Carcharocles chubutensis is a prehistoric megatoothed shark that lived during Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

, Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

, and Pliocene

Pliocene

The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

 epochs, approximately about 28 - 5 million years ago. This shark is considered to be a close relative of another prehistoric megatoothed shark, C. megalodon

Megalodon

The megalodon and ὀδούς ) is an extinct species of shark that lived roughly from 28 to 1.5 million years ago, during the Cenozoic Era .The taxonomic assignment of C...

. However, as is the case with C. megalodon, the classification of this species is disputed.

Fossil record

This species is also known from fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 teeth and some fossilized vertebral centra. Shark skeleton

Skeleton

The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...

 is composed of cartilage

Cartilage

Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...

 and not bone

Bone

Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

, and cartilage rarely gets fossilized. Hence, fossils of C. chubutensis are generally poorly preserved. Although the teeth of C. chubutensis are morphologically similar to teeth of C. 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

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, Cuba

Cuba

The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

, Puerto Rico

Puerto Rico

Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...

, Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, and Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

.

Size

C. chubutensis was larger than C. angustidens. Teeth of C. chubutensis can approach 130 mm in slant height (diagonal length), which according to size estimation method proposed by Gottfried at al, in 1996, indicate 12.2 m (40 ft) long specimen.

Paleoecology

Paleontological 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

C. chubutensis was likely an apex predator

Apex predator

Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...

 and commonly preyed upon fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...

, sea turtles, cetaceans (e.g. whales), and sirenids.

Phylogeny

As is the case with other known megatoothed sharks, the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of C. chubutensis remains in dispute. The Swiss naturalist Louis Agassiz

Louis Agassiz

Jean Louis Rodolphe Agassiz was a Swiss paleontologist, glaciologist, geologist and a prominent innovator in the study of the Earth's natural history. He grew up in Switzerland and became a professor of natural history at University of Neuchâtel...

 first identified this shark as a species of Carcharodon in 1843. In 1906, Ameghino

Florentino Ameghino

Florentino Ameghino was an Argentine naturalist, paleontologist, anthropologist and zoologist.Born in Luján, son of Italian immigrants, Ameghino was a self-taught naturalist, and focused his study on the lands of the southern Pampas...

 renamed this shark as C. chubutensis. In 1964, shark researcher, L. S. Glikman recognized the transition of Otodus obliquus

Otodus obliquus

Otodus obliquus is an extinct mackerel shark which lived during the Paleocene and Eocene epochs, approximately about 60 to 37.5 million years ago.-Known physiology:This shark is known from the fossil teeth and fossilized vertebral centra...

to C. auriculatus. In 1987, shark researcher, H. Cappetta reorganized the C. auriculatus - C. megalodon lineage and placed all related megatoothed sharks along with this species in the genus Carcharocles. Finally, the complete Otodus obliquus to C. megalodon progression became clear and has since gained the acceptance of many shark researchers.

Within the Carcharocles lineage; C. chubutensis is the succeeding species of C. angustidens and is succeeded by C. megalodon. In short, C. chubutensis is considered to be the ancestor of C. megalodon. However, due to its co-existence with C. megalodon during the Miocene and Pliocene epochs, it is regarded as a morpho-species.

See also

• List of prehistoric fish
• List of apex predators
• Largest prehistoric organisms
  Largest prehistoric organisms
  The largest prehistoric organisms include both vertebrate and invertebrate species. Many are described below, along with their typical range of size...
  
  

External links

• Carcharocles: Extinct Megatoothed shark from ELASMO