''Ceratodus'' (from , 'horn' and 'tooth') is an extinct genus of freshwater

lungfish Lungfish are freshwater vertebrates belonging to the class Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, inc ...

that was found worldwide during the

Mesozoic Era The Mesozoic Era is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles such as the dinosaurs, and of gymnosperms s ...

. It has been described as a "catch all", and a "

form genus Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of sc ...

" used to refer to the remains (typically toothplates) of a variety of lungfish belonging to the extinct family

Ceratodontidae Ceratodontidae is an extinct family of lungfish with fossils known worldwide from the earliest Triassic to the Eocene. Taxonomy Although the extant Queensland lungfish was formerly also classified in this family due to its similar appearance, ...

. Fossil evidence dates back to the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

. A wide range of fossil species from different time periods have been found around the world in places such as 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 ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Greenland Greenland is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

Egypt Egypt ( , ), officially the Arab Republic of Egypt, is a country spanning the Northeast Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via the Sinai Peninsula. It is bordered by the Mediterranean Sea to northe ...

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

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 ...

, and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

.Agnolin, F. L., Mateus O., Milàn J., Marzola M., Wings O., Adolfssen J. S., & Clemmensen L. B. (2018). Ceratodus tunuensis, sp. nov., a new lungfish (Sarcopterygii, Dipnoi) from the Upper Triassic of central East Greenland. Journal of Vertebrate Paleontology. e1439834 ''Ceratodus'' is believed to have become extinct sometime around the beginning of the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Epoch.

Species

The following species are known: * ''C. latissimus''

Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

, 1837 (

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

) - Late Triassic (

Rhaetian The Rhaetian is the latest age (geology), age of the Triassic period (geology), Period (in geochronology) or the uppermost stage (stratigraphy), stage of the Triassic system (stratigraphy), System (in chronostratigraphy). It was preceded by the N ...

) of England (

Westbury Formation The Westbury Formation is a geological Formation (geology), formation in England, one of the Penarth Group. It dates back to the Rhaetian.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Triassic, Europe)." In: Weishampel, David B. ...

) * ''C. eruciferus''

Cope A cope ( ("rain coat") or ("cape")) is a liturgical long mantle or cloak, open at the front and fastened at the breast with a band or clasp. It may be of any liturgical colour. A cope may be worn by any rank of the Catholic or Anglican clerg ...

, 1876 (''nomen dubium'') * ''C. hieroglyphus''

, 1876 (''nomen dubium'') * '' C. robustus'' Knight, 1898 - Late Jurassic (

Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 154.8 ±0.8 Ma and 149.2 ±0.7 Ma (million years ago). The Kimmeridgian follows the Oxfordian ...

Tithonian In the geological timescale, the Tithonian is the latest age (geology), age of the Late Jurassic Epoch and the uppermost stage (stratigraphy), stage of the Upper Jurassic Series. It spans the time between 149.2 ±0.7 annum, Ma and 143.1 ±0.6 (mi ...

) of Wyoming, US (

Morrison Formation The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltston ...

) * ''C. africanus'' Haug, 1905 * ''C. avus'' W. H. Ferguson 1906 - Early Cretaceous (

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

) of Victoria, Australia (

Wonthaggi Formation The Wonthaggi Formation is an informal geological Formation (geology), formation in Victoria, Australia whose strata date back to the Early Cretaceous. It is part of the Strzelecki Group within the Gippsland Basin. Dinosaur remains are among the ...

) * ''C. humei'' Priem, 1914 - Late Cretaceous (

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

) of Egypt (

Mut Formation Mut (; also transliterated as Maut and Mout) was a mother goddess worshipped in ancient Egypt. Her name means ''mother'' in the ancient Egyptian language. Mut had many different aspects and attributes that changed and evolved greatly over the ...

) * ''C. elegans'' Vollrath, 1923 * ''C. frazieri''

Ostrom Ostrom or Öström is a Swedish surname meaning "island stream". History Many of the Ostroms in North America are descendants of a Dutch immigrant to New Amsterdam in the 1600s. The name was van Oosteroom and originated in the area of Utrecht ...

, 1970 - Early Cretaceous (

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

) of Wyoming & Montana, US (Cloverly Formation), potentially

of New Jersey, US ( Mount Laurel Formation) * ''C. gustasoni'' Kirkland, 1987 - Late Cretaceous (

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

) of Utah, US (

Naturita Formation The Naturita Formation is a classification used in western Colorado and eastern Utah for a Cretaceous Period sedimentary geologic formation. This name was "applied to the upper or carbonaceous part of Dakota Group" by R.G. Young in 1960, namin ...

