Biology:Megalodon
Megalodon | |
---|---|
![]() | |
Model of megalodon jaws at the American Museum of Natural History | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Subclass: | Elasmobranchii |
Subdivision: | Selachimorpha |
Order: | Lamniformes |
Family: | †Otodontidae |
Genus: | †Otodus |
Species: | †O. megalodon
|
Binomial name | |
†Otodus megalodon | |
Synonyms[3][4][5][6][7] | |
List of synonyms
|
Otodus megalodon (/ˈmɛɡələdɒn/ MEG-əl-ə-don; meaning "big tooth"), commonly known as megalodon, is an extinct species of giant mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. O. megalodon was formerly thought to be a member of the family Lamnidae and a close relative of the great white shark (Carcharodon carcharias), but has been reclassified 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, 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 (Carcharodon carcharias), 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 estimate up to 20.3 meters (67 ft), although the modal lengths are estimated at 10.5 meters (34 ft). Extrapolation from a vertebral centra[Possibly "vertebral centrum"; "centra" is plural.] with dimensions based on the great white shark suggests that
- a megalodon about 16 meters (52 ft) long weighs up to 48 t (53 short tons; 47 long tons),
- one 17 meters (56 ft) long weighs up to 59 t (65 short tons; 58 long tons), and
- one 20.3 meters (67 ft) long (the maximum length) weighs up to 103 t (114 short tons; 101 long tons).
Extrapolating from a vertebral column and reconstructing a 3D model with dimensions based on all extant lamnid sharks suggests that a 16-meter-long (52 ft) individual may have been much larger than previous estimates, reaching an excess of 61.5 t (67.8 short tons; 60.5 long tons) in body mass; an individual of this size would have needed to consume 98,175 kcal per day. Their teeth were thick and robust, built for grabbing prey and breaking bone, and their large jaws could exert a bite force of up to 108,500 to 182,200 newtons (24,390 to 40,960 lbf).
Megalodon probably had a major impact on the structure of marine communities. The fossil record indicates that it had a cosmopolitan distribution. It probably targeted large prey, such as whales, seals and sea turtles. Juveniles inhabited warm coastal waters and fed on fish and small whales. Unlike the great white, which attacks prey from the soft underside, megalodon probably used its strong jaws to break through the chest cavity and puncture the heart and lungs of its prey.
The animal faced competition from whale-eating cetaceans, such as Livyatan and other macroraptorial sperm whales and possibly smaller ancestral killer whales (orcinus orca). As the shark preferred warmer waters, it is thought that oceanic cooling associated with the onset of the ice ages, coupled with the lowering of sea levels and resulting loss of suitable nursery areas, may have also contributed to its decline. A reduction in the diversity of baleen whales and a shift in their distribution toward polar regions may have reduced megalodon's primary food source. The shark's extinction coincides with a gigantism trend in baleen whales.
Classification
Prescientific and early research history
Megalodon teeth have been excavated and used since ancient times. They were a valued artifact amongst pre-Columbian cultures in the Americas for their large sizes and serrated blades, from which they were modified into projectile points, knives, jewelry, and funeral accessories.[8][9] At least some, such as the Panamanian Sitio Conte societies, seemed to have used them primarily for ceremonial purposes.[9] Mining[10] of megalodon teeth by the Algonquin peoples in the Chesapeake Bay and their selective trade with the Adena culture in Ohio occurred as early as 430 BC.[8] The earliest written account of megalodon teeth was by Pliny the Elder in an AD 73 volume of Historia Naturalis, who described them as resembling petrified human tongues that Roman folklorists believed to have fallen from the sky during lunar eclipses and called them glossopetrae ("tongue stones").[11] The purported tongues were later thought in a 12th-century Maltese tradition to have belonged to serpents that Paul the Apostle turned to stone while shipwrecked there, and were given antivenom powers by the saint.[12] Glossopetrae reappeared throughout Europe in late 13th to 16th century literature, ascribed with more supernatural properties that cured a wider variety of poisons. Use of megalodon teeth for this purpose became widespread among medieval and Renaissance nobility, who fashioned them into protective amulets and tableware to purportedly detoxify poisoned liquids or bodies that touched the stones. By the 16th century, teeth were directly consumed as ingredients of European-made Goa stones.[11]
The true nature of the glossopetrae as shark's teeth was held by some since at least 1554, when cosmographer André Thevet described it as hearsay, although he did not believe it. The earliest scientific argument for this view was made by Italian naturalist Fabio Colonna, who in 1616 published an illustration of a Maltese megalodon tooth alongside a great white shark's and noted their striking similarities. He argued that the former and its likenesses were not petrified serpent's tongues but actually the teeth of similar sharks that washed up on shore. Colonna supported this thesis through an experiment of burning glossopetrae samples, from which he observed carbon residue he interpreted as proving an organic origin.[12] However, interpretation of the stones as shark's teeth remained widely unaccepted. This was in part due the inability to explain how some of them are found far from the sea.[13] The shark tooth argument was academically raised again during the late 17th century by England scientists Robert Hooke, John Ray, and Denmark naturalist Niels Steensen (Latinized Nicholas Steno).[14] Steensen's argument in particular is most recognized as inferred from his dissection of the head of a great white caught in 1666. His 1667 report depicted engravings of a shark's head and megalodon teeth that became especially iconic. However, the illustrated head was not actually the head that Steensen dissected, nor were the fossil teeth illustrated by him. Both engravings were originally commissioned in the 1590s by Papal physician Michele Mercati, who also had in possession the head of a great white, for his book Metallotheca. The work remained unpublished in Steensen's time due to Mercati's premature death, and the former reused the two illustrations per suggestion by Carlo Roberto Dati, who thought a depiction of the actual dissected shark was unsuitable for readers.[15] Steensen also stood out in pioneering a stratigraphic explanation for how similar stones appeared further inland. He observed that rock layers bearing megalodon teeth contained marine sediments and hypothesized that these layers correlated to a period of flood that was later covered by terrestrial layers and uplifted by geologic activity.[13]
![](https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Recherches_sur_les_poissons_fossiles_%28Tab_29%29_%287267241882%29.jpg/250px-Recherches_sur_les_poissons_fossiles_%28Tab_29%29_%287267241882%29.jpg)
Switzerland naturalist Louis Agassiz gave megalodon its scientific name in his seminal 1833-1843 work Recherches sur les poissons fossiles (Research on fossil fish). He named it Carcharias megalodon in an 1835 illustration of the holotype and additional teeth, congeneric with the modern sand tiger shark.[1][2] The specific name is a portmanteau of the Ancient Greek words μεγάλος (megálos, meaning "big") and ὀδών (odṓn, meaning "tooth"),[16][17] combined meaning "big tooth." Agassiz referenced the name as early as 1832, but because specimens were not referenced they are not taxonomically recognized uses.[2] Formal description of the species was published in an 1843 volume, where Agassiz revised the name to Carcharodon megalodon as its teeth were far too large for the former genus and more alike to the great white shark.[1] He also erroneously identified several megalodon teeth as belonging to additional species eventually named Carcharodon rectidens, Carcharodon subauriculatus, Carcharodon productus, and Carcharodon polygurus.[1][18] Because Carcharodon megalodon appeared first in the 1835 illustration, the remaining names are considered junior synonyms under the principle of priority.[2][18]
Evolution
While the earliest megalodon remains have been reported from the Late Oligocene, around 28 million years ago (Mya),[19][20] there is disagreement as to when it appeared, with dates ranging to as young as 16 mya.[21] It has been thought that megalodon became extinct around the end of the Pliocene, about 2.6 Mya;[21][22] claims of Pleistocene megalodon teeth, younger than 2.6 million years old, are considered unreliable.[22] A 2019 assessment moves the extinction date back to earlier in the Pliocene, 3.6 Mya.[23][24]
Megalodon is considered to be a member of the family Otodontidae, genus Otodus, as opposed to its previous classification into Lamnidae, genus Carcharodon.[21][25][22][7][26] Megalodon's classification into Carcharodon was due to dental similarity with the great white shark, but most authors believe that this is due to convergent evolution. In this model, the great white shark is more closely related to the extinct broad-toothed mako (Isurus hastalis) than to megalodon, as evidenced by more similar dentition in those two sharks; megalodon teeth have much finer serrations than great white shark teeth. The great white shark is more closely related to the mako shark (Isurus spp.), with a common ancestor around 4 Mya.[27][28] Proponents of the former model, wherein megalodon and the great white shark are more closely related, argue that the differences between their dentition are minute and obscure.[29]:23–25
The genus Carcharocles contains four species: C. auriculatus, C. angustidens, C. chubutensis, and C. megalodon.[30]:30–31 The evolution of this lineage is characterized by the increase of serrations, the widening of the crown, the development of a more triangular shape, and the disappearance of the lateral cusps.[30]:28–31[31] The evolution in tooth morphology reflects a shift in predation tactics from a tearing-grasping bite to a cutting bite, likely reflecting a shift in prey choice from fish to cetaceans.[32] Lateral cusplets were finally lost in a gradual process that took roughly 12 million years during the transition between C. chubutensis and C. megalodon.[32] The genus was proposed by D. S. Jordan and H. Hannibal in 1923 to contain C. auriculatus. In the 1980s, megalodon was assigned to Carcharocles.[27][30]:30 Before this, in 1960, the genus Procarcharodon was erected by French ichthyologist Edgard Casier, which included those four sharks and was considered separate from the great white shark. It is since considered a junior synonym of Carcharocles.[30]:30 The genus Palaeocarcharodon was erected alongside Procarcharodon to represent the beginning of the lineage, and, in the model wherein megalodon and the great white shark are closely related, their last common ancestor. It is believed to be an evolutionary dead-end and unrelated to the Carcharocles sharks by authors who reject that model.[29]:70
Another model of the evolution of this genus, also proposed by Casier in 1960, is that the direct ancestor of the Carcharocles is the shark Otodus obliquus, which lived from the Paleocene through the Miocene epochs, 60 to 13 Mya.[28][31] The genus Otodus is ultimately derived from Cretolamna, a shark from the Cretaceous period.[7][33] In this model, O. obliquus evolved into O. aksuaticus, which evolved into C. auriculatus, and then into C. angustidens, and then into C. chubutensis, and then finally into C. megalodon.
