''Coronula diadema'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

whale barnacle Whale barnacles are species of acorn barnacle that belong to the family Coronulidae. They typically attach to baleen whales, and sometimes settle on toothed whales. The whale barnacles diverged from the turtle barnacles about three million year ...

that lives on the skin of

humpback whale The humpback whale (''Megaptera novaeangliae'') is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus ''Megaptera''. Adults range in length from and weigh up to . The hump ...

s and certain other species of whale. This species was first described by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in the 1767 12th edition of his ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

''.

Description

As its name suggests, ''Coronula diadema'' resembles a crown in appearance, but as it grows it becomes more cylindrical; large specimens may be tall and in diameter. There are six broad wall plates surrounding a hexagonal orifice at the top, which is protected by a pair of opercular valves. The plates have fine longitudinal striations and the lower half often have irregular transverse striations.

Distribution and habitat

''C. diadema'' is found on the external surface of whales. When discussing this species, the zoologist

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...

(who devoted much of his career to barnacles) stated that he knew of the precise locations where four specimens were found, the arctic seas around Scandinavia, the east coast of North America, near the coast of the British Isles, and from the

Gulf Stream The Gulf Stream, together with its northern extension the North Atlantic Current, North Atlantic Drift, is a warm and swift Atlantic Ocean, Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida a ...

. Another reported location was New Zealand, but Darwin suspected that this was an error, and might be ''

Coronula reginae ''Coronula'' is a genus of whale barnacles, containing the following species (those known only from the fossil record are marked '†'): *''Coronula aotea'' Fleming, 1959 † *''Coronula barbara'' Darwin, 1854 † *''Coronula bifida'' Bronn, 1831 ...

''. The host whales are mostly

baleen whale Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their ...

s, particularly

s (''Megaptera novaengliae''), with the barnacles attaching themselves to the head, the flukes, the flippers, various grooves and the genital slit. This barnacle has also been found on the

blue whale The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known to have ever existed. The blue whale's long and slender body can ...

(''Balaenoptera musculus''), the

southern right whale The southern right whale (''Eubalaena australis'') is a baleen whale, one of three species classified as right whales belonging to the genus ''Eubalaena''. Southern right whales inhabit oceans south of the Equator, between the latitudes of 20 ...

(''Eubalaena australis''), the

fin whale The fin whale (''Balaenoptera physalus''), also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a cetacean belonging to the parvorder of baleen whales. It is the second-longest species of cet ...

(''Balaenoptera physalus''), the

sperm whale The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus ''Physeter'' and one of three extant species in the sperm whale famil ...

(''Physeter macrocephalus'') and the

northern bottlenose whale The northern bottlenose whale (''Hyperoodon ampullatus'') is a species of beaked whale in the ziphiid family, being one of two members of the genus ''Hyperoodon''. The northern bottlenose whale was hunted heavily by Norway and Britain in the 19t ...

(''Hyperoodon ampullatus''). For 'the role of ''Coronula diadema'' on a humpback whale's pectoral fins helping it to defend its calves from killer whales, see Humpback whale#Fins.

Life cycle

Most barnacles are

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

s and can fertilíze each other but not themselves, so they need to be clustered closely together to be able to breed. An individual acting as a male extends his long

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do n ...

to impregnate the mantle cavity of another individual in close proximity. Here internal fertilisation takes place and the embryos are brooded until the first moult. The free-swimming nauplius larvae form part of the

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

and pass through six moults before becoming non-feeding

cyprid A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive ...

larvae. Laboratory experiments suggest that the cyprid larvae are induced to settle and undergo

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

into juvenile barnacles in response to chemical cues from the skin of suitable host whales.

Gallery

References

External links

* {{Taxonbar, from=Q4302742 Barnacles Crustaceans described in 1767 Taxa named by Carl Linnaeus