Conchoderma virgatum

(Spengler, 1790)

Description
Capitulum with five reduced valves widely separated from each other embedded in the membrane, quadrangular and not distinctly marked off from peduncle. Scutum trilobed; two ventral lobes along ventral margin, third lobe obliquely directed dorsally; umbo situated at the union of the three lobes; scuta imperfectly calcified in some specimens. Tergum linear, placed along upper margin of capitulum, variable in shape. Carina also linear, slightly bowed and of variable length; umbo subcentral. Peduncle flattened without scales.
Mouth parts similar to those of C. auritum. Mandible with five teeth and a shorter, pointed, lower corner. Maxilla I with four or five steps.
Cirri with protuberant segments, especially in cirri I and II. Five or six filamentary appendages; two or three situated below cirrus I, one below each of cirri III—V. No caudal appendages.
Hermaphrodite. Penis annulated, rather long as in other lepadids, and very setose.

Size
Capitulum ca. 35 mm long. Peduncle about the same length or a little shorter.

Colour
Capitulum and peduncle grey with some longitudinal, dark purplish brown bands.

Ecology
C. virgatum is found on ships' hulls, telegraph cables, or floating objects such as driftwood. It has also been found attached to the moonfish Mola mola, the sea snake Hydrus platurus, the eel Gymnothorax favagineus, whales, and other animals. It is often associated with Conchoderma auritum and Lepas species.

Depth range
Pelagic.

Distribution in the North Sea
Norway (single finds in Oslofjorden, the Bergen area, and Lofoten), Denmark (Hornbaek, Copenhagen, on ships), Bohuslan (a single find on a ship), Iceland, W of the Faeroes, S North Sea, and the Netherlands.

World distribution
Almost cosmopolitan. Circumglobal in tropical and subtropical seas, rare in boreal waters and not found in the Arctic region. As south as the Falkland Islands in the southern hemisphere.

[After Nilsson-Cantell, 1978]

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