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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.
Members of the Eugeneodontiformes are further classified into different families, the most well-preserved members that have been discovered are commonly placed within the families Helicoprionidae ("spiral saws"), and Edestidae ("those which devour"), the former containing the genera Helicoprion, Sarcoprion, and Parahelicoprion, and the latter ...
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.
Nomen oblitum (Latin for "forgotten name"): A name that has not been used in the scientific community for more than fifty years after its original proposal. Preoccupied name: A name that is formally published, but which has already been used for another taxon. This second use is invalid (as are all subsequent uses) and the name must be replaced.
Parahelicoprion is an extinct genus of shark-like cartilaginous fish that lived during the Early Permian.Two species are known ; P. clerci from Arta Beds of the Ural Mountains of Russia, and P. mariosuarezi from the Copacabana Formation of Bolivia.
BY RINA NAKANO, FOX40 SACRAMENTO COUNTY — Photos of a mysterious fish caught in the Delta last week are going viral. The photos were posted on Facebook by a woman who said she reeled it in near ...
Placoderms were among the first jawed fish (their jaws likely evolved from the first pair of gill arches), as well as the first vertebrates to have true teeth. They were also the first fish clade to develop pelvic fins , the second set of paired fins and the homologous precursor to hindlimbs in tetrapods .