Another model of the evolution of Carcharocles, proposed in 2001 by paleontologist Michael Benton, is that the three other species are actually a single species of shark that gradually changed over time between the Paleocene and the Pliocene, making it a chronospecies.[30]:17[20][34] Some authors suggest that C. auriculatus, C. angustidens, and C. chubutensis should be classified as a single species in the genus Otodus, leaving C. megalodon the sole member of Carcharocles.[20][35]
The genus Carcharocles may be invalid, and the shark may actually belong in the genus Otodus, making it Otodus megalodon.[5] A 1974 study on Paleogene sharks by Henri Cappetta erected the subgenus Megaselachus, classifying the shark as Otodus (Megaselachus) megalodon, along with O. (M.) chubutensis. A 2006 review of Chondrichthyes elevated Megaselachus to genus, and classified the sharks as Megaselachus megalodon and M. chubutensis.[5] The discovery of fossils assigned to the genus Megalolamna in 2016 led to a re-evaluation of Otodus, which concluded that it is paraphyletic, that is, it consists of a last common ancestor but it does not include all of its descendants. The inclusion of the Carcharocles sharks in Otodus would make it monophyletic, with the sister clade being Megalolamna.[7]
The cladogram below represents the hypothetical relationships between megalodon and other sharks, including the great white shark. Modified from Shimada et al. (2016),[7] Ehret et al., (2009),[28] and the findings of Siversson et al. (2013).[36][37][38]
Lamniformes |
| |||||||||||||||||||||||||||||||||||||||||||||
Biology
Appearance
![](https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lateral_view_of_otouds_megalodon.png/250px-Lateral_view_of_otouds_megalodon.png)
One interpretation on how megalodon appeared was that it was a robust-looking shark, and may have had a similar build to the great white shark. The jaws may have been blunter and wider than the great white, and the fins would have also been similar in shape, though thicker due to its size. It may have had a pig-eyed appearance, in that it had small, deep-set eyes.[39]
Another interpretation is that megalodon bore a similarity to the whale shark (Rhincodon typus) or the basking shark (Cetorhinus maximus). The tail fin would have been crescent-shaped, the anal fin and second dorsal fin would have been small, and there would have been a caudal keel present on either side of the tail fin (on the caudal peduncle). This build is common in other large aquatic animals, such as whales, tuna, and other sharks, in order to reduce drag while swimming. The head shape can vary between species as most of the drag-reducing adaptations are toward the tail-end of the animal.[30]:35–36
One associated set of megalodon remains was found with placoid scales, which are 0.3 to 0.8 millimetres (0.012 to 0.031 in) in maximum width, and have broadly spaced keels.[40]
Size
Due to fragmentary remains, there have been many contradictory size estimates for megalodon, as they can only be drawn from fossil teeth and vertebrae.[41]:87[42] The great white shark has been the basis of reconstruction and size estimation, as it is regarded as the best analogue to megalodon. Several total length estimation methods have been produced from comparing megalodon teeth and vertebrae to those of the great white.[39][43][44][26]
Megalodon size estimates vary depending on the method used, with maximum total length estimates ranging from 14.2–20.3 meters (47–67 ft).[39][44][26] A 2015 study estimated the average total body length at 10.5 meters (34 ft), calculated from 544 megalodon teeth, found throughout geological time and geography, including adults and juveniles.[45][25] In comparison, large great white sharks are generally around 6 meters (20 ft) in length, with a few contentious reports suggesting larger sizes.[46][47][39] The whale shark is the largest living fish, with one large female reported with a precaudal length of 15 meters (49 ft) and an estimated total length of 18.8 meters (62 ft).[46][48] It is possible that different populations of megalodon around the globe had different body sizes and behaviors due to different ecological pressures.[25] Megalodon is thought to have been the largest macropredatory shark that ever lived.[39]
"A C. megalodon about 16 meters long would have weighed about 48 metric tons (53 tons). A 17-meter (56-foot) C. megalodon would have weighed about 59 metric tons (65 tons), and a 20.3-meter (67 foot) monster would have topped off at 103 metric tons (114 tons)."[49]
In his 2015 book, The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution, Donald Prothero proposed the body mass estimates for different individuals of different length by extrapolating from a vertebral centra based on the dimensions of the great white,[49] a methodology also used for the 2008 study which supports the maximum mass estimate.[50]
In 2020, Cooper and his colleagues reconstructed a 2D model of megalodon based on the dimensions of all the extant lamnid sharks and suggested that a 16 meters (52 ft) long megalodon would have had a 4.65 m (15.3 ft) long head, 1.41 m (4 ft 8 in) tall gill slits, a 1.62 m (5 ft 4 in) tall dorsal fin, 3.08 m (10 ft 1 in) long pectoral fins, and a 3.85 m (12 ft 8 in) tall tail fin.[51] In 2022, Cooper and his colleagues also reconstructed a 3D model with the same basis as the 2020 study, resulting in a body mass estimate of 61.56 t (67.86 short tons; 60.59 long tons) for a 16 meters (52 ft) long megalodon (higher than the previous estimates); a vertebral column specimen named IRSNB P 9893 (formerly IRSNB 3121), belonging to a 46 year old individual from Belgium, was used for extrapolation. An individual of this size would have required 98,175 kcal per day, 20 times more than what the adult great white requires.[52]
Mature male megalodon may have had a body mass of 12.6 to 33.9 t (13.9 to 37.4 short tons; 12.4 to 33.4 long tons), and mature females may have been 27.4 to 59.4 t (30.2 to 65.5 short tons; 27.0 to 58.5 long tons), assuming that males could range in length from 10.5 to 14.3 meters (34 to 47 ft) and females 13.3 to 17 meters (44 to 56 ft).[39]
A 2015 study linking shark size and typical swimming speed estimated that megalodon would have typically swum at 18 kilometers per hour (11 mph)–assuming that its body mass was typically 48 t (53 short tons; 47 long tons)–which is consistent with other aquatic creatures of its size, such as the fin whale (Balaenoptera physalus) which typically cruises at speeds of 14.5 to 21.5 km/h (9.0 to 13.4 mph).[53] In 2022, Cooper and his colleagues converted this calculation into relative cruising speed (body lengths per second), resulting in an mean absolute cruising speed of 5 kilometers per hour (3.1 mph) and a mean relative cruising speed of 0.09 body lengths per second for a 16 meters (52 ft) long megalodon; the authors found their mean absolute cruising speed to be faster than any extant lamnid sharks and their mean relative cruising speed to be slower, consistent with previous estimates.[52]
Its large size may have been due to climatic factors and the abundance of large prey items, and it may have also been influenced by the evolution of regional endothermy (mesothermy) which would have increased its metabolic rate and swimming speed. The otodontid sharks have been considered to have been ectotherms, so on that basis megalodon would have been ectothermic. However, the largest contemporary ectothermic sharks, such as the whale shark, are filter feeders, while lamnids are regional endotherms, implying some metabolic correlations with a predatory lifestyle. These considerations, as well as tooth oxygen isotopic data and the need for higher burst swimming speeds in macropredators of endothermic prey than ectothermy would allow, imply that otodontids, including megalodon, were probably regional endotherms.[54]
In 2020, Shimada and colleagues suggested large size was instead due to intrauterine cannibalism, where the larger fetus eats the smaller fetus, resulting in progressively larger and larger fetuses, requiring the mother to attain even greater size as well as caloric requirements which would have promoted endothermy. Males would have needed to keep up with female size in order to still effectively copulate (which probably involved latching onto the female with claspers, like modern cartilaginous fish).[55]
Maximum estimates
The first attempt to reconstruct the jaw of megalodon was made by Bashford Dean in 1909, displayed at the American Museum of Natural History. From the dimensions of this jaw reconstruction, it was hypothesized that megalodon could have approached 30 meters (98 ft) in length. Dean had overestimated the size of the cartilage on both jaws, causing it to be too tall.[56][57]
In 1973, John E. Randall, an ichthyologist, used the enamel height (the vertical distance of the blade from the base of the enamel portion of the tooth to its tip) to measure the length of the shark, yielding a maximum length of about 13 meters (43 ft).[58] However, tooth enamel height does not necessarily increase in proportion to the animal's total length.[29]:99
In 1994, marine biologists Patrick J. Schembri and Stephen Papson opined that O. megalodon may have approached a maximum of around 24 to 25 meters (79 to 82 ft) in total length.[59][60]
In 1996, shark researchers Michael D. Gottfried, Leonard Compagno, and S. Curtis Bowman proposed a linear relationship between the great white shark's total length and the height of the largest upper anterior tooth. The proposed relationship is: total length in meters = − (0.096) × [UA maximum height (mm)]-(0.22).[61][39] Using this tooth height regression equation, the authors estimated a total length of 15.9 meters (52 ft) based on a tooth 16.8 centimeters (6.6 in) tall, which the authors considered a conservative maximum estimate. They also compared the ratio between the tooth height and total length of large female great whites to the largest megalodon tooth. A 6-meter (20 ft) long female great white, which the authors considered the largest 'reasonably trustworthy' total length, produced an estimate of 16.8 meters (55 ft). However, based on the largest female great white reported, at 7.1 meters (23 ft), they estimated a maximum estimate of 20.2 meters (66 ft).[39]
In 2002, shark researcher Clifford Jeremiah proposed that total length was proportional to the root width of an upper anterior tooth. He claimed that for every 1 centimeter (0.39 in) of root width, there are approximately 1.4 meters (4.6 ft) of shark length. Jeremiah pointed out 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 tool for estimating jaw perimeter. The largest tooth in Jeremiah's possession had a root width of about 12 centimeters (4.7 in), which yielded 16.5 meters (54 ft) in total length.[30]:88
In 2002, paleontologist Kenshu Shimada of DePaul University proposed a linear relationship between tooth crown height and total length after conducting anatomical analysis of several specimens, allowing any sized tooth to be used. Shimada stated that the previously proposed methods were based on a less-reliable evaluation of the dental homology between megalodon and the great white shark, and that the growth rate between the crown and root is not isometric, which he considered in his model. Using this model, the upper anterior tooth possessed by Gottfried and colleagues corresponded to a total length of 15 meters (49 ft).[62] Among several specimens found in the Gatún Formation of Panama, one upper lateral tooth was used by other researchers to obtain a total length estimate of 17.9 meters (59 ft) using this method.[35][63]
In 2019, Shimada revisited the size of megalodon and discouraged using non-anterior teeth for estimations, noting that the exact position of isolated non-anterior teeth is difficult to identify. Shimada provided maximum total length estimates using the largest anterior teeth available in museums. The tooth with the tallest crown height known to Shimada, NSM PV-19896, produced a total length estimate of 14.2 meters (47 ft). The tooth with the tallest total height, FMNH PF 11306, was reported at 16.8 centimeters (6.6 in). However, Shimada remeasured the tooth and found it actually to measure 16.2 centimeters (6.4 in). Using the total height tooth regression equation proposed by Gottfried and colleagues produced an estimate of 15.3 meters (50 ft).[26][44]
In 2021, Victor J. Perez, Ronny M. Leder, and Teddy Badaut proposed a method of estimating total length of megalodon from the sum of the tooth crown widths. Using more complete megalodon dentitions, they reconstructed the dental formula and then made comparisons to living sharks. The researchers noted that the 2002 Shimada crown height equations produce wildly varying results for different teeth belonging to the same shark (range of error of ± 9 metres (30 ft)), casting doubt on some of the conclusions of previous studies using that method. Using the largest tooth available to the authors, GHC 6, with a crown width of 13.3 centimeters (5.2 in), they estimated a maximum body length of approximately 20 meters (66 ft), with a range of error of approximately ± 3.5 metres (11 ft).[44] This maximum length estimate was also supported by Cooper and his colleagues in 2022.[52]
