Otodus chubutensis

Otodus chubutensis,[1] meaning "ear-shaped tooth of Chubut", from Ancient Greek ὠτ (ōt, meaning "ear") and ὀδούς (odoús, meaning "tooth") – thus, "ear-shaped tooth", is an extinct species of prehistoric megatoothed sharks in the genus Otodus, that lived during Oligocene, Miocene, and Pliocene epochs, approximately 28 – 5 million years ago.[2] The largest individuals were about 13.5 metres (44 ft) long. This shark is considered to be a close relative of the famous prehistoric megatoothed shark, O. megalodon.[2] However, as is the case with O. megalodon, the classification of this species is disputed.

Otodus chubutensis
Temporal range: Oligocene-Early Pliocene
~
Partially preserved O. chubutensis broken tooth with a slant height of 129 mm (5.1 in)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Lamniformes
Family: †Otodontidae
Genus: †Otodus
Species:
†O. chubutensis
Binomial name
†Otodus chubutensis
Ameghino, 1901
Synonyms
  • Carcharodon mexicanus
  • Carcharocles chubutensis
  • Carcharodon productus
  • Megaselachus chubutensis Glikman, 1964
  • Carcharodon subauriculatus Agassiz, 1843

Taxonomy

As is the case with other known megatoothed sharks, the genus of O. chubutensis remains in dispute.[3] The Swiss naturalist Louis Agassiz first identified this shark as a species of Carcharodon in 1843.[4] In 1906, Ameghino renamed this shark as C. chubutensis.[5] In 1964, shark researcher, L. S. Glikman recognized the transition of Otodus obliquus to C. auriculatus. In 1987, shark researcher, H. Cappetta reorganized the C. auriculatus - O. megalodon lineage and placed all related megatoothed sharks along with this species in the genus Carcharocles. Finally, the complete Otodus obliquus to O. megalodon progression became clear and has since gained the acceptance of many shark researchers.[6]

Within the Otodus lineage; O. chubutensis is the succeeding species of O. angustidens and is followed by O. megalodon.[2] In short, O. chubutensis is considered a possible ancestor of O. megalodon.[2][6][7] However, due to its co-existence with O. megalodon during the Miocene and Pliocene epochs, it is regarded as a morpho-species.[2]

Size

Otodus chubutensis was a large lamniform shark, with the largest individuals reaching a body length of 13.5 metres (44 ft).[8] Relatively large individuals reached body lengths of 9–11 metres (30–36 ft).[9] Smaller individuals were still about the size of the modern great white shark, reaching body lengths of 4.6–6.3 metres (15–21 ft).[10]

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.[11]

Diet

Otodus chubutensis was likely an apex predator and commonly preyed upon fish, sea turtles, cetaceans (e.g. whales), and sirenids.[11]

There is also potential evidence that Otodus hunted raptorial sperm whales; a tooth belonging to an undetermined 4 m (13 ft) physeteroid closely resembling those of Acrophyseter discovered in the Nutrien Aurora Phosphate Mine in North Carolina suggests that a megalodon or O. chubutensis may have aimed for the head of the sperm whale in order to inflict a fatal bite, the resulting attack leaving distinctive bite marks on the tooth. While scavenging behavior cannot be ruled out as a possibility, the placement of the bite marks is more consistent with predatory attacks than feeding by scavenging, as the jaw is not a particularly nutritious area to for a shark feed or focus on. The fact that the bite marks were found on the tooth's roots further suggest that the shark broke the whale's jaw during the bite, suggesting the bite was extremely powerful. The fossil is also notable as it stands as the first known instance of an antagonistic interaction between a sperm whale and an otodontid shark recorded in the fossil record.[12]

Fossil record

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. chubutensis are generally poorly preserved. Although the teeth of O. chubutensis are morphologically similar to teeth of O. megalodon,[13] they are comparatively slender with curved crown, and with presence of lateral heels feebly serrated.[11] Fossils of this species have been found in North America,[11] South America,[11] Africa,[14] and Europe.[15] Its fossils have also been discovered in Asia and Australia.[16]

