FACTOID # 18: Alaska spends more money per capita on elementary and secondary education than any other state.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Megalodon" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Megalodon
Megalodon
Fossil range: Miocene - Pleistocene
Megalodon tooth with great white shark's teeth.
Megalodon tooth with great white shark's teeth.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Lamniformes
Family: Lamnidae
Genus: Carcharodon
Species: C. megalodon
Binomial name
Carcharodon megalodon
Agassiz, 1843
Synonyms
  • Procarcharodon megalodon Casier, 1960
Sharks Portal

The megalodon (pronounced /mɛɡəlɑːdɒn/ or MEG-a-la-don; meaning "big tooth" or in Greek as μέγας 'οδόντος) was a giant shark that lived in prehistoric times, between about 18 million to 1.5 million years agoa[›] and was the apex predator of its time. It is the largest carnivorous fish known to have existed.[1] This species is a member of the lamnidae family but its classification is in dispute and a new genus has been proposed. Fossil evidence has revealed that megalodon fed upon large animals, including the early whales.[2] The Miocene Epoch is a period of time that extends from about 23. ... The Pleistocene epoch (IPA: ) on the geologic timescale is the period from 1,808,000 to 11,550 years BP. The Pleistocene epoch had been intended to cover the worlds recent period of repeated glaciations. ... Image File history File links Size of this preview: 746 × 600 pixelsFull resolution (3000 × 2412 pixel, file size: 2. ... Binomial name (Linnaeus, 1758) Range (in blue) For other uses, see Great White (disambiguation). ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... For other uses, see Animal (disambiguation). ... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... Subclasses and Orders See text. ... Superorders Batoidea (rays and skates) Selachimorpha (sharks) Elasmobranchii is the subclass of cartilaginous fish that includes skates, rays (batoidea) and sharks (selachii). ... Families Odontaspididae (sand tigers) Mitsukurinidae (goblin shark) Pseudocarchariidae (crocodile shark) Megachasmidae (megamouth shark) Alopiidae (thresher sharks) Cetorhinidae (basking shark) Lamnidae (mackerel sharks) Great Lamniformes is an order of sharks commonly known as the mackerel sharks. ... Lamnidae is a family of sharks. ... Binomial name Carcharodon carcharias (Linnaeus, 1758) The Great White Shark (Carcharodon carcharias), also known as White Pointer, White Shark or Amaletz, is an exceptionally large lamniform shark found in coastal surface waters in all major oceans. ... Latin name redirects here. ... Louis Agassiz After the 1906 San Francisco earthquake, Stanford President David Starr Jordan wrote, Somebody—Dr. Angell, perhaps—remarked that Agassiz was great in the abstract but not in the concrete. ... In scientific nomenclature, synonyms are different scientific names used for a single taxon. ... Image File history File linksMetadata Greyreefsharksmall2. ... For other uses, see Shark (disambiguation). ... Prehistory (Greek words προ = before and ιστορία = history) is the period of human history prior to the advent of writing (which marks the beginning of recorded history). ... Apex predators (also alpha predators, superpredators, or top-level predators) are predators that, as adults, are not normally preyed upon in the wild in significant parts of their ranges. ... This tigers sharp teeth and strong jaws are the classical physical traits expected from carnivorous mammalian predators A carnivore (IPA: ), meaning meat eater (Latin carne meaning flesh and vorare meaning to devour), is an animal that eats a diet consisting mainly of meat, whether it comes from live animals... For other uses, see Fish (disambiguation). ... Lamnidae is a family of sharks. ... For other uses, see Genus (disambiguation). ... For other uses, see Fossil (disambiguation). ... This article is about the animal. ...


Some cryptozoologists argue that this shark might still be alive today, probably living in deep waters, and often cite the examples of coelacanth and megamouth shark to support their claims.[2] However, such beliefs have earned no credibility in the mainstream scientific community. Nonetheless, megalodon has left a lasting impact on the minds of the people around the world, as a highly fascinating monster. Cryptozoology is the study of rumored or mythological animals that are presumed to exist, but for which conclusive proof does not yet exist; or are generally considered extinct, but occasionally reported. ... Families See text. ... Binomial name Megachasma pelagios Taylor, Compagno and Struhsaker, 1983 The megamouth shark, Megachasma pelagios, is an extremely rare and unusual species of shark, discovered in 1976, with 37 specimens known to be caught or sighted as of 2006. ... This article is about the legendary creature. ...