There are anecdotal reports of teeth larger than those found in museum collections.[26] Gordon Hubbell from Gainesville, Florida, possesses an upper anterior megalodon tooth whose maximum height is 18.4 centimeters (7.25 in), one of the largest known tooth specimens from the shark.[64] In addition, a 2.7-by-3.4-meter (9 by 11 ft) megalodon jaw reconstruction developed by fossil hunter Vito Bertucci contains a tooth whose maximum height is reportedly over 18 centimeters (7 in).[65]
Teeth and bite force
![A sideview of the inside of a megalodon jaw reconstruction showing five rows of teeth. Each row is more horizontal than the last, with the last row essentially resting on the jaw.](/wiki/images/thumb/f/f9/Megalodon_teeth.jpg/250px-Megalodon_teeth.jpg)
The most common fossils of megalodon are its teeth. Diagnostic characteristics include a triangular shape, robust structure, large size, fine serrations, a lack of lateral denticles, and a visible V-shaped neck (where the root meets the crown).[29]:55[35] The tooth met the jaw at a steep angle, similar to the great white shark. The tooth was anchored by connective tissue fibers, and the roughness of the base may have added to mechanical strength.[66] The lingual side of the tooth, the part facing the tongue, was convex; and the labial side, the other side of the tooth, was slightly convex or flat. The anterior teeth were almost perpendicular to the jaw and symmetrical, whereas the posterior teeth were slanted and asymmetrical.[67]
Megalodon teeth can measure over 180 millimeters (7.1 in) in slant height (diagonal length) and are the largest of any known shark species,[30]:33 implying it was the largest of all macropredatory sharks.[39] In 1989, a nearly complete set of megalodon teeth was discovered in Saitama, Japan. Another nearly complete associated megalodon dentition was excavated from the Yorktown Formations in the United States, and served as the basis of a jaw reconstruction of megalodon at the National Museum of Natural History (USNM). Based on these discoveries, an artificial dental formula was put together for megalodon in 1996.[29]:55[68]
The dental formula of megalodon is: 2.1.7.43.0.8.4. As evident from the formula, megalodon had four kinds of teeth in its jaws: anterior, intermediate, lateral, and posterior. Megalodon's intermediate tooth technically appears to be an upper anterior and is termed as "A3" because it is fairly symmetrical and does not point mesially (side of the tooth toward the midline of the jaws where the left and right jaws meet). Megalodon had a very robust dentition,[29]:20–21 and had over 250 teeth in its jaws, spanning 5 rows.[30]:iv It is possible that large megalodon individuals had jaws spanning roughly 2 meters (6.6 ft) across.[30]:129 The teeth were also serrated, which would have improved efficiency in cutting through flesh or bone.[27][30]:1 The shark may have been able to open its mouth to a 75° angle, though a reconstruction at the USNM approximates a 100° angle.[39]
In 2008, a team of scientists led by S. Wroe conducted an experiment to determine the bite force of the great white shark, using a 2.5-meter (8.2 ft) long specimen, and then isometrically scaled the results for its maximum size and the conservative minimum and maximum body mass of megalodon. They placed the bite force of the latter between 108,514 to 182,201 newtons (24,395 to 40,960 lbf) in a posterior bite, compared to the 18,216 newtons (4,095 lbf) bite force for the largest confirmed great white shark, and 7,495 newtons (1,685 lbf) for the placoderm fish Dunkleosteus. In addition, Wroe and colleagues pointed out that sharks shake sideways while feeding, amplifying the force generated, which would probably have caused the total force experienced by prey to be higher than the estimate.[50][69]
In 2021, Antonio Ballell and Humberto Ferrón used Finite Element Analysis modeling to examine the stress distribution of three types of megalodon teeth and closely related mega-toothed species when exposed to anterior and lateral forces, the latter of which would be generated when a shark shakes its head to tear through flesh. The resulting simulations identified higher levels of stress in megalodon teeth under lateral force loads compared to its precursor species such as O. obliquus and O. angusteidens when tooth size was removed as a factor. This suggests that megalodon teeth were of a different functional significance than previously expected, challenging prior interpretations that megalodon's dental morphology was primarily driven by a dietary shift towards marine mammals. Instead, the authors proposed that it was a byproduct of an increase in body size caused by heterochronic selection.[70]
Internal anatomy
Megalodon is represented in the fossil record by teeth, vertebral centra, and coprolites.[39][71] As with all sharks, the skeleton of megalodon was formed of cartilage rather than bone; consequently most fossil specimens are poorly preserved.[72] To support its large dentition, the jaws of megalodon would have been more massive, stouter, and more strongly developed than those of the great white, which possesses a comparatively gracile dentition. Its chondrocranium, the cartilaginous skull, would have had a blockier and more robust appearance than that of the great white. Its fins were proportional to its larger size.[39]
Some fossil vertebrae have been found. The most notable example is a partially preserved vertebral column of a single specimen, excavated in the Antwerp Basin, Belgium, in 1926. It comprises 150 vertebral centra, with the centra ranging from 55 millimeters (2.2 in) to 155 millimeters (6 in) in diameter. The shark's vertebrae may have gotten much bigger, and scrutiny of the specimen revealed that it had a higher vertebral count than specimens of any known shark, possibly over 200 centra; only the great white approached it.[39] Another partially preserved vertebral column of a megalodon was excavated from the Gram Formation in Denmark in 1983, which comprises 20 vertebral centra, with the centra ranging from 100 millimeters (4 in) to 230 millimeters (9 in) in diameter.[66]
The coprolite remains of megalodon are spiral-shaped, indicating that the shark may have had a spiral valve, a corkscrew-shaped portion of the lower intestines, similar to extant lamniform sharks. Miocene coprolite remains were discovered in Beaufort County, South Carolina, with one measuring 14 cm (5.5 in).[71]
Gottfried and colleagues reconstructed the entire skeleton of megalodon, which was later put on display at the Calvert Marine Museum in the United States and the Iziko South African Museum.[39][31] This reconstruction is 11.3 meters (37 ft) long and represents a mature male,[39]:61 based on the ontogenetic changes a great white shark experiences over the course of its life.[39]:65
Paleobiology
Range and habitat
Megalodon had a cosmopolitan distribution;[21][63] its fossils have been excavated from many parts of the world, including Europe, Africa, the Americas, and Australia.[29]:67[73] It most commonly occurred in subtropical to temperate latitudes.[21][29]:78 It has been found at latitudes up to 55° N; its inferred tolerated temperature range was 1–24 °C (34–75 °F).[note 1] It arguably had the capacity to endure such low temperatures due to mesothermy, the physiological capability of large sharks to maintain a higher body temperature than the surrounding water by conserving metabolic heat.[21]
Megalodon inhabited a wide range of marine environments (i.e., shallow coastal waters, areas of coastal upwelling, swampy coastal lagoons, sandy littorals, and offshore deep water environments), and exhibited a transient lifestyle. Adult megalodon were not abundant in shallow water environments, and mostly inhabited offshore areas. Megalodon may have moved between coastal and oceanic waters, particularly in different stages of its life cycle.[30]:33[75]
Fossil remains show a trend for specimens to be larger on average in the Southern Hemisphere than in the Northern, with mean lengths of 11.6 and 9.6 meters (38 and 31 ft), respectively; and also larger in the Pacific than the Atlantic, with mean lengths of 10.9 and 9.5 meters (36 and 31 ft) respectively. They do not suggest any trend of changing body size with absolute latitude, or of change in size over time (although the Carcharocles lineage in general is thought to display a trend of increasing size over time). The overall modal length has been estimated at 10.5 meters (34 ft), with the length distribution skewed towards larger individuals, suggesting an ecological or competitive advantage for larger body size.[25]
Locations of fossils
Megalodon had a global distribution and fossils of the shark have been found in many places around the world, bordering all oceans of the Neogene.[76]
Epoch | Formation | State | Continent |
---|---|---|---|
Pliocene | Luanda Formation | ![]() |
Africa |
![]() |
Africa | ||
![]() |
Africa | ||
Castell'Arquato Formation | ![]() |
Europe | |
Arenas de Huelva Formation | ![]() |
Europe | |
Esbarrondadoiro Formation | ![]() |
Europe | |
Touril Complex Formation | ![]() |
Europe | |
Red Crag Formation | ![]() |
Europe | |
San Mateo Formation | ![]() |
North America | |
Towsley Formation | ![]() |
North America | |
Bone Valley Formation | ![]() |
North America | |
Tamiami Formation | ![]() |
North America | |
Yorktown Formation | ![]() |
North America | |
Highlands Formation | ![]() |
North America | |
Refugio Formation | ![]() |
North America | |
San Diego Formation | ![]() |
North America | |
Tirabuzon Formation | ![]() |
North America | |
Onzole Formation | ![]() |
South America | |
Paraguaná Formation | ![]() |
South America | |
Black Rock Sandstone | ![]() |
Oceania | |
Cameron Inlet Formation | ![]() |
Oceania | |
Grange Burn Formation | ![]() |
Oceania | |
Loxton Sand Formation | ![]() |
Oceania | |
Whaler's Bluff Formation | ![]() |
Oceania | |
Tangahoe Formation | ![]() |
Oceania | |
Miocene | |||
![]() |
Africa | ||
Madagascar Basin | ![]() |
Africa | |
![]() |
Africa | ||
Varswater Formation | ![]() |
Africa | |
Baripada Limestone | ![]() |
Asia | |
Arakida Formation | ![]() |
Asia | |
Bihoku Group | ![]() |
Asia | |
Fujina Formation | ![]() |
Asia | |
Hannoura Formation | ![]() |
Asia | |
Hongo Formation | ![]() |
Asia | |
Horimatsu Formation | ![]() |
Asia | |
Ichishi Formation | ![]() |
Asia | |
Kurahara Formation | ![]() |
Asia | |
Maenami Formation | ![]() |
Asia | |
Matsuyama Group | ![]() |
Asia | |
Sekinobana Formation | ![]() |
Asia | |
Suso Formation | ![]() |
Asia | |
Takakubo Formation | ![]() |
Asia | |
Tonokita Formation | ![]() |
Asia | |
Tsurushi Formation | ![]() |
Asia | |
Wajimazaki Formation | ![]() |
Asia | |
Yoshii Formation | ![]() |
Asia | |
![]() |
Asia | ||
Burgeschleinitz Formation | ![]() |
Europe | |
Melker Sand Formation | ![]() |
Europe | |
Rzehakia Formation | ![]() |
Europe | |
Weissenegg Formation | ![]() |
Europe | |
Antwerpen Sands Member | ![]() |
Europe | |
![]() |
Europe | ||
Hrušky Formation | ![]() |
Europe | |
Gram Formation | ![]() |
Europe | |
Aquitaine Basin | ![]() |
Europe | |
![]() |
Europe | ||
Libano Sandstone | ![]() |
Europe | |
Blue Clay Formation | ![]() |
Europe | |
Globigerina Limestone[77] | ![]() |
Europe | |
Aalten Member | ![]() |
Europe | |
Breda Formation | ![]() |
Europe | |
Korytnica Clays | ![]() |
Europe | |
Leitha Limestone | ![]() |
Europe | |
Esbarrondadoiro Formation | ![]() |
Europe | |
Filakovo Formation | ![]() |
Europe | |
Arjona Formation | ![]() |
Europe | |
Calcarenites of Sant Elm | ![]() |
Europe | |
![]() |
Europe | ||
Monterey Formation | ![]() |
North America | |
Puente Formation | ![]() |
North America | |
Purisima Formation | ![]() |
North America | |
San Mateo Formation | ![]() |
North America | |
Santa Margarita Formation | ![]() |
North America | |
Temblor Formation | ![]() |
North America | |
Topanga Formation | ![]() |
North America | |
Bone Valley Formation | ![]() |
North America | |
Calvert Formation | ![]() |
North America | |
Kirkwood Formation | ![]() |
North America | |
![]() |
North America | ||
Cojímar Formation | ![]() |
North America | |
Kendance Formation | ![]() |
North America | |
![]() |
North America | ||
Aymamón Limestone | ![]() |
North America | |
Almejas Formation | ![]() |
North America | |
Carrillo Puerto Formation | ![]() |
North America | |
Chagres Formation | ![]() |
North America | |
Chucunaque Formation | ![]() |
North America | |
Gatún Formation | ![]() |
North America | |
Paraná Formation | ![]() |
South America | |
Bahía Inglesa Formation | ![]() |
South America | |
Coquimbo Formation | ![]() |
South America | |
Castilletes Formation | ![]() |
South America | |
Miramar Formation | ![]() |
South America | |
Pisco Formation | ![]() |
South America | |
