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Semibalanus balanoides
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Maxillopoda
Infraclass: Cirripedia
Darwin, 1854
Orders [1]

Thoracica is a superorder of crustaceans which contains the most familiar species of barnacles found on rocky coasts, such as Semibalanus balanoides and Chthamalus stellatus . They have six well-developed limbs, and may be either stalked or sessile. The carapace is heavily calcified. The group includes free-living and commensal species. [2]

Crustacean subphylum of arthropods

Crustaceans form a large, diverse arthropod taxon which includes such familiar animals as crabs, lobsters, crayfish, shrimps, prawns, krill, woodlice, and barnacles. The crustacean group is usually treated as a class under subphylum Mandibulata and because of recent molecular studies it is now well accepted that the crustacean group is paraphyletic, and comprises all animals in the Pancrustacea clade other than hexapods. Some crustaceans are more closely related to insects and other hexapods than they are to certain other crustaceans.

Barnacle infraclass of crustaceans

A barnacle is a type of arthropod constituting the infraclass 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 settings. They are sessile (nonmobile) suspension feeders, and have four nektonic larval stages. Around 70 barnacle species are currently known. The name "Cirripedia" is Greek, meaning "curl-footed". The study of barnacles is called cirripedology.

Coast Area where land meets the sea or ocean

The coast, also known as the coastline or seashore, is the area where land meets the sea or ocean, or a line that forms the boundary between the land and the ocean or a lake. A precise line that can be called a coastline cannot be determined due to the coastline paradox.


This article follows Martin and Davis in placing Thoracica as a superorder of Cirripedia and in the following classification of thoracicans down to the level of families: [3]

Superorder Thoracica Darwin, 1854

Heteralepadidae is a family of goose barnacles.

Lepadidae family of crustaceans

Lepadidae is a family of goose barnacles, erected by Charles Darwin in 1852. It contains the three genera Lepas, Conchoderma and Dosima.

Oxynaspididae is a family of goose barnacles in the order Lepadiformes.

Gooseneck barnacles (Lepas anatifera) Gooseneckbarnacles.jpg
Gooseneck barnacles ( Lepas anatifera )

Related Research Articles

Goose barnacle order of crustaceans

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.

Orthogastropoda was a major taxonomic grouping of snails and slugs, an extremely large subclass within the huge class Gastropoda according to the older taxonomy of the Gastropoda.

Thecostraca class of crustaceans

Thecostraca is a subclass of marine invertebrates containing about 1,320 described species. Many species have planktonic larvae which become sessile or parasitic as adults.

Chthamalidae family of crustaceans

The Chthamalidae are a family of chthamaloid barnacles, living entirely in intertidal/subtidal habitats, characterized by a primary shell wall of eight, six, or four plates, lacking imbricating plate whorls, and either membraneous or more rarely calcareous basis. They are not found below immediate subtidal habitats, and more likely are found in the highest tier of shallow-water barnacle fauna. They can be found in the most rigorous wave-washed locations, and some species are found in the surf zone above high tide mark, only receiving water from wave action at high tide.

Balanomorpha suborder of crustaceans

The Balanomorpha are a suborder of barnacles, containing familiar acorn barnacles of the seashore. The suborder contains these families:

The taxonomy of the Gastropoda, as revised by Winston Ponder and David R. Lindberg in 1997, is an older taxonomy of the class Gastropoda, the class of molluscs consisting of all snails and slugs. The full name of the work in which this taxonomy was published is Towards a phylogeny of gastropod molluscs: an analysis using morphological characters.

Apogastropoda infraclass of molluscs

Apogastropoda was previously used as a major taxonomic grouping of sea snails, marine gastropod molluscs. This infraclass mostly consisted of marine limpets and operculate snails. At least 20,000 species were considered to exist within the two clades that were included, Heterobranchia and Caenogastropoda.

Archaeobalanidae family of crustaceans

The Archaeobalanidae are a family of barnacles of the order Sessilia.

<i>Acasta</i> (genus) genus of crustaceans

Acasta is a genus of barnacles in the family Archaeobalanidae, containing the following species:

<i>Notochthamalus</i> genus of crustaceans

Notochthamalus scabrosus, the only species in the genus Notochthamalus, is a species of barnacle found along the south-western and south-eastern coasts of South America, from Peru to the Falkland Islands. The species is found almost exclusively higher in the intertidal zone than the mussel Perumytilus, often codistributed with the confamilial barnacle Chthamalus cirratus and Balanus flosculus.

