''Megactenopetalus'' is an extinct genus of

petalodont Petalodontiformes ("thin-plate teeth") is an extinct order of marine cartilaginous fish related to modern day chimaera found in what is now the United States of America and Europe.Lund, Richard, E. D. Grogan, and M. Fath. "On the relationships of ...

fish which lived from the late Early Permian through the

Late Permian Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...

. It is known from a single species: ''M. kaibabanus''. It was one of the last and largest petalodonts; estimates place it at 1.6 meters or 5.2 feet in length with a 20 centimeter or 7 inch mouth. It is known from the southwest of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

, and

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. The holotype was an upper left dentary which came from the Kaibab Formation on the northern rim of the

Grand Canyon The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is long, up to wide and attains a depth of over a mile (). The canyon and adjacent rim are contained within Grand Canyon Nati ...

. It is probably closely related to ''

Ctenoptychius ''Ctenoptychius'' (meaning "comb-folded", from the Greek language, Greek wiktionary:cteno-, κτείς or ''kteís'' meaning "comb" and wiktionary:πτυχή#Ancient_Greek, πτυχή or ''ptychos'' meaning "fold") is an extinct genus of Chondric ...

''.Ossian, C. (1976). Redescription of Megactenopetalus kaibabanus David 1944 (Chondrichthyes: Petalodontidae) with Comments on Its Geographic and Stratigraphic Distribution. ''Journal of Paleontology,'' ''50''(3), 392-397. Retrieved November 28, 2020, from

References

Petalodontiformes Permian cartilaginous fish Monotypic prehistoric cartilaginous fish genera {{paleo-holocephalan-stub