Psolus phantapus is a sea cucumber of up to 20 cm in length. Its cylindrical
body erect at each ends in a U-shape, is partially buried in sand or mud among stony bottoms. The posterior
side, at the end of which is the anus, is usually hidden under the substratum. The central part,
which is also hidden, forms a rectangular sole, strenghten by spicules. Many tube feet concentrate there,
a double row on each side and down the middle, so that the brown psolus may attached to stones. Its
body is yellowish brown to dark brown and its thick skin is covered with numerous small scales.
The only visible part is the anterior side with the introvert and the crown of 10 bushy tentacles that
surounds the mouth. The tentacles are pinkish white with orange patches. They are covered with mucus
on which micro-organisms stick ; then tentacles are one after the other put inside the mouth to collect
food. The introvert is pinkish white with pink dots that extend toward the mouth. Its skin is smooth and
it bears five rows of tube feet regularly spaced.
Psolus phantropus is found from 5 to 400 m deep in the Atlantic Ocean from the Celtic Sea (South Ireland) up to Norway, in the North Sea and up to the Arctic. In the North-West Atlantic, from Canada to Cape Cod, (North-East coasts of the USA).
(source : European Register of Marine Species)
Sole : Base clinging to substratum.
Spicule : Tiny calcareous element that stiffens the holothurian body.
Tube foot : Tube-shaped element ending by a sucker-disc used to attach to subtratum or to bring food particles into the mouth.
Introvert : Anterior part bearing the mouth and extensible and retractile inside the body.
Top Photo :
© Anne Frijsinger. Published with author's kind permission :
Psolus phantapus, Lysefjord, Rogaland, South-Western Norway. Depth 9 meters.
Text : Anne Bay-Nouailhat © 2008-2017.
Translation : Anne Bay-Nouailhat © 2008-2017.