''Cladodus'' is an extinct genus of

cartilaginous fish Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeleto ...

es in the family Ctenacanthidae. As the

name A name is a term used for identification by an external observer. They can identify a class or category of things, or a single thing, either uniquely, or within a given context. The entity identified by a name is called its referent. A person ...

implies, they are a type of

cladodont This is a typical Cladodont tooth, of a Glikmanius.html" ;"title="shark called ''Glikmanius">shark called ''Glikmanius'' Cladodont (from Latin cladus, meaning branch and Greek Odon, meaning tooth) is the term for a common category of early Devoni ...

, primitive

sharks Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...

with

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

designed to snag fish and

swallow The swallows, martins, and saw-wings, or Hirundinidae are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The ...

them whole, instead of sawing off chunks to swallow. Fossils of ''Cladodus'' have been found in Barkip, Scotland, Bundock and Laurel Formations, Australia and in the

Pitkin Formation The Pitkin Formation, or Pitkin Limestone, is a fossiliferous Formation (geology), geologic formation in northern Arkansas that dates to the Chesterian, Chesterian Series of the late Mississippian (geology), Mississippian. This formation was firs ...

(

Carboniferous period The Carboniferous ( ) is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the Permian Period, Ma. It is the fifth and penultimate perio ...

) in

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

, United States. In addition, fossils attributable to ''Cladodus'' are known from the

Manning Canyon Shale The Manning Canyon Shale is a geologic formation in Utah, United States. It preserves fossils dating back to the Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic ...

of Carboniferous age in the state of

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

Species

*†''Cladodus alternatus'' St. John & Worthen, 1875 *†''Cladodus angulatus'' Newberry & Worthen, 1866 *†''Cladodus bellifer'' St. John & Worthen, 1875 *†''Cladodus divaricatus'' Trautschold, 1874 *†''Cladodus elegans'' Newberry & Worthen, 1870 Remains (braincase and a tooth) have been found in Scotland (

Clackmannan Group The Clackmannan Group is the name given to a suite of rocks of late Dinantian and Namurian age laid down during the Carboniferous period in the Midland Valley of Scotland. Description The Group comprises a lower unit of coarse sandstones, ...

). *†''Cladodus eriensis'' Bryant, 1935 *†''Cladodus formosus'' Hay, 1902 *†''Cladodus gailensis'' Feichtinger ''et al.'', 2021 *†''Cladodus marginatus'' Agassiz, 1843 *†''Cladodus mirabilis'' Agassiz, 1843 (type species) *†''Cladodus pandatus'' St. John & Worthen, 1875 *†''Cladodus springeri'' St. John & Worthen, 1875 *†''Cladodus thomasi'' Turner, 1982 Known by teeth from the Lower Carboniferous Bundock Formation, North Queensland, and the

Tournaisian The Tournaisian is in the ICS geologic timescale the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. The Tournaisian age lasted from Ma to Ma. It is preceded by the Famennian (the uppermost st ...

Laurel Formation, Western Australia. Teeth reach 2.2-90 mm in length. This species was considered as a junior synonym of ''

Stethacanthus ''Stethacanthus'' is an extinct genus of shark-like cartilaginous fish which lived from the Late Devonian to Late Carboniferous epoch, dying out around 298.9 million years ago. Fossils have been found in Australia, Asia, Europe and North Ameri ...

obtusus'' by Lebedev (1996) but later reassigned to ''Cladodus'' due to a smaller number and distinct morphology of cusps. *†''Cladodus vanhornei'' St. John & Worthen, 1875 *†''Cladodus yunnanensis'' Pan, 1964

References

Ctenacanthiformes Prehistoric cartilaginous fish genera Mississippian fish of North America Taxa named by Louis Agassiz Fossil taxa described in 1843 Carboniferous fish of Europe Paleozoic fish of Australia Fossils of Austria {{Paleo-cartilaginous-fish-stub

Species

See also

References