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Otodontidae
Otodontidae is an extinct family of sharks belonging to the order Lamniformes. Its members have been described as megatoothed sharks. They lived from the Early Cretaceous to the Pliocene, and included genera such as ''Carcharocles'' and ''Otodus,'' including the giant megalodon. Recent studies of the newly described genus '' Megalolamna'' indicate that the members of the genus ''Carcharocles'' should be reclassified as members of the genus ''Otodus''. The genus ''Cretalamna ''Cretalamna'' is a genus of extinct otodontid shark that lived from the latest Early Cretaceous to Eocene epoch (about 103 to 46 million years ago). It is considered by many to be the ancestor of the largest sharks to have ever lived, '' Otodus ...'' which lived from the mid-Cretaceous-Paleogene is believed to be directly ancestral to ''Otodus,'' and thus to megalodon. References Shark families Albian first appearances Pliocene extinctions {{paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalodon
Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. It was formerly thought to be a member of the family Lamnidae and a close relative of the great white shark (''Carcharodon carcharias''). However, it is now classified into the extinct family Otodontidae, which diverged from the great white shark during the Early Cretaceous. While regarded as one of the largest and most powerful predators to have ever lived, the megalodon is only known from fragmentary remains, and its appearance and maximum size are uncertain. Scientists differ on whether it would have more closely resembled a stockier version of the great white shark, the whale shark (''Rhincodon typus''), the basking shark (''Cetorhinus maximus'') or the sand tiger shark (''Carcharias taurus''). The most recent estimate with the least error range suggests a maximum leng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamniformes
The Lamniformes (, from Greek ''lamna'' "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the great white, as well as more unusual representatives, such as the goblin shark and megamouth shark. Members of the order are distinguished by possessing two dorsal fins, an anal fin, five gill slits, eyes without nictitating membranes, and a mouth extending behind the eyes. Species in two families of Lamniformes – Lamnidae and Alopiidae – are distinguished for maintaining a higher body temperature than the surrounding water. Members of the group include macropredators, generally of medium-large size, including the largest macropredatory shark ever, the extinct '' Otodus megalodon,'' as well as large planktivores. The oldest member of the group is the small (~ long) carpet shark-like ''Palaeocarcharias,'' known from the Middle and Lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otodontidae
Otodontidae is an extinct family of sharks belonging to the order Lamniformes. Its members have been described as megatoothed sharks. They lived from the Early Cretaceous to the Pliocene, and included genera such as ''Carcharocles'' and ''Otodus,'' including the giant megalodon. Recent studies of the newly described genus '' Megalolamna'' indicate that the members of the genus ''Carcharocles'' should be reclassified as members of the genus ''Otodus''. The genus ''Cretalamna ''Cretalamna'' is a genus of extinct otodontid shark that lived from the latest Early Cretaceous to Eocene epoch (about 103 to 46 million years ago). It is considered by many to be the ancestor of the largest sharks to have ever lived, '' Otodus ...'' which lived from the mid-Cretaceous-Paleogene is believed to be directly ancestral to ''Otodus,'' and thus to megalodon. References Shark families Albian first appearances Pliocene extinctions {{paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretalamna
''Cretalamna'' is a genus of extinct otodontid shark that lived from the latest Early Cretaceous to Eocene epoch (about 103 to 46 million years ago). It is considered by many to be the ancestor of the largest sharks to have ever lived, ''Otodus angustidens'', ''Otodus chubutensis'', and ''Otodus megalodon''. Taxonomy Research History ''Cretalamna'' was first described by Swiss naturalist Louis Agassiz using five teeth previously identified as the common smooth-hound and collected by English paleontologist Gideon Mantell from the Southerham Grey Pit near Lewes, East Sussex. In his 1835 publication ''Rapport sur les poissons fossiles découverts en Angleterre'', he reidentified them as a new species of porbeagle shark under the taxon ''Lamna appendiculata''. In 1843, Agassiz published ''Recherches sur les poissons fossiles'', which reexamined Mantell's five teeth. Using them, eight additional teeth collected by Mantell, and twenty more teeth collected by various paleontol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharocles
''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth". Anatomy This shark is known from its fossilized teeth and vertebral centra. Like other elasmobranchs, the skeleton of ''Otodus'' was composed of cartilage and not bone, resulting in relatively few preserved skeletal structures appearing within the fossil record. The teeth of this shark are large with triangular crown, smooth cutting edges, and visible cusps on the roots. Some ''Otodus'' teeth also show signs of evolving serrations. Size estimation The fossils of ''Otodus'' indicate that it was a very large macro-predatory shark. The largest known teeth measure about in height. The vertebral centrum of this shark are over 12.7 cm (5 inch) wide. Scientists suggest that this shark at least reached in total length (TL), with a maximum length of . Dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalolamna
