''Perleidus'' is an extinct genus of ray-finned fish from the Triassic period. Fossils have been found in the Middle Triassic of Italy,

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

, and

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. The inclusion of Early Triassic species in the genus ''Perleidus'' was questioned.

Ecology

''Perleidus'' was a marine predatory fish, about in length. Its jaws hung vertically under the braincase, allowing them to open wide, a feature it shared with the earlier

palaeonisciform The Palaeonisciformes (Palaeoniscida) are an extinct order of early ray-finned fishes ( Actinopterygii). Palaeonisciformes ''sensu lato'' first appeared in the fossil record in the Late Silurian and last appeared in the Late Cretaceous. The na ...

fish, from which it may have been descended. Unlike those earlier fish, however, ''Perleidus'' and its relatives had highly flexible dorsal and

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

s, with a reduced number of fin rays. This would have made the fish more agile in the water.

Classification

The genus ''Perleidus'' currently comprises two species: ''P. altolepis'' (

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

) and ''P. sinensis''. The type species was originally described as ''

Semionotus ''Semionotus'' (from el, σημιον , 'mark' and el, νῶτος , 'back') is an extinct genus of ray-finned fish found throughout Northern Pangaea ( North America and Europe) during the late Triassic, becoming extinct in the Early Jurassic ...

altolepis'' by Wilhelm Deecke. The genus ''Perleidus'' was later erected for this species, named after the comune (municipality) of Perledo in the Province of Lecco in

Lombardy Lombardy ( it, Lombardia, Lombard language, Lombard: ''Lombardia'' or ''Lumbardia' '') is an administrative regions of Italy, region of Italy that covers ; it is located in the northern-central part of the country and has a population of about 10 ...

, northern Italy. Several species from the Early Triassic were subsequently referred to the genus ''Perleidus'' based on superficial resemblances. In 2017, a new genus, ''

Teffichthys ''Teffichthys'' is an extinct genus of ray-finned fish from the Early Triassic epoch. Fossils have been found in Madagascar and China, and possibly also in Angola, Canada, Greenland, and Svalbard. Classification The type species of ''Teffich ...

'', was erected for Early Triassic species of "''Perleidus''". ''Perleidus'' is the name giving taxon for the family

Perleididae Perleidiformes are an extinct order (biology), order of prehistoric ray-finned fish from the Triassic period (geology), period Although numerous Triassic taxa have been referred to Perleidiformes, which ones should be included for it to form a mo ...

and the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Perleidiformes Perleidiformes are an extinct order of prehistoric ray-finned fish from the Triassic period Although numerous Triassic taxa have been referred to Perleidiformes, which ones should be included for it to form a monophyletic group is a matter of on ...

References

Prehistoric neopterygii Prehistoric ray-finned fish genera Triassic bony fish Triassic fish of Asia Triassic fish of Europe {{paleo-rayfinned-fish-stub