Camacho Formation | ![]() |
South America | |
Cantaure Formation | ![]() |
South America | |
Caujarao Formation | ![]() |
South America | |
Socorro Formation | ![]() |
South America | |
Urumaco Formation | ![]() |
South America | |
Batesford Limestone | ![]() |
Oceania | |
Black Rock Sandstone | ![]() |
Oceania | |
Gippsland Limestone | ![]() |
Oceania | |
Mannum Formation | ![]() |
Oceania | |
Morgan Limestone | ![]() |
Oceania | |
Port Campbell Limestone | ![]() |
Oceania | |
![]() |
Oceania | ||
![]() |
Oceania | ||
Duho Formation[78] | ![]() |
Asia | |
Seogwipo Formation[79] | ![]() |
Asia |
Prey relationships
![A square piece of fossil bone with some roughly parallel grooves across it.](/wiki/images/thumb/f/f4/Meg_bitten_cetacean_vertebra.jpg/250px-Meg_bitten_cetacean_vertebra.jpg)
Though sharks are generally opportunistic feeders, megalodon's great size, high-speed swimming capability, and powerful jaws, coupled with an impressive feeding apparatus, made it an apex predator capable of consuming a broad spectrum of animals. Otodus megalodon was probably one of the most powerful predators to have existed.[52] A study focusing on calcium isotopes of extinct and extant elasmobranch sharks and rays revealed that megalodon fed at a higher trophic level than the contemporaneous great white shark ("higher up" in the food chain.)[80]
Fossil evidence indicates that megalodon preyed upon many cetacean species, such as dolphins, small whales, cetotheres, squalodontids (shark toothed dolphins), sperm whales, bowhead whales, and rorquals.[56][81][82] In addition to this, they also targeted seals, sirenians, and sea turtles.[75] The shark was an opportunist and piscivorous, and it would have also gone after smaller fish and other sharks.[56] Many whale bones have been found with deep gashes most likely made by their teeth.[29]:75 Various excavations have revealed megalodon teeth lying close to the chewed remains of whales,[29]:75[31] and sometimes in direct association with them.[83]
The feeding ecology of megalodon appears to have varied with age and between sites, like the modern great white shark. It is plausible that the adult megalodon population off the coast of Peru targeted primarily cetothere whales 2.5 to 7 meters (8.2 to 23 ft) in length and other prey smaller than itself, rather than large whales in the same size class as themselves.[81] Meanwhile, juveniles likely had a diet that consisted more of fish.[35][84]
Competition
Megalodon faced a highly competitive environment.[85] Its position at the top of the food chain[86] probably had a significant impact on the structuring of marine communities.[85][87] Fossil evidence indicates a correlation between megalodon and the emergence and diversification of cetaceans and other marine mammals.[29]:78[85] Juvenile megalodon preferred habitats where small cetaceans were abundant, and adult megalodon preferred habitats where large cetaceans were abundant. Such preferences may have developed shortly after they appeared in the Oligocene.[29]:74–75
Megalodon were contemporaneous with whale-eating toothed whales (particularly macroraptorial sperm whales and squalodontidae), which were also probably among the era's apex predators, and provided competition.[85] Some attained gigantic sizes, such as Livyatan, estimated between 13.5 to 17.5 meters (44 to 57 ft). Fossilized teeth of an undetermined species of such physeteroids from Lee Creek Mine, North Carolina, indicate it had a maximum body length of 8 to 10 m (26 to 33 ft) and a maximum lifespan of about 25 years. This is very different from similarly sized modern killer whales that live to 65 years, suggesting that unlike the latter, which are apex predators, these physeteroids were subject to predation from larger species such as megalodon or Livyatan.[88] By the Late Miocene, around 11 Mya, macroraptorials experienced a significant decline in abundance and diversity. Other species may have filled this niche in the Pliocene,[85][89] such as the fossil killer whale Orcinus citoniensis which may have been a pack predator and targeted prey larger than itself,[31][90][91][92] but this inference is disputed,[23] and it was probably a generalist predator rather than a marine mammal specialist.[93]
Megalodon may have subjected contemporaneous white sharks to competitive exclusion, as the fossil records indicate that other shark species avoided regions it inhabited by mainly keeping to the colder waters of the time.[94][29]:77 In areas where their ranges seemed to have overlapped, such as in Pliocene Baja California, it is possible that megalodon and the great white shark occupied the area at different times of the year while following different migratory prey.[29]:77[95] Megalodon probably also had a tendency for cannibalism, much like contemporary sharks.[96]
Feeding strategies
![A painting of a megalodon about to eat two small whales. The mouth is open, and two rows of teeth are visible only on the bottom jaw. There are two other sharks in the background.](/wiki/images/thumb/9/9e/VMNH_megalodon.jpg/250px-VMNH_megalodon.jpg)
Sharks often employ complex hunting strategies to engage large prey animals. Great white shark hunting strategies may be similar to how megalodon hunted its large prey.[97] Megalodon bite marks on whale fossils suggest that it employed different hunting strategies against large prey than the great white shark.[56]
One particular specimen–the remains of a 9-meter (30 ft) long undescribed Miocene baleen whale–provided the first opportunity to quantitatively analyze its attack behavior. Unlike great whites which target the underbelly of their prey, megalodon probably targeted the heart and lungs, with their thick teeth adapted for biting through tough bone, as indicated by bite marks inflicted to the rib cage and other tough bony areas on whale remains.[56] Furthermore, attack patterns could differ for prey of different sizes. Fossil remains of some small cetaceans, for example cetotheres, suggest that they were rammed with great force from below before being killed and eaten, based on compression fractures.[97]
There is also evidence that a possible separate hunting strategy existed for attacking raptorial sperm whales; a tooth belonging to an undetermined 4 m (13 ft) physeteroid closely resembling those of Acrophyseter discovered in the Nutrien Aurora Phosphate Mine in North Carolina suggests that a megalodon or O. chubutensis may have aimed for the head of the sperm whale in order to inflict a fatal bite, the resulting attack leaving distinctive bite marks on the tooth. While scavenging behavior cannot be ruled out as a possibility, the placement of the bite marks is more consistent with predatory attacks than feeding by scavenging, as the jaw is not a particularly nutritious area to for a shark feed or focus on. The fact that the bite marks were found on the tooth's roots further suggest that the shark broke the whale's jaw during the bite, suggesting the bite was extremely powerful. The fossil is also notable as it stands as the first known instance of an antagonistic interaction between a sperm whale and an otodontid shark recorded in the fossil record.[98]
During the Pliocene, larger cetaceans appeared.[99] Megalodon apparently further refined its hunting strategies to cope with these large whales. Numerous fossilized flipper bones and tail vertebrae of large whales from the Pliocene have been found with megalodon bite marks, which suggests that megalodon would immobilize a large whale before killing and feeding on it.[50][56]
Growth and reproduction
In 2010, Ehret estimated that megalodon had a fast growth rate nearly two times that of the extant great white shark. He also estimated that the slowing or cessation of somatic growth in megalodon occurred around 25 years of age, suggesting that this species had an extremely delayed sexual maturity.[100] In 2021, Shimada and colleagues calculated the growth rate of an approximately 9.2 m (30 ft) individual based on the Belgian vertebrate column specimen that presumably contains annual growth rings on three of its vertebrae. They estimated the individual died at 46 years of age, with a growth rate of 16 cm (6.3 in) per year, and a length of 2 m (6 ft 7 in) at birth. For a 15 m (49 ft) individual – which they considered to have been the maximum size attainable – this would equate to a lifespan of 88 to 100 years.[101] However, Cooper and his colleagues in 2022 estimated the length of this 46 year old individual at nearly 16 m (52 ft) based on the 3D reconstruction which resulted in the complete vertebral column to be 11.1 m (36 ft) long; the researchers claimed that this size estimate difference occurred due to the fact that Shimada and his colleagues extrapolated its size only based on the vertebral centra.[52]
Megalodon, like contemporaneous sharks, made use of nursery areas to birth their young in, specifically warm-water coastal environments with large amounts of food and protection from predators.[35] Nursery sites were identified in the Gatún Formation of Panama, the Calvert Formation of Maryland, Banco de Concepción in the Canary Islands,[102] and the Bone Valley Formation of Florida. Given that all extant lamniform sharks give birth to live young, this is believed to have been true of megalodon also.[103] Infant megalodons were around 3.5 meters (11 ft) at their smallest,[39]:61 and the pups were vulnerable to predation by other shark species, such as the great hammerhead shark (Sphyrna mokarran) and the snaggletooth shark (Hemipristis serra).[35] Their dietary preferences display an ontogenetic shift:[39]:65 Young megalodon commonly preyed on fish,[35] sea turtles,[75] dugongs,[30]:129 and small cetaceans; mature megalodon moved to off-shore areas and consumed large cetaceans.[29]:74–75
An exceptional case in the fossil record suggests that juvenile megalodon may have occasionally attacked much larger balaenopterid whales. Three tooth marks apparently from a 4-to-7-meter (13 to 23 ft) long Pliocene shark were found on a rib from an ancestral blue or humpback whale that showed evidence of subsequent healing, which is suspected to have been inflicted by a juvenile megalodon.[104][105]
Extinction
Climate change
The Earth experienced a number of changes during the time period megalodon existed which affected marine life. A cooling trend starting in the Oligocene 35 Mya ultimately led to glaciation at the poles. Geological events changed currents and precipitation; among these were the closure of the Central American Seaway and changes in the Tethys Ocean, contributing to the cooling of the oceans. The stalling of the Gulf Stream prevented nutrient-rich water from reaching major marine ecosystems, which may have negatively affected its food sources. The largest fluctuation of sea levels in the Cenozoic era occurred in the Plio-Pleistocene, between around 5 million to 12 thousand years ago, due to the expansion of glaciers at the poles, which negatively impacted coastal environments, and may have contributed to its extinction along with those of several other marine megafaunal species.[106] These oceanographic changes, in particular the sea level drops, may have restricted many of the suitable shallow warm-water nursery sites for megalodon, hindering reproduction.[107] Nursery areas are pivotal for the survival of many shark species, in part because they protect juveniles from predation.[108][35]
As its range did not apparently extend into colder waters, megalodon may not have been able to retain a significant amount of metabolic heat, so its range was restricted to shrinking warmer waters.[107][82][109] Fossil evidence confirms the absence of megalodon in regions around the world where water temperatures had significantly declined during the Pliocene.[29]:77 However, an analysis of the distribution of megalodon over time suggests that temperature change did not play a direct role in its extinction. Its distribution during the Miocene and Pliocene did not correlate with warming and cooling trends; while abundance and distribution declined during the Pliocene, megalodon did show a capacity to inhabit colder latitudes. It was found in locations with a mean temperature ranging from 12 to 27 °C (54 to 81 °F), with a total range of 1 to 33 °C (34 to 91 °F), indicating that the global extent of suitable habitat should not have been greatly affected by the temperature changes that occurred.[21] This is consistent with evidence that it was a mesotherm.[54]
Changing ecosystem
![A whale skull behind a glass wall](/wiki/images/thumb/9/97/Piscobalaena_nana.jpg/250px-Piscobalaena_nana.jpg)
