Amia Temporal range: [1] | |
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Bowfin in aquarium | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Clade: | Halecomorphi |
Order: | Amiiformes |
Family: | Amiidae |
Subfamily: | Amiinae |
Genus: | Amia Linnaeus, 1766 |
Type species | |
Amia calva Linnaeus, 1766 | |
Species | |
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Synonyms [2] [3] | |
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Amia, commonly called bowfin, is a genus of bony fish related to gars in the infraclass Holostei. They are regarded as taxonomic relicts, being the sole surviving species of the order Amiiformes, which dates from the Jurassic to the Eocene, persisting to the present. There are two living species in Amia, Amia calva and Amia ocellicauda , and a number of extinct species which have been described from the fossil record.
Competing hypotheses and debates continue over the evolution of Amia and relatives, including their relationship among basal extant teleosts, and organization of clades. [4] Bowfin are the last remaining member of Halecomorphi, a group that includes many extinct species in several families. [5] Halecomorphs were generally accepted as the sister group to Teleostei but not without question. While a halecostome pattern of neopterygian clades was produced in morphology-based analyses of extant actinopterygians, a different result was produced with fossil taxa which showed a monophyletic Holostei. Monophyletic Holostei were also recovered by at least two nuclear gene analyses, in an independent study of fossil and extant fish, [6] [7] and in an analysis of ultraconserved genomic elements. [8]
The extant ray-finned fish of the subclass Actinopterygii include 42 orders, 431 families and over 23,000 species. [9] They are currently classified into two infraclasses, Chondrostei (holosteans) and Neopterygii (teleost fishes). [10] Sturgeons, paddlefish, bichirs and reed fish compose the thirty-eight species of chondrosteans, and are considered relict species. Included in the over 23,000 species of neopterygians are eight relict species comprising gars and the bowfin. [9]
Neopterygians are the second major occurrence in the evolution of ray-finned fish and today include the majority of modern bony fish. [9] They are distinguished from their earlier ancestors by major changes to the jaws, shape of the skull, and tail. They are divided into three divisions:
List of species. [12] [ citation needed ]
The bowfin genome contains an intact ParaHox gene cluster, similar to the bichir and to most other vertebrates. This is in contrast, however, with teleost fish, which have a fragmented ParaHox cluster, probably because of a whole genome duplication event in their lineage. The presence of an intact ParaHox gene cluster suggests that bowfin ancestors separated from other fish before the last common ancestor of all teleosts appeared. Bowfin are thus possibly a better model to study vertebrate genome organization than common teleost model organisms such as zebrafish. [14]
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.
Osteichthyes, commonly referred to as the bony fish but in the 21st century also treated as a clade that includes the tetrapods, is a diverse superclass of vertebrate animals that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of extant fish are members of Osteichthyes, an extremely diverse and abundant group consisting of 45 orders, over 435 families and 28,000 species. It is the largest class of vertebrates in existence today.
The bowfin is a bony fish, native to North America. Common names include mudfish, mud pike, dogfish, grindle, grinnel, swamp trout, and choupique. It is regarded as a relict, being one of only two surviving species of the Halecomorphi, a group of fish that first appeared during the Early Triassic, around 250 million years ago. The bowfin is often considered a "primitive fish" because they have retained some morphological characteristics of their early ancestors. It is one of two species in the genus Amia, along with Amia ocellicauda, the eyespot bowfin. The closest living relatives of bowfins are gars, with the two groups being united in the clade Holostei.
The Amiiformes order of fish has only two extant species, the bowfins: Amia calva and Amia ocellicauda, the latter recognized as a separate species in 2022. These Amiiformes are found in the freshwater systems of North America, in the United States and parts of southern Canada. They live in freshwater streams, rivers, and swamps. The order first appeared in the Triassic, and the extinct members include both marine and freshwater species, many of which are morphologically disparate from bowfins, such as the caturids.
