Lepas anatifera is a pelagic barnacle that can be found attached to a variety of floating objects, including driftwood, bottles, boats, buoys, macroalgal rafts, and turtles. It can also be found on fixed objects such as rocks and off-shore structures. This species is most abundant in tropical and subtropical waters where sea temperatures exceed 18-20 ºC. (Castro, et al., 1999; NOBANIS, 2008; Patel, 1959)
The main characteristic of Lepas anatifera is its heart-shaped bivalve shell, called a capitulum, that can grow up to 5 cm in length and surrounds the body and limbs. The capitulum is composed of five striated, glossy white, calcareous plates. The first pair of calcareous plates are located at the aperture and the end of the peduncle. The second pair is more distal, located near the aperture. The fifth plate, the carina, creates a spine that connects all the valves to one another. The capitular valve allows extrusion and extraction of six food-catching tentacular structures called cirri. The barnacle attaches to objects using its stalk or peduncle, which ranges in length from 4-90 cm. The peduncle is a part of the head and is attached by a basal disc and covered by a tough cuticle that is unarmored and flexible. Beneath the cuticle lie longitudinal muscles. Attachment is maintained with cement produced from the glands of the peduncle. (Anderson, 1994; Cowles, 2005; Pfeiffer and Lowe, 1989; "Goose barnacle (Lepas anatifera)", 2010)
The eggs of Lepas anatifera are about 140-260 X 100-120 microns and hatch into free swimming larvae that undergo six specialized naupliar stages. Development to the 10 mm long, plankton-eating stage VI can take up to two months. The larvae then transforms into a cyprid, which is a non-feeding search and settlement stage. The cyprid larvae drift along the ocean currents until it identifies and attaches to a substratum. Once they are attached, cirri develop. Lepas anatifera reaches sexual maturity when the capitulum reaches 2.5 cm across. Sexual maturity occurs more slowly in cold waters than in warmer waters. Approximately 120 days after settlement these barnacles develop reproductive organs at temperatures between 10.2 to 18.4 ºC, but the reproductive development takes 30 days if the surface temperature of the water is around 25 ºC. (Anderson, 1994; Cowles, 2005; "Goose barnacle (Lepas anatifera)", 2010)
Unlike most barnacles, Lepas anatifera is hermaphroditic and individuals cross fertilize via a copulatory organ. The large protrusible penis is located on the ventral surface of the abdomen and its top is the opening of the male gonopore. The female gonopores are associated with the base of the first cirri. (Anderson, 1994)
Fertilization is internal and the young are brooded in the mantle cavity before they are released. (Cowles, 2005)
In Lepas anatifera, cross fertilization is followed by oviposition of the eggs in the mantle cavity. After oviposition they develop past their first embryonic stages. The newly fertilized eggs develop for about a week before being released as free swimming nauplii. (Anderson, 1994; Cowles, 2005)
Barnacles feed by using tentacular frills on their limbs called cirri. The legs and cirri are extended from between the valves of the captiulum.
Goose barnacles are sessile; they do not move unless they are torn from their current substrate. ("Goose barnacle (Lepas anatifera)", 2010)
Little is noted about the communication in Lepas anatifera.
Lepas anatifera is predatory, capturing prey (shrimp, polyps, young flying fish) with the cirri. Goose barnacles also filter currents, using a feathery filter feeding apparatus. Populations of L. anatifera can also be divided into two groups-monophagous and polyphagous consumers. These two groups differ in their prey size, location, diet composition and diversity, and feeding apparatus morphology. ("Feeding and spawning of the goose barnacle Lepas anatifera (Cirripedia, Lepadidae) on floating substrates in the open Northwestern Pacific Ocean", 2000; Anderson, 1994; Pfeiffer and Lowe, 1989; "Goose barnacle (Lepas anatifera)", 2010)
Adult Lepas anatifera are protected by an outer shell, but still may be preyed on by gastropods, starfish, crabs, and others. As larvae, the barnacles lack a shell, making them vulnerable to planktivores.
Fiona pinnata, a pelagic sea slug, is a known predator of Lepas anatifera. The sea slug uses its jaws to grasp the barnacle near the junction of the stalk and shell, and then uses its radula to rasp. The barnacle soon gapes open, allowing the sea slug to consume the prey. (Abbott, 1980)
Adult Lepas anatifera are filter feeders in the water and are food for various other species.
Lepas anatifera often attach to the hulls of ships, increasing the drag and reducing speed and efficiency. Thus, barnacles are often removed from ships' hulls. ("Goose barnacle (Lepas anatifera)", 2010)
Renee Mulcrone (editor), Special Projects.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the southern part of the New World. In other words, Central and South America.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.
A substance that provides both nutrients and energy to a living thing.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
fertilization takes place within the female's body
the area of shoreline influenced mainly by the tides, between the highest and lowest reaches of the tide. An aquatic habitat.
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
the area in which the animal is naturally found, the region in which it is endemic.
islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.
reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
an animal that mainly eats fish
mainly lives in oceans, seas, or other bodies of salt water.
non-motile; permanently attached at the base.
Attached to substratum and moving little or not at all. Synapomorphy of the Anthozoa
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)
Institute of Oceanology, Russian Academy of Sciences. Feeding and spawning of the goose barnacle Lepas anatifera (Cirripedia, Lepadidae) on floating substrates in the open Northwestern Pacific Ocean. 117851. Moscow: Russian Academy of Sciences. 2000.
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