''Arganodus'' 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 had a wide global distribution throughout much of the

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

period, with a single species surviving across

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

into the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

. It is the only member of the family Arganodontidae, although it is sometimes placed in the

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, ...

or synonymized with the genus ''

Asiatoceratodus ''Asiatoceratodus'' is an extinct genus of lungfish which lived during the Middle Triassic, Middle-Late Triassic, Jurassic and Cretaceous periods in what is now Asia (Kyrgyzstan), Africa (Ethiopia, Niger, Algeria, Morocco) and South America (Urug ...

''. It was first named by Martin in 1979 based on fossils found at Tizi n'Maâchou in the

Marrakech Marrakesh or Marrakech (; , ) is the fourth-largest city in Morocco. It is one of the four imperial cities of Morocco and is the capital of the Marrakesh–Safi Regions of Morocco, region. The city lies west of the foothills of the Atlas Mounta ...

area of

Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...

, in rocks of the

Timezgadiouine Formation The Timezgadiouine Formation, sometimes spelled as the Timesgadiouine Formation, is a Triassic geological formation in the Argana Basin of Morocco. It is a succession of red bed sediments spanning from the Olenekian to at least the Carnian, enco ...

belonging to the Argana Group (hence the generic name).

Taxonomy

''Arganodus'' contains the following species: * †''A. atlantis'' Martin, 1979 -

Carnian The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227.3 ...

of Morocco (Timezgadiouine Formation) and

Algeria Algeria, officially the People's Democratic Republic of Algeria, is a country in the Maghreb region of North Africa. It is bordered to Algeria–Tunisia border, the northeast by Tunisia; to Algeria–Libya border, the east by Libya; to Alger ...

(

Zarzaitine Formation Zarzaitine (also written Zarzaïtine) is an industrial village in the Communes of Algeria, commune of In Amenas, in In Amenas District, Illizi Province, eastern Algeria. It is a notable mining area, with significant deposits of sulphur and crude oi ...

) (=''Ceratodus arganensis'' Martin, 1979) * †''A. dorotheae'' (

Case Case or CASE may refer to: Instances * Instantiation (disambiguation), a realization of a concept, theme, or design * Special case, an instance that differs in a certain way from others of the type Containers * Case (goods), a package of relate ...

, 1921) - Middle

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

of Texas and

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

(

Tecovas Formation The Tecovas Formation is a geological Formation (geology), formation in the Texas panhandle and eastern New Mexico. It is one of several formations encompassed by the Late Triassic Dockum Group.Weishampel, David B; et al. (2004). "Dinosaur distri ...

), late Norian of

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

(

Chinle Formation The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In ...

Petrified Forest National Park Petrified Forest National Park is a national park of the United States in Navajo and Apache counties in northeastern Arizona. Named for its large deposits of petrified wood, the park covers about , encompassing semi-desert shrub steppe as wel ...

) * †''A. multicristatus'' (Vorobyeva & Minikh, 1968) - Late Olenekian of

European Russia European Russia is the western and most populated part of the Russia, Russian Federation. It is geographically situated in Europe, as opposed to the country's sparsely populated and vastly larger eastern part, Siberia, which is situated in Asia ...

(

Yarenskian Gorizont The Yarenskian Gorizont ("Yarenskian Horizon") is a major biostratigraphic unit in Russia corresponding to Upper Olenekian-age terrestrial sediments. It lies above the Ustmylian Gorizont of the Vetlugian Supergorizont, and is located below a shor ...

) and

Helgoland Heligoland (; , ; Heligolandic Frisian: , , Mooring Frisian: , ) is a small archipelago in the North Sea. The islands were historically possessions of Denmark, then became possessions of the United Kingdom from 1807 to 1890. Since 1890, the ...

(

Buntsandstein The Buntsandstein (German for ''coloured'' or ''colourful sandstone'') or Bunter sandstone is a lithostratigraphy, lithostratigraphic and allostratigraphy, allostratigraphic unit (a sequence of rock strata) in the Subsurface (geology), subsurface ...

), possibly early

Anisian In the geologic timescale, the Anisian is the lower stage (stratigraphy), stage or earliest geologic age, age of the Middle Triassic series (stratigraphy), series or geologic epoch, epoch and lasted from million years ago until million years ag ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

(

Holy Cross Mountains Sacred describes something that is dedicated or set apart for the service or worship of a deity; is considered worthy of spiritual respect or devotion; or inspires awe or reverence among believers. The property is often ascribed to objects (a ...

