''Heptranchias howelli'', the sevengill shark, is a nektonic carnivore in the genus ''

Heptranchias ''Heptranchias'' is a genus of sharks in the family Cow shark, Hexanchidae. Species *''Sharpnose sevengill shark, Heptranchias perlo'' (Pierre Joseph Bonnaterre, Bonnaterre, 1788) (sharpnose sevengill shark) *†''Heptranchias ezoensis'' Appl ...

''. It is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

species that ranged from 37.2 to 20.43 Ma.''Heptranchias howelli''
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.org

Fossil record

Teeth from ''Heptranchias howelli'' have been found in Europe. An antero-lateral tooth and an upper lateral tooth were found in

Faxe Faxe or Fakse is a town on the island of Zealand in eastern Denmark. It is located in Faxe Municipality in Region Zealand. The town is most known for the Faxe Brewery, Royal Unibrew, a relatively large brewery producing a range of beer and soft ...

Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...

in 2014 . In addition, two incomplete antero-lateral teeth and an upper anterior tooth are kept in a private collection.Adolfssen, J. S. and Ward, D. J. 2015. Neoselachians from the Danian (early Paleocene) of Denmark. Acta Palaeontologica Polonica 60 (2): 313–338. A 2015 study in yielded a complete lower tooth, 17 incomplete lower teeth, and an unidentified broken tooth.Carlsen, A.W. &Cuny, G. 2014. A study of the sharks and rays from the Lillebælt Clay (Early–Middle Eocene) of Denmark, and their palaeoecology by Bulletin of the Geological Society of Denmark, Vol. 62, pp. 39–88. ISSN 2245-7070. ( ww.2dgf.dk/publikationer/bulletin Link

Description

Teeth

The upper lateral teeth of the species have a long, acute, strongly sigmoid main cusp. This cusp is serrated and has a dispal cusplet. The main cusp of the antero-lateral teeth is triangular and carries eight mesial cusplets that increase in size along the lower mesial face. The antero-lateral teeth have six main cusplets, the sixth of which is very small. The first cusplet is slightly lower than the others. The cusps are inclined at about a 45-degree angle distally. The largest tooth found in Trelde Naes was mesio-distally, apico-basally and labio-langually. The root height ranged from .

Distribution

Fossils of ''Heptranchias howelli'' have been found in: ;Eocene *

La Meseta Formation The La Meseta Formation is a sedimentary sequence deposited during much of the Paleogene on Seymour Island off the coast of the Antarctic Peninsula. It is noted for its fossils, which include both marine organisms and the only terrestrial vertebr ...

Seymour Island Seymour Island or Marambio Island, is an island in the chain of 16 major islands around the tip of the Graham Land on the Antarctic Peninsula. Graham Land is the closest part of Antarctica to South America. It lies within the section of the isl ...

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British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

) *

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New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

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) ;Miocene * Uitpa Formation,

Cocinetas Basin The Cocinetas Basin () is a small sedimentary basin of approximately in northeasternmost Colombia. The wikt:onshore, onshore pull-apart basin is located in the departments of Colombia, department of La Guajira Department, La Guajira at the border ...

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References

{{Taxonbar, from=Q28431948 Heptranchias Eocene animals of North America Paleogene United States Fossils of Antarctica Paleogene Canada Fossils of British Columbia Miocene animals of South America Neogene Colombia Fossils of Colombia Fossil taxa described in 1946