Name: Cretoxyrhina
(Cretaceous jaws).
Phonetic: Creh-tox-ee-rye-nah.
Named By: Louis Agassiz - 1843.
Classification: Chordata, Chondrichthyes,
Elasmobranchii, Selachimorpha, Lamniformes, Cretoxyrhinidae.
Species: C. mantelli (type), C.
agassizensis, C. denticulata, C. vraconensis.
Type: Carnivore.
Size: Typically up to 7 meters long, though some remains indicate some individuals up to 8 meters long.
Known locations: Worldwide.
Time period: Cenomanian to Campanian of the
Cretaceous.
Fossil representation: Usually teeth, but some
impressions revealing the cartilaginous skeleton are also known.
Also
known as the 'Ginsu shark', Cretoxyrhina was one of
the
biggest sharks
of its
time, considerably bigger even than its contemporary
Squalicorax.
Cretoxyrhina was near the top of the food chain, and
it had a diet that
included almost anything that was in front of it, including mosasaurs.
There is also strong evidence for its predation of the bony fish
Xiphactinus,
a four to six meter long predator itself, and even the
large turtles of the day were fair game for Cretoxyrhina.
Cretoxyrhina
acquired the name 'Ginsu Shark' in reference to its teeth. At up to
seven centimetres long, the teeth are smooth and have thick enamel,
suggesting that they were for work against tough shells and bones. Like
the advert for Ginsu knifes said, they could cut through anything, and
Cretoxyrhina probably had little difficulty in
removing bite sized
chunks from whatever prey item it chose.
The
overall morphology for Cretoxyrhina is lamniform,
similar to a Great
White shark today. The tail also shows adaption form fast swimming,
enabling Cretoxyrhina to give chase after faster
prey.
Further reading
- Late Cretaceous sharks Cretoxyrhina and Cardabiodon
from Montana,
USA. Acta Palaeontologica Polonica 50 (2): 301–314. - Mikael Siverson
& Johan Lindren - 2005.
- Ontogenetic parameters and life history strategies of the late
Cretaceous lamniform shark, Cretoxyrhina mantelli,
based on verterbal
grown increments. - Journal of Vertebrate Paleontology 28: 21-33. - K.
Shimada - 2008.
- Caudal fin of the Late Cretaceous shark, Cretoxyrhina mantelli
(Lamniformes: Cretoxyrhinidae), morphometrically compared to that of
extant lamniform sharks, Society of Vertebrate Paleontology - Phillip
Sternes & Kenshu Shimada 2018.
- Large deadfall of the 'ginsu' shark Cretoxyrhina mantelli (Agassiz,
1835) (Neoselachii, Lamniformes) from the Upper Cretaceous of
northeastern Italy. - Cretaceous Research. 98 250–275. - Jacopo
Amalfitano, Luca Giusberti, Eliana Fornaciari, Fabio Marco Dalla
Vicchia, Valeria, Luciani, J�rgen Kriwet, Giorgio Carnevale - 2019.
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