Laytonia Temporal range: | |
---|---|
L. californica and Bolbocara | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Notacanthiformes |
Family: | Halosauridae |
Genus: | † Laytonia |
Type species | |
Laytonia californica David 1943 | |
Species | |
|
Laytonia is an extinct genus of prehistoric halosaur that lived in deep water off the North American Pacific Coast from the Zemorrian Epoch (comprising either the latest Oligocene or lower Miocene) until during the Upper Miocene subepoch, when tectonic uplift effectively destroyed the genus' habitat by making the deep water too shallow. [2]
There are two species recognized, the type species, L. californica, which is known from at least 2 whole fossils, and fossil scales from Upper Miocene strata of Southern California, and L. zemorrensis, known from fossil scales in Zemorrian strata (either Oligocene or Lower Miocene) from Oregon and California.
According to the fossils of L. californica, the living animals were very slender, and had a long, fringe-like dorsal fin running almost the entire length of the body, from the head to the tip of the tail. The dorsal fin forms two crests, a first, low crest on top of the back of the head, and a second, large crest near the upper back, above the pectoral fins.
The name comes from discoverer of the fossil, Melvin E. Layton.
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.
The Molidae comprise the family of the molas or ocean sunfishes, unusual fish whose bodies come to an end just behind the dorsal and anal fins, giving them a "half-fish" appearance. They are also the largest of the ray-finned bony fish, with the ocean sunfish Mola mola and southern sunfish, Mola alexandrini, both recorded at up to 4.6 m (15 ft) in length and 2,300 kg (5,100 lb) in weight.
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Dunkleosteus is an extinct genus of large armored, jawed fishes that existed during the Late Devonian period, about 382–358 million years ago. It consists of ten species, some of which are among the largest placoderms to have ever lived: D. terrelli, D. belgicus, D. denisoni, D. marsaisi, D. magnificus, D. missouriensis, D. newberryi, D. amblyodoratus, and D. raveri. The largest and most well known species is D. terrelli, which grew up to 8.79 m (28.8 ft) long and 4 t in weight. Dunkleosteus could quickly open and close its jaw, like modern-day suction feeders, and had a bite force of 6,000 N at the tip and 7,400 N at the blade edge. Numerous fossils of the various species have been found in North America, Poland, Belgium, and Morocco.
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Galeus is a genus of catshark, belonging to the family Scyliorhinidae, commonly known as sawtail catsharks in reference to a distinctive saw-toothed crest of enlarged dermal denticles, found along the upper edges of their caudal fins. They are found in the Atlantic, the western and central Pacific, and the Gulf of California, inhabiting deep waters at or close to the sea floor. Members of this genus are rather small, slim sharks with firm bodies and thick, rough skin. Their heads are usually fairly long and pointed, and have large mouths with well-developed furrows at the corners. They have large pectoral and anal fins, and two similar dorsal fins placed well back. Many species are ornately patterned with dark saddles and/or blotches. Sawtail catsharks feed on various invertebrates and fishes, and may be either egg-laying or live-bearing. These harmless sharks are sometimes caught as bycatch but are of minimal commercial value.
Carcharias is a genus of sand tiger sharks belonging to the family Odontaspididae. Once bearing many prehistoric species, all have gone extinct with the exception of the critically endangered sand tiger shark.
Otodus angustidens is a species of prehistoric megatoothed sharks in the genus Otodus, which lived during the Oligocene and Miocene epochs about 33 to 22 million years ago. This shark is related to another extinct megatoothed shark, Otodus megalodon.
Lazarussuchus is an extinct genus of amphibious reptile, known from the Cenozoic of Europe. It is the youngest known member of Choristodera, an extinct order of aquatic reptiles that first appeared in the Middle Jurassic. Fossils have been found in Late Paleocene, Late Oligocene, Early Miocene and Late Miocene deposits in France, Germany, and the Czech Republic. Two species have been named: the type species L. inexpectatus ("unexpected") from the late Oligocene of France. and L. dvoraki from the early Miocene of the Czech Republic. It was not a large animal; the skull of L. inexpectatus was only about 4.53 centimeters long (1.78 in), with the total preserved body and tail length being just over 30 centimetres. A complete specimen of Lazarussuchus with preserved soft tissue was found from the Late Paleocene of France, but has not been assigned to a species.
Caranx is a genus of tropical to subtropical marine fishes in the jack family Carangidae, commonly known as jacks, trevallies and kingfishes. They are moderate- to large-sized, deep-bodied fishes which are distinguished from other carangid genera by specific gill raker, fin ray and dentition characteristics. The genus is represented in the Pacific, Indian and Atlantic Oceans, inhabiting both inshore and offshore regions, ranging from estuaries and bays to deep reefs and offshore islands. All species are powerful predators, taking a variety of fish, crustaceans and cephalopods, while they in turn are prey to larger pelagic fishes and sharks. A number of fish in the genus have a reputation as powerful gamefish and are highly sought by anglers. They often make up high amounts of the catch in various fisheries, but are generally considered poor to fair table fishes.
Euzaphlegidae is a family of extinct escolar-like fish closely related to the snake mackerels. Fossils of euzaphlegids are found from Paleocene to Late Miocene-aged marine strata of Europe, the Caucasus Mountains, India, Iran, Turkmenistan, Italy, and Southern California.
Echidnocephalus troscheli is an extinct, prehistoric halosaur. Fossils are found from Campanian strata of Westphalia, Germany. The complete and incomplete fossil specimens that have been found suggest an animal already looking very much like modern halosaurs.
Absalomichthys velifer is an extinct, prehistoric manefish that lived during the Upper Miocene of what is now Southern California. Its dorsal fin was huge in comparison with living species.
Sparnodus is an extinct genus of prehistoric perciform fish in the family Sparidae. Species of this genus were nektonic carnivore. These fishes lived in the Cenozoic Era, in Oligocene and Paleocene.
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Allodelphis is an extinct genus of whale belonging to Allodelphinidae found in marine deposits of the eastern North Pacific.
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.