<i>Chelonibia</i> genus of crustaceans

Chelonibia is a genus of acorn barnacles in the monotypic family Chelonibiidae of the subphylum Crustacea. Its members are epizooic and live attached to manatees, turtles, marine molluscs, crabs and horseshoe crabs in all tropical and subtropical oceans. In a few instances, they have been found on sea snakes, alligators and inanimate substrates, but they are not found in the typical habitats of barnacles – on rocks, docks or boats.

The Chthamaloidea are a subdivision of Balanomorpha proposed by Newman and Ross to include barnacles with shell wall composed of rostrum, carina, and one to three pairs of latera, rarely supplemented with one or more whorls of basal imbricating plates. The rostrolatus enters the sheath, but rarely fuses with the rostrum, as in the three higher superfamilies. Shell plates are simple in construction, solid, and incorporate organic chitin between carbonate layers. Opercular plates are deeply interlocked, and in some genera, may become concrescent with age. Soft part morphology includes concave labrum without notch in the central part. Cirrus III more resembles Cirrus IV than II, or may be intermediate in structure. Caudal appendages present in some species.

The Catophragmidae are a family of barnacles in the superfamily Chthamaloidea with eight shell wall plates, surrounded by several whorls of imbricating plates. The basis is membranous.

<i>Catomerus</i> genus of crustaceans

Catomerus is a monotypic genus of intertidal/shallow water acorn barnacle that is found in warm temperate waters of Australia. The genus and species is very easily identified by whorls of small plates surrounding the base of the primary shell wall; no other shoreline barnacle species in the Southern Hemisphere has that feature. This species is considered to be a relic, as these plates are found only in primitive living lineages of acorn barnacles or in older fossil species. The fact that this is an intertidal species is unusual, because living primitive relic species are often found in more isolated habitats such as deep ocean basins and abyssal hydrothermal vents.

Chamaesipho is a genus of four-plated notochthamaline barnacles in the Pacific Ocean limited to Australian/New Zealand temperate waters. They are intertidal in preference, and tend to form crowded columnar colonies. They can be identified in the field by having a four-plated wall, an unfused rostrum, and narrow opercular plates. Elminius, which also inhabits the same area, has four plates in its shell wall. However, in Elminius, the rostrum and rostrolatera are fused completely, and the compound rostrum receives the alae of the adjacent carinolaterals. In Chamaesipho, the unfused rostrum bears alae, and closely resembles the carina in appearance.

<i>Nesochthamalus</i> genus of crustaceans

The barnacle genus Nesochthamalus was erected by Foster & Newman, 1987, to include sole species Chthamalus intertextus originally named by Darwin in 1854. It is widespread on islands in Western Pacific Ocean, including Hawaii, and presents combinations of unusual features which make easily recognizable for field workers. These include dirty white shell exterior with deep purple colored interior, operculars colored purple. Opercular plates on each side calcify together in all but youngest individuals, and cannot be separated or easily distinguished from each other. This feature is shared only by Rehderella belyaevi, but in latter species, scutum and tergum can be distinguished by raised ridge replacing old articular margin. Unique feature of Nesochthamalus is its basis. In young individuals, it is entirely membraneous, and with age, becomes secondarily calcareous progressively inwards, leaving only the center membraneous. As the basis calcifies, it rises off the substrate forming a saucer shape when viewed from the side. In addition, interior of shell is secondarily calcified.

Multicrustacea class of arthropods

The clade Multicrustacea constitutes the largest superclass of crustaceans, containing approximately four-fifths of all described crustacean species, including crabs, lobsters, shrimps, woodlice, prawns, krill, barnacles, crayfish, copepods, amphipods and others. The largest branch of multicrustacea is the class Malacostraca.


The Hexanauplia constitute a class of crustaceans, comprising three groups: the Copepoda, the Tantulocarida and the Thecostraca.

Euheterodonta is an infraclass of Mollusca in the class Bivalvia.


  1. WoRMS (2019). Thoracica. Accessed at: on 2019-01-16
  2. Robert D. Barnes (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 706. ISBN   978-0-03-056747-6.
  3. Joel W. Martin & George E. Davis (2001). An Updated Classification of the Recent Crustacea (PDF). Natural History Museum of Los Angeles County. pp. 132 pp.