Acanthodii or acanthodians is an extinct class of gnathostomes. They are currently considered to represent a paraphyletic grade of various fish lineages basal to extant Chondrichthyes, which includes living sharks, rays, and chimaeras. Acanthodians possess a mosaic of features shared with both osteichthyans and chondrichthyans. In general body shape, they were similar to modern sharks, but their epidermis was covered with tiny rhomboid platelets like the scales of holosteians.
Dapedium is an extinct genus of primitive neopterygian ray-finned fish. The first-described finding was an example of D. politum, found in the Lower Lias of Lyme Regis, on the Jurassic Coast of England. Dapedium lived in the late Triassic and Jurassic periods.
This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes.
Psarolepis is a genus of extinct bony fish which lived around 397 to 418 million years ago. Fossils of Psarolepis have been found mainly in South China and described by paleontologist Xiaobo Yu in 1998. It is not known certainly in which group Psarolepis belongs, but paleontologists agree that it probably is a basal genus and seems to be close to the common ancestor of lobe-finned and ray-finned fishes. In 2001, paleontologist John A. Long compared Psarolepis with onychodontiform fishes and refer to their relationships.
Birgeria is a genus of carnivorous marine ray-finned fish from the Triassic period. Birgeria had a global distribution. Fossils were found in Madagascar, Spitsbergen, Germany, Switzerland, Italy, Slovenia, China, Russia, Canada and Nevada, United States. The oldest fossils are from Griesbachian aged beds of the Wordie Creek Formation of East Greenland.
Tristichopterus, with a maximum length of sixty centimetres, is the smallest genus in the family of prehistoric lobe-finned fish, Tristichopteridae that was believed to have originated in the north and dispersed throughout the course of the Upper Devonian into Gondwana. Tristichopterus currently has only one named species, first described by Egerton in 1861. The Tristichopterus node is thought to have originated during the Givetian part of the Devonian. Tristichopterus was thought by Egerton to be unique for its time period as a fish with ossified vertebral centers, breaking the persistent notochord rule of most Devonian fish but this was later reinspected and shown to be only partial ossification by Dr. R. H. Traquair. Tristichopterus alatus closely resembles Eusthenopteron and this sparked some debate after its discovery as to whether it was a separate taxon.
Pteronisculus is an extinct genus of prehistoric ray-finned fish that lived during the Early Triassic and Middle Triassic epochs of the Triassic period worldwide.
Scanilepis is an extinct genus of prehistoric bony fish that lived during the Rhaetian-?Hettangian ages. The type species, S. dubia, is known from the Rhaetian freshwater deposits of the Bjuv member of the Höganäs Formation, southwestern Sweden. A second species, S. spitzbergensis was mentioned from the Hettangian of the Festning section of the Grøfjorden area in Spitsbergen, Norway but was never described.
Isadia is an extinct genus of prehistoric freshwater ray-finned fish from the order Eurynotoidiformes. It is known from the Permian of European Russia. The genus Amblypterina is partially considered a junior synonym of both Isadia and Kichkassia.
Bobasatrania is an extinct genus of prehistoric bony fish that survived the Permian-Triassic extinction event. Fossils of Bobasatrania were found in beds of Changhsingian to Ladinian age. It was most speciose during the Early Triassic.
Dipteronotus is an extinct genus of stem-neopterygian ray-finned fish that existed during the Middle and Late Triassic epochs in what is now Europe and Morocco. As a typical feature, it had several ridge scales in front of its dorsal fin that created a spine-like structure.
Urosthenes is an extinct genus of prehistoric bony fish that lived during the Lopingian to Middle Triassic epochs in what is now New South Wales, Australia.
Gyrolepis is an extinct genus of prehistoric ray-finned fish from the Middle-Late Triassic epochs in what is now Europe. It is known both from complete specimens and isolated skeletal elements, such as scales or teeth.
Eurynotoides is an extinct genus of prehistoric bony fish.
Phareodus is a genus of freshwater fish from the Paleocene to the Eocene of Australia, Europe and North and South America.
The piper gurnard, also known as the piper or the lyre gurnard, is a species of marine, demersal ray-finned fish from the family Triglidae, the gurnards and sea robins. It is found in the eastern Atlantic Ocean and the Mediterranean Sea. It is the only species in the monotypic genus Trigla.
Protobalistum imperiale is an extinct prehistoric tetraodontid bony fish that lived from the Lutetian epoch of Eocene Monte Bolca.
Asterolepis is an extinct genus of antiarch placoderms from the Devonian of North and South America and Europe. They were heavily armored flat-headed benthic detritivores with distinctive jointed limb-like pectoral fins and hollow spine. The armor plate gives the Asterolepis a box-like shape. Its pectoral fins are also armored but the caudal and dorsal fin are not. The first fossils were named by M. Eichwald in 1840 after noticing star-like markings on the fossils.
Dorypterus is a small, extinct genus of prehistoric ray-finned bony fish. It lived during the Wuchiapingian stage of the late Permian epoch in what is now Germany (Kupferschiefer) and England. It is a hypsisomatic bobasatraniiform with a high dorsal fin. Due to anatomical differences with other bobasatraniiforms, such as the presence of pelvic fins and the reduced scale cover, Dorypterus is placed in its own monotypic family, Dorypteridae.
Lebachacanthus is a genus of extinct xenacanth known from the late Carboniferous-Early Permian of Europe. During the late Paleozoic, xenacanths were the apex predators of freshwater ecosystems, preying on small amphibians.
