Botryllus schlosseri is a colonial ascidian forming encrusting flattened colonies of
4 to 5 cm in diameter.
The zooids are gathered in systems of 3 to 12 individuals around a common atrial siphon. These systems
look like stars dispatched through the colony within a common test.The siphons do not protude but form
numerous little holes opening and closing according to the colony activity. The star tunicate has various
colours: yellow, blue, brown-yellowish, green, mauve, reddish. The colour of the zooid is distinct from the
colour of the common test. Colonies encrusted rocks, seaweeds and even other ascidians.
It is found from low level water to 10 meters deep in the Atlantic Ocean, the North Sea, the English Channel and the
Mediterranean Sea.
(source : European Register of Marine Species)
Zooid : Individual, single animal.
Test : or tunic: thick layer secreted by the mantel containing cellulose and protecting the animal.
Atrial siphon : Opening through which water is expelled.
Botryllus schlosseri
Encrusting colony
Botryllus schlosseri
Colony
Botryllus schlosseri
Close view
Botryllus schlosseri
Close view
Botryllus schlosseri
Close view of the systems
Top photograph :
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Botryllus schlosseri,
Baie de concarneau, South-Brittany, West of France. Depth 6 meters.
Bottom photographs : © Wilfried Bay-Nouailhat. Published with author's kind permission :
Botryllus schlosseri, Encrusting colony. Baie de Lannion, North-Brittany, West France. Depth 10 meters.
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Botryllus schlosseri, Colony. Anse de Camaret, West Brittany, West of France. Depth 8 meters.
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Botryllus schlosseri, Close view. Pointe de Trévignon, South Brittany, West of France. Depth 8 meters.
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Botryllus schlosseri, Close view. Pointe de Trévignon, South Brittany, West of France. Depth 10 meters.
© Wilfried Bay-Nouailhat. Published with author's kind permission :
Botryllus schlosseri, Close view of the systems. Baie de Lannion, North Brittany, West of France. Depth 8 meters.
Text : Anne Bay-Nouailhat © 2005-2017.
Translation : Anne Bay-Nouailhat © 2007-2017.
