• Source: Otodus angustidens

Otodus angustidens is an extinct species of prehistoric megatoothed sharks in the genus Otodus, which lived during the Late Eocene and Miocene epochs about 34 to 21 million years ago. The largest individuals were about 11–12 metres (36–39 ft) long. This shark is related to another extinct megatoothed shark, the famous Otodus megalodon.




Taxonomy


The Swiss naturalist Louis Agassiz, first identified this shark as a species of genus Carcharodon in 1835.
In 1964, shark expert, L. S. Glikman recognized the transition of Otodus obliquus to C. auriculatus and moved C. angustidens to genus Otodus. (See "external links" below)
However, in 1987, shark expert H. Cappetta recognized the C. auriculatus - C. megalodon lineage and placed all related megatooth sharks along with this species in the genus Carcharocles. The complete Otodus obliquus to C. megalodon transition then became clear and has since gained the acceptance of many other experts with the passage of time. Within the Carcharocles lineage, C. angustidens is the species succeeding C. sokolovi and is followed by C. chubutensis.
In 2001, a discovery of the best preserved Carcharocles angustidens specimen to date by two scientists, Michael D. Gottfried and Ewan Fordyce, has been presented by the team as evidence for close morphological ties with the extant great white shark, and the team argued that Carcharocles angustidens, along with all other related megatooth sharks, including Carcharocles megalodon, should be assigned to Carcharodon as was done before by Louis Agassiz., although this is not internationally accepted by the scientific community.
A more recent study of the related Megalolamna's taxonomic relationships demonstrates the possibility that Otodus needs to include the species sometimes assigned to Carcharocles (i.e., the megatoothed lineage, including megalodon) in order to be monophyletic.




Size estimation


Like other known megatooth sharks, the fossils of O. angustidens indicate that it was considerably larger than the extant great white shark, with the largest individuals possibly measuring up to 11–12 metres (36–39 ft) long. A well preserved specimen from New Zealand is estimated at 9.3 m (31 ft) in length. This specimen had teeth measuring up to 9.87 cm (3.89 in) in diagonal length, and vertebral centra around 1.10 cm (0.43 in) in diameter. Smaller individuals were about 6–6.6 metres (20–22 ft) long, still larger than the avarage extant great white shark.




Dentition


The dental formula for O. angustidens is 2.1.5.43.0.6.3




Diet


O. angustidens was an apex predator and likely preyed upon penguins, fish, dolphins, and baleen whales.




Fossil record


As is the case with most extinct sharks, this species is also known from fossil teeth and some fossilized vertebral centra. Shark skeletons are composed of cartilage and not bone, and cartilage rarely gets fossilized. Hence, fossils of O. angustidens are generally poorly preserved. To date, the best preserved specimen of this species have been excavated from New Zealand, which comprises 165 associated teeth and about 35 associated vertebral centra. This specimen is around 26 million years old. O. angustidens teeth are noted for their triangular crowns and small side cusps that are fully serrated. The serrations are very sharp and very well pronounced. O. angustidens was a widely distributed species with fossils found in: A fossil bed in South Carolina suggests that O. angustidens utilized the area as a birthing ground and nursery for their pups, as 89% of the teeth found in the area belonged to juveniles, 3% belonged to infants, and 8% belonged to adults.

North America
Yazoo Formation, Alabama
Jewett Sand Formation, California
Clinchfield Formation, Georgia
Calvert Formation, Maryland
Jackson Group, Mississippi
Kirkwood Formation, New Jersey
Castle Hayne Formation, North Carolina
Hawthorne Formation, South Carolina
Chandler Bridge Formation, South Carolina
Europe
Malta
Paris Basin, France
Leipzig / Stoermthal, Germany
Asia
Ashiya Group, Japan
Oceania
Ettric, Jan Juc, Gambier Limestone, Clifton Formations, Australia
Otekaike Formation, New Zealand
Africa
South America
Dos Bocas Formation, Ecuador




See also



Prehistoric fish
Largest prehistoric organisms




References






Further reading


Glikman, L.S., 1980. Evolution of Cretaceous and Caenozoic Lamnoid Sharks:3-247, pls.1-33. Moscow.
Jordan, D.S. & Hannibal, H., 1923. Fossil Sharks and Rays of the Pacific Slope of North America. Bulletin of the Southern California Academy of Sciences, 22:27-63, plates 1–9.




External links


A large extinct white shark: Carcharodon angustidens from New Zealand Oligocene rocks.
Carcharocles: Extinct Megatoothed shark

Kata Kunci Pencarian:

• Otodus
• Otodus chubutensis
• Megalodon
• Lamniformes
• Otodus angustidens
• Otodus
• Otodus auriculatus
• Otodus sokolovi
• Otodus chubutensis
• Otodus aksuaticus
• Megalodon
• Cretalamna
• Lamniformes
• Largest prehistoric animals