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The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys.
Timeline of fish evolution. The evolution of fishes took place over a timeline which spans the Cambrian to the Cenozoic, including during that time in particular the Devonian, which has been dubbed the "age of fishes" for the many changes during that period. The Late Devonian extinctions played a crucial role in shaping the evolution of fish ...
A fish (pl.: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits.Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians.
Prehistoric fish are early fish that are known only from fossil records. They are the earliest known vertebrates, and include the first and extinct fish that lived through the Cambrian to the Quaternary. The study of prehistoric fish is called paleoichthyology. A few living forms, such as the coelacanth are also referred to as prehistoric fish ...
Common names of fish can refer to a single species; to an entire group of species, such as a genus or family; or to multiple unrelated species or groups. Ambiguous common names are accompanied by their possible meanings. Scientific names for individual species and higher taxa are included in parentheses.
Haikouichthys, a jawless fish, is popularized as one of the earliest fishes and probably a basal chordate or a basal craniate. [72] Ferns first appear in the fossil record about 360 million years ago in the late Devonian period. [73] Synapsids such as Dimetrodon were the largest terrestrial vertebrates in the Permian period, 299 to 251 million ...
Coelacanth. Coelacanths (/ ˈsiːləkænθ / ⓘ SEE-lə-kanth) (order Coelacanthiformes) are an ancient group of lobe-finned fish (Sarcopterygii) in the class Actinistia. [2][3] As sarcopterygians, they are more closely related to lungfish and tetrapods (which includes amphibians, reptiles, birds and mammals) than to ray-finned fish.
Most oceanic species (78 per cent, or 44 per cent of all fish species), live near the shoreline. These coastal fish live on or above the relatively shallow continental shelf. Only 13 per cent of all fish species live in the open ocean, off the shelf. Of these, 1 per cent are epipelagic, 5 per cent are pelagic, and 7 per cent are deep water. [16]