Enchodus Explained

Enchodus (from Greek, Modern (1453-);: ἔγχος, 'spear' and Greek, Modern (1453-);: ὀδούς 'tooth')[1] is an extinct genus of aulopiform ray-finned fish related to lancetfish and lizardfish. Species of Enchodus flourished during the Late Cretaceous, and there is some evidence that they may have survived to the Paleocene or Eocene; however, this may just represent reworked Cretaceous material.[2] [3] [4]

Taxonomy

Species of Enchodus are generally classified into two different clades, the North American and the Mediterranean. It has been proposed that this distinction is the result of several isolated events between the two populations over the Late Cretaceous.

Description

Enchodus species were small to medium in size, large species (E. zinensis) reached .[5] One of the genus' most notable attributes are the large "fangs" at the front of the upper and lower jaws and on the palatine bones, leading to its misleading nickname among fossil hunters and paleoichthyologists, "the saber-toothed herring". These fangs, along with a long sleek body and large eyes, suggest Enchodus was a predatory species.[6]

E. petrosus, with standard length around and sometimes over,[7] remains of which are common from the Niobrara Chalk, the Mooreville Chalk Formation, the Pierre Shale, and other geological formations deposited within the Western Interior Seaway and the Mississippi Embayment. Large individuals of this species had fangs measuring over in length, giving its skull an appearance somewhat reminiscent of modern deep-sea fishes, such as anglerfish and viperfish. Other species were considerably smaller, some like E. parvus were only some centimeters (a few inches) long.[8]

Despite being a formidable predator, remains of Enchodus are commonly found among the stomach contents of larger predators, including sharks, other bony fish, mosasaurs, plesiosaurs and seabirds such as Baptornis advenus.

Distribution

Enchodus fossils have been found all over the world. In North America, Enchodus remains have been recovered from most US states with fossiliferous Late Cretaceous rocks, including Kansas, Nebraska, Colorado, Alabama, Mississippi, Georgia, Tennessee, Wyoming, Texas, California, North Carolina, and New Jersey. Fossils also have been found in the Aguja and El Doctor Formations of Mexico and the Ashville, Vermillion River and Dinosaur Park Formations, and Brown Bed Member of Canada. The taxon is also known from coeval strata in Africa, the Middle East, Europe, southwest Asia and the Tiupampan Santa Lucía Formation and Maastrichtian El Molino Formation of Bolivia and the Paraíba, Pernambuco and Sergipe states of Brazil.[9] Potentially the latest Enchodus remains are known from the earliest Eocene of Barmer, India. However, it has also been suggested that all post-Cretaceous Enchodus records are just reworked material.

Further reading

External links

Notes and References

  1. Book: Roberts . George . An etymological and explanatory dictionary of the terms and language of geology . 1839 . Longman, Orme, Brown, Green, & Longmans . London . 55 . 30 December 2021 . English.
  2. Fielitz . Christopher . González-Rodríguez . Katia A. . A New Species of Enchodus (aulopiformes: Enchodontidae) from the Cretaceous (albian to Cenomanian) of Zimapán, Hidalgo, México . Journal of Vertebrate Paleontology . 2010 . 30 . 5 . 1343–1351 . 10.1080/02724634.2010.501438 . 40864352 . 2010JVPal..30.1343F . 84281080 .
  3. Rana . R. S. . Kumar . K. . Singh . H. . Rose . K. D. . Lower vertebrates from the Late Palaeocene–Earliest Eocene Akli Formation, Giral Lignite Mine, Barmer District, western India . Current Science . 2005 . 89 . 9 . 1606–1613 . 24110948 .
  4. Davis . Matthew P. . Fielitz . Christopher . Estimating divergence times of lizardfishes and their allies (Euteleostei: Aulopiformes) and the timing of deep-sea adaptations . Molecular Phylogenetics and Evolution . December 2010 . 57 . 3 . 1194–1208 . 10.1016/j.ympev.2010.09.003 . 20854916 .
  5. Díaz-Cruz . Jesús Alberto . Alvarado-Ortega . Jesús . Ramírez-Sánchez . Marcia M. . Bernard . Emma Louise . Allington-Jones . Lu . Graham . Mark . Phylogenetic morphometrics, geometric morphometrics and the Mexican fossils to understand evolutionary trends of enchodontid fishes . Journal of South American Earth Sciences . November 2021 . 111 . 103492 . 10.1016/j.jsames.2021.103492 . 2021JSAES.11103492D .
  6. Web site: Everhart, Mike. 2013. Enchodus sp. - The Sabre-Toothed Fish of the Cretaceous. Oceans of Kansas. https://web.archive.org/web/20221118171151/http://oceansofkansas.com/enchodus.html. November 18, 2022. live.
  7. Chida . Mori . Brinkman . Donald B. . Murray . Alison M. . A large, new dercetid fish (Teleostei: Aulopiformes) from the Campanian Bearpaw Formation of Alberta, Canada . Cretaceous Research . October 2023 . 150 . 105579 . 10.1016/j.cretres.2023.105579 . 2023CrRes.15005579C . 258803963 .
  8. Book: Everhart, M.J.. 2017. Oceans of Kansas, Second Edition: A Natural History of the Western Interior Sea (Life of the Past). Indiana University Press. 978-0253026323. 117.
  9. http://www.fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=35564 Enchodus

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