Sarcopterygii — sometimes considered synonymous with Crossopterygii — is a clade including both a group of bony fish commonly referred to as lobe-finned fish, and tetrapods. They are characterised by prominent muscular limb buds (lobes) within their fins, which are supported by articulated appendicular skeletons. This is in contrast to the other clade of bony fish, the Actinopterygii, which have only skin-covered bony spines supporting the fins.
Tooth enamel is one of the four major tissues that make up the tooth in humans and many animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, cementum, and dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface.
Dentin or dentine is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by enamel on the crown and cementum on the root and surrounds the entire pulp. By volume, 45% of dentin consists of the mineral hydroxyapatite, 33% is organic material, and 22% is water. Yellow in appearance, it greatly affects the color of a tooth due to the translucency of enamel. Dentin, which is less mineralized and less brittle than enamel, is necessary for the support of enamel. Dentin rates approximately 3 on the Mohs scale of mineral hardness. There are two main characteristics which distinguish dentin from enamel: firstly, dentin forms throughout life; secondly, dentin is sensitive and can become hypersensitive to changes in temperature due to the sensory function of odontoblasts, especially when enamel recedes and dentin channels become exposed.
Eusthenopteron is a genus of prehistoric sarcopterygian fishes known from several species that lived during the Late Devonian period, about 385 million years ago. It has attained an iconic status from its close relationship to tetrapods. Early depictions of animals of this genus show them emerging onto land, but paleontologists now widely agree that eusthenopteron species were strictly aquatic animals.
Miguasha Provincial Park is a protected area near Carleton-sur-Mer on the Gaspé Peninsula of Quebec in Canada. Created in 1985 by the Government of Quebec, Miguasha was designated a World Heritage Site in 1999 in recognition of its wealth of fossils, which display a crucial time during the evolution of life on Earth. Other names for this site are the Miguasha Fossil Site, the Bay of Escuminac Fossil Site, the Upper Devonian Escuminac Formation, and the Hugh-Miller Cliffs. It is also sometimes referred to on fossil specimens as 'Scaumenac Bay' or 'Scaumenac Bay P.Q.'
Tetrapodomorpha is a clade of vertebrates consisting of tetrapods and their closest sarcopterygian relatives that are more closely related to living tetrapods than to living lungfish. Advanced forms transitional between fish and the early labyrinthodonts, such as Tiktaalik, have been referred to as "fishapods" by their discoverers, being half-fish, half-tetrapods, in appearance and limb morphology. The Tetrapodomorpha contains the crown group tetrapods and several groups of early stem tetrapods, which includes several groups of related lobe-finned fishes, collectively known as the osteolepiforms. The Tetrapodomorpha minus the crown group Tetrapoda are the stem Tetrapoda, a paraphyletic unit encompassing the fish to tetrapod transition.
Cheirolepis is an extinct genus of marine and freshwater ray-finned fish that lived in the Devonian period of Europe and North America. It is the only genus yet known within the family Cheirolepididae and the order Cheirolepidiformes. It was among the most basal of the Devonian actinopterygians and is considered the first to possess the "standard" dermal cranial bones seen in later actinopterygians.
Tristichopterids (Tristichopteridae) were a diverse and successful group of fish-like tetrapodomorphs living throughout the Middle and Late Devonian. They first appeared in the Eifelian stage of the Middle Devonian. Within the group sizes ranged from a few tens of centimeters (Tristichopterus) to several meters.
The Fram Formation is an Upper Devonian (Frasnian) sequence of rock strata on Ellesmere Island that came into prominence in 2006 with the discovery in its rocks of examples of the transitional fossil, Tiktaalik, a sarcopterygian or lobe-finned fish showing many tetrapod characteristics. Fossils of Laccognathus embryi, a porolepiform lobe-finned fish, and Qikiqtania, a close relative of Tiktaalik, were also found in the formation. The Fram Formation is a Middle to Upper Devonian clastic wedge forming an extensive continental facies consisting of sediments derived from deposits laid down in braided stream systems that formed some 375 million years ago, at a time when the North American craton ("Laurentia") was straddling the equator.
Coelacanthus is a genus of extinct marine coelacanths known from the late Permian period. It was the first genus of coelacanths described, about a century before the discovery of the extant coelacanth Latimeria. The order Coelacanthiformes is named after it.
Elpistostege is an extinct genus of finned tetrapodomorphs that lived during the Frasnian age of the Late Devonian epoch. Its only known species, E. watsoni, was first described in 1938 by the British palaeontologist Thomas Stanley Westoll, based on a single partial skull roof discovered at the Escuminac Formation in Quebec, Canada.
Guiyu oneiros is one of the earliest articulated bony fish discovered. Fossils of Guiyu have been found in what is now Qujing, Yunnan, China, in late Silurian marine strata, about 425 million years old.
Porolepis is an extinct genus of porolepiform sarcopterygian fish, from the Early Devonian Dniester Series of Ukraine, which is rich in Porolepis remains, and also the Nellen Koepfchen Beds of Germany. It lived alongside the dubious lophotrochozoan Macrodontophion. It was first described in 1858 but Porolepis was not named as a sufficient species until 1891.
Cosmine is a spongy, bony material that makes up the dentine-like layers in the scales of the lobe-finned fishes of the class Sarcopterygii. Fish scales that include layers of cosmine are known as cosmoid scales.
Zanclodesmus willetti is an extinct species of archipolypodan millipede that lived in the Late Devonian period of North America, approximately 380 million years ago. It was described in 2005 based on a fossil discovered in the Escuminac Formation of Quebec, Canada two years prior. It was approximately 44 mm (1.7 in) long and 10 mm wide with 27 body segments, and had kidney shaped patches of ocelli. Each trunk segment had long, sickle-shaped extensions (paranota) projecting laterally, and was decorated on the dorsal surface with low rectangular bosses ("bumps") bordered by crescent-shaped bosses. The genus name Zanclodesmus derives from Greek Zanklon, meaning "sickle", in reference to the long, curved paranota, and desmus, a common root word in millipedes. The species name willietti honors Miguasha National Park warden Jason Willett, who discovered the fossil.
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.
The intertemporal bone is a paired cranial bone present in certain sarcopterygians and extinct amphibian-grade tetrapods. It lies in the rear part of the skull, behind the eyes.
This list of fossil fish research presented in 2021 is a list of new taxa of jawless vertebrates, placoderms, acanthodians, fossil cartilaginous fishes, bony fishes, and other fishes that were described during the year, as well as other significant discoveries and events related to paleoichthyology that occurred in 2021.
Triazeugacanthus is an extinct genus of spiny shark from the Devonian of Canada. It contains a single species, Triazeugacanthus affinis. With total length up to 5.272 centimetres (2.076 in), it is known from multiple ontogenetic stages.
