Botrylloides crystallinus

Crystal-ball sea squirt

Botrylloides crystallinus

Carro, France, 8 mètres, 2018, WBN

Botrylloides crystallinus

Carro, France, 11 mètres, 2018, WBN

Botrylloides crystallinus

Port-Cros, France, 25 mètres, 2018, WBN

Botrylloides crystallinus

Carro, France, 6 mètres, 2018, WBN

Botrylloides crystallinus

Carro, France, 9 mètres, 2018, WBN


Botrylloides crystallinus is a colonial sea squirt of globular to massive form which measures 3 to 8 cm in diameter. It lives fixed to the substrate by a narrow base. The transparent, crystalline tunic is white to straw yellow in color. It sometimes agglomerates some impurities on its surface. The zooids are arranged in rows around large common cloacal siphons. The oral siphon of each zooid is underlined by a white border which extends around atrial tongues which draws on the surface of the colony fine circles and geometric lines. The transparency of the colony also makes it possible to see fine white lines over the entire height of the zoids. Seasonal species, mainly present in winter and spring, the colonies take the end of their cycle as a globular and cartilaginous mass traversed by regressed zoids which draw 'zipper' systems on their surface. The colonies live in shaded areas, fixed on vertical rock walls or overhangs between 4 and more than 30 meters deep.


Botrylloides crystallinus is present in the Mediterranean from the east of the Rhône delta to Italy.

Image satellite: © Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community.

Données de distribution : Botrylloides crystallinus in GBIF Secretariat (2019). GBIF Backbone Taxonomy. Checklist dataset accessed via on 2022-12-03.


Source : World Register of Marine Species

! La connexion au serveur WoRMS est momentanément indisponible !

Page glossary

Colony : group of several individuals of the same species.

Zooid : individual.

Common cloacal siphon : aperture through which filtered water is expelled from the colonies.

Atrial tongue : more or less developed outgrowth above the atrial siphon of a zooid.

Atrial siphon atrial : aperture through which the animal expels the water it has filtered.

Bibliography and websites

Bay-Nouailhat A., Bay-Nouailhat W., Gasparini F. & Brunetti R., 2020. — Botrylloides crystallinus n. sp., a new Botryllinae Adams & Adams, 1858 (Ascidiacea) from Mediterranean Sea. Zoosystema 42 (9): 131-138.

Bay-Nouailhat A., Bay-Nouailhat W., 2020, Guide des tuniciers de l'Europe de l'Ouest. M&L éditions, Melgven.


Text : Wilfried Bay-Nouailhat, Anne Bay-Nouailhat © 2020 - 2022.

Photos : © Wilfried Bay-Nouailhat. Published with his kind permission.
Websites and reference works : Consult bibliography

How to cite this page

Bay-Nouailhat W., Bay-Nouailhat A., March 2020, Description of Botrylloides crystallinus, [On line], consulted on 2022 December 03.


Photographie de Wilfried Bay-Nouailhat

Wilfried Bay-Nouailhat

Diver - Naturalist
Underwater Photographer

Photographie de Anne Bay-Nouailhat

Anne Bay-Nouailhat

Project manager in marine environment
Professional diver - Naturalist

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