Pycnoclavella aurilucens

Small neon sea-squirt

   Pycnoclavella aurilucens is a colonial ascidian. Each zooid is 6 mm in height and 2 mm in diameter. They are joined together by a thick basal stolon encrusting rocks and may form colonies up to 10 cm in diameter. Zooids arise from a short stalk erected from the basal crust. The test is transparent and three spots of various colour, orange, yellow or white can be seen on the upper part of the branchial sac. In winter, zooids disappear, and the basal stolon is the only remaining part of the colony. In Spring, zooids bud from the stolon.
Small neon sea-squirts are attached to rocks or hydrarians from 5 to 25 meters deep in current-swept areas. It is found in the Atlantic Ocean, the English Channel and the Mediterranean Sea.

Classification:

 Phylum Chordata, subphylum Tunicata, class Ascidiacea, order Aplousobranchia, family Clavelinidae, Pycnoclavella aurilucens (Garstang, 1891).

Page glossary:

Zooid: Individual, single animal.
Stolon: Root-like element binding together the individuals of a colony.
Test: or tunic: thick layer secreted by the mantel containing cellulose and protecting the animal.

Authors:

Photographs:  © Wilfried Bay-Nouailhat. Published with author's kind permission.
Pycnoclavella aurilucens, Illes Medes, Costa Brava, East of Spain. Depth 4 meters.
Pycnoclavella aurilucens, Pointe de Trévignon, South-Brittany, West of France. Depth 8 meters.
Text:  Anne Bay-Nouailhat © 2006-2008.
Translation:  Anne Bay-Nouailhat © 2007-2008.