Contents

Taxonomy

The Swiss naturalist, Louis Agassiz, gave this shark its scientific name, Carcharodon megalodon in 1835,[3] in his research work Recherches sur les poissons fossiles (Research on fish fossils), which he completed in 1843. Due to the dental similarities of the teeth of the great white shark, Carcharodon carcharias, and megalodon, Agassiz proposed Carcharodon as the genus.[3] In-short, this shark is termed C. megalodon by shark researchers. However, it is often dubbed the "mega-tooth shark".-1... Louis Agassiz After the 1906 San Francisco earthquake, Stanford President David Starr Jordan wrote, Somebody—Dr. Angell, perhaps—remarked that Agassiz was great in the abstract but not in the concrete. ... For other uses, see Fish (disambiguation). ... The word dental could mean: Dental consonant, a linguistics term Dentistry, a medical profession Dental Auxillary Dental hygienist, a licensed practitioner Dental technician Any of a variety of other dental professions, such as Dental assistant, someone who works in a dentists office, but may not be a licensed medical... Types of teeth Molars are used for grinding up foods Carnassials are used for slicing food. ... Binomial name (Linnaeus, 1758) Range (in blue) For other uses, see Great White (disambiguation). ...


Classification dispute

Cladogram of the "hastalis hypothesis" highlighting the position of C. megalodon

Muizon et al. 1985[3]
Lamniformes 
void
void
void

I. hastalis It has been suggested that Clade be merged into this article or section. ... Families Odontaspididae (sand tigers) Mitsukurinidae (goblin shark) Pseudocarchariidae (crocodile shark) Megachasmidae (megamouth shark) Alopiidae (thresher sharks) Cetorhinidae (basking shark) Lamnidae (mackerel sharks) Great Lamniformes is an order of sharks commonly known as the mackerel sharks. ...



 void 

Sacaco Sp.



C. carcharias




void

C. megalodon




*Note: The hastalis hypothesis shows that C. carcharias is more closely related to I. hastalis than C. megalodon.[3]

There is a major disagreement among scientists as to how C. megalodon should be classified.[1][2] The controversy is that whether C. megalodon is a close relative of the extant great white shark or whether the two species are distant relatives. The trend among shark researchers is to dismiss the statement that C. megalodon is a close relative of the great white shark, in favor of citing convergent evolution as the reason for the dental similarity. A scientist, in the broadest sense, refers to any person that engages in a systematic activity to acquire knowledge or an individual that engages in such practices and traditions that are linked to schools of thought or philosophy. ... In evolutionary biology, convergent evolution is the process whereby organisms not closely related, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. ...


Megalodon within Carcharodon

As discussed above, the traditional view is that C. megalodon should be classified within the genus Carcharodon along with the great white shark. The Carcharodon proponents suggest that C. megalodon and C. carcharias share a common ancestor known as Carcharodon orientalis.[1][3][4]


Megalodon within Carcharocles

Around 1923, the genus, Carcharocles, was proposed by two shark researchers, D. S. Jordan and H. Hannibal, to classify a very similar shark C. auriculatus. Many marine biologists and paleontologists are now favoring the Carcharocles genus for C. megalodon.[1][2][3][5][6] One reason for this shift is that the teeth of C. megalodon are also similar to the teeth of some sharks that belong to Carcharocles lineage. The Carcharocles proponents suggest that the direct ancestor of the sharks belonging to the Carcharocles genus, is an ancient shark called Otodus obliquus, which lived during the Paleocene and Eocene epochs.[1][5] According to Carcharocles proponents, Otodus obliquus evolved in to Carcharocles aksuaticus,[1][5] which evolved in to Carcharocles auriculatus,[1][5] which evolved into Carcharocles augustidens,[1][5] which evolved into Carcharocles chubutensis,[1][5] which eventually evolved into meglodon.[1][5] Hence, the immediate ancestor of C. megalodon is Carcharocles chubutensis,[1][5] because it serves as the missing link between Carcharocles augustidens and C. megalodon and it bridges the loss of the "lateral cusps" that characterize C. megalodon.[1][5] Marine biology is the study of animal and plant life within saltwater ecosystems. ... A paleontologist carefully chips rock from a column of dinosaur vertebrae. ... Binomial name Otodus obliquus Agassiz, 1843 Otodus obliquus was a large prehistoric Makerel Shark which lived during the Paleocene- Eocene epochs, approximately 45-55 million years ago. ... The Paleocene, early dawn of the recent, is a geologic epoch that lasted from 65. ... hfajhfiudshfas == == == --24. ...


Carcharocles proponents also point out that the great white shark is more closely related to an ancient shark Isurus hastalis, the "broad tooth mako," than C. megalodon. This suggestion is given credence by many scientists due to some convincing evidence.[3][6][7] One reason is that the teeth of I. hastalis and C. carcharias are remarkably similar in shape, differing only in that the former lack the characteristic serrations of the latter.[1][3][7] Binomial name Isurus oxyrinchus Rafinesque, 1810 The Shortfin Mako Shark (Isurus oxyrinchus sharp nose), commonly just called Mako Shark despite not being the only species of mako, is a large shark of the Lamnidae family with a full-grown size of 2. ...


