Euselachii

Euselachii
Temporal range:
Silurian-Holocene[1]
Tiger Shark
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Chondrichthyes
Subclass:Elasmobranchii
Infraclass:Euselachii
Hay, 1902
Orders

See text

Euselachii are an infraclass of a class of cartilaginous fish. This group includes sharks and rays.[2][3][4]

Oceanic Whitetip Shark

Taxonomy

White shark

Of the 14 orders that compose Euselachii, 8 belong to the sharks, 6 to the rays, without an intermediate taxon separating sharks of rays. For this reason, some authors have separated Euselachii in two:

super-order Selachimorpha corresponding to orders of sharks; super-order Rajomorphii corresponding to the orders of rays, torpedoes, sawfish and guitar fish. For those who do not recognize these two super-orders, Euselachii therefore has for synonyms Pleurotremata, Selachimorpha and Rajomorphii.

Reproduction

Both oviparity and viviparity are found in Euselachii. Around 70% of sharks are viviparous[5], including some members of Carcharhiniformes such as requiem sharks and hammerhead sharks, while the remaining 30% of sharks as well as all rays are either oviparous or ovoviviparous.

Squatina squatina

List of Orders

References

  1. ↑ "Infraclass Euselachii Hay 1902". Fossilworks.org.
  2. ↑ Nelson, J. S. (2006). Fishes of the World (4 ed.). Hoboken, NJ: John Wiley & Sons. p. 49. ISBN 978-0-471-25031-9.
  3. ↑ "Euselachii". Integrated Taxonomic Information System. Retrieved 21 May 2018.
  4. ↑ "Fish glossary". FishBase.
  5. ↑ "Mating and Reproduction of Sharks", Shark Foundation
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