) * '' C. fossanovum'' Kirkland, 1998 * ''C. stewarti'' Milner & Kirkland, 2006 - Early Jurassic (

Hettangian The Hettangian is the earliest age and lowest stage of the Jurassic Period of the geologic timescale. It spans the time between 201.3 ± 0.2 Ma and 199.3 ± 0.3 Ma (million years ago). The Hettangian follows the Rhaetian (part of the Triass ...

Sinemurian In the geologic timescale, the Sinemurian is an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between 199.5 ±0.3 annu ...

) of Utah, US ( Moenave and Kayenta Formations) * ''C. texanus'' Parris ''et al.'', 2011 - Aptian/Albian of Texas, US (

Antlers Antlers are extensions of an animal's skull found in members of the Cervidae (deer) Family (biology), family. Antlers are a single structure composed of bone, cartilage, fibrous tissue, skin, nerves, and blood vessels. They are generally fo ...

and Twin Mountains Formations) * ''C. carteri'' Main ''et al.'', 2014 - Cenomanian of Texas, US (

Woodbine Formation The Woodbine Group is a geological formation in east Texas whose strata date back to the Early to Middle Cenomanian age of the Late Cretaceous. It is the producing formation of the giant East Texas Oil Field (also known as the "Black Giant") fr ...

) * ''C. kranzi'' Frederickson ''et al.'', 2016 - Albian of Maryland, US (

Arundel Formation The Arundel Formation, also known as the Arundel Clay, is a clay-rich sedimentary geological formation, rock formation, within the Potomac Group, found in Maryland of the United States of America. It dates to the Early Cretaceous, and is of late ...

) * ''C. kirklandi'' Frederickson & Cifelli, 2016 - Early Cretaceous (

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 137.05 ± 0.2 Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretac ...

) of Utah, US (

Cedar Mountain Formation The Cedar Mountain Formation is the name given to a distinctive sedimentary geologic formation in eastern Utah, spanning most of the early and mid-Cretaceous. The formation was named for Cedar Mountain (Utah), Cedar Mountain in northern Emery Cou ...

) * ''C. molossus'' Frederickson & Cifelli, 2016 - Cenomanian of Utah, US (Cedar Mountain Formation) * ''C. kempae'' Frederickson & Cifelli, 2016 - Valanginian of Utah, US (Cedar Mountain Formation) * ''C. nirumbee'' Frederickson & Cifelli, 2016 - Albian of Montana, US (

Cloverly Formation The Cloverly Formation is a formation (geology), geological formation of Early Cretaceous, Early and Late Cretaceous age (Valanginian to Cenomanian stage) that is present in parts of Montana, Wyoming, Colorado and Utah in the western United State ...

) * ''C. tunuensis'' Agnolin ''et al.'', 2018 - Late Triassic (Norian) of Greenland (

Fleming Fjord Formation The Fleming Fjord Formation, alternatively called the Fleming Fjord Group is an Upper Triassic geological formation in the northeastern coast of Jameson Land, Greenland. It consists of terrestrial sediments and is known for its fossil content. ...

) * ''C. guanganensis'' Wang ''et al.'', 2022 - Late Jurassic of China (

Shaximiao Formation The Shaximiao Formation () is a Middle to Late Jurassic aged geological formation in Sichuan, China, most notable for the wealth of dinosaurs fossils that have been excavated from its strata. The Shaximiao Formation is exposed in and around the ...

) *''C. shishkini'' Minikh, 2023 - Middle/Late Triassic (Ladinian/Carnian) of Orenburg, Russia

Gallery

File:Ceratodus tooth plates.JPG, ''Ceratodus'' tooth plates File:Ceratodus BW.jpg, ''Ceratodus''

References

Ceratodus
at The Paleobiology Database {{Taxonbar, from=Q1027599 Prehistoric lungfish genera Mesozoic bony fish Paleocene fish Eocene fish Cloverly Formation Triassic fish of Europe Jurassic fish of North America Cretaceous fish of North America Jurassic fish of Asia Late Cretaceous fish of Africa Cretaceous fish of Australia Fossils of the United States Fossils of England Fossils of China Fossils of Egypt Taxa named by Louis Agassiz Fossil taxa described in 1837