Anatomy and appearance

C. megalodon is known principally from fossil teeth and a few fossilized vertebral centra.[8] As with all other sharks, the megalodon skeleton was formed of cartilage and not bone, resulting in a poor skeletal fossil record.[2] The teeth are in many ways similar to great white shark teeth but are much larger and can measure up to more than 18 cm in slant.[1] A diagram of a thoracic vertebra. ... For other uses, see Skeleton (disambiguation). ... Cartilage is a type of dense connective tissue. ... This article is about the skeletal organs. ... A centimetre (American spelling centimeter, symbol cm) is a unit of length that is equal to one hundredth of a metre, the current SI base unit of length. ...


Nevertheless, it is extrapolations from the shape and size of the teeth of C. megalodon when compared with related modern sharks and studies of their physical characteristics, that provide us with our conceptions about what this ancient super-predator might have looked like in life. Thus far, the great white shark has been considered the favored model for the basis for the reconstruction of C. megalodon.[4][8] This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ...


Size estimation

Estimating the maximum size of C. megalodon is a highly controversial subject. An early jaw reconstruction of this shark, developed by Professor Bashford Dean in 1909, indicates a length of more than 25 metres (82 ft), but that jaw reconstruction is now considered to be inaccurate.[8] One reason is that the teeth used as posteriors in this jaw reconstruction were not true posterior teeth. However, several scientists have tried to solve this issue in later years and some examples are mentioned below. Human jaw front view Human jaw left view Human jaw top view The jaw is either of the two opposable structures forming, or near the entrance to, the mouth. ... Bashford Dean, (1867-1928) was an American zoologist, specializing in ichtyology and expert in medieval armor. ... This article is about the unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ...


In 1973, the ichthyiologist John E. Randall suggested a method to measure the size of the large sharks.[9] According to Randall, the enamel height of the largest tooth in the upper jaw of the shark can be used to determine its total length. He concluded that C. megalodon could grow to 13 metres (43 ft).[9] This article is about the unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ...


However, in 1996, three shark experts, Michael D. Gottfried, Leonard J. V. Compagno and S. Curtis Bowman, questioned the reliability of Randall's method. According to them, shark's tooth enamel height does not necessarily increase in proportion with the animal's total length.[4] Hence, Gottfried and his co-workers tried to solve this issue by means of conducting new research and analysis to create a method for measuring the size of large sharks (including C. megalodon) with much greater accuracy, which was published in 1996.b[›] Using this new method, the maximum size of megalodon was calculated to be 15.9 metres (52 ft) with a body mass of more than 50 short tons (45 MT).[4] But this calculation was based on a 168 mm (6⅝ inch) long upper anterior tooth, which was the biggest tooth in the possession of this team at the time. Since then, even larger C. megalodon teeth have been excavated which indicate that the shark could grow to more than 17 metres (56 ft).[1][10][11][12] Leonard Compagno is an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization (FAO) of the United Nations. ... This article is about the unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ... The short ton is a unit of mass equal to 907. ... This article is about the metric tonne. ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ... This article is about the unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ...

Megalodon tooth from the Miocene. Dimensions: 13 cm straight, 18 cm in diagonal.
Megalodon tooth from the Miocene. Dimensions: 13 cm straight, 18 cm in diagonal.
Megalodon with the great white shark and a human for scale.
Megalodon with the great white shark and a human for scale.

Shark researcher Cliff Jeremiah also has suggested a method to determine the size of the large sharks, including C. megalodon,[1] and his method is considered to be among the most reliable.[1] He suggested that the jaw perimeter of a shark is directly proportional to its total length, with the width of the roots of the largest teeth being a proxy for estimating jaw perimeter. For every centimeter of root width of the largest tooth, he asserts, there was approximately 4.5 feet of the shark. He concluded that C. megalodon could grow up to 18.2 metres (60 ft).[1] Many scientists acknowledge this conclusion.[1] Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1944 × 2592 pixels, file size: 1. ... Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1944 × 2592 pixels, file size: 1. ... The Miocene Epoch is a period of time that extends from about 23. ... This article is about the unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ...


Hence, from the research of several scientists, it is clear that C. megalodon is the largest macropredatory shark that has ever lived and is among the largest fishes known to have existed.[4]


Jaw dentition

Some scientists including Applegate and Espinosa published an artificial dental formula for C. megalodon in 1996.[8] Several modern C. megalodon jaw reconstructions are based on this dental formula. Dentition is the development of teeth and their arrangement in the mouth. ...


