Ascidiacea

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iAscidiacea
Sea Tulips, Pyura spinifera
Sea Tulips, Pyura spinifera
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Urochordata
Class: Ascidiacea
Nielsen, 1995
Orders

Aplousobranchia
Enterogona
Phlebobranchia
Pleurogona
Stolidobranchia

Ascidiacea (commonly known as the ascidians or sea squirts) is a class in the Tunicata subphylum of sac-like marine filter feeders. They are characterized by a tough outer "tunic" made of the polysaccharide tunicin whilst other tunicates are much less robust. Whilst adults are sessile (immobile), larvae resemble tadpoles and swim up and down in their marine environment. The larvae undergo a metamorphosis when a suitable place to attach is found. During this metamorphosis, the tail, along with the notochord and neural tube is reabsorbed, that is why tunicates are also referred as "urochordates" (uro=tail).

Like other tunicates, they also collect and concentrate vanadium in their blood, although the reason for this behaviour is not properly understood.

Examples of ascidians include Sea Tulips and the Solitary Ascidian.

Some ascidians are eaten in Japan, Korea, Chile, and France[1].

Ernst Haeckel's interpretation of several  ascidians. From Kunstformen der Natur (Artforms of Nature), 1904.
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Ernst Haeckel's interpretation of several ascidians. From Kunstformen der Natur (Artforms of Nature), 1904.

[edit] References

Wikimedia Commons has media related to:
  1. ^ Japanese wikipedia article on sea squirts (in Japanese).
[edit] Further general references

[edit] External link