''Megabalanus tintinnabulum'' is a species of large

barnacle 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 eros ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Balanidae The Balanidae comprise a family of barnacles of the order Balanomorpha. As a result of research published in 2021 by Chan et al., the members of the family Archaeobalanidae were merged with this family. Genera These genera belong to the family B ...

. It is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

. The specific name comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

' meaning a

handbell A handbell is a bell designed to be rung by hand. To ring a handbell, a ringer grasps the bell by its slightly flexible handle – traditionally made of leather, but often now made of plastic – and moves the arm to make the hinged cla ...

and probably refers to the fact that small groups of barnacles resemble clusters of miniature bells.

Taxonomy

When

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 ...

first described this species in 1758, he named it ''Balanus tintinnabulum''. The

lectotype In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

was depicted by

Georg Eberhard Rumphius Georg Eberhard Rumphius (originally: Rumpf; baptized c. 1 November 1627 – 15 June 1702) was a German-born botanist employed by the Dutch East India Company in what is now eastern Indonesia, and is best known for his work ''Herbarium Amboinense' ...

in 1705, the type locality being

Ambon Ambon may refer to: Places * Ambon Island, an island in Indonesia ** Ambon, Maluku, a city on Ambon Island, the capital of Maluku province ** Governorate of Ambon, a colony of the Dutch East India Company from 1605 to 1796 * Ambon, Morbihan, a c ...

, Indonesia. In a monograph on barnacles in 1854,

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 ...

described the species as being very variable and assigned it to Section A of the genus ''Balanus'', characterised by having the parietes, basis, and radii (different plates in the shell wall) permeated by minute pores. In 1916,

Henry Augustus Pilsbry Henry Augustus Pilsbry (7 December 1862 – 26 October 1957) was an American biologist, malacologist and carcinologist, among other areas of study. He was a dominant presence in many fields of invertebrate taxonomy for the better part of a centu ...

elevated ''Balanus tintinnabulum'' to subspecies rank and in subsequent years a number of varieties were described. Later it was placed in the subgenus ''Megabalanus'' and in 1976, Newman and Ross elevated ''Megabalanus'' to generic rank, giving species rank to each of the 22 subspecies of what had previously been known as ''Balanus (Megabalanus) tintinnabulum''.

Description

''M. tintinnabulum'' is a large barnacle, barrel-shaped or narrowly conical, up to tall and in diameter. It is distinguished from other members of the

by having ungrooved growth ridges on the

scutum The ''scutum'' (; plural ''scuta'') was a type of shield used among Italic peoples in antiquity, most notably by the army of ancient Rome starting about the fourth century BC. The Romans adopted it when they switched from the military formati ...

and by the parietes having no spines or spiny projections. The parietes can be either rough or smooth, and they are sometimes slightly folded. The basal margin of the shell is either straight or slightly sinuous. The colour is a pale shade of reddish or bluish purple, sometimes streaked longitudinally with a darker or lighter shade and sometimes with transverse bands of colour.

Distribution and habitat

''M. tintinnabulum'' is of tropical origin, perhaps being native to West Africa and parts of the Indo-Pacific. It is common on both the eastern and western coasts of India. It has spread to other parts of the world attached to the hulls of ships. It was observed on ships' hulls in the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

in 1764, and in 1998, it was found attached to buoys off the

Belgian Belgian may refer to: * Something of, or related to, Belgium * Belgians, people from Belgium or of Belgian descent * Languages of Belgium, languages spoken in Belgium, such as Dutch, French, and German *Ancient Belgian language, an extinct languag ...

coast. It was first observed in Western Australia in 1949 and arrived on the east coast of Australia by 1990. It is also found on reefs, bedrock, boulders, and timber structures down to about deep.''Megabalanus tintinnabulum'' (acorn barnacle)
Marine pests of Australia. Retrieved March 2, 2012.

Biology

Like other acorn barnacles, ''M. tintinnabulum'' is a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

. Specially adapted legs called cirri are extended through the opening at the top of the shell and are waved about at right angles to the flow of water past the shell. Food particles are caught by these, and the cirri are periodically withdrawn into the shell and the food scraped off. Eggs of ''M. tintinnabulum'' are fertilized internally by sperm from another barnacle nearby and start to develop into larvae within a few days. These are

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 ...

ic and disperse in 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 ...

. They pass through six naupliar stages and one cypris larval stage before settling on the seabed, undergoing

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 ...

and developing into juveniles. These cement themselves to the substrate and remain

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

for the rest of their lives.

Ecology

''M. tintinnabulum'' is found at or below the low-tide mark in the

littoral zone The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

and is part of the fouling community. It is found on the hulls of ships and on man-made structures in ports. It has a stable population structure and low mortality rate, and is a long-lived species. In the

South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by the shores of South China (hence the name), in the west by the Indochinese Peninsula, in the east by the islands of Taiwan and northwestern Phil ...

, molluscs and acorn barnacles, including ''Megabalanus tintinnabulum'', were primary foulers of hulls and other man-made structures and that their presence allowed

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

hydrozoa Hydrozoa (hydrozoans; ) are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specializ ...

ns, and

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...

ns to take hold. Empty but still attached shells of ''M. tintinnabulum'' are sometimes occupied by the tessellated blenny ('' Hypsoblennius invemar''). It not only uses a shell for a refuge, but the male also broods the fish's eggs inside.''Hypsoblennius invemar'', Smith-Vaniz & Acero P., 1980: Tessellated Blenny
USGS. Retrieved 2012-03-02.

References

{{Taxonbar, from=Q423685 Barnacles Crustaceans described in 1758 Taxa named by Carl Linnaeus