The dental formula of C. megalodon is:

2.1.7.4
3.0.8.4

As evident from the dental formula, the jaws of C. megalodon contained four different kinds of teeth.[8]

Paleontologists suggest that C. megalodon had a total of about 250 teeth.[1] In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... In chemistry a reactive intermediate is a short-lived high energy highly reactive molecule. ... The term lateral can refer to: an anatomical definition of direction. ... The English word POSTERIOR is identical to the original Latin adjective, and has two different uses : as an ADJECTIVE, it indicates that someone or something is behind another, either spatially or chronologically it also became a SUBSTANTIVE, indicating the rear-end, especially of a person, i. ...


Skeletal reconstruction

Aside from estimating the size of C. megalodon, Gottfried and his colleagues also have tried to determine how C. megalodon might have looked like in real life.[4] After conducting a comprehensive analysis of the available evidence, they concluded that C. megalodon was a very robust shark and it was more massively proportioned than many modern large sharks including C. carcharias due to several reasons including:

  • C. megalodon had a more massive, stouter and more strongly developed chondrocranium and jaws than those of modern macropredatory sharks, in order to functionally support a massive and very robust dentition.[4]
  • The fins of C. megalodon were significantly larger and thicker because they needed to be adapted for propulsion and control of movements of such a massive shark.[4]
  • It had a higher vertebral count than that of any large shark including C. carcharias.[4]

Gottfried and his colleagues eventually developed a model of the entire skeleton of C. megalodon with the above mentioned characteristics, which has been put on display in Calvert Marine Museum at Solomons island, Maryland in USA.[4][5][13] Official language(s) None (English, de facto) Capital Annapolis Largest city Baltimore Largest metro area Baltimore-Washington Metropolitan Area Area  Ranked 42nd  - Total 12,407 sq mi (32,133 km²)  - Width 101 miles (145 km)  - Length 249 miles (400 km)  - % water 21  - Latitude 37° 53′ N to 39° 43′ N... Motto: (traditional) In God We Trust (official, 1956–present) Anthem: The Star-Spangled Banner Capital Washington, D.C. Largest city New York City Official language(s) None at the federal level; English de facto Government Federal Republic  - President George W. Bush (R)  - Vice President Dick Cheney (R) Independence - Declared - Recognized...


Distribution, range and habitat

C. megalodon was a pelagic fish and it thrived in all the oceans of the world in its time, indicating dominance over the marine world. The teeth of this ancient shark have been excavated from many parts of the world, including Europe, North America, South America, Australia, New Zealand, Japan, South Africa, Malta and India.[1][8] The pelagic zone is the part of the open sea or ocean comprising the water column, i. ... Animated map exhibiting the worlds oceanic waters. ... For other uses, see Europe (disambiguation). ... North American redirects here. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ...


C. megalodon most likely inhabited warm water regions around the world.[2] Its range would not have been constricted by its reliance on warm waters as the oceans were noticeably warmer during the Miocene and early Pliocene. This would have made it possible for this species to flourish around the world, as evident from the fossil records. The Miocene Epoch is a period of time that extends from about 23. ... The Pliocene epoch (spelled Pleiocene in some older texts) is the period in the geologic timescale that extends from 5. ...


Paleoecology

C. megalodon is among the most highly studied prehistoric sharks. Paleontologist Robert W. Purdy has used the fossil record and ecology of the extant sharks to explore its paleoecology, with his findings published in 1996.[1][4] His research reveals some interesting facts about this shark and its behavior. Paleoecology uses data from fossils and subfossils to reconstruct the ecosystems of the past. ...


Diet

Megalodon chasing two juvenile whales

Assuming similar metabolic-weight ratios as those of the great white shark, it is estimated that, on average, C. megalodon would need to eat about one-fiftieth of its weight (or more than 2,000 pounds (910 kg) in food per day. This article is about the animal. ...


During the time when C. megalodon existed, the oceans were inhabited by a large variety of marine animals, including various species of whales. Several whale vertebrae and bones have been found with clear signs of large bite marks made by the teeth that match those of C. megalodon.[1][4][8] The teeth of C. megalodon are serrated,[1][3] which most likely helped in tearing the flesh of prey with great efficiency. Various excavations have revealed C. megalodon teeth lying close to the chewed remains of whales.[4][5] This evidence indicates a predator-prey relationship between C. megalodon and large marine animals including whales.[8]


Like other sharks, C. megalodon was certainly piscivorous as well.[2] However, because of its immense size, this shark was more reliant on large animals for food and its diet consisted of various species of whales including sperm whales,[1] Cetotherium,[2] and Odobenocetops,[14] and other large marine mammals including sirenians,[1] dolphins,[1] and pinnipeds.[2] This article does not adequately cite its references or sources. ... In nutrition, the diet is the sum of food consumed by a person or other organism. ... Binomial name Linnaeus, 1758 Sperm whale range (in blue) The sperm whale (Physeter macrocephalus) is the largest of all toothed whales and is the largest toothed animal alive, with adult males measuring up to 20. ... Paleo Template Project Cetotherium was a cetacean that looked more like modern whales of today. ... Species (type) Odobenocetops (tooth-walking whale) was a small whale from the Pliocene. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... Families Dugongidae Trichechidae For information about the Gothic Metal band, see Sirenia (band) Sirenia are herbivorous mammals of coastal waters. ... For other uses, see Dolphin (disambiguation). ... Families Odobenidae Otariidae Phocidae Pinnipeds (fin-feet, lit. ...