) * †''A. tiguidiensis'' (Tabaste, 1963) - Late Jurassic of Algeria ( Taouratine Group), Morocco (

Anoual Formation The Anoual Formation is a geological formation in the High Atlas of Morocco. It is early Bathonian In the geologic timescale the Bathonian is an age (geology), age and stage (stratigraphy), stage of the Middle Jurassic. It lasted from approxi ...

) &

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

(

Tacuarembó Formation The Tacuarembó Formation is a 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 ...

); Early Cretaceous of Niger (

Elrhaz Formation The Elrhaz Formation is a geological Formation (geology), formation in Niger, West Africa. Its strata date back to the Early Cretaceous, about 125 to 112 million years ago. Dinosaur remains are among the fossils that have been recovered from the ...

), Algeria (

Gara Samani Formation Gara may refer to: * Gara (newspaper), a bilingual Spanish newspaper * Gara (given name), a given name * Gara (surname), a surname Geography * Gara, Rohtas, a village in India *Gara, Srikakulam, a village in India *Gara, Hungary, a village in Hung ...

), and Brazil (

Alcântara Formation The Alcântara Formation is a geological Formation (geology), formation in Northeast Region, Brazil, northeastern Brazil whose strata date back to the Cenomanian of the Late Cretaceous. Fossil content Dinosaurs Sauropods Theropods ...

)

Indeterminate specimens have been found in the Redonda Formation,

and the

Cumnock Formation The Cumnock Formation is a Late Triassic-age geologic formation in North Carolina. It is found in the Sanford sub-basin of the Deep River Basin, the southernmost of the large Mesozoic basins forming the Newark Supergroup. It is the middle unit o ...

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

, although the North Carolinian specimens are smaller than most recorded specimens. Other indeterminate remains are also known from the Late Triassic of India and

Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...

. Possibly the oldest records of the genus are probable remains from the

Induan The Induan is the first age of the Early Triassic epoch in the geologic timescale, or the lowest stage of the Lower Triassic series in chronostratigraphy. It spans the time between 251.9 Ma and 249.9 Ma (million years ago). The Induan is so ...

of northwestern Australia. It has been suggested that shortly after the origin of ''Arganodus'' in the early Triassic, it spread into what is now Europe, evolving into ''A. multicristatus''. Before the Late Triassic, it diverged into two

vicariant Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...

lineages separated by the

Central Pangean Mountains The Central Pangean Mountains were an extensive northeast–southwest trending mountain range in the central portion of the supercontinent Pangaea during the Carboniferous, Permian and Triassic periods. They were formed as a result of collision be ...

: ''A. atlantis'' in the east, and ''A. dorotheae'' & the Cumnock species in the west, while going extinct in the European region. It eventually went extinct in

Laurasia Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pa ...

, but one species, ''A. tiguidensis'', managed to survive in

throughout the Jurassic and Cretaceous. Kemp (1998) placed ''Arganodus'' as a synonym of ''

'', and this taxonomy has been followed by many other authors, although others still retain them as different genera and families.

Paleoecology

''Arganodus'' was probably similar to modern lungfish, and lived in underwater burrows during dry periods until

monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...

s occurred.

References

External links

''Arganodus''
at the

Paleobiology Database The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ...

''Arganodus''
at Zipcodezoo.com
The Geographic Distribution and Biostratigraphy of Late Triassic-Early Jurassic Freshwater Fish Faunas of the Southwestern United States

Preliminary Review of the Early Jurassic (Hettangian) Fresh Water Lake Dixie Fish Fauna in the Whitmore Pointmemeber, Moenave Formation in Southwest Utah

{{Taxonbar, from=Q4789203 Prehistoric lungfish genera Induan genus first appearances Olenekian genera Carnian genera Bathonian genera Kimmeridgian genera Aptian genera Albian genus extinctions Triassic bony fish Jurassic bony fish Cretaceous bony fish Triassic fish of North America Triassic fish of Africa Triassic fish of Europe Jurassic fish of Africa Jurassic fish of South America Early Cretaceous fish of Africa Early Cretaceous fish of South America Late Triassic animals of North America Late Triassic animals of Africa Early Triassic animals of Europe Fossils of Morocco Fossils of Algeria Fossils of Niger Fossils of Uruguay Fossils of Brazil Fossils of Russia Fossils of Germany Fossils of Poland Fossils of the United States Fossils of Texas Fossils of North Carolina Chinle fauna Fossils of India Fossils of Turkey Triassic fish of Australia Fossil taxa described in 1979