Marine mammals attained their greatest diversity during the Miocene,[29]:71 such as with baleen whales with over 20 recognized Miocene genera in comparison to only six extant genera.[111] Such diversity presented an ideal setting to support a super-predator such as megalodon.[29]:75 By the end of the Miocene, many species of mysticetes had gone extinct;[85] surviving species may have been faster swimmers and thus more elusive prey.[30]:46 Furthermore, after the closure of the Central American Seaway, tropical whales decreased in diversity and abundance.[109] The extinction of megalodon correlates with the decline of many small mysticete lineages, and it is possible that it was quite dependent on them as a food source.[81] Additionally, a marine megafauna extinction during the Pliocene was discovered to have eliminated 36% of all large marine species including 55% of marine mammals, 35% of seabirds, 9% of sharks, and 43% of sea turtles. The extinction was selective for endotherms and mesotherms relative to poikilotherms, implying causation by a decreased food supply[106] and thus consistent with megalodon being mesothermic.[54] Megalodon may have been too large to sustain itself on the declining marine food resources.[107] The cooling of the oceans during the Pliocene might have restricted the access of megalodon to the polar regions, depriving it of the large whales which had migrated there.[109]
Competition from large odontocetes, such as macropredatory sperm whales which appeared in the Miocene, and a member of genus Orcinus (i.e., Orcinus citoniensis) in the Pliocene,[85][89] is assumed to have contributed to the decline and extinction of megalodon.[21][30]:46–47[107][112] But this assumption is disputed:[23] The Orcininae emerged in Mid-Pliocene with O. citoniensis reported from the Pliocene of Italy,[89][113] and similar forms reported from the Pliocene of England and South Africa,[89] indicating the capacity of these dolphins to cope with increasingly prevalent cold water temperatures in high latitudes.[89] These dolphins were assumed to have been macrophagous in some studies,[21] but on closer inspection, these dolphins are not found to be macrophagous and fed on small fishes instead.[113] On the other hand, gigantic macropredatory sperm whales such as Livyatan-like forms are last reported from Australia and South Africa circa 5 million years ago.[114][115][116] Others, such as Hoplocetus and Scaldicetus also occupied a niche similar to that of modern killer whales but the last of these forms disappeared during the Pliocene.[117][113] Members of genus Orcinus became large and macrophagous in the Pleistocene.[113]
Paleontologist Robert Boessenecker and his colleagues rechecked the fossil record of megalodon for carbon dating errors and concluded that it disappeared circa 3.5 million years ago.[23] Boessenecker and his colleagues further suggest that megalodon suffered range fragmentation due to climatic shifts,[23] and competition with white sharks might have contributed to its decline and extinction.[23] Competition with white sharks is assumed to be a factor in other studies as well,[118][21][112] but this hypothesis warrants further testing.[119] Multiple compounding environmental and ecological factors including climate change and thermal limitations, collapse of prey populations and resource competition with white sharks are believed to have contributed to decline and extinction of megalodon.[112]
The extinction of megalodon set the stage for further changes in marine communities. The average body size of baleen whales increased significantly after its disappearance, although possibly due to other, climate-related, causes.[120] Conversely the increase in baleen whale size may have contributed to the extinction of megalodon, as they may have preferred to go after smaller whales; bite marks on large whale species may have come from scavenging sharks. Megalodon may have simply become coextinct with smaller whale species, such as Piscobalaena nana.[110] The extinction of megalodon had a positive impact on other apex predators of the time, such as the great white shark, in some cases spreading to regions where megalodon became absent.[21][118][121]
In popular culture
![Painting of a three-masted ship sailing in the ocean](/wiki/images/thumb/5/5a/HMS_challenger_William_Frederick_Mitchell.jpg/250px-HMS_challenger_William_Frederick_Mitchell.jpg)
Megalodon has been portrayed in many works of fiction, including films and novels, and continues to be a popular subject for fiction involving sea monsters.[122] Reports of supposedly fresh megalodon teeth, such as those found by HMS Challenger in 1873 which were dated in 1959 by the zoologist Wladimir Tschernezky to be around 11,000 to 24,000 years old, helped popularise claims of recent megalodon survival amongst cryptozoologists.[123] These claims have been discredited, and are probably teeth that were well-preserved by a thick mineral-crust precipitate of manganese dioxide, and so had a lower decomposition rate and retained a white color during fossilization. Fossil megalodon teeth can vary in color from off-white to dark browns, greys, and blues, and some fossil teeth may have been redeposited into a younger stratum. The claims that megalodon could remain elusive in the depths, similar to the megamouth shark which was discovered in 1976, are unlikely as the shark lived in warm coastal waters and probably could not survive in the cold and nutrient-poor deep sea environment.[124][125]
Contemporary fiction about megalodon surviving into modern times was pioneered by the 1997 novel Meg: A Novel of Deep Terror by Steve Alten and its subsequent sequels. Megalodon subsequently began to feature in films, such as the 2003 direct to video Shark Attack 3: Megalodon, and later The Meg, a 2018 film based on the 1997 book which grossed over $500 million at the box office.[123][126]
Animal Planet's pseudo-documentary Mermaids included an encounter 1.6 mya between a pod of mermaids and a megalodon.[127] Later, in August 2013, the Discovery Channel opened its annual Shark Week series with another film for television, Megalodon: The Monster Shark Lives,[128] a controversial docufiction about the creature that presented alleged evidence in order to suggest that megalodons still lived. This program received criticism for being completely fictional and for inadequately disclosing its fictional nature; for example, all of the supposed scientists depicted were paid actors, and there was no disclosure in the documentary itself that it was fictional. In a poll by Discovery, 73% of the viewers of the documentary thought that megalodon was not extinct. In 2014, Discovery re-aired The Monster Shark Lives, along with a new one-hour program, Megalodon: The New Evidence, and an additional fictionalized program entitled Shark of Darkness: Wrath of Submarine, resulting in further backlash from media sources and the scientific community.[56][129][130][131] Despite the criticism from scientists, Megalodon: The Monster Shark Lives was a huge ratings success, gaining 4.8 million viewers, the most for any Shark Week episode up to that point.[132]
Megalodon teeth are the state fossil of North Carolina.[133]
See also
- List of prehistoric cartilaginous fish
- Prehistoric fish
- Largest prehistoric organisms
Notes
- ↑ Carbonated bioapatite from a megalodon tooth (of unknown source location) dated to 5.75 ± 0.9 Ma in age has been analyzed for isotope ratios of oxygen (18O/16O) and carbon (13C/12C), using a carbonate clumped-isotope thermometer methodology to yield an estimate of the ambient temperature in that individual's environment of 19 ± 4 °C.[74]
References
- ↑ 1.0 1.1 1.2 1.3 Agassiz, L. (1843) (in French). Recherches sur les poissons fossiles. 3. doi:10.5962/bhl.title.4275. https://www.biodiversitylibrary.org/bibliography/4275.
- ↑ 2.0 2.1 2.2 2.3 Brignon, A. (2021). "Historical and nomenclatural remarks on some megatoothed shark teeth (Elasmobranchii, Otodontidae) from the Cenozoic of New Jersey (U.S.A.)". Rivista Italiana di Paleontologia e Stratigrafia 127 (3): 595–625. doi:10.13130/2039-4942/16440. https://www.researchgate.net/publication/354765218.
- ↑ "Otodus (Megaselachus) megalodon (Agassiz, 1837)". http://shark-references.com/species/view/Otodus-Megaselachus-megalodon.
- ↑ Eastman, C. R. (1904). Maryland Geological Survey. 2. Baltimore, Maryland: Johns Hopkins University. p. 82. https://books.google.com/books?id=8XNGAAAAYAAJ&pg=PA82.
- ↑ 5.0 5.1 5.2 Cappetta, H. (1987). "Mesozoic and Cenozoic Elasmobranchii". Handbook of Paleoichthyology. 3B. München, Germany: Friedrich Pfeil. ISBN 978-3-89937-046-1. OCLC 829906016.
- ↑ Hay, O. P. (1901). "Bibliography and Catalogue of the Fossil Vertebrata of North America". Bulletin of the United States Geological Society (179): 308. https://books.google.com/books?id=ZmqWKhTAeqYC&pg=PA308.
- ↑ 7.0 7.1 7.2 7.3 7.4 Shimada, K.; Chandler, R. E.; Lam, O. L. T.; Tanaka, T.; Ward, D. J. (2016). "A new elusive otodontid shark (Lamniformes: Otodontidae) from the lower Miocene, and comments on the taxonomy of otodontid genera, including the 'megatoothed' clade". Historical Biology 29 (5): 1–11. doi:10.1080/08912963.2016.1236795.
- ↑ 8.0 8.1 Lowery, D.; Godfrey, S.J.; Eshelman, R. (2011). "Integrated geology, paleontology, and archaeology: Native American use of fossil shark teeth in the Chesapeake Bay region". Archaeology of Eastern North America 9: 93–108. https://www.jstor.org/stable/23265116.
- ↑ 9.0 9.1 Farrell, A.D. (2021). A Use-Wear and Functional Analysis of Precontact Shark Teeth Assemblages from Florida (MS). Florida State University.
- ↑ Jacobs, J.. "Hopewell Culture National Historical Park Sharks Teeth HOCU - 2832 and 4222". https://www.nps.gov/articles/000/inside-the-collections-hocu-2832-and-4222.htm.
- ↑ 11.0 11.1 Duffin, C.J. (2017). "Fossil Sharks' Teeth as Alexipharmics". in Philip Wexler. Toxicology of the Middle Ages and Renaissance. pp. 125–133. doi:10.1016/B978-0-12-809554-6.00012-3. ISBN 9780128095546.
- ↑ 12.0 12.1 Forli, M.; Guerrini, A. (2022). "Quaestio de Fossilibus: Glossopetres, Snake Tongues and Ceraunids". The History of Fossils over Centuries. pp. 41–83. doi:10.1007/978-3-031-04687-2_6. ISBN 978-3-031-04686-5.
- ↑ 13.0 13.1 Bressan, D. (14 January 2016). "How the Dissection Of A Shark's Head Revealed The True Nature Of Fossils". https://www.forbes.com/sites/davidbressan/2016/01/14/how-the-dissection-of-a-sharks-head-revealed-the-true-nature-of-fossils/?sh=428c61d4e8c0.
- ↑ "Nicholas Steno". https://ucmp.berkeley.edu/history/steno.html.
- ↑ Davidson, J.P. (2000). "Historical Point of View: Fish Tales: Attributing the First Illustration of a Fossil Shark's Tooth to Richard Verstegan (1605) and Nicolas Steno (1667)". Proceedings of the Academy of Natural Sciences of Philadelphia 150: 329–344. https://www.jstor.org/stable/4065077.
- ↑ μεγάλος. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project
- ↑ ὀδών. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project
- ↑ 18.0 18.1 Woodward, A.S. (1899). Catalogue of the fossil fishes in the British Museum (Natural History), Part I. Containing the Elasmobranchii. British Museum (Natural History). pp. 415–420. doi:10.5962/bhl.title.61854. https://www.biodiversitylibrary.org/item/211828#page/461/mode/1up.
- ↑ Yabe, H.; Goto, M.; Kaneko, N. (2004). "Age of Carcharocles megalodon (Lamniformes: Otodontidae): A review of the stratigraphic records". The Palaeontological Society of Japan 75: 7–15.
- ↑ 20.0 20.1 20.2 Gottfried, M. D.; Fordyce, R. E. (2001). "An associated specimen of Carcharodon angustidens (Chondrichthyes, Lamnidae) from the Late Oligocene of New Zealand, with comments on Carcharodon interrelationships". Journal of Vertebrate Paleontology 21 (4): 730–739. doi:10.1671/0272-4634(2001)021[0730:AASOCA2.0.CO;2]. http://www.thefossilforum.com/applications/core/interface/file/attachment.php?id=270846. Retrieved 6 November 2017.
- ↑ 21.00 21.01 21.02 21.03 21.04 21.05 21.06 21.07 21.08 21.09 21.10 21.11 Pimiento, C.; MacFadden, B. J.; Clements, C. F.; Varela, S.; Jaramillo, C.; Velez-Juarbe, J.; Silliman, B. R. (2016). "Geographical distribution patterns of Carcharocles megalodon over time reveal clues about extinction mechanisms". Journal of Biogeography 43 (8): 1645–1655. doi:10.1111/jbi.12754. Bibcode: 2016JBiog..43.1645P.
- ↑ 22.0 22.1 22.2 Pimiento, C.; Clements, C. F. (2014). "When Did Carcharocles megalodon Become Extinct? A New Analysis of the Fossil Record". PLOS ONE 9 (10): e111086. doi:10.1371/journal.pone.0111086. PMID 25338197. Bibcode: 2014PLoSO...9k1086P.
- ↑ 23.0 23.1 23.2 23.3 23.4 23.5 Boessenecker, R. W.; Ehret, D. J.; Long, D. J.; Churchill, M.; Martin, E.; Boessenecker, S. J. (2019). "The Early Pliocene extinction of the mega-toothed shark Otodus megalodon: a view from the eastern North Pacific". PeerJ 7: e6088. doi:10.7717/peerj.6088. PMID 30783558.
- ↑ Giant 'megalodon' shark extinct earlier than previously thought. Science Daily. 13 February 2019.
- ↑ 25.0 25.1 25.2 25.3 Pimiento, C.; Balk, M. A. (2015). "Body-size trends of the extinct giant shark Carcharocles megalodon: a deep-time perspective on marine apex predators". Paleobiology 41 (3): 479–490. doi:10.1017/pab.2015.16. PMID 26321775. Bibcode: 2015Pbio...41..479P.
- ↑ 26.0 26.1 26.2 26.3 26.4 Shimada, Kenshu (2019). "The size of the megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), revisited". Historical Biology 33 (7): 1–8. doi:10.1080/08912963.2019.1666840. ISSN 0891-2963.