Behavior

Most sharks are opportunistic predators and rely on a broad spectrum of prey coupled with scavenging. C. megalodon was unlikely to have been an exception to this rule.[2] Some large sharks (including the great white shark) employ ambush strategies against their prey during hunting. A shark usually attacks its prey with great force in the first attempt to inflict maximum possible damage. Then it circles its prey and waits for it to weaken, before dispatching it without facing any resistance. Some paleontologists suggest that C. megalodon also may have employed a similar hunting strategy against large potential prey, like adult whales. Several fossilized flipper bones, and caudal vertebrae of whales have been found with bite marks that were caused by the attacks from C. megalodon.[1][4] This evidence indicates that C. megalodon most likely injured and immobilized its prey by biting off its propulsive structures, before proceeding to feed on it.[1][4] This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ...


However, remains of a large prehistoric baleen whale have been excavated from Chesapeake Bay, which provided the first opportunity to quantitatively analyse the feeding behavior of C. megalodon, and this specimen revealed that the attacking behavior of C. megalodon was more aggressive than that of the great white shark.[12] One reason is that the shark apparently focused its attack on the bony portions of the prey, which great white sharks generally avoid.[12] The Chesapeake Bay - Landsat photo The Chesapeake Bay where the Susquehanna River empties into it. ...


From fossil evidence, juvenile C. megalodon individuals would mostly prefer to attack small-to-medium sized prey, such as porpoises, other sharks, pinnipeds and juvenile whales. Hence, through ontogeny C. megalodon proceeded to hunt larger animals.[4] In addition, fossil evidence suggests that the preferred breeding grounds of C. megalodon were mostly warm coastal regions.[4] Genera Neophocaena Phocoena - Harbor porpoise Phocoenoides - Dalls porpoise The porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. ... Families Odobenidae Otariidae Phocidae Pinnipeds (fin-feet, lit. ... Ontogeny (also ontogenesis or morphogenesis) describes the origin and the development of an organism from the fertilized egg to its mature form. ...


Extinction hypothesis

Megalodon and fossil shark teeth
Megalodon and fossil shark teeth

There are several hypotheses as to how an apex predator like C. megalodon suddenly became extinct after millions of years of existence. However, the extinction of large-bodied marine predators, such as pliosaurs, mosasaurs, ichthyosaurs and Basilosaurus, are instructive as to the possible mechanism involved. Image File history File links Size of this preview: 734 × 599 pixelsFull resolution (1536 × 1254 pixel, file size: 1. ... Image File history File links Size of this preview: 734 × 599 pixelsFull resolution (1536 × 1254 pixel, file size: 1. ... In biology and ecology, extinction is the ceasing of existence of a species or group of species. ... Families Cryptoclididae Elasmosauridae Plesiosauridae Pliosauridae Plesiosaurs (PLEE-see-oh-SORES) were large, carnivorous aquatic reptiles. ... Subfamilies Mosasaurinae Plioplatecarpinae Tylosaurinae Mosasaurs (from Latin Mosa, the Meuse river where the fossils were first discovered + Greek sauros, lizard) were serpentine marine reptiles, more closely related to snakes than to monitor lizards (Lee 1997). ... Families Ichthyosauridae Leptonectidae Mixosauridae Ophthalmosauridae Shastasauridae Stenopterygiidae Teretocnemidae Ichthyosaurs (Greek for fish lizard - ιχθυς meaning fish and σαυρος meaning lizard) were giant marine reptiles that resembled fish and dolphins. ... Species Basilosaurus (King Lizard) was a genus of cetacean that lived from 39 to 34 million years ago in the Eocene. ...


