Barnacles are a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and are hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. Around 1,000 barnacle species are currently known.
Thoracica is an infraclass 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.
The Reverend Thomas Roscoe Rede Stebbing was a British zoologist, who described himself as "a serf to natural history, principally employed about Crustacea". Educated in London and Oxford, he only took to natural history in his thirties, having worked as a teacher until then. Although an ordained Anglican priest, Stebbing promoted Darwinism in a number of popular works, and was banned from preaching as a result. His scientific works mostly concerned crustaceans, especially the Amphipoda and Isopoda, the most notable being his work on the amphipods of the Challenger expedition.
Epicaridea is a former suborder of isopods, now treated as an infraorder in suborder Cymothoida. They are ectoparasites that inhabit other crustaceans, namely ostracods, copepods, barnacles and malacostracans. Epicarideans are found globally. Epicaridea are generally less well researched than other isopods.
Armatobalanus is a genus of crustacean in family Balanidae. It contains at least the following species :
Megabalanus is a genus of barnacles in the family Balanidae. Members of the genus grow to 7 cm (2.8 in) in length and inhabit the lower intertidal zone.
Chthamalus is a genus of barnacles that is found along almost all non-boreal coasts of the northern hemisphere, as well as many regions in the southern hemisphere. These small barnacles have been studied in part because of the taxonomic confusion over a group of species that, by and large, are morphologically and ecologically quite similar. In recent years, molecular techniques have identified a number of cryptic species that have been subsequently confirmed by taxonomists using morphological measurements. Most recently the genus has been shown to be paraphyletic, with the genus Microeuraphia nested within Chthamalus.
Balanus nubilus, commonly called the giant acorn barnacle, is the world's largest barnacle, reaching a diameter of 15 cm (6 in) and a height of up to 30 cm (12 in), and containing the largest known muscle fibres.
Acasta is a genus of barnacles in the family Balanidae, containing the following species:
Cymothoida is the name of a suborder of isopod crustaceans with a mostly carnivorous or parasitic lifestyle. It contains more than 2,700 described species in four superfamilies. Members of the suborder are characterised by their specialised mouthparts which include a mandible with a tooth-like process which is adapted for cutting or slicing.
The Bopyridae are a family of isopod crustaceans in the suborder Cymothoida. There are 1223 individual species contained in this family. Members of the family are ectoparasites of crabs and shrimp. They live in the gill cavities or under the carapace where they cause a noticeable swelling. Fossil crustaceans have occasionally been observed to have a similar characteristic bulge.
Cancricepon is a genus of isopod crustaceans in the family Bopyridae. It has been synonymised with Merocepon Richardson, 1910.
The Cabiropidae are a family of isopod crustaceans in the suborder Cymothoida. The original description was made by Giard and Bonnier in 1887. Members of the family are hyperparasites of other parasitic isopods in the order and some are parasites on other free-living isopods.
The Hemioniscidae are a family of marine isopod crustaceans in the suborder Cymothoida. The original description was made by Bonnier in 1900. Members of this family are parasitic on cirripede barnacles.
The Cyproniscidae are a family of marine isopod crustaceans in the suborder Cymothoida. The original description was made by Bonnier in 1900. Members of this family are parasitic on other isopods.
The Podasconidae are a family of marine isopod crustaceans in the suborder Cymothoida. The original description was made by Giard and Bonnier in 1895. Members of this family are parasitic on amphipods.
Asconiscus is a genus in the Asconiscidae family of marine isopod crustaceans in the suborder Cymothoida, containing a single genus and a single species, Asconiscus simplex. The original description of the family was made by Bonnier in 1900. A. simplex is a parasite of the shrimp-like crustacean, Boreomysis arctica.
The Dajidae are a family of marine isopod crustaceans in the suborder Cymothoida. The original description was made by Giard and Bonnier in 1887. Members of this family are ectoparasites of krill. They resemble a fleshy growth on the krill's back, and make the host look as if it is wearing a rucksack. These genera are included in the family Dajidae:
Polybius henslowii is a species of crab, the only species in the genus Polybius. It is a capable swimmer and feeds in open water in the north-east Atlantic Ocean and western Mediterranean Sea.
Lamarckdromia beagle is a crab species in the family Dromiidae, described in 2022.
