Diazona violacea Savigny, 1816

Description

Diazona violacea s a colonial ascidian forming massive colonies of up to 40 cm in diameter and 20 cm in height. Young colonies are rather ball-shaped, whereas older ones are slightly flattened. The zooids are joined in a common gelatinous cushion-shaped base. The branchial parts of the zooids (the upper parts) are distinct and emerge of 2 cm from the base. The test is more or less translucent, white or yellowish. A vertical line draws the endostyle of each zooid; the atrial and oral siphons are underlined by a white margin and six white spots ornate the upper part of the pharynx. Diazona zooids resemble clavelina ones but their bases are different: a thick basal mass for Diazona versus a thin basal stolon for Clavelina.
At the end of summer, after reproduction time, zooids atrophy and there's only the basal mass left. In spring-time, the colony buds again from this base.

Distribution

Diazona violacea lives attached to rocks or stones covered by sand, in strong current-swept areas between 15 and 200 meters deep in the Atlantic Ocean, the English Channel and the Mediterranean Sea.

How to cite this page

Bay-Nouailhat A., January 2007, Description de Diazona violacea, [En ligne] https://www.mer-littoral.org/uk/32/diazona-violacea.php, consultée le 15 octobre 2026.