Labidiaster annulatus

from Wikipedia, the free encyclopedia
Labidiaster annulatus
Labidiaster annulatus

Labidiaster annulatus

Systematics
Sub-stem : Eleutherozoa (Eleutherozoa)
Class : Starfish (asteroidea)
Order : Pincer stars (Forcipulata)
Family : Heliasteridae
Genre : Labidiaster
Type : Labidiaster annulatus
Scientific name
Labidiaster annulatus
Sladen , 1889
Labidiaster annulatus , Antarctic Peninsula , 1962

Labidiaster annulatus is a species of starfish from the order of the pincer stars (Forcipulata) that is native to cold waters along the coast of Antarctica . The starfish has numerous thin arms and, with its pedicellaria, prey primarily on Antarctic krill and other crustaceans .

features

Labidiaster annulatus has a large, somewhat inflated central disc, which is raised compared to the approximately 40 to 45 long, thin arms, and can reach a diameter of about 60 cm. The Madreporenplatte is large and lies next to the edge of the central disc. The top of the starfish is covered with a meshed network of small, somewhat overlapping limestone plates. In the hat lying above there are numerous skin gills (papules), some smaller spines and large triangular pedicellariums . The upper side of the numerous arms is also covered with lime flakes in a pattern of rectangular meshes and with short spines, papules and pedicellaria. Dense rows of powerful pedicellariums sit at intervals on the arms. The mouth on the underside of the central disc is surrounded by further limestone plates. On the underside of each arm, a wide ambulacral furrow runs from the central disc to the arm tip, surrounded on each side by narrow, clearly separated limestone plates with two spines each, one facing the furrow and one outward. On each side of the ambulacral furrow is a series of suction feet .

Reproductive cycle

The development of Labidiaster annulatus takes place via a Bipinnaria larva, which drifts as plankton with the ocean currents for many months , and a Brachiolaria larva, which attaches to the substrate and metamorphoses into a starfish .

Distribution and occurrence

Labidiaster annulatus is found on the coasts of the Antarctic Peninsula , South Georgia, and the South Sandwich Islands . It lives from the intertidal zone to a depth of about 554 m, but mainly between 30 m and 400 m sea depth on sand, mud and gravel as well as between rocks.

nutrition

Labidiaster annulatus is an opportunistic predator and scavenger . He often climbs to the top of a rock or large sponge and holds on to a few arms while holding the others like fishing rods in the current. If an animal touches one of the arms, the pedicellariums snap shut and hold it tight. Adjacent arms wrap around the prey and extend it further to the mouth opening. The stomach is elastic and suitable for devouring large prey. The starfish can also prey on healthy crabs , but some of the animals initially seized manage to escape.

According to field observations and studies of stomach contents, Antarctic krill makes up the main prey, followed by amphipods . Are eaten among other things, brittle stars , including Ophionotus victoriae , small starfish and sediment with a high proportion of foraminifera . The remains of a 6 cm long fish were also found, which may have been taken in as carrion.

literature

Web links

Commons : Labidiaster annulatus  - collection of images, videos and audio files