Chondrichthyes is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or bony fishes, which have skeletons primarily composed of bone tissue. Chondrichthyes are jawed vertebrates with paired fins, paired nares, scales, and a heart with its chambers in series. The class is divided into two subclasses: Elasmobranchii and Holocephali.
Acanthodii or acanthodians is an extinct paraphyletic class of teleostome fish, sharing features with both bony fish and cartilaginous fish. In form they resembled sharks, but their epidermis was covered with tiny rhomboid platelets like the scales of holosteans. They represent several independent phylogenetic branches of fishes leading to the still extant Chondrichthyes.
The subclass Holocephali is a taxon of cartilaginous fish in the class Chondrichthyes. The earliest fossils are of teeth and come from the Devonian period. Little is known about these primitive forms, and the only surviving group in the subclass is the order Chimaeriformes. This group includes the rat fishes in the genus Chimaera, and the elephant fishes in the genus Callorhinchus. These fishes move by using sweeping movements of their large pectoral fins.
Teleostomi is an obsolete clade of jawed vertebrates that supposedly includes the tetrapods, bony fish, and the wholly extinct acanthodian fish. Key characters of this group include an operculum and a single pair of respiratory openings, features which were lost or modified in some later representatives. The teleostomes include all jawed vertebrates except the chondrichthyans and the extinct class Placodermi.
Stethacanthus is an extinct genus of shark-like holocephalian which lived from the Late Devonian to Late Carboniferous epoch, dying out around 298.9 million years ago. Fossils have been found in Asia, Europe and North America.
Acanthodes is an extinct genus of spiny shark. Fossils have been found in Europe, North America, and Australia.
Falcatus is an extinct genus of falcatid chondrichthyan which lived during the early Carboniferous Period in Bear Gulch bay and what is now Montana.
Stethacanthidae is an extinct family of prehistoric holocephalians. It is estimated to have existed approximately between 380 and 300 million years ago. Members of this family are noted for their peculiar dorsal fin.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2000.
Netsepoye is an extinct genus of cartilaginous fish distantly related to the modern order Chimaeriformes, containing the single species Netspoye hawesi. It lived more than 320 million years ago during the Late Mississippian.
Symmorium is a dubious genus of extinct stethacanthid holocephalian from the Devonian and Carboniferous of the United States (Illinois) and Russia. The type species, Symmorium reniforme, was named by Edward Drinker Cope in 1893 and several other species were originally classed under this genus, but they have since been classified into other genera such as Petalodus. Symmorium bears close similarity in size and appearance to Stethacanthus but the former is missing the "spine and brush" on its back. Some paleontologists think that the two forms are simply the males and females of related species, while other scientists think they were distinct genera.
Falcatidae is a family of Paleozoic holocephalians. Members of this family include Falcatus, a small fish from the Bear Gulch Limestone of Montana. The family first appeared around the start of the Carboniferous, and there is some evidence that they survived well into the early Cretaceous.
Echinochimaera is an extinct genus of fish, it was assigned to the order chimaera by Jack Sepkoski in 2002. The genus' name derives from the Greek εχινό (echino) meaning spiny, and chimaera.
Hybodontiformes, also called hybodonts, are an extinct subset of Elasmobranchii which existed from the late Devonian to the Late Cretaceous. They form the group of sharks closest to neoselachians, the clade of modern sharks and rays. Hybodonts were named and are distinguished based on their conical tooth shape. They comprised the main group of Jurassic sharks in Europe and North America. They survived into the Late Cretaceous before going extinct, possibly due to competition from other sharks. Lonchidion was one of the last hybodonts — its distinctive serrated fine spines occur in freshwater deposits from Wyoming alongside the fossils of the last dinosaurs, including Tyrannosaurus rex and Triceratops. Hybodontiformes are identified in the fossil record predominantly based on distinct teeth and fin spines. They were known to live in both fresh and salt water environments.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2009.
This list of fossil fishes described in 2014 is a list of new taxa of placoderms, fossil cartilaginous fishes and bony fishess of every kind that have been described during the year 2014, as well as other significant discoveries and events related to paleontology of fishes that occurred in the year 2014. The list only includes taxa at the level of genus or species.
This list of fossil fishes described in 2013 is a list of new taxa of placoderms, fossil cartilaginous fishes and bony fishess of every kind that have been described during the year 2013. The list only includes taxa at the level of genus or species.
This list of fossil fishes described in 2017 is a list of new taxa of jawless vertebrates, placoderms, acanthodians, fossil cartilaginous fishes, bony fishes and other fishes of every kind that are scheduled to be described during the year 2017, as well as other significant discoveries and events related to paleontology of fishes that are scheduled to occur in the year 2017. The list only includes taxa at the level of genus or species.
Dwykaselachus is an extinct genus of symmoriid, a cartilaginous fish that lived in what is now South Africa during the Permian period around 280 million years ago. It was first discovered in the 1980s, in a nodule of sediments from the Karoo Supergroup. Dwykaselachus was named based on Dwyka Group, the group of sedimentary geological formation in the southeastern part of Africa. It represents the place where the type species Dwykaselachus oosthuizeni was found.
This list of fossil fish described in 2018 is a list of new taxa of jawless vertebrates, placoderms, acanthodians, fossil cartilaginous fish, bony fish, and other fish of every kind that are scheduled to be described during the year 2018, as well as other significant discoveries and events related to paleontology of fish that are scheduled to occur in 2018.
