Ceratodontidae is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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

with fossils known from the earliest

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

to the

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

Taxonomy

Although the extant

Queensland lungfish The Australian lungfish (''Neoceratodus forsteri''), also known as the Queensland lungfish, Burnett salmon and barramunda, is the only surviving member of the family Neoceratodontidae. It is one of only six extant lungfish species in the world. ...

was formerly also classified in this family due to its similar appearance, phylogenetic evidence indicates that it belongs in a different family,

Neoceratodontidae Neoceratodontidae is a family of lungfish containing the extant Australian lungfish and several extinct genera. It and Lepidosirenidae represent the only lungfish families still extant. Fossils from this family are first known from Triassic-aged ...

. Despite the family's name, Neoceratodontidae actually diverged from other lungfish earlier than Ceratodontidae did, although both are estimated to have diverged during the

Late Carboniferous Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

along with the rest of

Ceratodontoidei Ceratodontoidei is a suborder of lungfish that is defined as "the clade including all taxa more closely related to ''Lepidosiren'', '' Neoceratodus'' and '' Gnathorhiza'' than to '' Uronemus'', '' Conchopoma'' and ''Sagenodus''". Members of this ...

. Due to diverging later, Ceratodontidae is also closer to the

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...

of the suborder Ceratodontoidei (which contains the extinct

Gnathorhizidae The Gnathorhizidae are an extinct family of lungfish that lived from the late Carboniferous until the middle Triassic. Gnathorhizid fossils have been found in North America, Madagascar, Australia, and possibly Eastern Europe and South Africa. T ...

and the extant

Lepidosirenidae Lepidosirenidae is a family of lungfish containing the genera ''Lepidosiren'' (the South American lungfish) and ''Protopterus'' (the African lungfish). Both genera were formerly thought to represent the distinct families Lepidosirenidae and Proto ...

) than Neoceratodontidae is. Ceratodontidae serves as a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

containing

Ptychoceratodontidae ''Ptychoceratodus'' is an extinct genus of lungfish living from Early Triassic to Middle Jurassic. It was established by Otto Jaekel for one species (''P. runcinatus''), transferred from ''Ceratodus'' genus. Type species is ''P. serratus'' from ...

, and

, whereas Neoceratodontidae is a sister group to the clade of Ceratodontidae and the other three families.

Genera

The following genera are known from the family: * †'' Ariguna'' * †''

Ceratodus ''Ceratodus'' (from el, κέρας , 'horn' and el, ὀδούς 'tooth') was a wide-ranging genus of extinct lungfish. Fossil evidence dates back to the Early Triassic. A wide range of fossil species from different time periods have been found ...

'' * †'' Epiceratodus'' * †'' Lupaceratodus'' * †''

Metaceratodus ''Metaceratodus'' is an extinct genus of prehistoric lungfish in the family Ceratodontidae, with an indeterminate specimen known from the Late Triassic (Norian)-aged Lissauer Breccia of Poland and more complete specimens known from the Late Cre ...

'' * †'' Microceratodus'' (?) * †'' Potamoceratodus'' * †'' Tellerodus'' * †'' Retodus'' '' Paraceratodus'' was also classified in this family but phylogenetic evidence supports it being the most basal member of

References

{{Taxonbar, from=Q3544436 Lungfish Taxa named by Theodore Gill Prehistoric lobe-finned fish families