A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through convergent evolution they have independently evolved external superficial fish-like body plans adapted to their marine environments, including most numerously fish, but also mammals such as cetaceans, and even extinct ancient marine reptiles such as various known species of ichthyosaurs. Most species have only one dorsal fin, but some have two or three.
Cirrhitidae, the hawkfishes, are a family of marine ray-finned fishes found in tropical seas and which are associated with coral reefs.
Xenacanthus is an extinct genus of xenacanth cartilaginous fish. It lived in freshwater environments, and fossils of various species have been found worldwide.
Osteolepis is an extinct genus of lobe-finned fish from the Devonian period. It lived in the Lake Orcadie of northern Scotland.
Stethacanthus is an extinct genus of shark-like cartilaginous fish which lived from the Late Devonian to Late Carboniferous epoch, dying out around 298.9 million years ago. Fossils have been found in Australia, Asia, Europe and North America.
Hybodus is an extinct genus of hybodont that lived from the Middle Triassic to the Late Cretaceous periods. Species closely related to the type species Hybodus reticulatus lived during the Early Jurassic epoch. Numerous species have been assigned to Hybodus spanning a large period of time, and it is currently considered a wastebasket taxon that is 'broadly polyphyletic' and requires reexamination.
Promissum is an extinct genus of conodonts, primitive chordates, that lived during the Upper Ordovician period.
Climatius is an extinct genus of spiny shark. This genus is known from the Early Devonian (Lochkovian) of Europe, previously considered Silurian remains actually belong to Nostolepis instead.
Pholidophorus is an extinct genus of stem-teleost fish. Numerous species were assigned to this genus in the past, but only the type species Pholidophorus latiusculus, from the Late Triassic of Europe, is considered to be a valid member of the genus today.
Protobrama is an extinct genus of teleost fish from the Cretaceous period of Lebanon.
Hypsidoris is an extinct genus of catfish, classified within its own family Hypsidoridae, from the Eocene epoch of North America.
Strunius is an extinct genus of lobe-finned fish from the Late Devonian period of Germany and Latvia.
The prickly dogfish is a poorly known species of dogfish shark in the family Oxynotidae, inhabiting temperate Australian and New Zealand waters. Reaching a length of 75 cm (30 in), this brown to gray shark has a very thick body with a prominent "humpback" and extremely rough skin. It is further characterized by two enormous, sail-like dorsal fins placed relatively close together. Both dorsal fins have a spine embedded mostly within the fleshy leading portion of the fin; the first dorsal spine is tilted forward.
Caracanthus, the coral crouchers, or orbicular velvetfishes, are a genus of ray-finned fishes. They live in coral reefs of the tropical Indo-Pacific. This genus is the only member of the monotypic subfamily Caracanthinae, part of the family Scorpaenidae.
Centropyge multicolor, the multicolor angelfish or pearlback angelfish, is a species of marine ray-finned fish, a marine angelfish belonging to the family Pomacanthidae. It is from the Pacific Ocean that sometimes makes its way into the aquarium trade. It grows to a size of 9 cm in length.
The snake mackerel is the sole species of fish in the monotypic genus Gempylus, belonging to the family Gempylidae. It is found worldwide in tropical and subtropical oceans between the latitudes of 42°N and 40°S; adults are known to stray into temperate waters. It is found to a depth of 600 meters. Populations of the snake mackerel from the Atlantic and the Indo-Pacific differ in vertebral count and number of first dorsal fin spines, and so may represent separate species.
The Upper Zambezi labeo is a species of cyprinid fish of the genus Labeo native to southern Africa.
Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only by muscles.
The Bean's sawtooth eel is an eel in the family Serrivomeridae. It was described by Theodore Gill and John Adam Ryder in 1883. It is a marine, deep water-dwelling eel which is known from throughout the Atlantic Ocean, the Indian Ocean, and the Western Pacific Ocean, including Iceland, South Africa, Réunion, and Australia. It dwells at a depth range of 0–5,998 metres (0–19,680 ft), and leads a solitary lifestyle. It migrates vertically at night. Males can reach a maximum total length of 78-80 centimetres, making it the largest sawtooth eel.
Zaniolepis frenata, also known as the shortspine combfish, is a species of ray-finned fish belonging to the family Zaniolepididae.The species occurs in the eastern Pacific Ocean.
