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Orthacodontidae
Orthacodontidae is an extinct family of sharks in the order Synechodontiformes. It contains twelve species within three genera. Some authors included it into Hexanchiformes or Lamniformes. Species * '' Occitanodus'' Guinot, Cappetta & Adnet, 2014 ** '' Occitanodus sudrei'' Guinot, Cappetta & Adnet Adnet is a town in the district of Hallein, in the Austrian state of Salzburg. It is famous for its marble and there is a marble museum in the middle of the town. Geography Adnet is situated near Hallein in the metropolitan area of Salzburg. Urba ..., 2014 * '' Orthacodus'' Woodward, 1889 ** '' Orthacodus longidens'' Agassiz, 1843 * '' Sphenodus'' Agassiz, 1843 ** '' Sphenodus alpinus'' Gümbel, 1861 ** '' Sphenodus longidens'' Agassiz, 1843 ** '' Sphenodus lundgreni'' Davis, 1890 ** '' Sphenodus macer'' Quenstedt, 1852 ** '' Sphenodus nitidus'' Wagner, 1862 ** '' Sphenodus planus'' Agassiz, 1843 ** '' Sphenodus rectidens'' Emmons, 1858 ** '' Sphenodus robustidens'' Seguenza, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexanchiformes
The Hexanchiformes are the order consisting of the most primitive types of sharks, and numbering just seven extant species. Fossil sharks that were apparently very similar to modern sevengill species are known from Jurassic specimens. Hexanchiform sharks have only one dorsal fin, either six or seven gill slits, and no nictitating membrane in the eyes. Shark teeth similar to those modern hexanchids are known from Devonian deposits in Antarctica and Australia, as well as Permian deposits in Japan. If these are in fact hexanchids, this may be the only extant order of elasmobranchs to have survived after the Permian extinction (and by extension, the oldest extant order of elasmobranchs). The frilled sharks of the genus ''Chlamydoselachus'' are very different from the cow sharks, and have been proposed to be moved to a distinct order, Chlamydoselachiformes. Classification Living species *Family Chlamydoselachidae Garman 1884 (frilled sharks) **''Chlamydoselachus'' Garman, 1884 ** ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synechodontiformes
Synechodontiformes is an extinct order of prehistoric sharks, known from the Permian to the Paleogene. They are considered to be members of Neoselachii, the group that contains modern sharks and rays. Their placement in the group is uncertain, some authors have considered them to be Galeomorphii, galeomorph crown-group sharks, while others have considered them to represent a stem-group to modern sharks. They have sometimes been considered a paraphyletic grouping, but Klug (2010) recovered the group as monophyletic. Members of the clade are united by two synapomorphies, "pseudopolyaulacorhize tooth root pattern present; labial root depression in basal view present". The oldest possible member of the clade are teeth from the early Permian (Cisuralian) of the Ural Mountains. Taxonomy Primarily after Klug (2010) * †Orthacodontidae de Beaumont, 1960 ** †''Sphenodus'' Agassiz, 1843 Early Jurassic - Paleocene **†''Occitanodus'' Guinot, Cappetta & Adnet, 2014, France, Early Creta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Cartilaginous Fish Families
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark Families
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term "shark" has also been used to refer to all extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts and xenacanths. The oldest modern sharks are known from the Early Jurassic. They range in size from the small dwarf lanternshark (''Etmopterus perryi''), a deep sea species that is only in length, to the whale shark (''Rhincodon typus''), the largest fish in the world, which reaches approximately in length. Sharks are found in all seas and are common to depths up to . They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater and fres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous Sharks
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic Sharks
The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined. By the beginning of the Jurassic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giuseppe Seguenza
Giuseppe Seguenza (June 8, 1833 in Messina – February 3, 1889 in Messina) was an Italian naturalist and geologist. Early life Giuseppe Seguenza was born on June 8, 1833, in Italy. Because his father expected him to follow in his footsteps and become a pharmacist, Seguenza studied under his father, who also owned his own pharmacy. Later, Seguenza chose to study the geological and mineralogical sciences. Scientific research At the age of 23, Giuseppe Seguenza discovered that all the products of the emanations of Vulcano (one of the Aeolian Islands) contained arsenic compounds. Afterward, he published other scientific works that earned him the attention of scholars in Europe and the silver medal at the Paris Exposition. He was appointed Professor of Natural History at the Maurolico School, then the Technical Institute of Messina, and finally earned a professorship at the University of Messina. There followed other work around the metalliferous deposits of Fiumedinisi, land a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
