Clavelina dellavallei reaches 3 cm per zooid. Small Mediterranean colonial ascidian (Clavelinidae) with body in erect transparent tubes in colonies, each zooid with two purple-magenta to blue-purple longitudinal bands on transparent body (distinction from C. lepadiformis with white-yellow bands), siphons clearly visible at top. Lives from 3 to 50 m on Mediterranean rocky reefs and caves. Prefers shaded environments. Colonial filter feeder. Mediterranean macro dive photo subject for sciaphilic fixed fauna enthusiasts, caves and overhangs.
