Perleidus
Encyclopedia
Perleidus is an extinct genus of ray-finned fish from the Triassic
period. Fossils have been found worldwide.
Perleidus was a freshwater predatory fish, about 15 centimetres (5.9 in) in length. Its jaws hung vertically under the braincase, allowing them to open wide, a feature it shared with the earlier palaeonisciform
fish, from which it may have been descended. Unlike those earlier fish, however, Perleidus and its relatives had highly flexible dorsal
and anal fins, with a reduced number of fin rays. This would have made the fish more agile in the water.
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
period. Fossils have been found worldwide.
Perleidus was a freshwater predatory fish, about 15 centimetres (5.9 in) in length. Its jaws hung vertically under the braincase, allowing them to open wide, a feature it shared with the earlier palaeonisciform
Palaeonisciformes
Palaeonisciformes is an extinct order of early ray-finned fishes . It is not a natural group, but is instead a paraphyletic assemblage of the early members of several ray-finned fish lineages...
fish, from which it may have been descended. Unlike those earlier fish, however, Perleidus and its relatives had highly flexible dorsal
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
and anal fins, with a reduced number of fin rays. This would have made the fish more agile in the water.