Locations
South America[17]
North America
Europe
  • Bolognano Formation, Italy

See also

References
  1. 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.
  2. Renz, Mark (2002). Megalodon: Hunting the Hunter. PaleoPress. pp. 26–30. ISBN 0-9719477-0-8.
  3. 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. ISSN 0272-4634. S2CID 86092645.
  4. Klimley, Peter; Ainley, David (1996). Great White Sharks: The Biology of Carcharodon carcharias. Academic Press. ISBN 0-12-415031-4.
  5. Andres, Lutz. "Megatooth Fossils Found at the Calvert Cliffs of Maryland". Archived from the original on 26 August 2022. Retrieved 10 September 2022.
  6. Andres, Lutz (2002). "C. megalodon — Megatooth Shark, Carcharodon versus Carcharocles". Retrieved 2010-05-10.
  7. Bruner, John (1997). "The "Megatooth" shark, Carcharodon megalodon". Mundo Marino Revista Internacional de Vida Marina.
  8. 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.
  9. Perez, Victor; Leder, Ronny; Badaut, Teddy (2021). "Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions". Palaeontologia Electronica. 24 (1): 1–28. doi:10.26879/1140.
  10. McCormack, Jeremy; Griffiths, Michael L.; Kim, Sora L.; Shimada, Kenshu; Karnes, Molly; Maisch, Harry; Pederzani, Sarah; Bourgon, Nicolas; Jaouen, Klervia; Becker, Martin A.; Jöns, Niels (31 May 2022). "Trophic position of Otodus megalodon and great white sharks through time revealed by zinc isotopes". Nature Communications. 13 (1): 2980. Bibcode:2022NatCo..13.2980M. doi:10.1038/s41467-022-30528-9. ISSN 2041-1723. PMC 9156768. PMID 35641494. S2CID 249235478.
  11. Aguilera O.; Augilera E. R. D. (2004). "Giant-toothed White Sharks and Wide-toothed Mako (Lamnidae) from the Venezuela Neogene: Their Role in the Caribbean, Shallow-water Fish Assemblage". Caribbean Journal of Science. 40 (3): 362–368.
  12. STEPHEN J. GODFREY; JOHN R. NANCE; NORMAN L. RIKER (2021). "Otodus-bitten sperm whale tooth from the Neogene of the Coastal Eastern United States" (PDF). Acta Palaeontologica Polonica. 66 (3): 599–603.
  13. Nyberg K.G; Ciampaglio C.N; Wray G.A (2006). "Tracing the ancestry of the GREAT WHITE SHARK". Journal of Vertebrate Paleontology. 26 (4): 806–814. doi:10.1671/0272-4634(2006)26[806:TTAOTG]2.0.CO;2. ISSN 0272-4634. S2CID 53640614.
  14. Cook, Todd D.; Alison M. Murray; Elwyn L. Simons; Yousry S. Attia; Prithijit Chatrath (18 February 2010). "A Miocene selachian fauna from Moghra, Egypt". Historical Biology. Egypt. 22 (1–3): 78–87. doi:10.1080/08912960903249329. S2CID 128469722.
  15. Marsili, Stefano; Giorgio Carnevale; Ermanno Danesea; Giovanni Bianuccia; Walter Landinia (March 2007). "Early Miocene vertebrates from Montagna della Maiella, Italy". Annales de Paléontologie. Italy: Elsevier. 93 (1): 27–66. Bibcode:2007AnPal..93...27M. doi:10.1016/j.annpal.2007.01.001.
  16. Harry M. Maisch, IV; Martin A. Becker; John A. Chamberlain, Jr. (2018). "Lamniform and Carcharhiniform Sharks from the Pungo River and Yorktown Formations (Miocene–Pliocene) of the Submerged Continental Shelf, Onslow Bay, North Carolina, USA". Copeia. 106 (2): 353–374. doi:10.1643/OT-18-016. S2CID 91348616.
  17. Otodus chubutensis at Fossilworks.org
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