''Megalolamna'' is an extinct genus of lamniform shark that belongs to the family Otodontidae. Its name comes from the similarity of its teeth to those of the extant shark genus ''Lamna.'' It is known from the early Miocene Chilcatay Formation of Peru, Oi and O'oshimojo Formations of Japan, and the Jewett Sand Formation of California and Pungo River Formation, North Carolina in the United States, implying a cosmopolitan distribution. The largest specimen is estimated to have measured about long. Taxonomy It is considered to be the sister genus of ''Otodus''. The study of ''Megalolamna'''s taxonomic relationships also demonstrates the possibility that ''Otodus'' needs to include the species sometimes assigned to ''Carcharocles'' (i.e., the megatoothed lineage, including megalodon Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otodus
''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth". Anatomy This shark is known from its fossilized teeth and vertebral centra. Like other elasmobranchs, the skeleton of ''Otodus'' was composed of cartilage and not bone, resulting in relatively few preserved skeletal structures appearing within the fossil record. The teeth of this shark are large with triangular crown, smooth cutting edges, and visible cusps on the roots. Some ''Otodus'' teeth also show signs of evolving serrations. Size estimation The fossils of ''Otodus'' indicate that it was a very large macro-predatory shark. The largest known teeth measure about in height. The vertebral centrum of this shark are over 12.7 cm (5 inch) wide. Scientists suggest that this shark at least reached in total length (TL), with a maximum length of . D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parotodus
''Parotodus'', commonly known as the false-toothed mako shark (or false mako shark), is an extinct genus of mackerel shark that lived approximately 53 to one million years ago during the Eocene and Pleistocene epochs. Its teeth, which are found worldwide, are often prized by fossil collectors due to their rarity. The scarcity of fossils is because ''Parotodus'' likely primarily inhabited open oceans far away from the continents. Description Initially appearing as a small shark, ''Parotodus'' gradually increased in size over geologic time and by the Neogene period became one of the largest sharks of its time. A 1999 study estimated the genus to have measured up to in length. The teeth of ''Parotodus'' are distinctively curved and rarely show feeding damage, which suggests that it mainly preyed on soft-bodied animals. Paleontologists speculate that this included other sharks, including the contemporaneous Megalodon. Classification Due to the general scarcity and ambiguity of fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kenolamna
''Kenolamna'' is an extinct genus of mackerel shark from the Cretaceous period known only from isolated teeth. It is named in honor of Kenneth McNamara, former curator of Paleontology at the Western Australian Museum. It is tentatively placed in the family Otodontidae, and is closest in design to ''Cretalamna'' and '' Paleocarcharodon'' though it is unclear how closely related it is to either. Currently, it is a monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ... genus containing only the species ''K. gunsoni''. References Cretaceous sharks Fossils of Australia Otodontidae Prehistoric shark genera {{Paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeocarcharodon
''Palaeocarcharodon'', also known as the pygmy white shark, is a genus of shark within the family Otodontidae that lived about 61.7 to 55.8 Ma during the Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pal .... It currently contains a sole species ''P. orientalis''. Description Teeth of ''Palaeocarcharodon'' are triangular, labio-lingually compressed, with quite irregular serrations and serrate lateral cusplets. They can reach a size of about .G. R. Case. - Palaeocarcharodon Orientalis (SINZOW) (Neoselachii: Cretoxyrhinidae), from the Paleocene of Maryland - Lab. de Paléontologie des Vertébrés, 1989 File:Palaeocarcharodon orientalis 1.jpg, Tooth of ''Palaeocarcharodon'' from Atlas mountain in Morocco. 60 mya, long 3 cm. References Otodontidae Prehistoric fish ... [...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] |
John Wiley And Sons
John Wiley & Sons, Inc., commonly known as Wiley (), is an American multinational publishing company founded in 1807 that focuses on academic publishing and instructional materials. The company produces books, journals, and encyclopedias, in print and electronically, as well as online products and services, training materials, and educational materials for undergraduate, graduate, and continuing education students. History The company was established in 1807 when Charles Wiley opened a print shop in Manhattan. The company was the publisher of 19th century American literary figures like James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe, as well as of legal, religious, and other non-fiction titles. The firm took its current name in 1865. Wiley later shifted its focus to scientific, technical, and engineering subject areas, abandoning its literary interests. Wiley's son John (born in Flatbush, New York, October 4, 1808; died in East Orange, Ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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