- ↑ 27.0 27.1 27.2 27.3 Nyberg, K. G.; Ciampaglio C. N.; Wray G. A. (2006). "Tracing the ancestry of the great white shark, Carcharodon carcharias, using morphometric analyses of fossil teeth". Journal of Vertebrate Paleontology 26 (4): 806–814. doi:10.1671/0272-4634(2006)26[806:TTAOTG2.0.CO;2].
- ↑ 28.0 28.1 28.2 28.3 Ehret D. J.; Hubbell G.; Macfadden B. J. (2009). "Exceptional preservation of the white shark Carcharodon from the early Pliocene of Peru". Journal of Vertebrate Paleontology 29 (1): 1–13. doi:10.1671/039.029.0113.
- ↑ 29.00 29.01 29.02 29.03 29.04 29.05 29.06 29.07 29.08 29.09 29.10 29.11 29.12 29.13 29.14 29.15 29.16 29.17 Klimley, Peter; Ainley, David (1996). "Evolution". Great White Sharks: The Biology of Carcharodon carcharias. San Diego, California: Academic Press. ISBN 978-0-12-415031-7. OCLC 212425118. https://books.google.com/books?id=2My8M5tL-KIC&pg=PA9.
- ↑ 30.00 30.01 30.02 30.03 30.04 30.05 30.06 30.07 30.08 30.09 30.10 30.11 30.12 30.13 30.14 Renz, Mark (2002). Megalodon: Hunting the Hunter. Lehigh Acres, Florida: PaleoPress. pp. 1–159. ISBN 978-0-9719477-0-2. OCLC 52125833. https://books.google.com/books?id=cMRe5GmDXmUC.
- ↑ 31.0 31.1 31.2 31.3 31.4 Andres, Lutz (2002). "C. megalodon — Megatooth Shark, Carcharodon versus Carcharocles". fossilguy.com. http://www.fossilguy.com/topics/megshark/megshark.htm.
- ↑ 32.0 32.1 Perez, V. J.; Godfrey, S. J.; Kent, B. W.; Weems, R. E.; Nance, J. R. (2019). "The transition between Carcharocles chubutensis and Carcharocles megalodon (Otodontidae, Chondrichthyes): lateral cusplet loss through time". Journal of Vertebrate Paleontology 38 (6): e1546732. doi:10.1080/02724634.2018.1546732.
- ↑ Siverson, M.; Lindgren, J.; Newbrey, M.G.; Cederström, P.; Cook, T.D. (2013). "Late Cretaceous (Cenomanian-Campanian) mid-palaeolatitude sharks of Cretalamna appendiculata type". Acta Palaeontologica Polonica: 2. doi:10.4202/app.2012.0137. http://www.app.pan.pl/archive/published/app58/app20120137_acc.pdf.
- ↑ Benton, M. J.; Pearson, P. N. (2001). "Speciation in the fossil record". Trends in Ecology and Evolution 16 (7): 405–411. doi:10.1016/s0169-5347(01)02149-8. PMID 11403874.
- ↑ 35.0 35.1 35.2 35.3 35.4 35.5 35.6 35.7 Pimiento, Catalina; Ehret, Dana J.; MacFadden, Bruce J.; Hubbell, Gordon (2010). Stepanova, Anna. ed. "Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama". PLOS ONE 5 (5): e10552. doi:10.1371/journal.pone.0010552. PMID 20479893. Bibcode: 2010PLoSO...510552P.
- ↑ Siversson, M.; Lindgren, J.; Newbrey, M.G.; Cederström, P.; Cook, T.D. (2015). "Cenomanian–Campanian (Late Cretaceous) mid-palaeolatitude sharks of Cretalamna appendiculata type". Acta Palaeontologica Polonica 60 (2): 339–384. doi:10.4202/app.2012.0137. http://www.app.pan.pl/archive/published/app60/app20120137.pdf.
- ↑ Vivian, G. (2013). "Research debunks Great White lineage". http://www.australasianscience.com.au/news/august-2013/research-debunks-great-white-lineage.html.
- ↑ "Palaeontological detective work unravels evolution of megatooth sharks". 2013. http://museum.wa.gov.au/about/latest-news/palaeontological-detective-work-unravels-evolution-megatooth-sharks.
- ↑ 39.00 39.01 39.02 39.03 39.04 39.05 39.06 39.07 39.08 39.09 39.10 39.11 39.12 39.13 39.14 39.15 39.16 39.17 Gottfried, MD; Compagno, LJV; Bowman, SC (1996). "Size and skeletal anatomy of the giant megatooth shark Carcharodon megalodon". in Klimley; Ainley. Great White Sharks: The Biology of Carcharodon carcharias. San Diego, California: Academic Press. pp. 55–89. ISBN 978-0124150317. https://books.google.com/books?id=2My8M5tL-KIC&q=Gottfried.
- ↑ Shimada, Kenshu; Yamaoka, Yuta; Kurihara, Yukito; Takakuwa, Yuji; Maisch, Harry M.; Becker, Martin A.; Eagle, Robert A.; Griffiths, Michael L. (23 June 2023). "Tessellated calcified cartilage and placoid scales of the Neogene megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), offer new insights into its biology and the evolution of regional endothermy and gigantism in the otodontid clade" (in en). Historical Biology: 1–15. doi:10.1080/08912963.2023.2211597. ISSN 0891-2963.
- ↑ Renz, Mark (2002). Megalodon: Hunting the Hunter. Lehigh Acres, Florida: PaleoPress. pp. 1–159. ISBN 978-0-9719477-0-2. OCLC 52125833. https://books.google.com/books?id=cMRe5GmDXmUC.
- ↑ Portell, Roger; Hubell, Gordon; Donovan, Stephen; Green, Jeremy; Harper, David; Pickerill, Ron (2008). "Miocene sharks in the Kendeace and Grand Bay formations of Carriacou, The Grenadines, Lesser Antilles". Caribbean Journal of Science 44 (3): 279–286. doi:10.18475/cjos.v44i3.a2. http://caribjsci.org/Dec08/44_279-286.pdf.
- ↑ Pimiento, Catalina; Ehret, Dana J.; MacFadden, Bruce J.; Hubbell, Gordon (2010). Stepanova, Anna. ed. "Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama". PLOS ONE 5 (5): e10552. doi:10.1371/journal.pone.0010552. PMID 20479893. Bibcode: 2010PLoSO...510552P.
- ↑ 44.0 44.1 44.2 44.3 Perez, Victor; Leder, Ronny; Badaut, Teddy (2021). "Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions". Palaeontologia Electronica 24 (1): 1–28. doi:10.26879/1140. https://palaeo-electronica.org/content/2021/3284-estimating-lamniform-body-size.
- ↑ Pimiento, C.; MacFadden, B. J.; Clements, C. F.; Varela, S.; Jaramillo, C.; Velez-Juarbe, J.; Silliman, B. R. (2016). "Geographical distribution patterns of Carcharocles megalodon over time reveal clues about extinction mechanisms". Journal of Biogeography 43 (8): 1645–1655. doi:10.1111/jbi.12754. Bibcode: 2016JBiog..43.1645P.
- ↑ 46.0 46.1 McClain, Craig R.; Balk, Meghan A.; Benfield, Mark C.; Branch, Trevor A.; Chen, Catherine; Cosgrove, James; Dove, Alistair D.M.; Gaskins, Lindsay C. et al. (13 January 2015). "Sizing ocean giants: patterns of intraspecific size variation in marine megafauna" (in en). PeerJ 3: e715. doi:10.7717/peerj.715. ISSN 2167-8359. PMID 25649000.
- ↑ I., Castro, Jose (2011). Sharks of North America.. Oxford University Press, USA. ISBN 978-0-19-978097-6. OCLC 958576172. http://worldcat.org/oclc/958576172.
- ↑ Borrell, Asunción; Aguilar, Alex; Gazo, Manel; Kumarran, R. P.; Cardona, Luis (1 December 2011). "Stable isotope profiles in whale shark (Rhincodon typus) suggest segregation and dissimilarities in the diet depending on sex and size" (in en). Environmental Biology of Fishes 92 (4): 559–567. doi:10.1007/s10641-011-9879-y. ISSN 1573-5133. Bibcode: 2011EnvBF..92..559B. https://doi.org/10.1007/s10641-011-9879-y.
- ↑ 49.0 49.1 Prothero, Donald R. (25 August 2015). "09. Mega-Jaws: The Largest Fish. Carcharocles" (in en). The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution. New York Chichester, West Sussex: Columbia University Press. pp. 96–110. doi:10.7312/prot17190-010. ISBN 978-0-231-53942-5.
- ↑ 50.0 50.1 50.2 Wroe, S.; Huber, D. R.; Lowry, M.; McHenry, C.; Moreno, K.; Clausen, P.; Ferrara, T. L.; Cunningham, E. et al. (2008). "Three-dimensional computer analysis of white shark jaw mechanics: how hard can a great white bite?". Journal of Zoology 276 (4): 336–342. doi:10.1111/j.1469-7998.2008.00494.x. http://www.bio-nica.info/Biblioteca/Wroe2008GreatWhiteSharkBiteForce.pdf.
- ↑ Cooper, J. A.; Pimiento, C.; Ferrón, H. G.; Benton, M. J. (2020). "Body dimensions of the extinct giant shark Otodus megalodon: a 2D reconstruction". Scientific Reports 10 (14596): 14596. doi:10.1038/s41598-020-71387-y. PMID 32883981. Bibcode: 2020NatSR..1014596C.
- ↑ 52.0 52.1 52.2 52.3 52.4 Cooper, J.A.; Hutchinson, J.R.; Bernvi, D.C.; Cliff, G.; Wilson, R.P.; Dicken, M.L.; Menzel, J.; Wroe, S. et al. (2022). "The extinct shark Otodus megalodon was a transoceanic superpredator: Inferences from 3D modeling". Science Advances 8 (33): eabm9424. doi:10.1126/sciadv.abm9424. ISSN 2375-2548. PMID 35977007. Bibcode: 2022SciA....8M9424C.
- ↑ Jacoby, D. M. P.; Siriwat, P.; Freeman, R.; Carbone, C. (2015). "Is the scaling of swim speed in sharks driven by metabolism?". Biology Letters 12 (10): 20150781. doi:10.1098/rsbl.2015.0781. PMID 26631246.
- ↑ 54.0 54.1 54.2 Ferrón, H. G. (2017). "Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks". PLOS ONE 12 (9): e0185185. doi:10.1371/journal.pone.0185185. PMID 28938002. Bibcode: 2017PLoSO..1285185F.
- ↑ Shimada, K.; Becker, M. A.; Griffiths, M. L. (2020). "Body, jaw, and dentition lengths of macrophagous lamniform sharks, and body size evolution in Lamniformes with special reference to 'off-the-scale' gigantism of the megatooth shark, Otodus megalodon". Historical Biology 33 (11): 1–17. doi:10.1080/08912963.2020.1812598.
- ↑ 56.0 56.1 56.2 56.3 56.4 56.5 56.6 Prothero, D. R. (2015). "Mega-Jaws". The Story of Life in 25 Fossils. New York, New York: Columbia University Press. pp. 96–110. ISBN 978-0-231-17190-8. OCLC 897505111. https://books.google.com/books?id=QjkjBQAAQBAJ&pg=PA96.
- ↑ Helfman, G.; Burgess, G. H. (2014). Sharks: The Animal Answer Guide. Baltimore, Maryland: Johns Hopkins University Press. p. 19. ISBN 978-1-4214-1310-5. OCLC 903293986. https://books.google.com/books?id=miZ8AwAAQBAJ&pg=PA19.
- ↑ Randall, John E. (1973). "Size of the Great White Shark (Carcharodon)". Science Magazine 181 (4095): 169–170. doi:10.1126/science.181.4095.169. PMID 17746627. Bibcode: 1973Sci...181..169R.
- ↑ Schembri, Patrick (1994). "Malta's Natural Heritage". Natural Heritage. In: 105–124. https://www.researchgate.net/publication/242261710.
- ↑ Papson, Stephen (1992). "Copyright: Cross the Fin Line of Terror". Journal of American Culture 15 (4): 67–81. doi:10.1111/j.1542-734X.1992.1504_67.x.
