Hemicalypterus Temporal range: Late Triassic, ~ | |
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Skeletal reconstruction | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | † Dapediiformes |
Family: | † Dapediidae |
Genus: | † Hemicalypterus Schaeffer, 1967 |
Species: | †H. weiri |
Binomial name | |
†Hemicalypterus weiri Schaeffer, 1967 | |
Hemicalypterus is an extinct genus of prehistoric ray-finned fish that lived during the late Triassic period (approx. 221.4 to 205.6 Ma). It contains a single species, Hemicalypterus weiri. Fossils have been collected in the southwestern United States, including Utah and New Mexico. [1] Hemicalypterus belonged to the family Dapediidae, and like other members of its family, it was a deep-bodied fish with a covering of thick ganoid scales. It differed from other dapediids in lacking scales on the posterior part of the body, and in possessing unusual, multicuspid teeth. These teeth were similar to those of modern-day herbivorous fish, which indicates that Hemicalypterus may have been a herbivore as well. [2]
Actinopterygii, members of which are known as ray-finned fishes, is a clade of the bony fishes. They comprise over 50% of living vertebrate species.
Osteichthyes, popularly referred to as the bony fish, is a diverse taxonomic group of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species. It is the largest class of vertebrates in existence today. The group Osteichthyes is divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 420 million years old, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes.
Saurichthys is an extinct genus of predatory ray-finned fish from the Triassic period. It is the name giving genus of the family Saurichthyidae. This family also includes the Permian Eosaurichthys (China) and the Jurassic Saurorhynchus from Europe and North America.
Holostei is a group of ray-finned bony fish. It is divided into two major clades, the Halecomorphi, represented by a single living species, the bowfin, as well as the Ginglymodi, the sole living representatives being the gars (Lepisosteidae), represented by seven living species in two genera. The earliest members of the clade appeared during the Early Triassic, over 250 million years ago.
Acanthomorpha is an extraordinarily diverse taxon of teleost fishes with spiny-rays. The clade contains about one third of the world's modern species of vertebrates: over 14,000 species.
Birgeria is a genus of carnivorous marine ray-finned fish from the Triassic period. Birgeria had a global distribution. Fossils were found in Madagascar, Spitsbergen, Germany, Switzerland, Italy, Slovenia, China, Russia, Canada and Nevada, United States. The oldest fossils are from Griesbachian aged beds of the Wordie Creek Formation of East Greenland.
Aetheolepis is an extinct genus of ray-finned fish which lived in freshwater environments in what is now Western Australia and New South Wales during the Jurassic period. It contains one species, A. mirabilis. Aetheolepis was previously thought to be an archaeomaenid, until a 2016 study instead recovered it as a member of the family Dapediidae. Like other dapediids, it had a deep, discoid-shaped body. Fossils of A. mirabilis have been found in the Talbragar River fossil beds of New South Wales and the Colalura Sandstone of Western Australia. It was named by Arthur Smith Woodward in 1865 along with other Talbragar fish.
Watsonulus is an extinct genus of prehistoric ray-finned fish that lived during the Early Triassic epoch in what is now Madagascar. It may have also existed in what is now Himachal Pradesh, India, during the Induan age.
Habroichthys is an extinct genus of prehistoric bony fish that lived during the early Ladinian stage of the Middle Triassic epoch, 242 to 232 million years ago. It has been found in Austria, China, Italy, Slovenia, and Switzerland.
Bobasatrania is an extinct genus of prehistoric bony fish that survived the Permian-Triassic extinction event. Fossils of Bobasatrania were found in beds of Changhsingian to Ladinian age. It was most speciose during the Early Triassic. The genus was named after the locality Bobasatrana in northeast Madagascar, from where the type species was described.
Boreosomus is an extinct genus of Triassic ray-finned fish. It was first described from the Arctic island of Spitsbergen, but was later also discovered in other parts of the world. Boreosomus had a worldwide distribution during the Early Triassic. Fossils of Boreosomus were found, apart from Spitsbergen, in Greenland, Madagascar and Canada. The type species is Boreosomus arcticus.
Dandya is an extinct genus of ray-finned fish belonging to the family Dapediidae. It contains one species, D. ovalis. It is known from the Late Triassic of Lombardy, Northern Italy.
Gyrolepis is an extinct genus of prehistoric ray-finned fish from the Middle-Late Triassic epochs in what is now Europe. It is known both from complete specimens and isolated skeletal elements, such as scales or teeth.
Ptycholepis is an extinct genus of prehistoric ray-finned fish having the head and opercular bones ornamented with ridges of ganoin, minute teeth, and thick scales.
Occithrissops is an extinct genus of prehistoric ray-finned fish of the Jurassic, known for its fearsome yet small appearance. The genus name of Occithrissops derives from the Latin word "Occi" (killing) and the Greek words "thriss" (fish) and "ṓps" (“face”). Similar in relationship to the Thrissops, it was a slightly larger predatory teleost fish with serrated pelvic fins, a cleft tail, and a bony tongue similar to the Arapaima and formerly mentioned Thrissops, bearing small teeth for catching small slippery prey like squid, invertebrates and fish. The bony tongue assisted the fish in consuming hard shelled invertebrates which included small nektonic Jurassic ammonites, which despite the growing decline of ammonoids were still prevalent and plentiful for their time.
Bobasatraniiformes is an extinct order of durophagous ray-finned fish that existed from the late Permian to the Middle Triassic in both marine and freshwater environments. The order includes two families: Bobasatraniidae, with the genera Bobasatrania, Ebenaqua, and Ecrinesomus, and Dorypteridae, comprising only the genus Dorypterus (monotypy). Bobasatraniiformes had a somewhat global distribution; fossils are found in Africa (Madagascar), Asia (Pakistan), Australia, Europe, and North America.
The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fish lineages belong to the Agnatha, or jawless fish. Early examples include Haikouichthys. During the late Cambrian, eel-like jawless fish called the conodonts, and small mostly armoured fish known as ostracoderms, first appeared. Most jawless fish are now extinct; but the extant lampreys may approximate ancient pre-jawed fish. Lampreys belong to the Cyclostomata, which includes the extant hagfish, and this group may have split early on from other agnathans.
Archaeomaenidae is an extinct family of stem-teleost fish found in freshwater environments of Jurassic New South Wales of Australia, China, and Antarctica, and in Lower Cretaceous New South Wales and Mongolia.
Dorypterus is a small, extinct genus of prehistoric ray-finned bony fish. It lived during the Wuchiapingian stage of the late Permian epoch in what is now Germany (Kupferschiefer) and England. It is a hypsisomatic bobasatraniiform with a high dorsal fin. Due to anatomical differences with other bobasatraniiforms, such as the presence of pelvic fins and the reduced scale cover, Dorypterus is placed in its own monotypic family, Dorypteridae.
Dapediidae is an extinct family of neopterygian ray-finned fish that lived during the Triassic and Jurassic periods. It is the only family of the order Dapediiformes. Its members were historically placed within the ginglymodian family Semionotidae, but were moved to their own family in 1966.