Pisaster brevispinus
Encyclopedia
Pisaster brevispinus, commonly called the Pink Sea Star, Giant Pink Sea Star, or Short-spined Sea Star, is a Pacific Ocean
sea star
.
.
Pisaster brevispinus is usually found on sand or mud substrate where it catches its prey such as clams
or sand dollars. Smaller individuals are sometimes seen on rocks or pilings where they prey on mussels, barnacles, and tubeworms. This species is also known to scavenge on dead fish
and squid
. The giant pink sea star does not tolerate being out of water very well, so it is generally found on the beach only during very low tides. It usually lives at a depth of 600 feet.
. These feet have strong suckers that can pry apart clams and mussels. They can also attach onto a rock to keep the organism stationary. The Pink Star also has many predators. The most common predators of these creatures are sharks, manta rays, and large bony fish.
develops from an embryo
into a larva which feeds on small algae
. During its planktic period the larva
proceeds through several developmental phases going from gastrula to bipinnaria
to brachiolaria
. Towards the end of the last stage the larva develops a large sack like structure, a primordium, and begins searching for a suitable surface on which to settle.
After settling into a home, the larva changes into a juvenile starfish. This process takes about 2 days. Initially the juvenile starfish has only 5 arms but additional arms develop rapidly as the starfish begins to feed on encrusting algae
. At the end of 6 months the starfish is about 1 cm in size and begins to feed on corals. The starfish becomes sexually mature at the end of its second year by which time it has grown to about 20 cm in diameter. After 3–4 years (when the starfish is about 35 cm in size) it is thought to go into a senile phase where growth declines dramatically and reproduction is low. This phase has been identified only in the laboratory. It is not known how long starfish live however, they have been kept in aquaria
for as long as 8 years.
. Where the main character, Spongebob, is the the neighbor and best friend of Patrick Star
, a pink Starfish.
Pacific 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...
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...
.
Description
The Pink Star is a very unusual color, a bright shade of pink. Although such a color would lead to the species being eaten regularly in darker-colored environments, it blends right in to its bright coral reef home. The Pink Star can reach a diameter of two feet while weighing up to two pounds, and has spines less than 2mm long. It has a soft, flabby texture that allows it to bend slightly to stay on coralCoral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
.
Pisaster brevispinus is usually found on sand or mud substrate where it catches its prey such as clams
CLaMS
CLaMS is a modular chemistry transport model system developed at Forschungszentrum Jülich, Germany. CLaMS was first described by McKenna et al. and was expanded into three dimensions by Konopka et al....
or sand dollars. Smaller individuals are sometimes seen on rocks or pilings where they prey on mussels, barnacles, and tubeworms. This species is also known to scavenge on dead 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 squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
. The giant pink sea star does not tolerate being out of water very well, so it is generally found on the beach only during very low tides. It usually lives at a depth of 600 feet.
Behavior and adaptations
The Pink Star's many adaptations allow for a thriving population through the world's oceans. One of these is regeneration, a trait shared by all sea stars: any part of the Pink Star can grow into a whole new sea star as long as it has part of the central disk. Another adaptation is its coarse, hard skin for protection. Animals like to stay clean, and the Pink Star has developed an interesting way to keep clean. It has microscopic pinchers on its skin called pedicellaria to keep the skin clean. It has eyespots at the end of each arm to see in every direction, which are useful for detecting predators. This sea star has eyespots that can see in the light and in the dark. One of the most important adaptations a sea creature could have is tube feetTube feet
Tube feet are the many small tubular projections found most famously on the oral face of a sea star's arms, but are characteristic of the water vascular system of the echinoderm phylum which also includes sea urchins, sand dollars and sea cucumbers and many other sea creatures.Tube feet function in...
. These feet have strong suckers that can pry apart clams and mussels. They can also attach onto a rock to keep the organism stationary. The Pink Star also has many predators. The most common predators of these creatures are sharks, manta rays, and large bony fish.
Reproduction and life cycle
Starfish commonly reproduce using a method called free-spawning. This means that they release their gametes into the water, where they will hopefully be fertilized by the gamete from the opposite sex. It is thought that groups, when they are ready to spawn, use environmental signals to coordinate their timing. Once fertilization has occurred the eggEgg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
develops from an embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
into a larva which feeds on small algae
Phytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
. During its planktic period the larva
Larva
A larva 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...
proceeds through several developmental phases going from gastrula to bipinnaria
Bipinnaria
A bipinnaria is the first stage in the larval development of most starfish, and is usually followed by a brachiolaria stage. Movement and feeding is accomplished by the bands of cilia. Starfish that brood their young generally lack a bipinnaria stage, with the eggs developing directly into...
to brachiolaria
Brachiolaria
A brachiolaria is the second stage of larval development in many sea stars; it follows the bipinnaria. Brachiolaria have bilateral symmetry, unlike the adult sea stars, which have a pentaradial symmetry...
. Towards the end of the last stage the larva develops a large sack like structure, a primordium, and begins searching for a suitable surface on which to settle.
After settling into a home, the larva changes into a juvenile starfish. This process takes about 2 days. Initially the juvenile starfish has only 5 arms but additional arms develop rapidly as the starfish begins to feed on encrusting algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
. At the end of 6 months the starfish is about 1 cm in size and begins to feed on corals. The starfish becomes sexually mature at the end of its second year by which time it has grown to about 20 cm in diameter. After 3–4 years (when the starfish is about 35 cm in size) it is thought to go into a senile phase where growth declines dramatically and reproduction is low. This phase has been identified only in the laboratory. It is not known how long starfish live however, they have been kept in aquaria
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
for as long as 8 years.
In Popular Culture
The species Piaster brevispinus was made famous through the children's show Spongebob SquarepantsSpongeBob SquarePants
SpongeBob SquarePants is an American animated television series, created by marine biologist and animator Stephen Hillenburg. Much of the series centers on the exploits and adventures of the title character and his various friends in the underwater city of "Bikini Bottom"...
. Where the main character, Spongebob, is the the neighbor and best friend of Patrick Star
Patrick Star
Patrick Star is the deuteragonist of the Nickelodeon animated comedy series SpongeBob SquarePants, created by creator Stephen Hillenburg and voiced by Bill Fagerbakke. Patrick's most significant character trait is his lack of common sense, which sometimes makes him a negative influence on his best...
, a pink Starfish.