- ↑ Gottfried, M. D.; Fordyce, R. E. (2001). "An associated specimen of Carcharodon angustidens (Chondrichthyes, Lamnidae) from the Late Oligocene of New Zealand, with comments on Carcharodon interrelationships". Journal of Vertebrate Paleontology 21 (4): 730–739. doi:10.1671/0272-4634(2001)021[0730:AASOCA2.0.CO;2]. http://www.thefossilforum.com/applications/core/interface/file/attachment.php?id=270846. Retrieved 6 November 2017.
- ↑ Shimada, Kenshu (2002). "The relationship between the tooth size and total body length in the white shark, Carcharodon carcharias (Lamniformes: Lamnidae)". Journal of Fossil Research 35 (2): 28–33.
- ↑ 63.0 63.1 Pimiento, Catalina; Gerardo González-Barba; Dana J. Ehret; Austin J. W. Hendy; Bruce J. MacFadden; Carlos Jaramillo (2013). "Sharks and Rays (Chondrichthyes, Elasmobranchii) from the Late Miocene Gatun Formation of Panama". Journal of Paleontology 87 (5): 755–774. doi:10.1666/12-117. Bibcode: 2013JPal...87..755P. http://stri.si.edu/sites/publications/PDFs/STRI-W_Pimiento_et_al_2013_Sharks_and_Rays_from_Gatun.pdf.
- ↑ Crane, B. (2017). "A Prehistoric Killer, Buried in Muck". The New Yorker. https://www.newyorker.com/tech/elements/a-prehistoric-killer-buried-in-muck. Retrieved 10 December 2017.
- ↑ Mustain, A. (2011). "For Sale: World's Largest Shark Jaws". LiveScience. https://www.livescience.com/14255-shark-jaws-worlds-largest-auction.html.
- ↑ 66.0 66.1 Almgreen, S. E. Bendix (15 November 1983). "Carcharodon megalodon from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoïn". Bulletin of the Geological Society of Denmark 32: 1–32. doi:10.37570/bgsd-1983-32-01. NAID 10012345550.
- ↑ Reolid, M.; Molina, J. M. (2015). "Record of Carcharocles megalodon in the Eastern Guadalquivir Basin (Upper Miocene, South Spain)". Estudios Geológicos 71 (2): e032. doi:10.3989/egeol.41828.342.
- ↑ Uyeno, T.; Sakamoto, O.; Sekine, H. (1989). "The Description of an Almost Complete Tooth Set of Carcharodon megalodon from a Middle Miocene Bed in the Saitama Prefecture, Japan". Saitama Museum of Natural History Bulletin 7: 73–85.
- ↑ Anderson, P.S.L.; Westneat, M. (2009). "A biomechanical model of feeding kinematics for Dunkleosteus terrelli (Arthrodira, Placodermi)". Paleobiology 35 (2): 251–269. doi:10.1666/08011.1. Bibcode: 2009Pbio...35..251A.
- ↑ Ballell, A.; Ferrón, H.G. (2021). "Biomechanical insights into the dentition of megatooth sharks (Lamniformes: Otodontidae)". Scientific Reports 11 (1232): 1232. doi:10.1038/s41598-020-80323-z. PMID 33441828.
- ↑ 71.0 71.1 Stringer, G. L.; King, L. (2012). "Late Eocene Shark Coprolites from the Yazoo Clay in Northeastern Louisiana". New Mexico Museum of Natural History and Science, Bulletin. Vertebrate Corpolites 57: 301. https://books.google.com/books?id=C_MoCgAAQBAJ&pg=PA301.
- ↑ "Megalodon Shark Facts and Information: The Details". fossilguy.com. http://www.fossilguy.com/gallery/vert/fish-shark/carcharocles/carcharocles.htm.
- ↑ Fitzgerald, Erich (2004). "A review of the Tertiary fossil Cetacea (Mammalia) localities in Australia". Memoirs of Museum Victoria 61 (2): 183–208. doi:10.24199/j.mmv.2004.61.12.
- ↑ Löffler, N.; Fiebig, J.; Mulch, A.; Tütken, T.; Schmidt, B.C.; Bajnai, D.; Conrad, A.C.; Wacker, U. et al. (2019). "Refining the temperature dependence of the oxygen and clumped isotopic compositions of structurally bound carbonate in apatite". Geochimica et Cosmochimica Acta 253: 19–38. doi:10.1016/j.gca.2019.03.002. Bibcode: 2019GeCoA.253...19L.
- ↑ 75.0 75.1 75.2 Aguilera O.; Augilera E. R. D. (2004). "Giant-toothed White Sharks and Wide-toothed Mako (Lamnidae) from the Venezuela Neogene: Their Role in the Caribbean, Shallow-water Fish Assemblage". Caribbean Journal of Science 40 (3): 362–368. https://www.researchgate.net/publication/228741311.
- ↑ 76.0 76.1 Carcharocles megalodon at fossilworks.org (retrieved 28 August 2017)
- ↑ "Young Prince George gifted 23m-year-old tooth from extinct shark found in Malta". Times of Malta. 27 September 2020. https://timesofmalta.com/articles/view/young-prince-george-gifted-23m-year-old-tooth-from-extinct-shark-found.820588.
- ↑ Yun, C. (2020). "New example of Cosmopolitodus hastalis (Lamniformes, Lamnidae) from the Miocene South Korea". Zoodiversity 54 (5): 433–438. doi:10.15407/zoo2020.05.433.
- ↑ Choi, Seung; Lee, Yuong-Nam (2017). "A review of vertebrate body fossils from the Korean Peninsula and perspectives" (in en). Geosciences Journal 21 (6): 867–889. doi:10.1007/s12303-017-0040-6. ISSN 1226-4806. Bibcode: 2017GescJ..21..867C. http://link.springer.com/10.1007/s12303-017-0040-6.
- ↑ Martin, J. E.; Tacail, T.; Sylvain, A.; Catherine, G.; Vincent, B. (2015). "Calcium isotopes reveal the trophic position of extant and fossil elasmobranchs". Chemical Geology 415: 118–125. doi:10.1016/j.chemgeo.2015.09.011. Bibcode: 2015ChGeo.415..118M.
- ↑ 81.0 81.1 81.2 Collareta, A.; Lambert, O.; Landini, W.; Di Celma, C.; Malinverno, E.; Varas-Malca, R.; Urbina, M.; Bianucci, G. (2017). "Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru". Palaeogeography, Palaeoclimatology, Palaeoecology 469: 84–91. doi:10.1016/j.palaeo.2017.01.001. Bibcode: 2017PPP...469...84C.
- ↑ 82.0 82.1 Morgan, Gary S. (1994). "Whither the giant white shark?". Paleontology Topics 2 (3): 1–2. https://www.priweb.org/files/pubtext/item_pdf_289.pdf.
- ↑ Augilera, Orangel A.; García, Luis; Cozzuol, Mario A. (2008). "Giant-toothed white sharks and cetacean trophic interaction from the Pliocene Caribbean Paraguaná Formation". Paläontologische Zeitschrift 82 (2): 204–208. doi:10.1007/BF02988410. ISSN 0038-2353. Bibcode: 2008PalZ...82..204A.
- ↑ Landini, W.; Altamirano-Sera, A.; Collareta, A.; Di Celma, C.; Urbina, M.; Bianucci, G. (2017). "The late Miocene elasmobranch assemblage from Cerro Colorado (Pisco Formation, Peru)". Journal of South American Earth Sciences 73: 168–190. doi:10.1016/j.jsames.2016.12.010. Bibcode: 2017JSAES..73..168L.
- ↑ 85.0 85.1 85.2 85.3 85.4 85.5 85.6 85.7 Lambert, O.; Bianucci, G.; Post, P.; de Muizon, C.; Salas-Gismondi, R.; Urbina, M.; Reumer, J. (2010). "The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru". Nature 466 (7302): 105–108. doi:10.1038/nature09067. PMID 20596020. Bibcode: 2010Natur.466..105L.
- ↑ Compagno, Leonard J. V. (1989). "Alternative life-history styles of cartilaginous fishes in time and space". Environmental Biology of Fishes 28 (1–4): 33–75. doi:10.1007/BF00751027.
- ↑ Ferretti, Francesco; Boris Worm; Gregory L. Britten; Michael R. Heithaus; Heike K. Lotze1 (2010). "Patterns and ecosystem consequences of shark declines in the ocean". Ecology Letters 13 (8): 1055–1071. doi:10.1111/j.1461-0248.2010.01489.x. PMID 20528897. Bibcode: 2010EcolL..13.1055F. http://wormlab.biology.dal.ca/ramweb/papers-total/Ferretti%20et%20al%202010_Ecol_Lett.pdf. Retrieved 19 February 2011.
- ↑ Gilbert, K.N.; Ivany, L.C.; Uhen, M.D. (2018). "Living fast and dying young: life history and ecology of a Neogene sperm whale". Journal of Vertebrate Paleontology 38 (2): e1439038. doi:10.1080/02724634.2018.1439038. Bibcode: 2018JVPal..38E9038G.
- ↑ 89.0 89.1 89.2 89.3 89.4 Heyning, John; Dahlheim, Marilyn (1988). "Orcinus orca". Mammalian Species (304): 1–9. doi:10.2307/3504225. http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-304-01-0001.pdf.
- ↑ Bianucci, Giovanni; Walter, Landini (2006). "Killer sperm whale: a new basal physeteroid (Mammalia, Cetacea) from the Late Miocene of Italy". Zoological Journal of the Linnean Society 148 (1): 103–131. doi:10.1111/j.1096-3642.2006.00228.x.
- ↑ Lindberg, D. R.; Pyenson, N. D. (2006). "Evolutionary Patterns in Cetacea: Fishing Up Prey Size through Deep Time". Whales, Whaling, and Ocean Ecosystems. University of California Press. p. 77. ISBN 978-0-520-24884-7. https://books.google.com/books?id=daY_utPoJGAC&pg=PA77.
- ↑ Boessenecker, R. W. (2013). "A new marine vertebrate assemblage from the Late Neogene Purisima Formation in Central California, part II: Pinnipeds and Cetaceans". Geodiversitas 35 (4): 815–940. doi:10.5252/g2013n4a5. https://zenodo.org/record/4538200.
- ↑ Bianucci, G. (1997). "Hemisyntrachelus cortesii (Cetacea, Delphinidae) from the Pliocene Sediments of Campore Quarry (Salsomaggiori Terme, Italy". Bollettino della Societa Paleontologica Italiana 36 (1): 75–83). https://www.researchgate.net/publication/244994854.
- ↑ Antunes, M.T.; Legoinha, P.; Balbing, A. (2015). "Megalodon, mako shark and planktonic foraminifera from the continental shelf off Portugal and their age". Geologica Acta 13: 181–190. http://dspace.uevora.pt/rdpc/handle/10174/17685.
- ↑ "Paleoecology of Megalodon and the White Shark". Biology of Sharks and Rays. http://www.elasmo-research.org/education/evolution/paleoecology.htm.
- ↑ Tanke, Darren; Currie, Philip (1998). "Head-Biting Behaviour in Theropod Dinosaurs: Paleopathological Evidence". Gaia (15): 167–184. http://www.arca.museus.ul.pt/ArcaSite/obj/gaia/MNHNL-0000781-MG-DOC-web.PDF.
- ↑ 97.0 97.1 Godfrey, S. J.; Altman, J. (2005). "A Miocene Cetacean Vertebra Showing a Partially Healed Compression Factor, the Result of Convulsions or Failed Predation by the Giant White Shark, Carcharodon megalodon". Jeffersoniana (16): 1–12. http://www.vmnh.net/content/File/Research_and_Collections/Jeffersoniana_Number_16.pdf. Retrieved 1 October 2017.
- ↑ Stephen J. Godfrey; John R. Nance; Norman L. Riker (2021). "Otodus-bitten sperm whale tooth from the Neogene of the Coastal Eastern United States". Acta Palaeontologica Polonica 66 (3): 599–603. http://app.pan.pl/archive/published/app66/app008202020.pdf.
