Species: A. mentula
Ascidia mentula is a large solitary sea squirt that can be over 18 cm in length. Its elongate body is usually smooth, often with low rounded swellings. The test is thick, cartilaginous and translucent red – pink, or greenish – olive green, although it can be grey in low light deeper waters. This species is usually attached to the substratum on its left side, unlike most ascidians which attach at the base. Its siphons are inconspicuous with small lobes often bearing white bands or spots. The inhalant (oral) siphon is terminal and the exhalant (atrial) siphon is half to three quarters down the body and can be obscured by detritus and encrusting growths.
Ascidia mentula feeds on plankton that it filters from seawater with a mucous net. Breeding takes place mainly in the summer. Fertilization is external and the tadpole larvae spend a short time in the plankton before settling on the seabed, undergoing metamorphosis and becoming juveniles.
Habitat and Distribution
This species can be found on the lower shore down to 2300 meters depth. Often found in shaded gullies and crevices on the rocky shore and attached to Laminaria holdfasts but also on large shells and stones on sand and mud. This species is tolerant of salinities down to 20. It is registered from the west coast of Norway to the Mediterranean and the Black Sea.