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St. Mary's Formation
The St. Marys Formation is a geologic formation in Maryland and Virginia, United States. It preserves fossils dating back to the Miocene Epoch of the Neogene period. It is the youngest Miocene formation present in the Calvert Cliffs and is part of the Chesapeake Group. Vertebrate paleofauna A diverse vertebrate paleofauna is known from the St. Marys Formation: See also * List of fossiliferous stratigraphic units in Virginia * Paleontology in Virginia Paleontology in Virginia refers to paleontological research occurring within or conducted by people from the U.S. state of Virginia. The geologic column in Virginia spans from the Cambrian to the Quaternary. During the early part of the Paleozoic ... References External links * Geologic formations of the United States Neogene geology of Virginia Neogene Maryland Paleontology in Maryland {{Virginia-geologic-formation-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squalus
''Squalus'' is a genus of dogfish sharks in the family Squalidae. Commonly known as spurdogs, these sharks are characterized by smooth dorsal fin spines, teeth in upper and lower jaws similar in size, caudal peduncle with lateral keels; upper precaudal pit usually present, and caudal fin without subterminal notch. In spurdogs, the hyomandibula (the bone connecting the braincase to the jaws) is oriented at a right angle to the neurocranium, while in other sharks, the hyomandibula runs more parallel to the body. This led some to think that the upper jaw of ''Squalus'' would not be as protractile as the jaws of other sharks. However, a study that compared different jaw suspension types in sharks showed that this is not the case and that ''Squalus'' is quite capable of protruding its upper jaw during feeding.Wilga, C.D., Motta, P.J. & Sanford, C.P. (2007): Evolution and ecology of feeding in elasmobranchs. ''Integrative and Comparative Biology, 47 (1): 55-69.'' The name comes from '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thresher Shark
Thresher sharks are large lamniform sharks of the family Alopiidae found in all temperate and tropical oceans of the world; the family contains three extant species, all within the genus ''Alopias''. All three thresher shark species have been listed as vulnerable to extinction by the World Conservation Union since 2007 (IUCN). All are popular sport fish. In addition, they are hunted for their meat, livers (for shark liver oil), skin (for leather), and fins for use in shark-fin soup. They do not appear to be a threat to humans. Taxonomy The genus and family name derive from the Greek word , , meaning fox. As a result, the long-tailed or common thresher shark, ''Alopias vulpinus'', is also known as the fox shark. The common name is derived from a distinctive, thresher-like tail or caudal fin which can be as long as the body of the shark itself. Species The three extant thresher shark species are all in the genus ''Alopias''. The possible existence of a hitherto unrecognize ... [...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 length e ... [...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 . Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharomodus Escheri
''Carcharomodus escheri'', commonly nicknamed the serrated mako shark or Escher's mako shark, is an extinct lamnid that lived during the Miocene. It has been formerly thought to have been the transitional between the broad-toothed "mako" ''Cosmopolitodus hastalis'' and the modern great white, but is now considered to be an evolutionary dead-end with the discovery of ''Carcharodon hubbelli''. Fossil examples have been found along northern Atlantic coastlines and in parts of Western and Central Europe. Etymology ''Carcharomodus'' is derived from the Ancient Greek κάρχαρος "kárkharos" meaning "jagged", όμοιος "omoios" meaning "similar", and δόντι "donti" meaning "tooth". The name was combined with the genus ''Carcharodon'' in reference to the similarity of ''C. escheris dentition with that of the modern great white shark. The species name ''escheri'' is named in honor of Escher. Thus, the species name literally means "Escher's similar to ''Carcharodon'' tooth". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharomodus
''Carcharomodus'' is an extinct genus of lamnid shark The Lamnidae are the family of mackerel sharks known as white sharks. They are large, fast-swimming predatory fish found in oceans worldwide, though prefer environments with colder water. The name of the family is formed from the Greek word ''lam .... Its only species is currently '' C. escheri''. References Prehistoric shark genera Monotypic fish genera Lamnidae {{paleo-shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great White Shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. It is notable for its size, with larger female individuals growing to in length and in weight at maturity. However, most are smaller; males measure , and females measure on average. According to a 2014 study, the lifespan of great white sharks is estimated to be as long as 70 years or more, well above previous estimates, making it one of the longest lived cartilaginous fishes currently known. According to the same study, male great white sharks take 26 years to reach sexual maturity, while the females take 33 years to be ready to produce offspring. Great white sharks can swim at speeds of 25 km/h (16 mph) for short bursts and to depths of . The great white shark is an apex predator, as it has no known natural predators other than, on v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharodon Hastalis
''Cosmopolitodus'' is an extinct genus of mackerel shark that lived between thirty to one million years ago during the late Oligocene to the Early Pleistocene epochs. Its type species is ''Cosmopolitodus hastalis'', the broad-tooth mako (other common names include the extinct giant mako and broad-tooth white shark). In 2021, ''Isurus planus'' was reassigned to the genus, and thus became the second species '' C. planus''. Its teeth can reach lengths up to 3.5 in (7.5 cm) and are found worldwide. It is believed to be an ancestor to the great white shark, an argument supported by the transitional species ''Carcharodon hubbelli'', but as of 2021, no phylogenetic analyses have been done for proof. Taxonomy Etymology ''Cosmopolitodus'' is derived from the Ancient Greek κοσμοπολίτης "''kosmopolítēs''" meaning "citizen of the world" and ὀδών "''odṓn''" meaning "tooth". The specific name ''hastalis'' may be derived from the Latin word ''hasta'' meaning "spear". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharodon
''Carcharodon'' () is a genus of sharks within the family Lamnidae. The only extant member is the great white shark (''Carcharodon carcharias''). Hubell's white shark (''Carcharodon hubbelli'') is an extinct member of this genus. Megalodon was once placed in this genus but is now placed in the genus ''Otodus,'' in their separate family Otodontidae. The name of the genus comes from the Greek words ''karchar s' ( κάρχαρος, meaning "jagged" or "sharp") and ''odōn'' ( ὀδών, "teeth") giving the Greek for "sharp" or "jagged tooth." A genus of giant carnivorous dinosaur, with sharp, slicing teeth of similar function to those of ''Carcharodon'' sharks was given the related name ''Carcharodontosaurus''. Species * '' Carcharodon carcharias'' (Linnaeus, 1758) (the great white shark) *†''Carcharodon hubbelli ''Carcharodon hubbelli'', also known as Hubbell's white shark, is an extinct species of white shark that evolved between 8 and 5 million years ago during the Late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhincodon Typus Teeth
The whale shark (''Rhincodon typus'') is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. The largest confirmed individual had a length of .McClain CR, Balk MA, Benfield MC, Branch TA, Chen C, Cosgrove J, Dove ADM, Gaskins LC, Helm RR, Hochberg FG, Lee FB, Marshall A, McMurray SE, Schanche C, Stone SN, Thaler AD. 2015. "Sizing ocean giants: patterns of intraspecific size variation in marine megafauna". ''PeerJ'' 3:e715 . The whale shark holds many records for size in the animal kingdom, most notably being by far the largest living nonmammalian vertebrate. It is the sole member of the genus ''Rhincodon'' and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984 it was classified as ''Rhiniodon'' into Rhinodontidae. The whale shark is found in open waters of the tropical oceans and is rarely found in water below . Studies looking at vertebral growth bands and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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