Scientists believe that C. megalodon disappeared due to a variety of reasons.[2] The geological and climatic conditions of the world when C. megalodon existed, were considerably different from those now. It is possible that these major climatic changes may not have proved to be favorable for C. megalodon. Some notable climatic shifts are:

  • During the late Pliocene and Pleistocene epochs there were significant ice ages,[15][16] which cooled the oceans significantly.[8]
  • From the fossil record, whale migatory patterns from the end Pliocene have been reconstructed, suggesting that some species migrated to polar regions, effectively "getting out of the range" of C. megalodon.[2][8]
  • Prolonged disturbance of food chains can wipe out predators with massive metabolic requirements. During the Pliocene, some species of whales and dolphins (e.g. Odobenocetops) became extinct. As these species would most likely have been among the potential prey of C. megalodon,[2] sustaining the dietary requirements of such a large predator would have become increasingly difficult.
  • In addition, wide-scale glaciation trapped much of the oceanic salt water during the late Pliocene and Pleistocene through-out the ice ages. At its height sea levels dropped significantly, restricting many shallow coastal areas, that have been thought to serve as breeding grounds for the C. megalodon pups.[2]

Consequently, a hypothesis can be constructed, that at the end of the Pliocene, the polar seas became too cold for C. megalodon to survive. Several species of whales, including cetotheriids, became extinct during the late Pliocene, while some whale species showed a trend towards the cooler polar regions. Many of the shallow warm water regions dried out at that time, that may have been breeding grounds for C. megalodon. As such, these significant disturbances in the ecosystem would have caused major problems for C. megalodon. Being unable to follow the surviving whale species into the polar seas the food supply of C. megalodon lessened, which over time lead to the extinction of the species.[2] Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... Location of the polar regions Northern Hemisphere permafrost (permanently frozen ground) in purple. ... Species (type) Odobenocetops (tooth-walking whale) was a small whale from the Pliocene. ... A glaciation (a created composite term meaning Glacial Period, referring to the Period or Era of, as well as the process of High Glacial Activity), often called an ice age, is a geological phenomenon in which massive ice sheets form in the Arctic and Antarctic and advance toward the equator. ... This article is about common table salt. ... For other uses, see Ecological Systems Theory. ...


Relict

Carcharodontosaurus tooth from the Sahara Desert with a C. megalodon tooth, and a 25 mm diameter coin (US quarter).
Carcharodontosaurus tooth from the Sahara Desert with a C. megalodon tooth, and a 25 mm diameter coin (US quarter).

While scientists contend that available evidence shows that C. megalodon is extinct, the idea of a relict population seems to have seized the public imagination.[1][2] Evidence supporting such ideas is generally seen as scant, ambiguous and lacking sufficient credibility.[1][2] Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (3072 × 2304 pixel, file size: 2. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (3072 × 2304 pixel, file size: 2. ... Species C. saharicus (Depéret & Savornin, 1927) (type) Carcharodontosaurus (/kɑː.kɑː.ɹə.ˈdÉ’n. ... The Sahara is the worlds second largest desert (second to Antarctica), over 9,000,000 km² (3,500,000 mi²), located in northern Africa and is 2. ... A quarter is a coin worth one-quarter of a United States dollar, or 25 cents. ... For other uses, see Extinction (disambiguation). ... The term relict is used to refer to surviving remnants of natural phenomena. ...


C. megalodon teeth have been discovered that some argue date to as recently as 10,000 to 15,000 years ago. This claim is based on the discovery of two teeth from the South Pacific by the HMS Challenger scientific expedition (these teeth were dated by estimating the amount of time it took for manganese to accumulate on them, although it is quite possible the teeth were fossilized long before being encrusted). Problems with this dating method include the simple fact that deposition of manganese oxide on the seafloor is not constant, and can only serve as a minimum age. In all likelihood, these teeth are probably much older.[2] The South Pacific is an area in the southern Pacific Ocean. ... The fifth HMS Challenger (launched 1858) was a steam assisted British naval corvette. ... General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ...


Scientists now suggest that these recent estimates for these teeth are inaccurate, and being based on an outdated testing methodology. Another possible explanation is that some C. megalodon teeth might have been eroded from pre-Pleistocene deposits and re-deposited in the much younger strata, such as those from the late Pleistocene.[2]


Megamouth analogy

Some proponents of modern-day C. megalodon survival suggest that the shark might be lurking in the deep waters and often cite the case of the megamouth shark as an example and state that the oceans can still harbor large species unknown to man.[2] However, the research has suggested that the megamouth shark is a false analogy to the possible existence of C. megalodon, unless the proposed individual was a highly specialized mesopelagic planktivore with poorly calcified skeleton; C. megalodon was certainly not such a creature.[2] Binomial name Megachasma pelagios Taylor, Compagno and Struhsaker, 1983 The megamouth shark, Megachasma pelagios, is an extremely rare and unusual species of shark, discovered in 1976, with 37 specimens known to be caught or sighted as of 2006. ... This article does not cite any references or sources. ...


