Chondrosteiformes on:
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Chondrosteidae is a
Chondrosteidae is a family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
of extinct marine actinopterygian
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 ...
fishes, known from the Early Jurassic of Europe. They are closely related to modern sturgeons
Sturgeon (from Old English ultimately from Proto-Indo-European language, Proto-Indo-European *''str̥(Hx)yón''-) is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the ...
and paddlefish
Paddlefish (family Polyodontidae) are a family of ray-finned fish belonging to order Acipenseriformes, and one of two living groups of the order alongside sturgeons (Acipenseridae). They are distinguished from other fish by their elongated rost ...
of the order Acipenseriformes
Acipenseriformes is an order (biology), order of basal (phylogenetics), basal Actinopterygii, ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct family (biology), families C ...
, and are either placed as part of that order or the separate order Chondrosteiformes within the Chondrostei
Chondrostei is a subclass of non- neopterygian ray-finned fish. While the term originally referred to the paraphyletic grouping of all non-neopterygian ray-finned fish, it was redefined by Patterson in 1982 to be a clade comprising the Acipenser ...
. Three genera are known, '' Chondrosteus'', '' Gyrosteus'', and '' Strongylosteus''. Included species were of large size, with body lengths ranging from up to . Their skeleton was largely made up of bones (unlike living chondrosteans), but ossification
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...
was reduced compared to other ray-fins.
See also
*Prehistoric fish
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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 ...
* List of prehistoric bony fish
This list of prehistoric bony fish is an attempt to create a comprehensive listing of all Genus, genera from the fossil record that have ever been considered to be bony fish (class Osteichthyes), excluding purely vernacular terms. The list includ ...
References
External links
* Acipenseriformes Fossils of Great Britain Jurassic fish of Europe Jurassic bony fish Prehistoric ray-finned fish families {{Jurassic-fish-stub