- ↑ Deméré, Thomas A.; Berta, Annalisa; McGowen, Michael R. (2005). "The taxonomic and evolutionary history of fossil and modern balaenopteroid mysticetes". Journal of Mammalian Evolution 12 (1/2): 99–143. doi:10.1007/s10914-005-6944-3.
- ↑ Ehret D.J. (2010). "Chapter 5 – Macroevolution, Age, and Growth of the Megatoothed Sharks (Lamniformes Otodonridae)". Paleobiology and taxonomy of extinct lamnid and otodontid sharks (Chondrichthyes, Elasmobranchii, Lamniformes). pp. 100–136. https://ufdcimages.uflib.ufl.edu/UF/E0/04/23/97/00001/ehret_d.pdf.
- ↑ S., Kenshu; Bonnan, M. F.; Becker, M. A.; Griffiths, M. L. (2021). "Ontogenetic growth pattern of the extinct megatooth shark Otodus megalodon – implications for its reproductive biology, development, and life expectancy". Historical Biology 33 (12): 3254–3259. doi:10.1080/08912963.2020.1861608. Bibcode: 2021HBio...33.3254S.
- ↑ "Identifican en Canarias fósiles de 'megalodón', el tiburón más grande que ha existido" (in es). Europa Press Noticias SA. 2013. http://www.europapress.es/islas-canarias/noticia-identifican-canarias-fosiles-megalodon-tiburon-mas-grande-mayor-depredador-marino-existido-20130902152010.html.
- ↑ Dulvy, N. K.; Reynolds, J. D. (1997). "Evolutionary transitions among egg-laying, live-bearing and maternal inputs in sharks and rays". Proceedings of the Royal Society B: Biological Sciences 264 (1386): 1309–1315. doi:10.1098/rspb.1997.0181. Bibcode: 1997RSPSB.264.1309D.
- ↑ Godfrey, Stephen (2004). "The Ecphora". The Newsletter of Calvert Marine Museum Fossil Club 19 (1): 1–13. http://calvertmarinemuseum.com/cmmfc/newsletter/CMMFC_Newsletter_2004-04.pdf.
- ↑ Kallal, R. J.; Godfrey, S. J.; Ortner, D. J. (27 August 2010). "Bone Reactions on a Pliocene Cetacean Rib Indicate Short-Term Survival of Predation Event". International Journal of Osteoarchaeology 22 (3): 253–260. doi:10.1002/oa.1199.
- ↑ 106.0 106.1 Pimiento, C.; Griffin, J. N.; Clements, C. F.; Silvestro, D.; Varela, S.; Uhen, M. D.; Jaramillo, C. (2017). "The Pleistocene Marine Megafauna Extinction and its Impact on Functional Diversity". Nature Ecology and Evolution 1 (8): 1100–1106. doi:10.1038/s41559-017-0223-6. PMID 29046566. Bibcode: 2017NatEE...1.1100P. https://cronfa.swan.ac.uk/Record/cronfa34515.
- ↑ 107.0 107.1 107.2 107.3 "The Extinction of Megalodon". Biology of Sharks and Rays. http://www.elasmo-research.org/education/evolution/megalodon_extinction.htm.
- ↑ Reilly, Michael (29 September 2009). "Prehistoric Shark Nursery Spawned Giants". Discovery News. http://news.discovery.com/animals/megalodon-nursery-prehistoric-sharks.html.
- ↑ 109.0 109.1 109.2 Allmon, Warren D.; Steven D. Emslie; Douglas S. Jones; Gary S. Morgan (2006). "Late Neogene Oceanographic Change along Florida's West Coast: Evidence and Mechanisms". The Journal of Geology 104 (2): 143–162. doi:10.1086/629811. Bibcode: 1996JG....104..143A.
- ↑ 110.0 110.1 Collareta, A.; Lambert, O.; Landini, W.; Bianucci, G. (2017). "Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru". Palaeogeography, Palaeoclimatology, Palaeoecology 469: 84–91. doi:10.1016/j.palaeo.2017.01.001. Bibcode: 2017PPP...469...84C.
- ↑ Dooly A.C.; Nicholas C. F.; Luo Z. X. (2006). "The earliest known member of the rorqual–gray whale clade (Mammalia, Cetacea)". Journal of Vertebrate Paleontology 24 (2): 453–463. doi:10.1671/2401.
- ↑ 112.0 112.1 112.2 McCormack, Jeremy; Griffiths, Michael L.; Kim, Sora L.; Shimada, Kenshu; Karnes, Molly; Maisch, Harry; Pederzani, Sarah; Bourgon, Nicolas et al. (31 May 2022). "Trophic position of Otodus megalodon and great white sharks through time revealed by zinc isotopes" (in en). Nature Communications 13 (1): 2980. doi:10.1038/s41467-022-30528-9. ISSN 2041-1723. PMID 35641494. Bibcode: 2022NatCo..13.2980M.
- ↑ 113.0 113.1 113.2 113.3 Citron, Sara; Geisler, Jonathan H.; Alberto, Collareta; Giovanni, Bianucci (2022). "Systematics, phylogeny and feeding behavior of the oldest killer whale: a reappraisal of Orcinus citoniensis (Capellini, 1883) from the Pliocene of Tuscany (Italy)". Bollettino della Società Paleontologica Italiana 61 (2): 167–186. doi:10.4435/BSPI.2022.13.
- ↑ "Huge Tooth Reveals Prehistoric Moby Dick in Melbourne". Australasian Science Magazine. http://www.australasianscience.com.au/article/issue-april-2016/huge-tooth-reveals-prehistoric-moby-dick-melbourne.html.
- ↑ "Move over Moby Dick: Meet Melbourne's own mega whale". The Sydney Morning Herald. 21 April 2016. https://www.smh.com.au/technology/move-over-moby-dick-meet-melbournes-own-mega-whale-20160421-gobhl6.html.
- ↑ Govender, R (2021). "Early Pliocene fossil cetaceans from Hondeklip Bay, Namaqualand, South Africa". Historical Biology 33 (4): 574–593. doi:10.1080/08912963.2019.1650273. Bibcode: 2021HBio...33..574G.
- ↑ Hampe, O. (2006). "Middle/late Miocene hoplocetine sperm whale remains (Odontoceti: Physeteridae) of North Germany with an emended classification of the Hoplocetinae". Fossil Record 9 (1): 61–86. doi:10.1002/mmng.200600002. Bibcode: 2006FossR...9...61H.
- ↑ 118.0 118.1 Antunes, Miguel Telles; Balbino, Ausenda Cáceres (2010). "The Great White Shark Carcharodon carcharias (Linne, 1758) in the Pliocene of Portugal and its Early Distribution in Eastern Atlantic". Revista Española de Paleontología 25 (1): 1–6. http://recyt.fecyt.es/index.php/REP/article/viewFile/11488/7741.
- ↑ Kast, Emma R.; Griffiths, Michael L.; Kim, Sora. L.; Rao, Zixuan C.; Shimada, Kensu; Becker, Martin A.; Maisch, Harry M.; Eagle, Robert A. et al. (22 June 2022). "Cenozoic megatooth sharks occupied extremely high trophic positions". Science Advances 8 (25): eabl6529. doi:10.1126/sciadv.abl6529. PMID 35731884. Bibcode: 2022SciA....8L6529K.
- ↑ Slater, G. J.; Goldbogen, J. A.; Pyenson, N. D. (2017). "Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics". Proceedings of the Royal Society B: Biological Sciences 284 (1855): 20170546. doi:10.1098/rspb.2017.0546. PMID 28539520.
- ↑ Sylvain, Adnet; A. C. Balbino; M. T. Antunes; J. M. Marín-Ferrer (2010). "New fossil teeth of the White Shark (Carcharodon carcharias) from the Early Pliocene of Spain. Implication for its paleoecology in the Mediterranean". Neues Jahrbuch für Geologie und Paläontologie 256 (1): 7–16. doi:10.1127/0077-7749/2009/0029.
- ↑ Weinstock, J. A. (2014). The Ashgate Encyclopedia of Literary and Cinematic Monsters. Farnham, United Kingdom: Routledge. pp. 107–108. ISBN 978-1-4094-2562-5. OCLC 874390267. https://books.google.com/books?id=PHbeCwAAQBAJ&pg=PA107.
- ↑ 123.0 123.1 Guimont, Edward (5 October 2021). "The Megalodon: A Monster of the New Mythology" (in en). M/C Journal 24 (5). doi:10.5204/mcj.2793. ISSN 1441-2616. https://journal.media-culture.org.au/index.php/mcjournal/article/view/2793.
- ↑ Roesch, B. S. (1998). "A Critical Evaluation of the Supposed Contemporary Existence of Carcharocles megalodon". The Cryptozoology Review 3 (2): 14–24. http://web.ncf.ca/bz050/megalodon.html. Retrieved 11 November 2014.
- ↑ "Does Megalodon Still Live?". Biology of Sharks and Rays. http://www.elasmo-research.org/education/evolution/megalodon_lives.htm.
- ↑ "The Meg (2018)". https://www.boxofficemojo.com/movies/?id=wbeventfilm2018.htm.
- ↑ Sid Bennett (director) (27 May 2012). Mermaids (Motion picture). Animal Planet.
- ↑ "Shark Week 'Megalodon: The Monster Shark Lives' Tries To Prove Existence Of Prehistoric Shark (VIDEO)". Huff Post Green. 5 August 2013. http://www.huffingtonpost.com/2013/08/05/shark-week-megalodon-monster-shark-video_n_3706120.html?ir=Green.
- ↑ Winston, B.; Vanstone, G.; Chi, W. (2017). "A Walk in the Woods". The Act of Documenting: Documentary Film in the 21st Century. New York, New York: Bloomsbury Publishing. ISBN 978-1-5013-0918-2. OCLC 961183719. https://books.google.com/books?id=9yZ7DQAAQBAJ&pg=PA27.
- ↑ Flanagin, J. (2014). "Sorry, Fans. Discovery Has Jumped the Shark Week.". New York Times. http://op-talk.blogs.nytimes.com/2014/08/15/sorry-fans-discovery-has-jumped-the-shark-week.
- ↑ Shiffman, David (15 August 2014). "Shark Week Is Lying Again About Monster Megalodon Sharks" (in en). https://slate.com/technology/2014/08/shark-week-megalodon-films-discovery-channel-lies-about-extinct-monster-sharks.html.
- ↑ O'Connell, Mikey (5 August 2013). "TV Ratings: Shark Week Hits Record Highs With Fake 'Megalodon' Doc" (in en-US). https://www.hollywoodreporter.com/tv/tv-news/tv-ratings-shark-week-hits-599707/.
- ↑ "Fossil, Fossilized Teeth of the Megalodon Shark | NCpedia". https://ncpedia.org/fossil-fossilized-teeth-megalodon.
Further reading
- Dickson, K. A.; Graham, J. B. (November–December 2004). "Evolution and consequences of endothermy in fishes". Physiological and Biochemical Zoology 77 (6): 998–1018. doi:10.1086/423743. PMID 15674772.
- Kent, Bretton W. (1994). Fossil Sharks of the Chesapeake Bay Region. Columbia, Md.: Egan Rees & Boyer. ISBN 978-1-881620-01-3. OCLC 918266672. https://books.google.com/books?id=7cFJAQAAMAAJ.
External links
- Paleontological videos
- Shark Week Special on megalodon with Pat McCarthy and John Babiarz on YouTube with comments on its extinction.
- Expert view: information about megalodon on YouTube (featuring expert Dana Ehret)
- Lamniform sharks: 110 million years of ocean supremacy on YouTube (featuring expert Mikael Siverson)
- The Rise and Fall of the Neogene Giant Sharks on YouTube (featuring expert Bretton Kent)
Wikidata ☰ Q163873 entry
![]() | Original source: https://en.wikipedia.org/wiki/Megalodon.
Read more |