Otodus chubutensis

Otodus chubutensis
Temporal range: Late Oligocene-Middle Miocene,
Partially preserved O. chubutensis broken tooth with a slant height of 129 mm (5.1 in)
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Division: Selachii
Order: Lamniformes
Family: †Otodontidae
Genus: †Otodus
Species:
†O. chubutensis
Binomial name
†Otodus chubutensis
Ameghino, 1901
Synonyms
  • Carcharodon mexicanus Agassiz, 1843
  • Carcharocles chubutensis? Jordan & Hannibal, 1923
  • Carcharodon chubutensis (Ameghino, 1901)
  • Carcharodon productus Agassiz, 1843
  • Megaselachus chubutensis Glikman, 1964
  • Otodus subauriculatus (Agassiz, 1843)
  • Carcharocles subauriculatus (Jordan & Hannibal, 1923)
  • Procarcharodon subauriculatus Leriche, 1942
  • Carcharodon subauriculatus Agassiz, 1843
  • Carcharodon megalodon chubutensis Ameghino, 1908
  • Procarcharodon chubutensis Leriche, 1942
  • Otodus turgidus? Agassiz, 1839
  • Carcharocles turgidus? Jordan & Hannibal, 1923
  • Carcharodon turgidus? Agassiz, 1839

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, lived from Late Oligocene to Middle Miocene, between 28 and 11.6 milion years ago.[2] The largest individuals were about 13.5 metres (44 ft) long. This shark is considered a close relative of the famous prehistoric megatoothed shark Otodus megalodon.[3]

Taxonomy

As is the case with other known megatoothed sharks, the genus of O. chubutensis remains in dispute.[4] The Swiss naturalist Louis Agassiz first identified this shark as a species of Carcharodon in 1843, naming It as C. subauriculatus based in MLP 12-3724 specimen.[5] In 1906, Ameghino renamed this shark as Carcharodon chubutensis based in the MACN-A 12927.[6] Some time later, it was discovered that C. subauriculatus would be a junior synonym of C. chubutensis.[7] In 1964, shark researcher, L. S. Glikman recognized the transition of Otodus obliquus to O. auriculatus. In 1987, shark researcher, H. Cappetta reorganized the O. auriculatus - O. megalodon lineage and placed all related megatoothed sharks along with this species in the genus Carcharocles ( now Otodus).[8] Finally, the complete Otodus obliquus to O. megalodon progression became clear and has since gained the acceptance of many shark researchers.[9]

Within the Otodus lineage; O. chubutensis is the succeeding species of O. angustidens and is followed by O. megalodon.[3] In short, O. chubutensis is considered a possible ancestor of O. megalodon.[3][9][10] However, due to its co-existence with O. megalodon during the Miocene and Pliocene epochs, it is regarded as a morpho-species.[3]

Description

Evolution of O. obliquus to O. megalodon based in teeth.

Otodus chubutensis was a large lamniform shark, with the largest individuals reaching a body length maximum of 13.5 metres (44 ft).[11] Relatively large individuals reached body lengths of 9–11 metres (30–36 ft).[12] 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). O. chubutensis was one of the largest sharks of its time.[13][3]

Teeth

The teeth of O. chubutensis is very similar to O. megalodon, but It differs from O. megalodon by having concave teeth, a more robust root, the crown is more inflated and triangular, less irregular, the serrations are slightly rounded, robust, with the cusp being more visible than in O. megalodon, which has a smaller cusp than in O. chubutensis. Therefore, O. chubutensis may or may not have cusps, just as O. megalodon may have slightly visible cusps; O. chubutensis, in its broader and less common form, may have widely vestigial or absent cusps.

Paleoecology

O. chubutensis was a apex predator like Megalodon.(by Karen Carr)

O. chubutensis was the apex predator of the Miocene era and occupied an extremely high trophic level. 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.[14]

Diet

Otodus chubutensis was likely an apex predator and commonly preyed upon fish, sea turtles, cetaceans (e.g. whales), and sirenids.[14]

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.[15]

There is also evidence that eurhinodelphinids where also hunted in a similar way. Three Neogene odontocete peduncular caudal vertebrae from the Pliocene Yorktown Formation show bilateral gouge marks consistent with having been actively bitten and wedged between adjacent teeth of Megalodon or O. chubutensis. None of the vertebrae show any signs of healing. The occurrence of bite marks suggests the event was an active predation event rather than a scavenging event.[16]

