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Helicoprion is a genus of extinct shark-like [1] eugeneodont fish. Almost all fossil specimens are of spirally arranged clusters of the individuals' teeth, called "tooth whorls", which in life were embedded in the lower jaw. As with most extinct cartilaginous fish, the skeleton is mostly unknown.
The study of prehistoric fish is called paleoichthyology. A few living forms, such as the coelacanth are also referred to as prehistoric fish, or even living fossils, due to their current rarity and similarity to extinct forms. Fish which have become recently extinct are not usually referred to as prehistoric fish.
The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (nomina dubia), or were not formally published (nomina nuda), as well as junior synonyms of more established names, and genera that are no longer considered agnathans. Modern forms are excluded from this list.
Helicoprion bessonovi, teeth at the front of the lower jaw (reversed for more natural position) Restoration of Romerodus (Caseodontidae). The Eugeneodontiformes, (also called Eugeneodontida) is an extinct and poorly known order of cartilaginous fishes.
Coelacanths (/ ˈ s iː l ə k æ n θ / ⓘ 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.
This list of prehistoric cartilaginous fish genera is an attempt to create a comprehensive listing of all genera that have ever been included in the class chondrichthyes and are known from the fossil record. This list excludes purely vernacular terms, genera that are now considered invalid, doubtful (nomina dubia), or were not formally ...
Ornithoprion is a genus of extinct cartilaginous fish in the family Caseodontidae. The only species, O. hertwigi, lived during the Moscovian stage of the Pennsylvanian, between 315.2 to 307 million years ago, and is known from black shale deposits in what is now the Midwestern United States.
List of prehistoric brittle stars; List of prehistoric bryozoan genera; List of prehistoric chitons; List of prehistoric foraminifera genera; List of ichthyosaur genera; List of marine gastropod genera in the fossil record; List of plesiosaur genera; List of prehistoric malacostracans; List of prehistoric medusozoan genera; List of prehistoric ...