Name: Cardabiodon.
Phonetic: Car-doe-by-o-don.
Named By: Mikael Siverson‭ ‬-‭ ‬1999.
Classification: Chordata,‭ ‬Chondrichthyes,‭ ‬Elasmobranchii,‭ ‬Lamniformes,‭ ‬Cardabiodontidae.
Species: C.‭ ‬ricki‭ (‬type‭)‬,‭ ‬C.‭ ‬venator.
Diet: Carnivore/Piscivore.
Size: Studies of vertebrae‭ ‬and jaw reconstructions‭ ‬indicate an upper size of‭ ‬5.5‭ ‬meters.
Known locations: Fossil locations known to include Australia,‭ ‬North America and Russia.‭ ‬There is speculation that discoveries in England and Kazakhstan may actually represent further remains.
Time period: Cenomanian to early Turonian of the Cretaceous.
Fossil representation: Initially described from‭ ‬100‭ ‬teeth and‭ ‬15‭ ‬vertebrae,‭ ‬further remains including those of a second species have now been included,‭ ‬including placoid scales.

       Cardabiodon is a genus of shark that is known to have lived during at least the Cenomanian and early Turonian periods of the late Cretaceous.‭ ‬First named from fossil teeth and vertebrae discovered in Australia,‭ ‬further examples are known from North America and Russia,‭ ‬as well as speculated in other locations.‭ ‬However,‭ ‬so far Cardabiodon fossils have only been found in fossil deposits that depict what were temperate locations,‭ ‬with a notable absence in tropical waters‭ (‬for the late Cretaceous period‭)‬.‭ ‬This would indicate that Cardabiodon preferred cooler waters,‭ ‬though probably not to the extent of the polar cold.‭ ‬Cardabiodon fossils are also known from what were fairly deep ocean floor locations,‭ ‬revealing that Cardabiodon were mostly pelagic‭ (‬open water‭) ‬predators.
       Large Cardabiodon are generally accepted as ranging between five and five and a half meters long.‭ ‬At the time of the initial description of Cardabiodon as a genus in‭ ‬1999,‭ ‬Mikael Siverson estimated the total length of the holotype individual to be at least five meters in length.‭ ‬In a‭ ‬2005‭ ‬paper by Siverson and Lindgren,‭ ‬the holotype individual was stated as being five hundred and forty centimetres long,‭ ‬by comparing the best preserved vertebrae and comparing it to vertebrae of Carcharodon carcharias‭ (‬great white shark‭)‬.‭ ‬In a‭ ‬2013‭ ‬paper by Newbrey et al,‭ ‬the upper length of Cardabiodon‭ ‬upon the basis of existing fossils‭ ‬was stated as five and a half meters.
       So far Cardabiodon seems to have been comparable to the large modern predatory lamniform sharks that we know today,‭ ‬but still quite a bit smaller than the largest recorded great white shark which was a little over six meters long.‭ ‬The shark that Cardabiodon is most often compared to however Cretoxyrhina,‭ ‬an extinct genus of shark that is also known to have lived in the Cretaceous period at the same time as Cardabiodon.‭ ‬Both of these shark genera are known to have keeled placoid scales which reduced drag when swimming through water,‭ ‬which in turn strongly suggests that both Cardabiodon and Cretoxyrhina were active predators suited for fast swimming.‭ ‬One difference between Cardabiodon and Cretoxyrhina however is that Cretoxyrhina is known from both tropical and temperate deposits,‭ ‬implying that Cretoxyrhina had a greater tolerance to differences in temperature.‭
       Swimming in the late Cretaceous seas,‭ ‬Cardabiodon would have likely encountered many other genera of sharks other than just Cretoxyrhina.‭ ‬However at this time the seas would have also been filled with a multitude of marine reptiles,‭ ‬ranging from plesiosaurs,‭ ‬pliosaurs,‭ ‬marine crocodiles to even early mosasaurs.‭ ‬Some of these may have formed part of the diet for a hungry Cardabiodon,‭ ‬though in turn,‭ ‬Cardabiodon may itself have been occasional prey to some of these predators,‭ ‬such as the large pliosaur Brachauchenius, especially when younger.

Cardabiodon, Cretolamna, Cretoxyrhina, Hybodus, Ptychodus, Scapanorhynchus, Squalicorax.

Further reading
-‭ ‬A new large lamniform shark from the uppermost Gearle Siltstone‭ (‬Cenomanian,‭ ‬Late Cretaceous‭) ‬of Western Australia.‭ ‬-‭ ‬Transactions of the Royal Society of Edinburgh:‭ ‬Earth Sciences,‭ ‬90:‭ ‬49-66.‭ ‬-‭ ‬Mikael Siverson‭ ‬-‭ ‬1999.
-‭ ‬Late Cretaceous sharks Cretoxyrhina and Cardabiodon from Montana,‭ ‬USA.‭ ‬Acta Palaeontologica Polonica‭ ‬50‭ (‬2‭)‬:‭ ‬301‭–‬314.‭ ‬-‭ ‬Mikael Siverson‭ & ‬Johan Lindren‭ ‬-‭ ‬2005.
-‭ ‬The first record of the large Cretaceous lamniform shark,‭ ‬Cardabiodon ricki,‭ ‬from North America and a new empirical test for its presumed antitropical distribution.‭ ‬-‭ ‬Journal of Vertebrate Paleontology‭ ‬30‭ (‬3‭)‬:‭ ‬643‭–‬649.‭ ‬-‭ ‬Todd D.‭ ‬Cook,‭ ‬Mark V.‭ ‬H.‭ ‬Wilson‭ & ‬Michael G.‭ ‬Newbrey‭ ‬-‭ ‬2010.
-‭ ‬Vertebral morphology,‭ ‬dentition,‭ ‬age,‭ ‬growth,‭ ‬and ecology of the large‭ ‬lamniform shark Cardabiodon ricki.‭ ‬-‭ ‬Acta palaeontologica Polonica‭ ‬-‭ ‬Michael G.‭ ‬Newbrey,‭ ‬Mikael Siverson,‭ ‬Todd D.‭ ‬Cook,‭ ‬Allison M.‭ ‬Fotheringham‭ & ‬Rebecca L.‭ ‬Sanchez‭ ‬-‭ ‬2013.
- Vertebral Morphology, Dentition, Age, Growth, and Ecology of the Large Lamniform Shark Cardabiodon ricki. - Acta Palaeontologica Polonica. 60 (4): 877–897. - Michael G. Newbrey, Mikael Siverson, Todd D. Cook, Allison M. Fotheringham & Rebecca L. Sanchez - 2015.


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