''Ptychoceratodus'' is an extinct genus of

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 ...

living from

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 ...

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

. It was established by

Otto Jaekel Otto Max Johannes Jaekel (21 February 1863 – 6 March 1929) was a German paleontologist and geologist. Biography Jaekel was born in Nowa Sól, Neusalz (Nowa Sól), Prussian Silesia, the son of a builder and the youngest of seven children. He st ...

for one species (''P. runcinatus''), transferred from '' Ceratodus'' genus. Type species is ''P. serratus'' from the

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epoch (geology), epochs of the Triassic period (geology), period or the middle of three series (stratigraphy), series in which the Triassic system (stratigraphy), system is di ...

of Switzerland and Germany. ''Ptychoceratodus'' had two pairs of massive dental plates, bearing 4-6 acute ridges. Its

skull roof The skull roof or the roofing bones of the skull are a set of bones covering the brain, eyes and nostrils in bony fishes, including land-living vertebrates. The bones are derived from dermal bone and are part of the dermatocranium. In com ...

was composed from massive, plate-like bones. In the central part of skull roof was localized an unossified

fenestra A fenestra (fenestration; : fenestrae or fenestrations) is any small opening or pore, commonly used as a term in the biology, biological sciences. It is the Latin word for "window", and is used in various fields to describe a pore in an anatomy, ...

. Most of the ''Ptychoceratodus'' findings are isolated dental plates, some associated with jaws. Other parts of skull or postcranial skeleton are relatively rarely found as fossils. The anatomy of skull is the best recognized in ''P. serratus'', whereas less complete cranial material is available also for ''P. concinuus, P. phillipsi,'' and ''P. rectangulus''. Although ''Ptychoceratodus'' is known exclusively from 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 ...

and

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

, there were also

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 ...

specimens referred to this genus. However, they are more often regarded as representants of '' Metaceratodus''. ''Ptychoceratodus'' is the only member of the family Ptychoceratodontidae. The first named species is ''P. phillipsi'' by

Louis 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 ...

in 1837 as a species of ''Ceratodus'' and later moved to the genus ''Ptychoceratodus''. Occurrences of ''Ptychoceratodus'' come mainly from Europe. However, occurrences from other continents suggest it was dispersed globally during the Triassic. After 2010, the new fossil material behind the Europe was reported from South America, India, and

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 ...

Fossil distribution

Fossils of ''Ptychoceratodus'' have been found in: ''Ptychoceratodus''at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org ;Triassic * Burgersdorp Formation, ( ''Cynognathus'' Assemblage Zone), Early Triassic (

Olenekian In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...

), South Africa (''?Ptychoceratodus'' sp.) * Lipovskaya Formation, Early Triassic (Olenekian), Russia (''P. donensis'') * Erfurt Formation, Middle Triassic (

Ladinian The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic ...

), Germany (''P. serratus'') * Weser Formation,

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 ...

, Germany (''P. concinnus'') * Potrerillos Formation,

, Argentina (''P. cuyanus'') *

Tiki Formation The Tiki Formation is a Late Triassic (Carnian to Norian) geologic Formation (geology), formation in Madhya Pradesh, northern India. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been re ...

, Carnian, India (''P. oldhami'') * Marnes de Châlins Formation,

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 ...

France (''P. rectangulus'') * Löwenstein Formation, Alaunian (Norian), Germany (''P. rectangulus'') * Grès à Avicula contorta Formation,

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 ...

, France (''P. phillipsi'') *

Santa Maria Formation The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age (Late Triassic), and is notable for its fossils of cynodonts, " rauisuchian" pseudosuchians, and early dinosaurs and othe ...

, Brazil (''P. cf. phillipsi'') * Fleming Fjord Formation, Norian, Greenland (''P. rectangulus'') * Grabowa Formation, Carnian, Poland (''P. roemeri'') ;Jurassic *

Inferior Oolite Group The Inferior Oolite is a sequence of Jurassic age sedimentary rocks in Europe. It was deposited during the Middle Jurassic.Weishampel, David B; et al. (2004). "Dinosaur distribution (Middle Jurassic, Europe)." In: Weishampel, David B.; Dodson, Pet ...

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 ...

(''P. phillipsi'')

References

Prehistoric lobe-finned fish genera Early Triassic first appearances Olenekian genera Ladinian genera Carnian genera Norian genera Rhaetian genera Tithonian genera Maastrichtian genera Late Cretaceous genus extinctions Triassic animals of Africa Prehistoric fish of Africa Triassic fish of Europe Jurassic fish of Asia Late Cretaceous fish of South America Fossils of Argentina Triassic Argentina Cañadón Asfalto Basin Fossils of China Fossils of France Fossils of Germany Fossils of India Fossils of Russia Fossils of South Africa Fossils of Thailand Fossil taxa described in 1926 Long stubs with short prose {{paleo-lobefinned-fish-stub

Fossil distribution

See also

References