Superregnum: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Classis: Chondrichthyes
Subclassis: Elasmobranchii
Infraclassis: Euselachii
Division/Cohort: Neoselachii
Subdivision/Subcohort: Selachii
Superordo: Galeomorphii
Ordo: Lamniformes
Familia: †Otodontidae
Genus: †Otodus
Subgenera: †O. (Megaselachus) – †O. (Otodus)
Species: †O. aksuaticus – †O. angustidens – †O. auriculatus – †O. hastalis – †O. limhamnensis – †O. megalodon – †O. minor – †O. naidini – †O. obliquus – †O. poseidoni – †O. sokolovi
Name
Otodus Agassiz, 1843
References
Agassiz, L. 1833–1844. Recherches sur les poissons fossiles. 1420 pp. Imprimerie de Petitpierre, Neuchâtel. Reference page.
Otodus is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name Otodus comes from Ancient Greek ὠτ (ōt, meaning "ear") and ὀδούς (odoús, meaning "tooth") – thus, "ear-shaped tooth".
Anatomy
This shark is known from its fossilized teeth and vertebral centra.[1] Like other elasmobranchs, the skeleton of Otodus was composed of cartilage and not bone, resulting in relatively few preserved skeletal structures appearing within the fossil record. The teeth of this shark are large with triangular crown, smooth cutting edges, and visible cusps on the roots. Some Otodus teeth also show signs of evolving serrations.[1][2]
A lingual (tongue-side) view of O. obliquus teeth from the Eocene near Khouribga, Morocco
Size estimation
The fossils of Otodus indicate that it was a very large macro-predatory shark.[2] The largest known teeth measure about 104 millimetres (4.1 in) in height.[3] The vertebral centrum of this shark are over 12.7 cm (5 inch) wide.[2] Scientists suggest that this shark at least reached 9.1 metres (30 ft) in total length (TL),[2] with a maximum length of 12.2 metres (40 ft).[4] However, the largest if not type species, O. megalodon, could reach 52 feet, averaging closer to 45.
Distribution
Otodus had a worldwide distribution, as fossils have been excavated from Africa, Asia, Europe, and North America.[1]
Diet
Otodus likely preyed upon large bony fish, other sharks, and from the Eocene until the genus' extinction during the Miocene, marine mammals. It was among the top predators of its time.
Evolution
It is widely believed that the genus originates from a lineage of sharks belonging to the genus Cretalamna, due to strong similarities in tooth morphology.[5] Scientists determined that Otodus evolved into the genus Carcharocles, given substantial fossil evidence in the form of transitional teeth.[1][2] Some teeth have been excavated from the sediments of the Nanjemoy Formation in Maryland, USA, Ypres clay in Belgium, and western Kazakhstan, which are morphologically very similar to Otodus teeth but with lightly serrated cusplets and a serrated cutting edge. These transitional fossils suggest a worldwide evolutionary event, and support the theory that Otodus eventually evolved into Otodus aksuaticus and thus initiated the Carcharocles lineage.[1] A more recent study of 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]
See also
Prehistoric fish
iconSharks portal iconPaleontology portal
References
Bourdon, Jim, Otodus
Renz, Mark (2002), Megalodon: Hunting the Hunter, PaleoPress, pp. 26–30, ISBN 0-9719477-0-8
"Huge OTODUS OBLIQUUS shark tooth with pathology". Archived from the original on July 22, 2011. Retrieved May 21, 2011.
Gordon Hubbel (2006). "Virtual Tour of Private Shark Museum". Retrieved 2014-02-12.
Ebersole, Jun A.; Ehret, Dana J. (2018-01-08). "A new species of Cretalamna sensu stricto (Lamniformes, Otodontidae) from the Late Cretaceous (Santonian-Campanian) of Alabama, USA". PeerJ. 6: e4229. doi:10.7717/peerj.4229. ISSN 2167-8359. PMC 5764036. PMID 29333348.
Shimada, K.; Chandler, R. E.; Lam, O. L. T.; Tanaka, T.; Ward, D. J. (2016-10-03). "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.
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