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,[17] they are comparatively slender with curved crown, and with presence of lateral heels feebly serrated.[14] Fossils of this species have been found in North America,[14] South America,[14] Africa,[18] and Europe.[19] Its fossils have also been discovered in Asia and Australia.[20] The fossil record confirmed for this species spans from the Late Oligocene to the Middle Miocene, while fossils with forms similar to this species are found as far back as the Early Pliocene strata. This suggests that O. chubutensis coexisted with Megalodon for a long time as a variant form.[21]

Locations

South America[22]
  • Chilcatay Formation, Pisco Formation, Peru
  • Pirabas Formation, Brazil
  • Jimol Formation, Colombia
  • Cantaure Formation, Venezuela
North America
  • Culebra Formation, Panama
  • Arcadia Formation, Florida
  • Pungo River Formation, North Carolina
  • Calvert Formation, Delaware
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. ^ Maisch IV, Harry M.; Becker, Martin A.; Chamberlain Jr., John A. (2020). "Macroborings in Otodus megalodon and Otodus chubutensis shark teeth from the submerged shelf of Onslow Bay, North Carolina, USA: implications for processes of lag deposit formation". Ichnos. 27 (2): 122–141. Bibcode:2020Ichno..27..122M. doi:10.1080/10420940.2019.1697257.
  3. ^ a b c d e Renz, Mark (2002). Megalodon: Hunting the Hunter. PaleoPress. pp. 26–30. ISBN 0-9719477-0-8.
  4. ^ 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.
  5. ^ Klimley, Peter; Ainley, David (1996). Great White Sharks: The Biology of Carcharodon carcharias. Academic Press. p. 31. ISBN 0-12-415031-4.
  6. ^ Andres, Lutz. "Megatooth Fossils Found at the Calvert Cliffs of Maryland". Archived from the original on 26 August 2022. Retrieved 10 September 2022.
  7. ^ Rivadeneira, M.M., Villafaña, J.A. (2018). "The modulating role of traits on the biogeographic dynamics of chondrichthyans from the Neogene to the present". Paleobiology: 251–262. doi:10.1017/pab.2018.7.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ 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. Bibcode:2017HBio...29..704S. doi:10.1080/08912963.2016.1236795. ISSN 0891-2963.
  9. ^ a b Andres, Lutz (2002). "C. megalodon — Megatooth Shark, Carcharodon versus Carcharocles". Retrieved 2010-05-10.
  10. ^ Bruner, John (1997). "The "Megatooth" shark, Carcharodon megalodon". Mundo Marino Revista Internacional de Vida Marina.
  11. ^ 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.
  12. ^ 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.
  13. ^ 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.
  14. ^ a b c d e 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" (PDF). Caribbean Journal of Science. 40 (3): 362–368.
  15. ^ Godfrey, Stephen J.; Nance, John R.; Riker, Norman L. (2021). "Otodus-bitten sperm whale tooth from the Neogene of the Coastal Eastern United States" (PDF). Acta Palaeontologica Polonica. 66 (3): 599–603. doi:10.4202/app.00820.2020.
  16. ^ Godfrey, Stephen; Ellwood, Mike; Groff, Stephen; Verdin, Michael (2018). "Carcharocles-Bitten Odontocete Caudal Vertebrae from the Coastal Eastern United States". Acta Palaeontologica Polonica. 63. doi:10.4202/app.00495.2018.
  17. ^ 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.
  18. ^ 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. 22 (1–3). Egypt: 78–87. Bibcode:2010HBio...22...78C. doi:10.1080/08912960903249329. S2CID 128469722.
  19. ^ Marsili, Stefano; Giorgio Carnevale; Ermanno Danesea; Giovanni Bianuccia; Walter Landinia (March 2007). "Early Miocene vertebrates from Montagna della Maiella, Italy". Annales de Paléontologie. 93 (1). Italy: Elsevier: 27–66. Bibcode:2007AnPal..93...27M. doi:10.1016/j.annpal.2007.01.001.
  20. ^ 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.
  21. ^ Perez, V. J., Godfrey, S. J., Kent, B. W., Weems, R. E., & Nance, J. R. (2018). The transition between Carcharocles chubutensis and Carcharocles megalodon (Otodontidae, Chondrichthyes): lateral cusplet loss through time. Journal of Vertebrate Paleontology, 38(6). https://doi.org/10.1080/02724634.2018.1546732
  22. ^ Otodus chubutensis at Fossilworks.org
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