Actinopterygii, members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of skin supported by radially extended thin bony spines called lepidotrichia, as opposed to the bulkier, fleshy lobed fins of the sister class Sarcopterygii. Resembling folding fans, the actinopterygian fins can easily change shape and wetted area, providing superior thrust-to-weight ratios per movement compared to sarcopterygian and chondrichthyian fins. The fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the articulation between these fins and the internal skeleton.
Pomacentridae is a family of ray-finned fish, comprising the damselfishes and clownfishes. This family were formerly placed in the order Perciformes but are now regarded as being incertae sedis in the subseries Ovalentaria in the clade Percomorpha. They are primarily marine, while a few species inhabit freshwater and brackish environments. They are noted for their hardy constitutions and territoriality. Many are brightly colored, so they are popular in aquaria.
The Atheriniformes, also known as the silversides, are an order of ray-finned fishes that includes the Old World silversides and several less-familiar families, including the unusual Phallostethidae. The order includes at least 354 species. They are found worldwide in tropical and temperate marine and freshwater environments.
Beloniformes is an order composed of six families of freshwater and marine ray-finned fish:
Blenny is a common name for many types of fish, including several families of percomorph marine, brackish, and some freshwater fish sharing similar morphology and behaviour. Six families are considered "true blennies", grouped under the order Blenniiformes; its members are referred to as blenniiformids. About 151 genera and nearly 900 species have been described within the order. The order was formerly classified as a suborder of the Perciformes but the 5th Edition of Fishes of the World divided the Perciformes into a number of new orders and the Blenniiformes were placed in the percomorph clade Ovalentaria alongside the such taxa as Cichliformes, Mugiliformes and Gobiesociformes.
The order Cephalaspidea, also known as the headshield slugs and bubble snails, is a major taxon of sea slugs and bubble snails, marine gastropod mollusks within the larger clade Euopisthobranchia. Bubble shells is another common name for these families of marine gastropods, some of which have thin bubble-like shells. This clade contains more than 600 species.
Cirrina or Cirrata is a suborder and one of the two main divisions of octopuses. Cirrate octopuses have a small, internal shell and two fins on their head, while their sister suborder Incirrina has neither. The fins of cirrate octopods are associated with a unique cartilage-like shell in a shell sac. In cross-section, the fins have distinct proximal and distal regions, both of which are covered by a thin surface sheath of muscle.
Opistognathidae, the jawfishes, are a family of fishes which have been classified within the order Perciformes, suborder Percoidei but many authorities now classify this family within the clade Ovalentaria and consider that its affinities within that clade are uncertain, i.e. it is incertae sedis. The family includes about 80 species. They are native to warmer parts of the Atlantic, Pacific and Indian Oceans, where found from the shallows to depths of a few hundred meters. The species level taxonomy is complex and the family includes several undescribed species.
Grammatidae is a small family of ray-finned fishes which were formerly placed in the order Perciformes but are now regarded as being incertae sedis in the subseries Ovalentaria in the clade Percomorpha. They are commonly known as basslets. They are marine fish found in the tropical western Atlantic Ocean.
Leaffishes are small fishes of the family Polycentridae. According to FishBase, it only includes the genera Monocirrhus and Polycentrus from fresh and brackish water in tropical South America. Although included in the Asian leaffish family Nandidae by FishBase, most recent authorities place the African Afronandus and Polycentropsis in Polycentridae. Polycentridae were formerly placed in the order Cichliformes but are now regarded as being incertae sedis in the subseries Ovalentaria in the clade Percomorpha.
The dottybacks are a family, Pseudochromidae, of fishes which were formerly classified in the order Perciformes, but this has been revised and the family is regarded as of uncertain affinities, or incertae sedis within the Ovalentaria, a clade within the Percomorpha. Around 152 species belong to this family.
The longfins, also known as roundheads or spiny basslets, are a family, Plesiopidae, which were formerly placed in the order Perciformes but are now regarded as being incertae sedis in the subseries Ovalentaria in the clade Percomorpha. They are elongated fishes, found in the Indian Ocean and western Pacific Ocean.
Acanthopterygii is a superorder of bony fishes in the class Actinopterygii. Members of this superorder are sometimes called ray-finned fishes for the characteristic sharp, bony rays in their fins; however this name is often given to the class Actinopterygii as a whole.
Zoarcoidei is a suborder of marine ray-finned fishes belonging to the order Perciformes. The suborder includes the wolffishes, gunnels and eelpouts. The suborder includes about 400 species. These fishes predominantly found in the boreal seas of the northern hemisphere but they have colonised the southern hemisphere.
Cichliformes is an order of fishes. Its members were previously classified under the order Perciformes, but now many authorities consider it to be an independent order within the subseries Ovalentaria.
The Anabantiformes, is an order of bony fish (Teleostei) proposed in 2009. They are collectively known as labyrinth fish, are an order of air-breathing freshwater ray-finned fish with two suborders, five families and at least 207 species. In addition, some authorities expand the order to include the suborder Nandoidei, which includes three families - the Nandidae, Badidae and Pristolepididae - that appear to be closely related to the Anabantiformes. The order, and these three related families, are part of a monophyletic clade which is a sister clade to the Ovalentaria, the other orders in the clade being Synbranchiformes, Carangiformes, Istiophoriformes and Pleuronectiformes. This clade is sometimes referred to as the Carangaria but is left unnamed and unranked in Fishes of the World. This group of fish are found in Asia and Africa, with some species introduced in United States of America.
The Atherinomorpha is a clade of fishes in the superorder Acanthopterygii, the ray-finned fishes, consisting of three orders. The clade is ranked as an infraseries within the subseries Ovalentaria, which in turn is ranked within the wider Percomorpha clade.
Acanthuriformes is an order of ray-finned fishes, part of the Percomorpha clade. Some authorities place the fishes in the order within the Acanthuriformes in the suborders Acanthuroidea and Percoidea of the order Perciformes.
Teleosteomorpha is a clade of ray-finned fishes containing all teleost fish and their closest extinct relatives. Also in this group are two diverse Mesozoic fish orders, the Aspidorhynchiformes and the Pachycormiformes. Several other non-teleostomorph teleosteans existed throughout the Mesozoic, although not as dominant as the two main clades in the group.
The Priacanthiformes is a proposed order of marine ray-finned fishes. The order comprises two families, the Priacanthidae and the Cepolidae, which bear very little morphological similarity to each other but which have been shown to be sister taxa in repeated molecular analyses. The exact placement of the order within the series Eupercaria is incertae sedis. However, the more traditional classification followed in the 5th Edition of the Fishes of the World places both these families within the order Perciformes.