The Amiidae are a family of basal ray-finned fishes. The bowfin and the eyespot bowfin are the only two species to survive today, although additional species in all four subfamilies of Amiidae are known from Jurassic, Cretaceous, and Eocene fossils.
Actinopteri is the sister group of Cladistia (bichirs) in the class Actinopterygii.
Neopterygii is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant fishes, and over half of all living vertebrate species. While living holosteans include only freshwater taxa, teleosts are diverse in both freshwater and marine environments. Many new species of teleosts are scientifically described each year.
Lepisosteiformes is an order of ray-finned fish and the only living members of the clade Ginglymodi. Its only extant representatives are the gar, and it is defined as all members of Ginglymodi that are more closely related to gar than to the extinct Semionotiformes, the other major grouping of ginglymodians. They are one of two extant orders in the infraclass Holostei alongside the Amiiformes.
Holostei is a group of ray-finned bony fish. It is divided into two major clades, the Halecomorphi, represented by the single living genus, Amia with two species, the bowfins, as well as the Ginglymodi, the sole living representatives being the gars (Lepisosteidae), represented by seven living species in two genera. The earliest members of the clade, which are putative "semionotiforms" such as Acentrophorus and Archaeolepidotus, are known from the Middle to Late Permian and are among the earliest known neopterygians.
Pachycormiformes is an extinct order of marine ray-finned fish known from the Early Jurassic to the end of the Cretaceous. It only includes a single family, Pachycormidae. They were characterized by having serrated pectoral fins, reduced pelvic fins and a bony rostrum. Pachycormiformes are morphologically diverse, containing both tuna and swordfish-like carnivorous forms, as well as edentulous suspension-feeding forms.
Halecostomi is the name of a group of neopterygian fish uniting the halecomorphs and the teleosts, the largest group of extant ray-finned fish.
Asialepidotus is an extinct genus of prehistoric marine ray-finned fish that lived during the Ladinian stage of the Middle Triassic epoch. It contains a single species, A. shingyiensis, from Guizhou, China.
Prohalecites is an extinct genus of ray-finned fish from the Ladinian and possibly Carnian (Triassic) of Italy. It is the oldest known teleosteomorph, a group that includes extant teleosts and their close fossil relatives.
Cipactlichthys is a genus of extinct holostean fish from the Lower Cretaceous of Mexico. The only known species is Cipactlichthys scutatus.
Halecomorphi is a taxon of ray-finned bony fish in the clade Neopterygii. The only extant Halecomorph species are the bowfin and eyespot bowfin, but the group contains many extinct species in several families in the order Amiiformes, as well as the extinct orders Ionoscopiformes, Panxianichthyiformes, and Parasemionotiformes. The fossil record of halecomorphs goes back at least to the Early Triassic epoch.
Percomorpha is a large clade of ray-finned fish with more than 17 000 known species that includes the tuna, seahorses, gobies, cichlids, flatfish, wrasse, perches, anglerfish, and pufferfish.
Sinamiidae is an extinct family of ray-finned fish. They are halecomorph fishes endemic to Early Cretaceous freshwater environments in East and Southeast Asia.
Ginglymodi is a clade of ray-finned fish containing modern-day gars (Lepisosteidae) & their extinct relatives in the order Lepisosteiformes, the extinct orders Semionotiformes and Kyphosichthyiformes, and various other extinct taxa. Ginglymodi is one of the two major subgroups of the infraclass Holostei, the other one being Halecomorphi, which contains the bowfin and eyespot bowfin and their fossil relatives.
Parasemionotiformes is an extinct order of neopterygian ray-finned fish that existed globally during the Triassic period. It comprises the families Parasemionotidae and Promecosominidae. Many of the included genera are monotypic and most species lived during the Early Triassic epoch.
Fishes are a paraphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal taxonomy. Traditional classification divides fish into three extant classes, and with extinct forms sometimes classified within those groups, sometimes as their own classes: