassicornis, sometimes ranging up to 5 ft. in length. This anemone exhibits both intracellular and extracellular digestion. Food is caught within the tentacles which then move the prey towards the oral disc.
are known predators of this anemone. Demasterias imbricata (Asteroidea) and Aeolidia papillosa
(Gastropoda) are two notably frequent predator species. Urticina crassicornis senses predation through a simple nerve net spanning along its column and tentacle walls. For protection, U. crassicornis inverts its tentacles to the inside of its body column and projects nematocysts. Minimal locomotion is possible if the organism is sensing extreme danger. Some species of amphipods
are parasites
of U. crassicornis living within its body cavity for the benefits of housing and food. These species are not affected by the nematocysts of U. crassicornis, which has the ability to kill other species of crustacean.
and sexual reproduction
. In the Atlantic populations, eggs and sperm are held and fertilized within the body column. The young are brooded between the mesenteries of the body and are emitted as smallish, well developed, young anemones. Spawning occurs in the spring amongst Puget Sound populations, when eggs (yolky, 0.7 mm in diameter) and sperm are released into the sea for fertilization. Urticina crassicornis's major sperm chromosomal proteins have been found to be two specialized histone H1 proteins which indicate a strong relation to the chromosomal proteins of bird and amphibians. After fertilization, a solid and ciliated blastula is created due to superficial cleavage. Six days following fertilization, a cone-shaped and benthic, larval planula develops. These planula then settle onto small rocks or the empty tubes of some annelid worms and rapidly develop into small anemones. 12 days after settlement, 8 tentacles appear. Further growth is slow – two months after settlement, 12 tentacles appear and the anemone is 0.88 mm in diameter; one year after settlement, the anemone has 35 tentacles and is 10 mm in diameter. Growth is proportional to food intake, not age. When starved, this anemone can stay alive for 9 months but does not grow. Urticina crassicornis is sexually mature with a diameter of 10 – 15 mm, being at least one year old.
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...
formerly known as Tealia crassicornis and commonly referred to as the Christmas Anemone. Its habitat includes a large portion of global coastal areas and it lives a solitary life for up to 80 years of age.
Description
Urticina crassicornis is biradially symmetrical and ranges from 2 - 12.7 cm tall with a width of 1 - 7.6 cm. This sea anemone has a solid basal plate which is always flat. Its column can be olive green with or without red spots; solid red; cream; or brown, always with small, inconspicuous tubercles but no acontia. Its tubercles are not white and do not usually accumulate bits of sand, gravel and shell. The tentacles, superior of the column and usually 100 in number, are green to opaque cream with red and white striations and semi-transparent when extended. The tentacles are conical, thick and blunt and arranged in 3 - 5 circular rings around the oral disc. The oral disc has no white striations and usually has the same color scheme as the tentacles.Geographical Range and Habitat
In the Pacific OceanPacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, Urticina crassicornis ranges from intertidal and subtidal zones of the Pribilof Islands
Pribilof Islands
The Pribilof Islands are a group of four volcanic islands off the coast of mainland Alaska, in the Bering Sea, about north of Unalaska and 200 miles southwest of Cape Newenham. The Siberia coast is roughly northwest...
, Alaska to Monterey, California. In the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, it is found in intertidal and subtidal zones ranging from the Arctic Ocean
Arctic Ocean
The Arctic Ocean, located in the Northern Hemisphere and mostly in the Arctic north polar region, is the smallest and shallowest of the world's five major oceanic divisions...
above Newfoundland, Canada to Cape Cod
Cape Cod
Cape Cod, often referred to locally as simply the Cape, is a cape in the easternmost portion of the state of Massachusetts, in the Northeastern United States...
, Massachusetts and also along the coasts of Western Europe. In the state of Washington this sea anemone more commonly frequents the Puget Sound
Puget Sound
Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...
compared to the Pacific Ocean front. It is found in a lower intertidal, upper subtidal zone - 30 m deep, inhabiting well protected and shaded areas. Urticina crassicornis is a benthic and sessile organism, firmly attached only to hard substrata. This sea anemone is frequently found on docks, wood pilings, and under large rock outcroppings.
Feeding
A non-selective and opportunistic predator, Urticina crassicornis, may feed on crabCrab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...
s, mussel
Mussel
The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...
s, gastropods, chiton
Chiton
Chitons are small to large, primitive marine molluscs in the class Polyplacophora.There are 900 to 1,000 extant species of chitons in the class, which was formerly known as Amphineura....
s, barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
s, fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, and sometimes sea star
Sea star
Starfish or sea stars are echinoderms belonging to the class Asteroidea. The names "starfish" and "sea star" essentially refer to members of the class Asteroidea...
s and stranded jellies. A peculiar prey, the sun star, Pycnopodia helianthoides commonly known as the "Sunflower Star", is found in Washington state and has a size much greater than U. crassicornis, sometimes ranging up to 5 ft. in length. This anemone exhibits both intracellular and extracellular digestion. Food is caught within the tentacles which then move the prey towards the oral disc.
Predators, Parasites, and Protection
In the Pacific, certain species of both Asteroidea and GastropodaGastropoda
The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...
are known predators of this anemone. Demasterias imbricata (Asteroidea) and Aeolidia papillosa
Aeolidia papillosa
Aeolidia papillosa is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Aeolidiidae. A. papillosa has many common names including the shaggy mouse nudibranch or the shag rug nudibranch, in part due to its shape and its numerous flattened cerata that make it look...
(Gastropoda) are two notably frequent predator species. Urticina crassicornis senses predation through a simple nerve net spanning along its column and tentacle walls. For protection, U. crassicornis inverts its tentacles to the inside of its body column and projects nematocysts. Minimal locomotion is possible if the organism is sensing extreme danger. Some species of amphipods
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
are parasites
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
of U. crassicornis living within its body cavity for the benefits of housing and food. These species are not affected by the nematocysts of U. crassicornis, which has the ability to kill other species of crustacean.
Reproduction
Urticina crassicornis produces by both asexualAsexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
and sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
. In the Atlantic populations, eggs and sperm are held and fertilized within the body column. The young are brooded between the mesenteries of the body and are emitted as smallish, well developed, young anemones. Spawning occurs in the spring amongst Puget Sound populations, when eggs (yolky, 0.7 mm in diameter) and sperm are released into the sea for fertilization. Urticina crassicornis's major sperm chromosomal proteins have been found to be two specialized histone H1 proteins which indicate a strong relation to the chromosomal proteins of bird and amphibians. After fertilization, a solid and ciliated blastula is created due to superficial cleavage. Six days following fertilization, a cone-shaped and benthic, larval planula develops. These planula then settle onto small rocks or the empty tubes of some annelid worms and rapidly develop into small anemones. 12 days after settlement, 8 tentacles appear. Further growth is slow – two months after settlement, 12 tentacles appear and the anemone is 0.88 mm in diameter; one year after settlement, the anemone has 35 tentacles and is 10 mm in diameter. Growth is proportional to food intake, not age. When starved, this anemone can stay alive for 9 months but does not grow. Urticina crassicornis is sexually mature with a diameter of 10 – 15 mm, being at least one year old.