''Otodus chubutensis'', meaning "ear-shaped tooth of

Chubut Chubut may refer to: * Chubut Province, Argentina * Chubut River in the Chubut Province * Chubut steamer duck The Chubut steamer duck or white-headed flightless steamer duck (''Tachyeres leucocephalus'') is a flightless duck endemic to Argenti ...

", from Ancient Greek ὠτ (ōt, meaning "ear") and ὀδούς (odoús, meaning "tooth") – thus, "ear-shaped tooth", is an extinct species of

prehistoric Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use o ...

megatoothed sharks in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

Otodus ''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth". Anatomy This shark is ...

'', that lived during

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

, and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

. This shark is considered to be a close relative of the famous prehistoric megatoothed shark, '' O. megalodon''. However, as is the case with ''O. megalodon'', the classification of this species is disputed.

Taxonomy

As is the case with other known megatoothed sharks, the

of ''O. chubutensis'' remains in dispute. The

Swiss Swiss may refer to: * the adjectival form of Switzerland * Swiss people Places * Swiss, Missouri *Swiss, North Carolina * Swiss, West Virginia * Swiss, Wisconsin Other uses * Swiss-system tournament, in various games and sports *Swiss Internati ...

naturalist

Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he rec ...

first identified this shark as a species of ''

Carcharodon ''Carcharodon'' () is a genus of sharks within the family Lamnidae. The only extant member is the great white shark (''Carcharodon carcharias''). Hubell's white shark (''Carcharodon hubbelli'') is an extinct member of this genus. Megalodon ...

'' in 1843. In 1906, Ameghino renamed this shark as ''C. chubutensis''. In 1964, shark researcher, L. S. Glikman recognized the transition of ''

Otodus obliquus ''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth". Anatomy This shark is ...

'' to ''C. auriculatus''. In 1987, shark researcher, H. Cappetta reorganized the ''

C. auriculatus ''Otodus auriculatus'' is an extinct species of large sharks in the genus '' Otodus'' of the family Otodontidae, closely related to the sharks of the genus '' Otodus'', and also closely related to the later species megalodon. Its teeth were larg ...

'' - ''O. megalodon'' lineage and placed all related megatoothed sharks along with this species in the genus ''

Carcharocles ''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth". Anatomy This shark is ...

''. Finally, the complete ''Otodus obliquus'' to ''O. megalodon'' progression became clear and has since gained the acceptance of many shark researchers. Within the ''Otodus'' lineage; ''O. chubutensis'' is the succeeding species of '' O. angustidens'' and is followed by ''O. megalodon''. In short, ''O. chubutensis'' is considered a possible ancestor of ''O. megalodon''. However, due to its co-existence with ''O. megalodon'' during the Miocene and Pliocene epochs, it is regarded as a morpho-species.

Size

''Otodus chubutensis'' was larger than '' O. angustidens''. Teeth of ''C. chubutensis'' can approach in slant height (diagonal length), which according to a size estimation method proposed by Gottfried ''et al.'', in 1996, indicate a long specimen.

Paleoecology

Paleontological Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

research suggests that this species may have changed habitat preferences through time, or it may have had enough behavioral flexibility to occupy different environments at different times.

Diet

''Otodus chubutensis'' was likely an

apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic le ...

and commonly preyed upon

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

sea turtles Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the flatback sea turtle, flatback, green sea turtle, green ...

cetaceans Cetacea (; , ) is an infraorder of aquatic mammals that includes whales, dolphins, and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel t ...

(e.g.

whales Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins a ...

), and sirenids.

Fossil record

This species is also known from

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, te ...

and some fossilized

vertebral centra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

. Shark

skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

s are composed of cartilage and not

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, an ...

, and cartilage rarely gets

ized. Hence, fossils of ''O. chubutensis'' are generally poorly preserved. Although the teeth of ''O. chubutensis'' are morphologically similar to teeth of ''O. megalodon'', they are comparatively slender with curved crown, and with presence of lateral heels feebly serrated. Fossils of this species have been found in North America,

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

Locations

;South America''Otodus chubutensis''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cre ...

.org * Chilcatay Formation, Peru * Pirabas Formation, Brazil *

Jimol Formation The Jimol Formation ( es, Formación Jimol, N1j) is a fossiliferous geological formation of the Cocinetas Basin in the northernmost department of La Guajira. The formation consists of calcareous lithic and fossiliferous sandstones, siltstones ...

, Colombia * Cantaure Formation, Venezuela ;North America * Culebra Formation, Panama *

Arcadia Formation The Arcadia Formation and its sub-unit, the Tampa Member, are Late Oligocene geologic formations in North Florida, United States. It is part of the Hawthorn Group. Age Period: Paleogene to Neogene Epoch: Early Late Oligocene through Pliocene F ...

, Florida *

Pungo River Formation The Pungo River Formation is a geologic formation in North Carolina. It preserves fossils dating back to the Middle Miocene. Economic significance The Pungo River Formation is mined extensively for its phosphorite deposits. See also * List ...

, North Carolina *

Calvert Formation The Calvert Formation is a geologic formation in Maryland, Virginia, and Delaware. It preserves fossils dating back to the early to middle Miocene epoch of the Neogene period. The formation is a destination for amateur fossil hunters as well as ...

, Delaware ;Europe *

Bolognano Formation Bolognano is a '' comune'' (municipality) and town in the province of Pescara in the Abruzzo Abruzzo (, , ; nap, label=Neapolitan language, Abruzzese Neapolitan, Abbrùzze , ''Abbrìzze'' or ''Abbrèzze'' ; nap, label=Sabino dialect, Aquil ...

, Italy

References

External links

Carcharocles: Extinct Megatoothed shark
from ELASMO

from Fossilguy.com {{Taxonbar, from=Q5038155 chubutensis Oligocene sharks Miocene sharks Pliocene sharks Prehistoric fish of Africa Fossils of Egypt Prehistoric fish of Europe Fossils of Italy Paleogene fish of North America Neogene fish of North America Prehistoric fish of South America Paleogene animals of South America Neogene animals of South America Paleogene Argentina Neogene Argentina Fossils of Argentina Fossil taxa described in 1843 Taxa named by Louis Agassiz