Vertebrates are animals with a vertebral column, and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain.
A flatfish is a member of the ray-finned demersal fish order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through or around the head during development. Some species face their left sides upward, some face their right sides upward, and others face either side upward.
Lungfish are freshwater vertebrates belonging to the class Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Lungfish represent the closest living relatives of the tetrapods. The mouths of lungfish typically bear tooth plates, which are used to crush hard shelled organisms.
The frilled shark, also known as the lizard shark, is one of the two extant species of shark in the family Chlamydoselachidae. The frilled shark is considered a living fossil, because of its primitive, anguilliform (eel-like) physical traits, such as a dark-brown color, amphistyly, and a 2.0 m (6.6 ft)–long body, which has dorsal, pelvic, and anal fins located towards the tail. The common name, frilled shark, derives from the fringed appearance of the six pairs of gill slits at the shark's throat.
Ophidiiformes is an order of ray-finned fish that includes the cusk-eels, pearlfishes, viviparous brotulas, and others. Members of this order have small heads and long slender bodies. They have either smooth scales or no scales, a long dorsal fin and an anal fin that typically runs into the caudal fin. They mostly come from the tropics and subtropics, and live in both freshwater and marine habitats, including abyssal depths. They have adopted a range of feeding methods and lifestyles, including parasitism. The majority are egg-laying, but some are viviparous.
Synbranchiformes, often called swamp eels, though that name can also refer specifically to Synbranchidae, is an order of ray-finned fishes that are eel-like but have spiny rays, indicating that they belong to the superorder Acanthopterygii.
Halosaurs are eel-shaped fishes found only at great ocean depths. As the family Halosauridae, halosaurs are one of two families within the order Notacanthiformes; the other being the deep-sea spiny eels, Notacanthidae. Halosaurs are thought to have a worldwide distribution, with some 17 species in three genera represented. Only a handful of specimens have been observed alive, all in chance encounters with Remotely operated underwater vehicles.
Latimeria is a rare genus of fish which contains the two only living species of coelacanth. It includes two extant species: the West Indian Ocean coelacanth and the Indonesian coelacanth. They follow the oldest known living lineage of Sarcopterygii, which means they are more closely related to lungfish and tetrapods than to the common ray-finned fishes and cartilaginous fishes.
The Congridae are the family of conger and garden eels. Congers are valuable and often large food fishes, while garden eels live in colonies, all protruding from the sea floor after the manner of plants in a garden. The family includes over 220 species in 32 genera.
The Anguillidae are a family of ray-finned fish that contains the freshwater eels. All the extant species and six subspecies in this family are in the genus Anguilla, and are elongated fish of snake-like bodies, with long dorsal, caudal and anal fins forming a continuous fringe. They are catadromous, spending their adult lives in freshwater, but migrating to the ocean to spawn.
The superorder Elopomorpha contains a variety of types of fishes that range from typical silvery-colored species, such as the tarpons and ladyfishes of the Elopiformes and the bonefishes of the Albuliformes, to the long and slender, smooth-bodied eels of the Anguilliformes. The one characteristic uniting this group of fishes is they all have leptocephalus larvae, which are unique to the Elopomorpha. No other fishes have this type of larvae.
The speckled moray eel is a moray eel found in the eastern Pacific Ocean, around the Galapagos Islands and along the Central American coast from Costa Rica to Colombia. It is also found in the Gulf of California. It reaches a length of about 170 cm.
Lee Rogers Berger is an American-born South African paleoanthropologist and National Geographic Explorer-in-Residence. He is best known for his discovery of the Australopithecus sediba type site, Malapa; his leadership of Rising Star Expedition in the excavation of Homo naledi at Rising Star Cave; and the Taung Bird of Prey Hypothesis.
The wolf eel is a species of marine ray-finned fish belonging to the family Anarhichadidae, the wolf fishes. It is found in the North Pacific Ocean. Despite its common name and resemblance, it is not a true eel. It is the only species in the monotypic genus Anarrhichthys.
Branchial arches or gill arches are a series of paired bony/cartilaginous "loops" behind the throat of fish, which support the fish gills. As chordates, all vertebrate embryos develop pharyngeal arches, though the eventual fate of these arches varies between taxa. In all jawed fish (gnathostomes), the first arch pair develops into the jaw, the second gill arches develop into the hyomandibular complex, and the remaining posterior arches support the gills. In tetrapods, a mostly terrestrial clade evolved from lobe-finned fish, many pharyngeal arch elements are lost, including the gill arches. In amphibians and reptiles, only the oral jaws and a hyoid apparatus remains, and in mammals and birds the hyoid is simplified further to support the tongue and floor of the mouth. In mammals, the first and second pharyngeal arches also give rise to the auditory ossicles.
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish, and hypogean fish.
Eels are ray-finned fish belonging to the order Anguilliformes, which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage and are usually predators.
Anguillavus is an extinct genus of basal marine eel that lived during the Late Cretaceous of Lebanon, where it is known from the Sannine Formation.
Panturichthys fowleri, commonly known as Fowler's shortfaced eel, is an eel in the family Heterenchelyidae. It was described by Adam Ben-Tuvia in 1953, originally under the genus Lophenchelys. It is a subtropical, marine eel which is known from a single specimen collected from Israel, in the Mediterranean Sea. The holotype specimen was discovered dwelling at a depth range of 27–55 metres.
Bathycongrus aequoreus is an eel in the family Congridae. It was described by Charles Henry Gilbert and Frank Cramer in 1897, originally under the genus Congermuraena. It is a marine, deep water-dwelling eel which is known from Hawaii, in the eastern central Pacific Ocean. It dwells at a depth range of 300–686 metres, prefers deeper water and leads a benthic lifestyle.
