Myledaphus

Myledaphus
Temporal range: Turonian-Maastrichtian (possible Paleogene occurrences)
Myledaphus bipartitus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Rhinopristiformes
Family: Rhinobatidae
Genus: †Myledaphus
Cope, 1876[1]
Type species
†Myledaphus bipartitus
Cope, 1876
Other species
  • †Myledaphus tritus
    Nessov in Nessov & Udovitschenko, 1986[2]
  • †Myledaphus pustulosus
    Cook, Newbrey, Brinkman, & Kirkland, 2014[3]
  • †Myledaphus araucanus
    Otero, 2019[4]

Myledaphus is an extinct genus of guitarfish. It currently contains four valid species found in North America (M. bipartitus, M. pustulosus), South America (M. araucanus), and Central Asia (M. tritus).[4] It is confirmed to have lived during the Late Cretaceous, with possible occurrences in the Paleocene and early Eocene.[3][5] While the genus is mostly known from teeth, two partial skeletons of M. bipartitus have been found in the Dinosaur Park Formation of Alberta.[6]

Biology

Tooth of Myledaphus bipartitus
Close up of Myledaphus bipartitus jaws.

Myledaphus remains have been found both in marine and fluvial (freshwater) deposits, suggesting it could tolerate a range of salinity.[7] In the Hell Creek Formation, composed predominantly of floodplain and riverine deposits, Myledaphus teeth are very common, accounting for a significant fraction of vertebrate remains found in microsites.[7]

Skeleton of M. bipartitus

Myledaphus has a durophagus dentition with blunt, polygonal-shaped (hexagonal to rhombic) teeth tessellated into a pavement suited for crushing and grinding hard-bodied prey. Many of their teeth show wear consistent with feeding on mollusks, which were common in the rivers of North America during the Late Cretaceous.[7]

References

  1. ^ Cope, E.D. (1876). "Descriptions of some vertebrate remains from the Fort Union beds of Montana". Proceedings of the Academy of Natural Sciences of Philadelphia. 28: 248–261.
  2. ^ Nessov, L.A.; Udovitschenko, N.I. (1986). "Novyye nakhodki ostatkov pozvonochnykh mela i paleogena Sredney Azii [New findings of vertebrate remains from the Cretaceous and Paleogene of Central Asia]". Voprosy Paleontologii. 9: 129–136.
  3. ^ a b Cook, T.D.; Newbrey, M.G.; Brinkman, D.B.; Kirkland, J.I. (2014). "Euselachians from the freshwater deposits of the Hell Creek Formation of Montana". Geological Society of America Special Paper. 503: 229–246. doi:10.1130/2014.2503(08). ISBN 978-0-8137-2503-1.
  4. ^ a b Otero, R.A. (2019). "Myledaphus araucanus sp. nov. (Batomorphi, Rajiformes incertae sedis), a new Late Cretaceous ray from the austral Pacific, and first occurrence of the genus in the Southern Hemisphere". Cretaceous Research. 100: 82–90. Bibcode:2019CrRes.100...82O. doi:10.1016/j.cretres.2019.03.025.
  5. ^ Cappetta, H. (2012). Handbook of Paleoichthyology. Volume 3E. Chondrichthyes. Mesozoic and Cenozoic Elasmobranchii: Teeth. Munich: Verlag Dr. Friedrich Pfeil. ISBN 978-3-89937-148-2.
  6. ^ Neuman, A.G.; Brinkman, D.B. (2005). "Fishes of the fluvial beds". In Currie, P.J.; Koppelhus, E.B. (eds.). Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Bloomington, IN: Indiana University Press. pp. 167–185. ISBN 978-0253345950.
  7. ^ a b c Hoffman, Brian L. et al. “Dental Structure of the Late Cretaceous (Maastrichtian) Guitarfish (Neoselachii: Batoidea) Myledaphus pustulosus from the Hell Creek Formation of Garfield County, Montana.” Transactions of the Kansas Academy of Science 121 (2018): 279 - 296.


Stub icon

This article about prehistoric Batoidea is a stub. You can help Wikipedia by expanding it.