''Parotodus'', commonly known as the false-toothed mako shark (or false mako shark), is an extinct genus of

mackerel shark The Lamniformes (, from Greek ''lamna'' "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the gr ...

that lived approximately 53 to one million years ago during the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

and

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

epochs In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

. Its teeth, which are found worldwide, are often prized by fossil collectors due to their rarity. The scarcity of fossils is because ''Parotodus'' likely primarily inhabited open oceans far away from the continents.

Description

Initially appearing as a small shark, ''Parotodus'' gradually increased in size over geologic time and by the

Neogene The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...

period became one of the largest sharks of its time. A 1999 study estimated the genus to have measured up to in length. The teeth of ''Parotodus'' are distinctively curved and rarely show feeding damage, which suggests that it mainly preyed on soft-bodied animals. Paleontologists speculate that this included other sharks, including the contemporaneous

Megalodon Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. It was formerly thought to be a member ...

Classification

Due to the general scarcity and ambiguity of fossils, the

familiar In European folklore of the medieval and early modern periods, familiars (sometimes referred to as familiar spirits) were believed to be supernatural entities that would assist witches and cunning folk in their practice of magic. According to re ...

placement remains uncertain. Several proposals suggest classifying the genus as a mega-toothed shark, cardabiodont, archaeolamnid,

thresher shark Thresher sharks are large lamniform sharks of the family Alopiidae found in all temperate and tropical oceans of the world; the family contains three extant species, all within the genus ''Alopias''. All three thresher shark species have been ...

, or

white shark The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. It is nota ...

. Currently, three valid species are generally recognized within ''Parotodus''. These include ''P. benedenii'', ''P. pavlovi'', and ''P. mangyshlakensis''. However, some scientists, especially those who identify ''Parotodus'' as a cardabiodont, do not recognize the latter two as members of the genus. A fourth species was reported by Ward, Nakatani, and Bernard in a 2017 poster from the Oligocene of Japan. The poster stated that the new species is to be named after Yasuhiro Fudouji, the paleontologist who discovered the

type specimens In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes t ...

, and will be formally described in an upcoming paper. However, the scientific name was not explicitly stated to avoid an accidental invalidation of the taxon.

Fossil records

The genus is often regarded as a rare species despite its presence in ocean deposits worldwide. As a result, it is often prized by fossil collectors. Paleontologists believe that ''Parotodus'' likely inhabited primarily open oceans like the modern

oceanic whitetip shark The oceanic whitetip shark (''Carcharhinus longimanus''), also known as shipwreck shark, Brown Milbert's sand bar shark, brown shark, lesser white shark, nigano shark, oceanic white-tipped whaler, and silvertip shark, is a large pelagic requiem ...

and

blue shark The blue shark (''Prionace glauca''), also known as the great blue shark, is a species of requiem shark, in the family Carcharhinidae, which inhabits deep waters in the world's temperate and tropical oceans. Averaging around and preferring co ...

. This would explain why fossils of a cosmopolitan animal are so rare, given that open oceans are seldom represented in terrestrial fossil deposits. This hypothesis is additionally supported by how ''Parotodus'' teeth are unusually common in nodule deposits under the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

and

Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

Oceans and on islands located far away from continental lands. ''Parotodus'' fossils have been recovered from fossil deposits in the

Azores ) , motto =( en, "Rather die free than subjected in peace") , anthem= ( en, "Anthem of the Azores") , image_map=Locator_map_of_Azores_in_EU.svg , map_alt=Location of the Azores within the European Union , map_caption=Location of the Azores wi ...

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, the

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, and dredged from the Pacific and Indian Oceans.

Description

Classification

Fossil records

References

See also