''Conchoderma virgatum'' is a species of

goose barnacle Goose barnacles, also called stalked barnacles or gooseneck barnacles, are filter-feeding crustaceans that live attached to hard surfaces of rocks and flotsam in the ocean intertidal zone. Goose barnacles formerly made up the taxonomic order Ped ...

in the family

Lepadidae Lepadidae is a family of goose barnacles, erected by Charles Darwin in 1852. There are about five genera and more than 20 described species in Lepadidae. Genera These genera belong to the family Lepadidae: * ''Conchoderma'' von Olfers, 1814 (wha ...

. It is a

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

species found in open water in most of the world's oceans attached to drifting objects or marine organisms.

Description

''Conchoderma virgatum'' has a flexible, flattened, scale-less peduncle (stalk) which is attached to a solid surface, and a capitulum (body) with five smooth, four-sided plates, widely separated from each other and not clearly demarcated from the peduncle. The total length of this goose barnacle is about , half of which is the peduncle. Overall, the colour is grey, but there are some dark purplish-brown longitudinal streaks.

Distribution

''Conchoderma virgatum'' has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

, being found in all the world's oceans attached to a wide range of drifting and swimming objects, as well as

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

habitats.

Ecology

''Conchoderma virgatum'' is found attached to a wider range of floating objects and

nekton Nekton or necton (from the ) refers to the actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms ...

than goose barnacles in the genus ''

Lepas ''Lepas'' is a genus of goose barnacles in the family Lepadidae. Species Species in the genus include: * '' Lepas anatifera'' Linnaeus, 1758 * ''Lepas anserifera'' Linnaeus, 1767 * '' Lepas australis'' Darwin, 1851 * ''Lepas hilli ''Lepas'' ...

''. This species seems to have evolved from the same common ancestry as '' Conchoderma auritum'', which occurs on

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

s, and '' Alepas'' which occur on

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...

. Most attachments are to inanimate objects such as buoys and the hulls of ships, but it has been recorded as being attached to

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

sea snake Sea snakes, or coral reef snakes, are elapid snakes that inhabit marine environments for most or all of their lives. They belong to two subfamilies, Hydrophiinae and Laticaudinae. Hydrophiinae also includes Australasian terrestrial snakes, wher ...

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

s and whales, and at least thirteen species of fish. Direct attachment to fish is infrequent, perhaps because of the

mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...

produced by the skin; in one example, four of the barnacles were attached to a single spine of a spot-fin porcupinefish (''Diodon hystrix''). This barnacle also attaches to several species of

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s, and on one occasion was observed attached to an

isopod Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...

that was parasitic on an orange filefish (''Aluterus schoepfii''). Like most barnacles, ''Conchoderma virgatum'' is a filter feeder. A number of modified legs known as "cirri" can be extended into the

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

. These feathery appendages beat rhythmically and catch plankton and small organic particles, drawing them into the mouth.

References

{{Taxonbar, from=Q6568143 Maxillopoda Crustaceans described in 1789 Crustaceans of the Atlantic Ocean Crustaceans of the Indian Ocean Crustaceans of the Pacific Ocean