Research concludes that C. megalodon was a large carnivorous shark that adapted to a warm and food-rich marine habitat and was an active predator of large animals like whales. Such a creature would not be able to survive in the cold, food-poor deep-sea.[2]


Supposed C. megalodon sightings

Some relatively recent reports of large shark-like creatures have been interpreted as surviving C. megalodon, but such reports are usually considered misidentification of basking sharks, whale sharks or submarines. Binomial name (Gunnerus, 1765) Range (in blue) The basking shark, Cetorhinus maximus, is the second largest fish, after the whale shark. ... Binomial name (Smith, 1828) Range of whale shark The whale shark, Rhincodon typus, is a slow filter feeding shark that is the largest living fish species. ... For other uses, see Submarine (disambiguation). ...


One well-known example was reported by writer David G. Stead in his book Sharks and Rays of Australian Seas, that was released in 1963. The brief excerpt of this account is mentioned below:

In the year 1918 I recorded the sensation that had been caused among the "outside" crayfish men at Port Stephens, when, for several days, they refused to go to sea to their regular fishing grounds in the vicinity of Broughton Island. The men had been at work on the fishing grounds---which lie in deep water---when an immense shark of almost unbelievable proportions put in an appearance, lifting pot after pot containing many crayfishes, and taking, as the men said, "pots, mooring lines and all". These crayfish pots, it should be mentioned, were about 3 feet 6 inches [1.06 m] in diameter and frequently contained from two to three dozen good-sized crayfish each weighing several pounds. The men were all unanimous that this shark was something the like of which they had never dreamed of. In company with the local Fisheries Inspector I questioned many of the men very closely and they all agreed as to the gigantic stature of the beast.[1][2]

This report received considerable attention from the media, and David G. Stead himself believed in the account. Most shark experts, however, after careful examination of this account questioned its authenticity, as the sailors themselves were giving contradictory statements regarding the details of the event, including the size factor of the mystery animal. Hence, those sailors were most likely exaggerating the details of the event. One critic even said that those sailors might have concocted this story, after they lost their crab pots in an accident.[1]


Another well-known account was reported by writer Zane Grey and his son Loren in 1933. His actual comments have been narrated by Gross in 1987: Zane Grey (January 31, 1872 – October 23, 1939) was an American author best known for his popular adventure novels and pulp fiction that presented an idealized image of the rugged Old West. ...

At first I thought it was a whale, but when the great brown tail rose in the ship’s wake as the fish moved ponderously away from the liner, I knew immediately that it was a monstrous shark. The huge round head appeared to be at least 10 to 12 feet across if not more ... It was my belief that this huge, yellowish, barnacled creature must have been at least 40 or 50 feet long. He was not a whale shark: the whale shark has a distinctive white purplish green appearance with large brown spots and much narrower head. So what was he---perhaps a true prehistoric monster of the deep?[2]

After careful examination of this case, most shark experts concluded that Grey's description of the animal still closely matches that of the whale shark and he was wrong about the color of the animal. An expert, Castro, gives a good explanation of the coloring of the skin of whale sharks. He points out that many white or yellowish spots can be observed on the skin of whale sharks. Their heads are very wide, squarish, yet slightly rounded.[2]


In fiction and popular culture

Ever since the remains of C. megalodon were discovered, it has been an object of fascination. It has been portrayed in several works of fiction, including films and novels, and continues to hold its place among the most popular subjects for fictional works involving sea monsters. It is, however, interesting to note that in most of these works of fiction, C. megalodon is shown to surface from the vast depths of the oceans, either as a result of human intervention or through natural means. For other uses, see Fiction (disambiguation). ... The Sea Monsters beastiary. ...


Films

  • Shark Hunter (2001)
  • Shark Attack 3: Megalodon (2002)
  • Megalodon (2004)
  • Hai-Alarm auf Mallorca (2004)
  • Meg (to be released)

Novels

  • Extinct Charles Wilson (1997)
  • Meg: A Novel of Deep Terror Steve Alten (1997)
  • The Trench Steve Alten (2000)
  • From the Dark Below Cari McKnight (2001)
  • Meg: Primal Waters Steve Alten (2004)
  • Meg: Hell's Aquarium Steve Alten (2008)
  • Meg: Night Stalkers Steve Alten (to be released)

lisa Belkova woz ehe! ...

Television

  • Sea Monsters: A Walking with Dinosaurs Trilogy (2003)

Games

  • Shark! Hunting the Great White (2001)
  • Sea Monsters Adventure (2003)

Misc

  • The band Mastodon dedicated a song to C. megalodon on their album Leviathan.
  • A variable volume mixed gas closed circuit rebreather developed by a company, InnerSpace Systems Corp, is called the Megalodon Rebreather.
  • Small C. megalodon teeth are often used for developing shark tooth necklaces.
  • Some stamps have also been dedicated to C. megalodon.

Mastodon is a Grammy-nominated[1] band from Atlanta, Georgia. ... Leviathan is a concept album by metal band Mastodon, released in 2004. ... This article is about the breathing apparatus. ... For other senses of this word, see necklace (disambiguation). ... This 1974 stamp from Japan depicts a Class 8620 steam locomotive. ...

