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Otodus angustidens; Temporal range: Late Eocene-Early Miocene; ~34–21 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Order:	Lamniformes
Family:	†Otodontidae
Genus:	†Otodus
Species:	†O. angustidens
Binomial name
	†Otodus angustidens; Agassiz, 1843
Subspecies
	O. a. turgidus? (Agassiz, 1839); O. a. angustidens? (Agassiz, 1835);
Synonyms
	Carcharocles angustidens Carcharodon angustidens Agassiz, 1843; Otodus latidens? Agassiz, 1843;

Otodus angustidens^[3] 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.^[4] 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.^[4]

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.^[4]

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.,^[5] 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.^[6]

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.^[7]^[8] A well preserved specimen from New Zealand is estimated at 9.3 m (31 ft) in length.^[5] 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.^[5] Smaller individuals were about 6–6.6 metres (20–22 ft) long, still larger than the avarage extant great white shark.^[9]^[5]

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.^[5] 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:^[10] 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.^[11]

North America

Europe

Asia

Ashiya Group, Japan

Oceania

Africa^[5]

South America^[5]

Dos Bocas Formation, Ecuador

References

^ Agassiz, Agassiz. "Otodus angustidens turgidus". Shark-References. 1839. Retrieved October 11, 2024.
^ Agassiz, Agassiz. "Otodus angustidens angustidens". Shark-References. 1835. Retrieved October 11, 2024.
^ 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. S2CID 89080495.
^ ^a ^b ^c Renz, Mark (2002). Megalodon: Hunting the Hunter. PaleoPress. pp. 26–30. ISBN 0-9719477-0-8.
^ ^a ^b ^c ^d ^e ^f ^g 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:AASOCA]2.0.CO;2. S2CID 86092645.
^ Shimada, Kenshu; Chandler, Richard E.; Lam, Otto Lok Tao; Tanaka, Takeshi; Ward, David J. (2017-07-04). "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): 704–714. doi:10.1080/08912963.2016.1236795. ISSN 0891-2963.
^ Kast, Emma R.; Griffiths, Michael L.; Kim, Sora. L.; Rao, Zixuan C.; Shimada, Kensu; Becker, Martin A.; Maisch, Harry M.; Eagle, Robert A.; Clarke, Chelesia A.; Neumann, Allison N.; Karnes, Molly E.; Lüdecke, Tina; Leichliter, Jennifer N.; Martínez-García, Alfredo; Akhtar, Alliya A.; Wang, Xingchen T.; Haug, Gerald H.; Sigman, Daniel M. (22 June 2022). "Cenozoic megatooth sharks occupied extremely high trophic positions". Science Advances. 8 (25): eabl6529. Bibcode:2022SciA....8L6529K. doi:10.1126/sciadv.abl6529. PMC 9217088. PMID 35731884.
^ Miller, Addison E.; Gibson, Matthew L.; Boessenecker, Robert W. (2021). "A megatoothed shark (Carcharocles angustidens) nursery in the Oligocene Charleston Embayment, South Carolina, USA". Palaeontologia Electronica. 24 (2). a19. doi:10.26879/1148.
^ Trif, N.; Ciobanu, R.; Vlad, C.A. (2016). "The first record of the giant shark Otodus megalodon (Agassiz, 1835) from Romania". Brukenthal. Acta Musei. 11 (3): 507–526.
^ Carcharocles angustidens at Fossilworks.org
^ "24 million-year-old nursery for baby megasharks discovered in South Carolina". Live Science. 19 October 2020.
^ "C. angustidens fossils from Black River Fossils". Archived from the original on 2016-06-24. Retrieved 2010-06-02.
^ Miller, A. E.; Gibson, M. L.; Boessenecker, R. W. (2021). "A megatoothed shark (Carcharocles angustidens) nursery in the Oligocene Charleston Embayment, South Carolina, USA". Palaeontologia Electronica. 24 (2): Article number 24.2.a19. doi:10.26879/1148.