See also

// Sharks belong to the superorder Selachimorpha in the subclass Elasmobranchii in the class Chondrichthyes. ... Prehistoric fish are various groups of fishes that lived before recorded history. ... This is a partial list of predators that are not preyed upon as healthy adults in the wild. ...

Notes

  • ^ a:  The oldest C. megalodon teeth found are about 18 million years old.[1] Though, C. megalodon became extinct in the Pliestocene epoch probably about 1.5 million years ago.[2]
  • ^ b:  The actual method is: "Megatooth's" Total Length in meters = [− (0.22) + (0.096) × (Slant height of tooth in [mm])].[4] Though, this method has often been interpreted as: "Megatooth's" Total Length in meters = [(0.96) × (Slant height of tooth in [cm] − (0.22))], because it yields same results.[10]
  • ^ c:  In the case of C. megalodon, this tooth appears to be upper anterior and is technically termed as "A3" because it is fairly symmetrical and does not points mesially, but this tooth is still designated as an intermediate tooth.[3] However, in the case of the great white shark, the intermediate tooth does points mesially. This point has often been raised in the Carcharodon vs. Carcharocles debate regarding the megalodon and favors the case of Carcharocles proponents.

References

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah Renz, Mark (2002). Megalodon: Hunting the Hunter. PaleoPress. ISBN 0-9719477-0-8. 
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Roesch, Ben (1998), The Cryptozoology Review: A Critical Evaluation of the Supposed Contemporary Existence of Carcharodon Megalodon., <http://www.ncf.carleton.ca/~bz050/megalodon.html>
  3. ^ a b c d e f g h i j Kevin G.N, Charles N.C, Gregory A.W (2006). "Tracing the ancestry of the GREAT WHITE SHARK" (PDF). Retrieved on 2007-12-25.
  4. ^ a b c d e f g h i j k l m n o p q r Klimley, Peter & Ainley, David (1996), Great White Sharks: The Biology of Carcharodon carcharias, Academic Press, ISBN 0124150314
  5. ^ a b c d e f g h i j k Andres, Lutz (2002). C. megalodon - Megatooth Shark, Carcharodon versus Carcharocles. Retrieved on 2008-01-16.
  6. ^ a b Bowling, Stuart (1997). C. Megalodon.
  7. ^ a b Alter, Steven (2001). Origin of the Modern Great White Shark. Retrieved on 2008-01-13.
  8. ^ a b c d e f g h i j Bruner, John. "The Megatooth shark", FLMNH. Retrieved on 2008-01-16. 
  9. ^ a b Randall, John (July 1973). "Size of the Great White Shark (Carcharodon)". Science Magazine: 169-170. 
  10. ^ a b Kowinsky, Jayson (2002). The Size of Megalodons. Retrieved on 2008-01-12.
  11. ^ Alter, Steven. "Megalodon", Fossil News - Journal of Amateur Paleontology, 1997. Retrieved on 2007-12-14. 
  12. ^ a b c Riordon, James (June 1999). "Hell's teeth". NewScientist Magazine (2190): 32. 
  13. ^ Arnold, Caroline (2000). Giant Shark: Megalodon, Prehistoric Super Predator. Houghton Mifflin, 18-19. ISBN 9780395914199. 
  14. ^ Fact File: Odobenocetops. BBC. Retrieved on 2008-03-21.
  15. ^ Pliocene epoch. Retrieved on 2008-01-16.
  16. ^ Pliestocene epoch. Retrieved on 2008-01-16.

PDF is an abbreviation with several meanings: Portable Document Format Post-doctoral fellowship Probability density function There also is an electronic design automation company named PDF Solutions. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 359th day of the year (360th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 13th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 12th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 348th day of the year (349th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 80th day of the year (81st in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ...

External links

Wikimedia Commons has media related to:
Wikispecies has information related to:
Carcharodon megalodon

Image File history File links Wikispecies-logo. ... Wikispecies is a wiki-based online project supported by the Wikimedia Foundation that aims to create a comprehensive free content catalogue of all species (including animalia, plantae, fungi, bacteria, archaea, and protista). ...

Educational videos

The Adobe Flash Player is a widely distributed multimedia and application player created and distributed by Macromedia (a division of Adobe Systems). ...

  Results from FactBites:
 
Megalodon Article (998 words)
Carcharocles megalodon was by far the largest predator (land or sea) to have ever lived.
The megalodon thrived in the temperate waters during the Miocene and Pliocene epochs.
The exact time the megalodon became extinct is uncertain, however the megalodon probably lasted until the middle of the Pliocene epoch (approximately 2.5 - 3 million years ago).
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m